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6260 lines
214 KiB
6260 lines
214 KiB
/* |
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LodePNG version 20131222 |
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|
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Copyright (c) 2005-2013 Lode Vandevenne |
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|
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This software is provided 'as-is', without any express or implied |
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warranty. In no event will the authors be held liable for any damages |
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arising from the use of this software. |
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|
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Permission is granted to anyone to use this software for any purpose, |
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including commercial applications, and to alter it and redistribute it |
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freely, subject to the following restrictions: |
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|
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1. The origin of this software must not be misrepresented; you must not |
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claim that you wrote the original software. If you use this software |
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in a product, an acknowledgment in the product documentation would be |
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appreciated but is not required. |
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|
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2. Altered source versions must be plainly marked as such, and must not be |
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misrepresented as being the original software. |
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|
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3. This notice may not be removed or altered from any source |
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distribution. |
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*/ |
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|
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/* |
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The manual and changelog are in the header file "lodepng.h" |
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Rename this file to lodepng.cpp to use it for C++, or to lodepng.c to use it for C. |
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*/ |
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|
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#include "lodepng.h" |
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|
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#include <stdio.h> |
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#include <stdlib.h> |
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|
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#ifdef LODEPNG_COMPILE_CPP |
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#include <fstream> |
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#endif /*LODEPNG_COMPILE_CPP*/ |
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#define VERSION_STRING "20131222" |
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|
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/* |
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This source file is built up in the following large parts. The code sections |
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with the "LODEPNG_COMPILE_" #defines divide this up further in an intermixed way. |
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-Tools for C and common code for PNG and Zlib |
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-C Code for Zlib (huffman, deflate, ...) |
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-C Code for PNG (file format chunks, adam7, PNG filters, color conversions, ...) |
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-The C++ wrapper around all of the above |
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*/ |
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|
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/*The malloc, realloc and free functions defined here with "lodepng_" in front |
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of the name, so that you can easily change them to others related to your |
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platform if needed. Everything else in the code calls these. Pass |
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-DLODEPNG_NO_COMPILE_ALLOCATORS to the compiler, or comment out |
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#define LODEPNG_COMPILE_ALLOCATORS in the header, to disable the ones here and |
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define them in your own project's source files without needing to change |
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lodepng source code. Don't forget to remove "static" if you copypaste them |
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from here.*/ |
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#ifdef LODEPNG_COMPILE_ALLOCATORS |
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static void* lodepng_malloc(size_t size) |
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{ |
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return malloc(size); |
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} |
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static void* lodepng_realloc(void* ptr, size_t new_size) |
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{ |
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return realloc(ptr, new_size); |
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} |
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|
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static void lodepng_free(void* ptr) |
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{ |
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free(ptr); |
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} |
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#else /*LODEPNG_COMPILE_ALLOCATORS*/ |
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void* lodepng_malloc(size_t size); |
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void* lodepng_realloc(void* ptr, size_t new_size); |
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void lodepng_free(void* ptr); |
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#endif /*LODEPNG_COMPILE_ALLOCATORS*/ |
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|
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/* ////////////////////////////////////////////////////////////////////////// */ |
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/* ////////////////////////////////////////////////////////////////////////// */ |
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/* // Tools for C, and common code for PNG and Zlib. // */ |
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/* ////////////////////////////////////////////////////////////////////////// */ |
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/* ////////////////////////////////////////////////////////////////////////// */ |
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|
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/* |
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Often in case of an error a value is assigned to a variable and then it breaks |
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out of a loop (to go to the cleanup phase of a function). This macro does that. |
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It makes the error handling code shorter and more readable. |
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|
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Example: if(!uivector_resizev(&frequencies_ll, 286, 0)) ERROR_BREAK(83); |
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*/ |
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#define CERROR_BREAK(errorvar, code)\ |
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{\ |
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errorvar = code;\ |
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break;\ |
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} |
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|
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/*version of CERROR_BREAK that assumes the common case where the error variable is named "error"*/ |
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#define ERROR_BREAK(code) CERROR_BREAK(error, code) |
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|
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/*Set error var to the error code, and return it.*/ |
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#define CERROR_RETURN_ERROR(errorvar, code)\ |
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{\ |
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errorvar = code;\ |
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return code;\ |
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} |
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|
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/*Try the code, if it returns error, also return the error.*/ |
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#define CERROR_TRY_RETURN(call)\ |
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{\ |
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unsigned error = call;\ |
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if(error) return error;\ |
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} |
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|
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/* |
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About uivector, ucvector and string: |
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-All of them wrap dynamic arrays or text strings in a similar way. |
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-LodePNG was originally written in C++. The vectors replace the std::vectors that were used in the C++ version. |
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-The string tools are made to avoid problems with compilers that declare things like strncat as deprecated. |
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-They're not used in the interface, only internally in this file as static functions. |
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-As with many other structs in this file, the init and cleanup functions serve as ctor and dtor. |
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*/ |
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#ifdef LODEPNG_COMPILE_ZLIB |
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/*dynamic vector of unsigned ints*/ |
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typedef struct uivector |
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{ |
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unsigned* data; |
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size_t size; /*size in number of unsigned longs*/ |
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size_t allocsize; /*allocated size in bytes*/ |
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} uivector; |
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|
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static void uivector_cleanup(void* p) |
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{ |
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((uivector*)p)->size = ((uivector*)p)->allocsize = 0; |
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lodepng_free(((uivector*)p)->data); |
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((uivector*)p)->data = NULL; |
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} |
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|
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/*returns 1 if success, 0 if failure ==> nothing done*/ |
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static unsigned uivector_resize(uivector* p, size_t size) |
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{ |
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if(size * sizeof(unsigned) > p->allocsize) |
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{ |
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size_t newsize = size * sizeof(unsigned) * 2; |
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void* data = lodepng_realloc(p->data, newsize); |
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if(data) |
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{ |
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p->allocsize = newsize; |
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p->data = (unsigned*)data; |
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p->size = size; |
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} |
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else return 0; |
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} |
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else p->size = size; |
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return 1; |
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} |
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|
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/*resize and give all new elements the value*/ |
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static unsigned uivector_resizev(uivector* p, size_t size, unsigned value) |
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{ |
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size_t oldsize = p->size, i; |
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if(!uivector_resize(p, size)) return 0; |
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for(i = oldsize; i < size; i++) p->data[i] = value; |
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return 1; |
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} |
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|
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static void uivector_init(uivector* p) |
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{ |
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p->data = NULL; |
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p->size = p->allocsize = 0; |
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} |
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|
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#ifdef LODEPNG_COMPILE_ENCODER |
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/*returns 1 if success, 0 if failure ==> nothing done*/ |
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static unsigned uivector_push_back(uivector* p, unsigned c) |
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{ |
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if(!uivector_resize(p, p->size + 1)) return 0; |
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p->data[p->size - 1] = c; |
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return 1; |
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} |
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|
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/*copy q to p, returns 1 if success, 0 if failure ==> nothing done*/ |
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static unsigned uivector_copy(uivector* p, const uivector* q) |
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{ |
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size_t i; |
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if(!uivector_resize(p, q->size)) return 0; |
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for(i = 0; i < q->size; i++) p->data[i] = q->data[i]; |
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return 1; |
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} |
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#endif /*LODEPNG_COMPILE_ENCODER*/ |
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#endif /*LODEPNG_COMPILE_ZLIB*/ |
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|
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/* /////////////////////////////////////////////////////////////////////////// */ |
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|
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/*dynamic vector of unsigned chars*/ |
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typedef struct ucvector |
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{ |
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unsigned char* data; |
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size_t size; /*used size*/ |
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size_t allocsize; /*allocated size*/ |
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} ucvector; |
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|
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/*returns 1 if success, 0 if failure ==> nothing done*/ |
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static unsigned ucvector_resize(ucvector* p, size_t size) |
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{ |
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if(size * sizeof(unsigned char) > p->allocsize) |
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{ |
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size_t newsize = size * sizeof(unsigned char) * 2; |
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void* data = lodepng_realloc(p->data, newsize); |
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if(data) |
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{ |
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p->allocsize = newsize; |
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p->data = (unsigned char*)data; |
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p->size = size; |
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} |
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else return 0; /*error: not enough memory*/ |
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} |
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else p->size = size; |
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return 1; |
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} |
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#ifdef LODEPNG_COMPILE_PNG |
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static void ucvector_cleanup(void* p) |
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{ |
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((ucvector*)p)->size = ((ucvector*)p)->allocsize = 0; |
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lodepng_free(((ucvector*)p)->data); |
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((ucvector*)p)->data = NULL; |
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} |
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static void ucvector_init(ucvector* p) |
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{ |
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p->data = NULL; |
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p->size = p->allocsize = 0; |
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} |
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|
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#ifdef LODEPNG_COMPILE_DECODER |
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/*resize and give all new elements the value*/ |
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static unsigned ucvector_resizev(ucvector* p, size_t size, unsigned char value) |
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{ |
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size_t oldsize = p->size, i; |
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if(!ucvector_resize(p, size)) return 0; |
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for(i = oldsize; i < size; i++) p->data[i] = value; |
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return 1; |
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} |
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#endif /*LODEPNG_COMPILE_DECODER*/ |
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#endif /*LODEPNG_COMPILE_PNG*/ |
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|
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#ifdef LODEPNG_COMPILE_ZLIB |
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/*you can both convert from vector to buffer&size and vica versa. If you use |
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init_buffer to take over a buffer and size, it is not needed to use cleanup*/ |
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static void ucvector_init_buffer(ucvector* p, unsigned char* buffer, size_t size) |
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{ |
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p->data = buffer; |
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p->allocsize = p->size = size; |
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} |
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#endif /*LODEPNG_COMPILE_ZLIB*/ |
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|
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#if (defined(LODEPNG_COMPILE_PNG) && defined(LODEPNG_COMPILE_ANCILLARY_CHUNKS)) || defined(LODEPNG_COMPILE_ENCODER) |
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/*returns 1 if success, 0 if failure ==> nothing done*/ |
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static unsigned ucvector_push_back(ucvector* p, unsigned char c) |
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{ |
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if(!ucvector_resize(p, p->size + 1)) return 0; |
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p->data[p->size - 1] = c; |
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return 1; |
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} |
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#endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)*/ |
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|
|
|
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/* ////////////////////////////////////////////////////////////////////////// */ |
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|
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#ifdef LODEPNG_COMPILE_PNG |
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#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS |
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/*returns 1 if success, 0 if failure ==> nothing done*/ |
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static unsigned string_resize(char** out, size_t size) |
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{ |
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char* data = (char*)lodepng_realloc(*out, size + 1); |
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if(data) |
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{ |
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data[size] = 0; /*null termination char*/ |
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*out = data; |
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} |
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return data != 0; |
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} |
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|
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/*init a {char*, size_t} pair for use as string*/ |
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static void string_init(char** out) |
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{ |
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*out = NULL; |
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string_resize(out, 0); |
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} |
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|
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/*free the above pair again*/ |
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static void string_cleanup(char** out) |
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{ |
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lodepng_free(*out); |
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*out = NULL; |
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} |
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static void string_set(char** out, const char* in) |
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{ |
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size_t insize = strlen(in), i = 0; |
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if(string_resize(out, insize)) |
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{ |
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for(i = 0; i < insize; i++) |
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{ |
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(*out)[i] = in[i]; |
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} |
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} |
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} |
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#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ |
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#endif /*LODEPNG_COMPILE_PNG*/ |
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|
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/* ////////////////////////////////////////////////////////////////////////// */ |
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|
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unsigned lodepng_read32bitInt(const unsigned char* buffer) |
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{ |
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return (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3]; |
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} |
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|
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#if defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER) |
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/*buffer must have at least 4 allocated bytes available*/ |
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static void lodepng_set32bitInt(unsigned char* buffer, unsigned value) |
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{ |
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buffer[0] = (unsigned char)((value >> 24) & 0xff); |
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buffer[1] = (unsigned char)((value >> 16) & 0xff); |
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buffer[2] = (unsigned char)((value >> 8) & 0xff); |
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buffer[3] = (unsigned char)((value ) & 0xff); |
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} |
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#endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)*/ |
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#ifdef LODEPNG_COMPILE_ENCODER |
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static void lodepng_add32bitInt(ucvector* buffer, unsigned value) |
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{ |
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ucvector_resize(buffer, buffer->size + 4); /*todo: give error if resize failed*/ |
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lodepng_set32bitInt(&buffer->data[buffer->size - 4], value); |
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} |
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#endif /*LODEPNG_COMPILE_ENCODER*/ |
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|
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/* ////////////////////////////////////////////////////////////////////////// */ |
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/* / File IO / */ |
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/* ////////////////////////////////////////////////////////////////////////// */ |
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|
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#ifdef LODEPNG_COMPILE_DISK |
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|
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unsigned lodepng_load_file(unsigned char** out, size_t* outsize, const char* filename) |
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{ |
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FILE* file; |
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long size; |
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|
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/*provide some proper output values if error will happen*/ |
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*out = 0; |
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*outsize = 0; |
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file = fopen(filename, "rb"); |
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if(!file) return 78; |
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|
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/*get filesize:*/ |
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fseek(file , 0 , SEEK_END); |
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size = ftell(file); |
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rewind(file); |
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|
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/*read contents of the file into the vector*/ |
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*outsize = 0; |
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*out = (unsigned char*)lodepng_malloc((size_t)size); |
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if(size && (*out)) (*outsize) = fread(*out, 1, (size_t)size, file); |
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|
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fclose(file); |
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if(!(*out) && size) return 83; /*the above malloc failed*/ |
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return 0; |
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} |
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|
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/*write given buffer to the file, overwriting the file, it doesn't append to it.*/ |
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unsigned lodepng_save_file(const unsigned char* buffer, size_t buffersize, const char* filename) |
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{ |
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FILE* file; |
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file = fopen(filename, "wb" ); |
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if(!file) return 79; |
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fwrite((char*)buffer , 1 , buffersize, file); |
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fclose(file); |
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return 0; |
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} |
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|
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#endif /*LODEPNG_COMPILE_DISK*/ |
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|
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/* ////////////////////////////////////////////////////////////////////////// */ |
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/* ////////////////////////////////////////////////////////////////////////// */ |
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/* // End of common code and tools. Begin of Zlib related code. // */ |
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/* ////////////////////////////////////////////////////////////////////////// */ |
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/* ////////////////////////////////////////////////////////////////////////// */ |
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|
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#ifdef LODEPNG_COMPILE_ZLIB |
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#ifdef LODEPNG_COMPILE_ENCODER |
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/*TODO: this ignores potential out of memory errors*/ |
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#define addBitToStream(/*size_t**/ bitpointer, /*ucvector**/ bitstream, /*unsigned char*/ bit)\ |
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{\ |
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/*add a new byte at the end*/\ |
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if(((*bitpointer) & 7) == 0) ucvector_push_back(bitstream, (unsigned char)0);\ |
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/*earlier bit of huffman code is in a lesser significant bit of an earlier byte*/\ |
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(bitstream->data[bitstream->size - 1]) |= (bit << ((*bitpointer) & 0x7));\ |
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(*bitpointer)++;\ |
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} |
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|
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static void addBitsToStream(size_t* bitpointer, ucvector* bitstream, unsigned value, size_t nbits) |
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{ |
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size_t i; |
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for(i = 0; i < nbits; i++) addBitToStream(bitpointer, bitstream, (unsigned char)((value >> i) & 1)); |
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} |
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|
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static void addBitsToStreamReversed(size_t* bitpointer, ucvector* bitstream, unsigned value, size_t nbits) |
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{ |
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size_t i; |
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for(i = 0; i < nbits; i++) addBitToStream(bitpointer, bitstream, (unsigned char)((value >> (nbits - 1 - i)) & 1)); |
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} |
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#endif /*LODEPNG_COMPILE_ENCODER*/ |
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|
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#ifdef LODEPNG_COMPILE_DECODER |
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|
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#define READBIT(bitpointer, bitstream) ((bitstream[bitpointer >> 3] >> (bitpointer & 0x7)) & (unsigned char)1) |
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|
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static unsigned char readBitFromStream(size_t* bitpointer, const unsigned char* bitstream) |
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{ |
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unsigned char result = (unsigned char)(READBIT(*bitpointer, bitstream)); |
|
(*bitpointer)++; |
|
return result; |
|
} |
|
|
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static unsigned readBitsFromStream(size_t* bitpointer, const unsigned char* bitstream, size_t nbits) |
|
{ |
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unsigned result = 0, i; |
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for(i = 0; i < nbits; i++) |
|
{ |
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result += ((unsigned)READBIT(*bitpointer, bitstream)) << i; |
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(*bitpointer)++; |
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} |
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return result; |
|
} |
|
#endif /*LODEPNG_COMPILE_DECODER*/ |
|
|
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/* ////////////////////////////////////////////////////////////////////////// */ |
|
/* / Deflate - Huffman / */ |
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
|
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#define FIRST_LENGTH_CODE_INDEX 257 |
|
#define LAST_LENGTH_CODE_INDEX 285 |
|
/*256 literals, the end code, some length codes, and 2 unused codes*/ |
|
#define NUM_DEFLATE_CODE_SYMBOLS 288 |
|
/*the distance codes have their own symbols, 30 used, 2 unused*/ |
|
#define NUM_DISTANCE_SYMBOLS 32 |
|
/*the code length codes. 0-15: code lengths, 16: copy previous 3-6 times, 17: 3-10 zeros, 18: 11-138 zeros*/ |
|
#define NUM_CODE_LENGTH_CODES 19 |
|
|
|
/*the base lengths represented by codes 257-285*/ |
|
static const unsigned LENGTHBASE[29] |
|
= {3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, |
|
67, 83, 99, 115, 131, 163, 195, 227, 258}; |
|
|
|
/*the extra bits used by codes 257-285 (added to base length)*/ |
|
static const unsigned LENGTHEXTRA[29] |
|
= {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, |
|
4, 4, 4, 4, 5, 5, 5, 5, 0}; |
|
|
|
/*the base backwards distances (the bits of distance codes appear after length codes and use their own huffman tree)*/ |
|
static const unsigned DISTANCEBASE[30] |
|
= {1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, |
|
769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577}; |
|
|
|
/*the extra bits of backwards distances (added to base)*/ |
|
static const unsigned DISTANCEEXTRA[30] |
|
= {0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, |
|
8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13}; |
|
|
|
/*the order in which "code length alphabet code lengths" are stored, out of this |
|
the huffman tree of the dynamic huffman tree lengths is generated*/ |
|
static const unsigned CLCL_ORDER[NUM_CODE_LENGTH_CODES] |
|
= {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; |
|
|
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
|
|
/* |
|
Huffman tree struct, containing multiple representations of the tree |
|
*/ |
|
typedef struct HuffmanTree |
|
{ |
|
unsigned* tree2d; |
|
unsigned* tree1d; |
|
unsigned* lengths; /*the lengths of the codes of the 1d-tree*/ |
|
unsigned maxbitlen; /*maximum number of bits a single code can get*/ |
|
unsigned numcodes; /*number of symbols in the alphabet = number of codes*/ |
|
} HuffmanTree; |
|
|
|
/*function used for debug purposes to draw the tree in ascii art with C++*/ |
|
/* |
|
static void HuffmanTree_draw(HuffmanTree* tree) |
|
{ |
|
std::cout << "tree. length: " << tree->numcodes << " maxbitlen: " << tree->maxbitlen << std::endl; |
|
for(size_t i = 0; i < tree->tree1d.size; i++) |
|
{ |
|
if(tree->lengths.data[i]) |
|
std::cout << i << " " << tree->tree1d.data[i] << " " << tree->lengths.data[i] << std::endl; |
|
} |
|
std::cout << std::endl; |
|
}*/ |
|
|
|
static void HuffmanTree_init(HuffmanTree* tree) |
|
{ |
|
tree->tree2d = 0; |
|
tree->tree1d = 0; |
|
tree->lengths = 0; |
|
} |
|
|
|
static void HuffmanTree_cleanup(HuffmanTree* tree) |
|
{ |
|
lodepng_free(tree->tree2d); |
|
lodepng_free(tree->tree1d); |
|
lodepng_free(tree->lengths); |
|
} |
|
|
|
/*the tree representation used by the decoder. return value is error*/ |
|
static unsigned HuffmanTree_make2DTree(HuffmanTree* tree) |
|
{ |
|
unsigned nodefilled = 0; /*up to which node it is filled*/ |
|
unsigned treepos = 0; /*position in the tree (1 of the numcodes columns)*/ |
|
unsigned n, i; |
|
|
|
tree->tree2d = (unsigned*)lodepng_malloc(tree->numcodes * 2 * sizeof(unsigned)); |
|
if(!tree->tree2d) return 83; /*alloc fail*/ |
|
|
|
/* |
|
convert tree1d[] to tree2d[][]. In the 2D array, a value of 32767 means |
|
uninited, a value >= numcodes is an address to another bit, a value < numcodes |
|
is a code. The 2 rows are the 2 possible bit values (0 or 1), there are as |
|
many columns as codes - 1. |
|
A good huffmann tree has N * 2 - 1 nodes, of which N - 1 are internal nodes. |
|
Here, the internal nodes are stored (what their 0 and 1 option point to). |
|
There is only memory for such good tree currently, if there are more nodes |
|
(due to too long length codes), error 55 will happen |
|
*/ |
|
for(n = 0; n < tree->numcodes * 2; n++) |
|
{ |
|
tree->tree2d[n] = 32767; /*32767 here means the tree2d isn't filled there yet*/ |
|
} |
|
|
|
for(n = 0; n < tree->numcodes; n++) /*the codes*/ |
|
{ |
|
for(i = 0; i < tree->lengths[n]; i++) /*the bits for this code*/ |
|
{ |
|
unsigned char bit = (unsigned char)((tree->tree1d[n] >> (tree->lengths[n] - i - 1)) & 1); |
|
if(treepos > tree->numcodes - 2) return 55; /*oversubscribed, see comment in lodepng_error_text*/ |
|
if(tree->tree2d[2 * treepos + bit] == 32767) /*not yet filled in*/ |
|
{ |
|
if(i + 1 == tree->lengths[n]) /*last bit*/ |
|
{ |
|
tree->tree2d[2 * treepos + bit] = n; /*put the current code in it*/ |
|
treepos = 0; |
|
} |
|
else |
|
{ |
|
/*put address of the next step in here, first that address has to be found of course |
|
(it's just nodefilled + 1)...*/ |
|
nodefilled++; |
|
/*addresses encoded with numcodes added to it*/ |
|
tree->tree2d[2 * treepos + bit] = nodefilled + tree->numcodes; |
|
treepos = nodefilled; |
|
} |
|
} |
|
else treepos = tree->tree2d[2 * treepos + bit] - tree->numcodes; |
|
} |
|
} |
|
|
|
for(n = 0; n < tree->numcodes * 2; n++) |
|
{ |
|
if(tree->tree2d[n] == 32767) tree->tree2d[n] = 0; /*remove possible remaining 32767's*/ |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
Second step for the ...makeFromLengths and ...makeFromFrequencies functions. |
|
numcodes, lengths and maxbitlen must already be filled in correctly. return |
|
value is error. |
|
*/ |
|
static unsigned HuffmanTree_makeFromLengths2(HuffmanTree* tree) |
|
{ |
|
uivector blcount; |
|
uivector nextcode; |
|
unsigned bits, n, error = 0; |
|
|
|
uivector_init(&blcount); |
|
uivector_init(&nextcode); |
|
|
|
tree->tree1d = (unsigned*)lodepng_malloc(tree->numcodes * sizeof(unsigned)); |
|
if(!tree->tree1d) error = 83; /*alloc fail*/ |
|
|
|
if(!uivector_resizev(&blcount, tree->maxbitlen + 1, 0) |
|
|| !uivector_resizev(&nextcode, tree->maxbitlen + 1, 0)) |
|
error = 83; /*alloc fail*/ |
|
|
|
if(!error) |
|
{ |
|
/*step 1: count number of instances of each code length*/ |
|
for(bits = 0; bits < tree->numcodes; bits++) blcount.data[tree->lengths[bits]]++; |
|
/*step 2: generate the nextcode values*/ |
|
for(bits = 1; bits <= tree->maxbitlen; bits++) |
|
{ |
|
nextcode.data[bits] = (nextcode.data[bits - 1] + blcount.data[bits - 1]) << 1; |
|
} |
|
/*step 3: generate all the codes*/ |
|
for(n = 0; n < tree->numcodes; n++) |
|
{ |
|
if(tree->lengths[n] != 0) tree->tree1d[n] = nextcode.data[tree->lengths[n]]++; |
|
} |
|
} |
|
|
|
uivector_cleanup(&blcount); |
|
uivector_cleanup(&nextcode); |
|
|
|
if(!error) return HuffmanTree_make2DTree(tree); |
|
else return error; |
|
} |
|
|
|
/* |
|
given the code lengths (as stored in the PNG file), generate the tree as defined |
|
by Deflate. maxbitlen is the maximum bits that a code in the tree can have. |
|
return value is error. |
|
*/ |
|
static unsigned HuffmanTree_makeFromLengths(HuffmanTree* tree, const unsigned* bitlen, |
|
size_t numcodes, unsigned maxbitlen) |
|
{ |
|
unsigned i; |
|
tree->lengths = (unsigned*)lodepng_malloc(numcodes * sizeof(unsigned)); |
|
if(!tree->lengths) return 83; /*alloc fail*/ |
|
for(i = 0; i < numcodes; i++) tree->lengths[i] = bitlen[i]; |
|
tree->numcodes = (unsigned)numcodes; /*number of symbols*/ |
|
tree->maxbitlen = maxbitlen; |
|
return HuffmanTree_makeFromLengths2(tree); |
|
} |
|
|
|
#ifdef LODEPNG_COMPILE_ENCODER |
|
|
|
/* |
|
A coin, this is the terminology used for the package-merge algorithm and the |
|
coin collector's problem. This is used to generate the huffman tree. |
|
A coin can be multiple coins (when they're merged) |
|
*/ |
|
typedef struct Coin |
|
{ |
|
uivector symbols; |
|
float weight; /*the sum of all weights in this coin*/ |
|
} Coin; |
|
|
|
static void coin_init(Coin* c) |
|
{ |
|
uivector_init(&c->symbols); |
|
} |
|
|
|
/*argument c is void* so that this dtor can be given as function pointer to the vector resize function*/ |
|
static void coin_cleanup(void* c) |
|
{ |
|
uivector_cleanup(&((Coin*)c)->symbols); |
|
} |
|
|
|
static void coin_copy(Coin* c1, const Coin* c2) |
|
{ |
|
c1->weight = c2->weight; |
|
uivector_copy(&c1->symbols, &c2->symbols); |
|
} |
|
|
|
static void add_coins(Coin* c1, const Coin* c2) |
|
{ |
|
size_t i; |
|
for(i = 0; i < c2->symbols.size; i++) uivector_push_back(&c1->symbols, c2->symbols.data[i]); |
|
c1->weight += c2->weight; |
|
} |
|
|
|
static void init_coins(Coin* coins, size_t num) |
|
{ |
|
size_t i; |
|
for(i = 0; i < num; i++) coin_init(&coins[i]); |
|
} |
|
|
|
static void cleanup_coins(Coin* coins, size_t num) |
|
{ |
|
size_t i; |
|
for(i = 0; i < num; i++) coin_cleanup(&coins[i]); |
|
} |
|
|
|
static int coin_compare(const void* a, const void* b) { |
|
float wa = ((const Coin*)a)->weight; |
|
float wb = ((const Coin*)b)->weight; |
|
return wa > wb ? 1 : wa < wb ? -1 : 0; |
|
} |
|
|
|
static unsigned append_symbol_coins(Coin* coins, const unsigned* frequencies, unsigned numcodes, size_t sum) |
|
{ |
|
unsigned i; |
|
unsigned j = 0; /*index of present symbols*/ |
|
for(i = 0; i < numcodes; i++) |
|
{ |
|
if(frequencies[i] != 0) /*only include symbols that are present*/ |
|
{ |
|
coins[j].weight = frequencies[i] / (float)sum; |
|
uivector_push_back(&coins[j].symbols, i); |
|
j++; |
|
} |
|
} |
|
return 0; |
|
} |
|
|
|
unsigned lodepng_huffman_code_lengths(unsigned* lengths, const unsigned* frequencies, |
|
size_t numcodes, unsigned maxbitlen) |
|
{ |
|
unsigned i, j; |
|
size_t sum = 0, numpresent = 0; |
|
unsigned error = 0; |
|
Coin* coins; /*the coins of the currently calculated row*/ |
|
Coin* prev_row; /*the previous row of coins*/ |
|
unsigned numcoins; |
|
unsigned coinmem; |
|
|
|
if(numcodes == 0) return 80; /*error: a tree of 0 symbols is not supposed to be made*/ |
|
|
|
for(i = 0; i < numcodes; i++) |
|
{ |
|
if(frequencies[i] > 0) |
|
{ |
|
numpresent++; |
|
sum += frequencies[i]; |
|
} |
|
} |
|
|
|
for(i = 0; i < numcodes; i++) lengths[i] = 0; |
|
|
|
/*ensure at least two present symbols. There should be at least one symbol |
|
according to RFC 1951 section 3.2.7. To decoders incorrectly require two. To |
|
make these work as well ensure there are at least two symbols. The |
|
Package-Merge code below also doesn't work correctly if there's only one |
|
symbol, it'd give it the theoritical 0 bits but in practice zlib wants 1 bit*/ |
|
if(numpresent == 0) |
|
{ |
|
lengths[0] = lengths[1] = 1; /*note that for RFC 1951 section 3.2.7, only lengths[0] = 1 is needed*/ |
|
} |
|
else if(numpresent == 1) |
|
{ |
|
for(i = 0; i < numcodes; i++) |
|
{ |
|
if(frequencies[i]) |
|
{ |
|
lengths[i] = 1; |
|
lengths[i == 0 ? 1 : 0] = 1; |
|
break; |
|
} |
|
} |
|
} |
|
else |
|
{ |
|
/*Package-Merge algorithm represented by coin collector's problem |
|
For every symbol, maxbitlen coins will be created*/ |
|
|
|
coinmem = numpresent * 2; /*max amount of coins needed with the current algo*/ |
|
coins = (Coin*)lodepng_malloc(sizeof(Coin) * coinmem); |
|
prev_row = (Coin*)lodepng_malloc(sizeof(Coin) * coinmem); |
|
if(!coins || !prev_row) |
|
{ |
|
lodepng_free(coins); |
|
lodepng_free(prev_row); |
|
return 83; /*alloc fail*/ |
|
} |
|
init_coins(coins, coinmem); |
|
init_coins(prev_row, coinmem); |
|
|
|
/*first row, lowest denominator*/ |
|
error = append_symbol_coins(coins, frequencies, numcodes, sum); |
|
numcoins = numpresent; |
|
qsort(coins, numcoins, sizeof(Coin), coin_compare); |
|
if(!error) |
|
{ |
|
unsigned numprev = 0; |
|
for(j = 1; j <= maxbitlen && !error; j++) /*each of the remaining rows*/ |
|
{ |
|
unsigned tempnum; |
|
Coin* tempcoins; |
|
/*swap prev_row and coins, and their amounts*/ |
|
tempcoins = prev_row; prev_row = coins; coins = tempcoins; |
|
tempnum = numprev; numprev = numcoins; numcoins = tempnum; |
|
|
|
cleanup_coins(coins, numcoins); |
|
init_coins(coins, numcoins); |
|
|
|
numcoins = 0; |
|
|
|
/*fill in the merged coins of the previous row*/ |
|
for(i = 0; i + 1 < numprev; i += 2) |
|
{ |
|
/*merge prev_row[i] and prev_row[i + 1] into new coin*/ |
|
Coin* coin = &coins[numcoins++]; |
|
coin_copy(coin, &prev_row[i]); |
|
add_coins(coin, &prev_row[i + 1]); |
|
} |
|
/*fill in all the original symbols again*/ |
|
if(j < maxbitlen) |
|
{ |
|
error = append_symbol_coins(coins + numcoins, frequencies, numcodes, sum); |
|
numcoins += numpresent; |
|
} |
|
qsort(coins, numcoins, sizeof(Coin), coin_compare); |
|
} |
|
} |
|
|
|
if(!error) |
|
{ |
|
/*calculate the lenghts of each symbol, as the amount of times a coin of each symbol is used*/ |
|
for(i = 0; i < numpresent - 1; i++) |
|
{ |
|
Coin* coin = &coins[i]; |
|
for(j = 0; j < coin->symbols.size; j++) lengths[coin->symbols.data[j]]++; |
|
} |
|
} |
|
|
|
cleanup_coins(coins, coinmem); |
|
lodepng_free(coins); |
|
cleanup_coins(prev_row, coinmem); |
|
lodepng_free(prev_row); |
|
} |
|
|
|
return error; |
|
} |
|
|
|
/*Create the Huffman tree given the symbol frequencies*/ |
|
static unsigned HuffmanTree_makeFromFrequencies(HuffmanTree* tree, const unsigned* frequencies, |
|
size_t mincodes, size_t numcodes, unsigned maxbitlen) |
|
{ |
|
unsigned error = 0; |
|
while(!frequencies[numcodes - 1] && numcodes > mincodes) numcodes--; /*trim zeroes*/ |
|
tree->maxbitlen = maxbitlen; |
|
tree->numcodes = (unsigned)numcodes; /*number of symbols*/ |
|
tree->lengths = (unsigned*)lodepng_realloc(tree->lengths, numcodes * sizeof(unsigned)); |
|
if(!tree->lengths) return 83; /*alloc fail*/ |
|
/*initialize all lengths to 0*/ |
|
memset(tree->lengths, 0, numcodes * sizeof(unsigned)); |
|
|
|
error = lodepng_huffman_code_lengths(tree->lengths, frequencies, numcodes, maxbitlen); |
|
if(!error) error = HuffmanTree_makeFromLengths2(tree); |
|
return error; |
|
} |
|
|
|
static unsigned HuffmanTree_getCode(const HuffmanTree* tree, unsigned index) |
|
{ |
|
return tree->tree1d[index]; |
|
} |
|
|
|
static unsigned HuffmanTree_getLength(const HuffmanTree* tree, unsigned index) |
|
{ |
|
return tree->lengths[index]; |
|
} |
|
#endif /*LODEPNG_COMPILE_ENCODER*/ |
|
|
|
/*get the literal and length code tree of a deflated block with fixed tree, as per the deflate specification*/ |
|
static unsigned generateFixedLitLenTree(HuffmanTree* tree) |
|
{ |
|
unsigned i, error = 0; |
|
unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned)); |
|
if(!bitlen) return 83; /*alloc fail*/ |
|
|
|
/*288 possible codes: 0-255=literals, 256=endcode, 257-285=lengthcodes, 286-287=unused*/ |
|
for(i = 0; i <= 143; i++) bitlen[i] = 8; |
|
for(i = 144; i <= 255; i++) bitlen[i] = 9; |
|
for(i = 256; i <= 279; i++) bitlen[i] = 7; |
|
for(i = 280; i <= 287; i++) bitlen[i] = 8; |
|
|
|
error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DEFLATE_CODE_SYMBOLS, 15); |
|
|
|
lodepng_free(bitlen); |
|
return error; |
|
} |
|
|
|
/*get the distance code tree of a deflated block with fixed tree, as specified in the deflate specification*/ |
|
static unsigned generateFixedDistanceTree(HuffmanTree* tree) |
|
{ |
|
unsigned i, error = 0; |
|
unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned)); |
|
if(!bitlen) return 83; /*alloc fail*/ |
|
|
|
/*there are 32 distance codes, but 30-31 are unused*/ |
|
for(i = 0; i < NUM_DISTANCE_SYMBOLS; i++) bitlen[i] = 5; |
|
error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DISTANCE_SYMBOLS, 15); |
|
|
|
lodepng_free(bitlen); |
|
return error; |
|
} |
|
|
|
#ifdef LODEPNG_COMPILE_DECODER |
|
|
|
/* |
|
returns the code, or (unsigned)(-1) if error happened |
|
inbitlength is the length of the complete buffer, in bits (so its byte length times 8) |
|
*/ |
|
static unsigned huffmanDecodeSymbol(const unsigned char* in, size_t* bp, |
|
const HuffmanTree* codetree, size_t inbitlength) |
|
{ |
|
unsigned treepos = 0, ct; |
|
for(;;) |
|
{ |
|
if(*bp >= inbitlength) return (unsigned)(-1); /*error: end of input memory reached without endcode*/ |
|
/* |
|
decode the symbol from the tree. The "readBitFromStream" code is inlined in |
|
the expression below because this is the biggest bottleneck while decoding |
|
*/ |
|
ct = codetree->tree2d[(treepos << 1) + READBIT(*bp, in)]; |
|
(*bp)++; |
|
if(ct < codetree->numcodes) return ct; /*the symbol is decoded, return it*/ |
|
else treepos = ct - codetree->numcodes; /*symbol not yet decoded, instead move tree position*/ |
|
|
|
if(treepos >= codetree->numcodes) return (unsigned)(-1); /*error: it appeared outside the codetree*/ |
|
} |
|
} |
|
#endif /*LODEPNG_COMPILE_DECODER*/ |
|
|
|
#ifdef LODEPNG_COMPILE_DECODER |
|
|
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
/* / Inflator (Decompressor) / */ |
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
|
|
/*get the tree of a deflated block with fixed tree, as specified in the deflate specification*/ |
|
static void getTreeInflateFixed(HuffmanTree* tree_ll, HuffmanTree* tree_d) |
|
{ |
|
/*TODO: check for out of memory errors*/ |
|
generateFixedLitLenTree(tree_ll); |
|
generateFixedDistanceTree(tree_d); |
|
} |
|
|
|
/*get the tree of a deflated block with dynamic tree, the tree itself is also Huffman compressed with a known tree*/ |
|
static unsigned getTreeInflateDynamic(HuffmanTree* tree_ll, HuffmanTree* tree_d, |
|
const unsigned char* in, size_t* bp, size_t inlength) |
|
{ |
|
/*make sure that length values that aren't filled in will be 0, or a wrong tree will be generated*/ |
|
unsigned error = 0; |
|
unsigned n, HLIT, HDIST, HCLEN, i; |
|
size_t inbitlength = inlength * 8; |
|
|
|
/*see comments in deflateDynamic for explanation of the context and these variables, it is analogous*/ |
|
unsigned* bitlen_ll = 0; /*lit,len code lengths*/ |
|
unsigned* bitlen_d = 0; /*dist code lengths*/ |
|
/*code length code lengths ("clcl"), the bit lengths of the huffman tree used to compress bitlen_ll and bitlen_d*/ |
|
unsigned* bitlen_cl = 0; |
|
HuffmanTree tree_cl; /*the code tree for code length codes (the huffman tree for compressed huffman trees)*/ |
|
|
|
if((*bp) >> 3 >= inlength - 2) return 49; /*error: the bit pointer is or will go past the memory*/ |
|
|
|
/*number of literal/length codes + 257. Unlike the spec, the value 257 is added to it here already*/ |
|
HLIT = readBitsFromStream(bp, in, 5) + 257; |
|
/*number of distance codes. Unlike the spec, the value 1 is added to it here already*/ |
|
HDIST = readBitsFromStream(bp, in, 5) + 1; |
|
/*number of code length codes. Unlike the spec, the value 4 is added to it here already*/ |
|
HCLEN = readBitsFromStream(bp, in, 4) + 4; |
|
|
|
HuffmanTree_init(&tree_cl); |
|
|
|
while(!error) |
|
{ |
|
/*read the code length codes out of 3 * (amount of code length codes) bits*/ |
|
|
|
bitlen_cl = (unsigned*)lodepng_malloc(NUM_CODE_LENGTH_CODES * sizeof(unsigned)); |
|
if(!bitlen_cl) ERROR_BREAK(83 /*alloc fail*/); |
|
|
|
for(i = 0; i < NUM_CODE_LENGTH_CODES; i++) |
|
{ |
|
if(i < HCLEN) bitlen_cl[CLCL_ORDER[i]] = readBitsFromStream(bp, in, 3); |
|
else bitlen_cl[CLCL_ORDER[i]] = 0; /*if not, it must stay 0*/ |
|
} |
|
|
|
error = HuffmanTree_makeFromLengths(&tree_cl, bitlen_cl, NUM_CODE_LENGTH_CODES, 7); |
|
if(error) break; |
|
|
|
/*now we can use this tree to read the lengths for the tree that this function will return*/ |
|
bitlen_ll = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned)); |
|
bitlen_d = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned)); |
|
if(!bitlen_ll || !bitlen_d) ERROR_BREAK(83 /*alloc fail*/); |
|
for(i = 0; i < NUM_DEFLATE_CODE_SYMBOLS; i++) bitlen_ll[i] = 0; |
|
for(i = 0; i < NUM_DISTANCE_SYMBOLS; i++) bitlen_d[i] = 0; |
|
|
|
/*i is the current symbol we're reading in the part that contains the code lengths of lit/len and dist codes*/ |
|
i = 0; |
|
while(i < HLIT + HDIST) |
|
{ |
|
unsigned code = huffmanDecodeSymbol(in, bp, &tree_cl, inbitlength); |
|
if(code <= 15) /*a length code*/ |
|
{ |
|
if(i < HLIT) bitlen_ll[i] = code; |
|
else bitlen_d[i - HLIT] = code; |
|
i++; |
|
} |
|
else if(code == 16) /*repeat previous*/ |
|
{ |
|
unsigned replength = 3; /*read in the 2 bits that indicate repeat length (3-6)*/ |
|
unsigned value; /*set value to the previous code*/ |
|
|
|
if(*bp >= inbitlength) ERROR_BREAK(50); /*error, bit pointer jumps past memory*/ |
|
if (i == 0) ERROR_BREAK(54); /*can't repeat previous if i is 0*/ |
|
|
|
replength += readBitsFromStream(bp, in, 2); |
|
|
|
if(i < HLIT + 1) value = bitlen_ll[i - 1]; |
|
else value = bitlen_d[i - HLIT - 1]; |
|
/*repeat this value in the next lengths*/ |
|
for(n = 0; n < replength; n++) |
|
{ |
|
if(i >= HLIT + HDIST) ERROR_BREAK(13); /*error: i is larger than the amount of codes*/ |
|
if(i < HLIT) bitlen_ll[i] = value; |
|
else bitlen_d[i - HLIT] = value; |
|
i++; |
|
} |
|
} |
|
else if(code == 17) /*repeat "0" 3-10 times*/ |
|
{ |
|
unsigned replength = 3; /*read in the bits that indicate repeat length*/ |
|
if(*bp >= inbitlength) ERROR_BREAK(50); /*error, bit pointer jumps past memory*/ |
|
|
|
replength += readBitsFromStream(bp, in, 3); |
|
|
|
/*repeat this value in the next lengths*/ |
|
for(n = 0; n < replength; n++) |
|
{ |
|
if(i >= HLIT + HDIST) ERROR_BREAK(14); /*error: i is larger than the amount of codes*/ |
|
|
|
if(i < HLIT) bitlen_ll[i] = 0; |
|
else bitlen_d[i - HLIT] = 0; |
|
i++; |
|
} |
|
} |
|
else if(code == 18) /*repeat "0" 11-138 times*/ |
|
{ |
|
unsigned replength = 11; /*read in the bits that indicate repeat length*/ |
|
if(*bp >= inbitlength) ERROR_BREAK(50); /*error, bit pointer jumps past memory*/ |
|
|
|
replength += readBitsFromStream(bp, in, 7); |
|
|
|
/*repeat this value in the next lengths*/ |
|
for(n = 0; n < replength; n++) |
|
{ |
|
if(i >= HLIT + HDIST) ERROR_BREAK(15); /*error: i is larger than the amount of codes*/ |
|
|
|
if(i < HLIT) bitlen_ll[i] = 0; |
|
else bitlen_d[i - HLIT] = 0; |
|
i++; |
|
} |
|
} |
|
else /*if(code == (unsigned)(-1))*/ /*huffmanDecodeSymbol returns (unsigned)(-1) in case of error*/ |
|
{ |
|
if(code == (unsigned)(-1)) |
|
{ |
|
/*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol |
|
(10=no endcode, 11=wrong jump outside of tree)*/ |
|
error = (*bp) > inbitlength ? 10 : 11; |
|
} |
|
else error = 16; /*unexisting code, this can never happen*/ |
|
break; |
|
} |
|
} |
|
if(error) break; |
|
|
|
if(bitlen_ll[256] == 0) ERROR_BREAK(64); /*the length of the end code 256 must be larger than 0*/ |
|
|
|
/*now we've finally got HLIT and HDIST, so generate the code trees, and the function is done*/ |
|
error = HuffmanTree_makeFromLengths(tree_ll, bitlen_ll, NUM_DEFLATE_CODE_SYMBOLS, 15); |
|
if(error) break; |
|
error = HuffmanTree_makeFromLengths(tree_d, bitlen_d, NUM_DISTANCE_SYMBOLS, 15); |
|
|
|
break; /*end of error-while*/ |
|
} |
|
|
|
lodepng_free(bitlen_cl); |
|
lodepng_free(bitlen_ll); |
|
lodepng_free(bitlen_d); |
|
HuffmanTree_cleanup(&tree_cl); |
|
|
|
return error; |
|
} |
|
|
|
/*inflate a block with dynamic of fixed Huffman tree*/ |
|
static unsigned inflateHuffmanBlock(ucvector* out, const unsigned char* in, size_t* bp, |
|
size_t* pos, size_t inlength, unsigned btype) |
|
{ |
|
unsigned error = 0; |
|
HuffmanTree tree_ll; /*the huffman tree for literal and length codes*/ |
|
HuffmanTree tree_d; /*the huffman tree for distance codes*/ |
|
size_t inbitlength = inlength * 8; |
|
|
|
HuffmanTree_init(&tree_ll); |
|
HuffmanTree_init(&tree_d); |
|
|
|
if(btype == 1) getTreeInflateFixed(&tree_ll, &tree_d); |
|
else if(btype == 2) error = getTreeInflateDynamic(&tree_ll, &tree_d, in, bp, inlength); |
|
|
|
while(!error) /*decode all symbols until end reached, breaks at end code*/ |
|
{ |
|
/*code_ll is literal, length or end code*/ |
|
unsigned code_ll = huffmanDecodeSymbol(in, bp, &tree_ll, inbitlength); |
|
if(code_ll <= 255) /*literal symbol*/ |
|
{ |
|
if((*pos) >= out->size) |
|
{ |
|
/*reserve more room at once*/ |
|
if(!ucvector_resize(out, ((*pos) + 1) * 2)) ERROR_BREAK(83 /*alloc fail*/); |
|
} |
|
out->data[(*pos)] = (unsigned char)(code_ll); |
|
(*pos)++; |
|
} |
|
else if(code_ll >= FIRST_LENGTH_CODE_INDEX && code_ll <= LAST_LENGTH_CODE_INDEX) /*length code*/ |
|
{ |
|
unsigned code_d, distance; |
|
unsigned numextrabits_l, numextrabits_d; /*extra bits for length and distance*/ |
|
size_t start, forward, backward, length; |
|
|
|
/*part 1: get length base*/ |
|
length = LENGTHBASE[code_ll - FIRST_LENGTH_CODE_INDEX]; |
|
|
|
/*part 2: get extra bits and add the value of that to length*/ |
|
numextrabits_l = LENGTHEXTRA[code_ll - FIRST_LENGTH_CODE_INDEX]; |
|
if(*bp >= inbitlength) ERROR_BREAK(51); /*error, bit pointer will jump past memory*/ |
|
length += readBitsFromStream(bp, in, numextrabits_l); |
|
|
|
/*part 3: get distance code*/ |
|
code_d = huffmanDecodeSymbol(in, bp, &tree_d, inbitlength); |
|
if(code_d > 29) |
|
{ |
|
if(code_ll == (unsigned)(-1)) /*huffmanDecodeSymbol returns (unsigned)(-1) in case of error*/ |
|
{ |
|
/*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol |
|
(10=no endcode, 11=wrong jump outside of tree)*/ |
|
error = (*bp) > inlength * 8 ? 10 : 11; |
|
} |
|
else error = 18; /*error: invalid distance code (30-31 are never used)*/ |
|
break; |
|
} |
|
distance = DISTANCEBASE[code_d]; |
|
|
|
/*part 4: get extra bits from distance*/ |
|
numextrabits_d = DISTANCEEXTRA[code_d]; |
|
if(*bp >= inbitlength) ERROR_BREAK(51); /*error, bit pointer will jump past memory*/ |
|
|
|
distance += readBitsFromStream(bp, in, numextrabits_d); |
|
|
|
/*part 5: fill in all the out[n] values based on the length and dist*/ |
|
start = (*pos); |
|
if(distance > start) ERROR_BREAK(52); /*too long backward distance*/ |
|
backward = start - distance; |
|
if((*pos) + length >= out->size) |
|
{ |
|
/*reserve more room at once*/ |
|
if(!ucvector_resize(out, ((*pos) + length) * 2)) ERROR_BREAK(83 /*alloc fail*/); |
|
} |
|
|
|
for(forward = 0; forward < length; forward++) |
|
{ |
|
out->data[(*pos)] = out->data[backward]; |
|
(*pos)++; |
|
backward++; |
|
if(backward >= start) backward = start - distance; |
|
} |
|
} |
|
else if(code_ll == 256) |
|
{ |
|
break; /*end code, break the loop*/ |
|
} |
|
else /*if(code == (unsigned)(-1))*/ /*huffmanDecodeSymbol returns (unsigned)(-1) in case of error*/ |
|
{ |
|
/*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol |
|
(10=no endcode, 11=wrong jump outside of tree)*/ |
|
error = (*bp) > inlength * 8 ? 10 : 11; |
|
break; |
|
} |
|
} |
|
|
|
HuffmanTree_cleanup(&tree_ll); |
|
HuffmanTree_cleanup(&tree_d); |
|
|
|
return error; |
|
} |
|
|
|
static unsigned inflateNoCompression(ucvector* out, const unsigned char* in, size_t* bp, size_t* pos, size_t inlength) |
|
{ |
|
/*go to first boundary of byte*/ |
|
size_t p; |
|
unsigned LEN, NLEN, n, error = 0; |
|
while(((*bp) & 0x7) != 0) (*bp)++; |
|
p = (*bp) / 8; /*byte position*/ |
|
|
|
/*read LEN (2 bytes) and NLEN (2 bytes)*/ |
|
if(p >= inlength - 4) return 52; /*error, bit pointer will jump past memory*/ |
|
LEN = in[p] + 256 * in[p + 1]; p += 2; |
|
NLEN = in[p] + 256 * in[p + 1]; p += 2; |
|
|
|
/*check if 16-bit NLEN is really the one's complement of LEN*/ |
|
if(LEN + NLEN != 65535) return 21; /*error: NLEN is not one's complement of LEN*/ |
|
|
|
if((*pos) + LEN >= out->size) |
|
{ |
|
if(!ucvector_resize(out, (*pos) + LEN)) return 83; /*alloc fail*/ |
|
} |
|
|
|
/*read the literal data: LEN bytes are now stored in the out buffer*/ |
|
if(p + LEN > inlength) return 23; /*error: reading outside of in buffer*/ |
|
for(n = 0; n < LEN; n++) out->data[(*pos)++] = in[p++]; |
|
|
|
(*bp) = p * 8; |
|
|
|
return error; |
|
} |
|
|
|
static unsigned lodepng_inflatev(ucvector* out, |
|
const unsigned char* in, size_t insize, |
|
const LodePNGDecompressSettings* settings) |
|
{ |
|
/*bit pointer in the "in" data, current byte is bp >> 3, current bit is bp & 0x7 (from lsb to msb of the byte)*/ |
|
size_t bp = 0; |
|
unsigned BFINAL = 0; |
|
size_t pos = 0; /*byte position in the out buffer*/ |
|
|
|
unsigned error = 0; |
|
|
|
(void)settings; |
|
|
|
while(!BFINAL) |
|
{ |
|
unsigned BTYPE; |
|
if(bp + 2 >= insize * 8) return 52; /*error, bit pointer will jump past memory*/ |
|
BFINAL = readBitFromStream(&bp, in); |
|
BTYPE = 1 * readBitFromStream(&bp, in); |
|
BTYPE += 2 * readBitFromStream(&bp, in); |
|
|
|
if(BTYPE == 3) return 20; /*error: invalid BTYPE*/ |
|
else if(BTYPE == 0) error = inflateNoCompression(out, in, &bp, &pos, insize); /*no compression*/ |
|
else error = inflateHuffmanBlock(out, in, &bp, &pos, insize, BTYPE); /*compression, BTYPE 01 or 10*/ |
|
|
|
if(error) return error; |
|
} |
|
|
|
/*Only now we know the true size of out, resize it to that*/ |
|
if(!ucvector_resize(out, pos)) error = 83; /*alloc fail*/ |
|
|
|
return error; |
|
} |
|
|
|
unsigned lodepng_inflate(unsigned char** out, size_t* outsize, |
|
const unsigned char* in, size_t insize, |
|
const LodePNGDecompressSettings* settings) |
|
{ |
|
unsigned error; |
|
ucvector v; |
|
ucvector_init_buffer(&v, *out, *outsize); |
|
error = lodepng_inflatev(&v, in, insize, settings); |
|
*out = v.data; |
|
*outsize = v.size; |
|
return error; |
|
} |
|
|
|
static unsigned inflate(unsigned char** out, size_t* outsize, |
|
const unsigned char* in, size_t insize, |
|
const LodePNGDecompressSettings* settings) |
|
{ |
|
if(settings->custom_inflate) |
|
{ |
|
return settings->custom_inflate(out, outsize, in, insize, settings); |
|
} |
|
else |
|
{ |
|
return lodepng_inflate(out, outsize, in, insize, settings); |
|
} |
|
} |
|
|
|
#endif /*LODEPNG_COMPILE_DECODER*/ |
|
|
|
#ifdef LODEPNG_COMPILE_ENCODER |
|
|
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
/* / Deflator (Compressor) / */ |
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
|
|
static const size_t MAX_SUPPORTED_DEFLATE_LENGTH = 258; |
|
|
|
/*bitlen is the size in bits of the code*/ |
|
static void addHuffmanSymbol(size_t* bp, ucvector* compressed, unsigned code, unsigned bitlen) |
|
{ |
|
addBitsToStreamReversed(bp, compressed, code, bitlen); |
|
} |
|
|
|
/*search the index in the array, that has the largest value smaller than or equal to the given value, |
|
given array must be sorted (if no value is smaller, it returns the size of the given array)*/ |
|
static size_t searchCodeIndex(const unsigned* array, size_t array_size, size_t value) |
|
{ |
|
/*linear search implementation*/ |
|
/*for(size_t i = 1; i < array_size; i++) if(array[i] > value) return i - 1; |
|
return array_size - 1;*/ |
|
|
|
/*binary search implementation (not that much faster) (precondition: array_size > 0)*/ |
|
size_t left = 1; |
|
size_t right = array_size - 1; |
|
while(left <= right) |
|
{ |
|
size_t mid = (left + right) / 2; |
|
if(array[mid] <= value) left = mid + 1; /*the value to find is more to the right*/ |
|
else if(array[mid - 1] > value) right = mid - 1; /*the value to find is more to the left*/ |
|
else return mid - 1; |
|
} |
|
return array_size - 1; |
|
} |
|
|
|
static void addLengthDistance(uivector* values, size_t length, size_t distance) |
|
{ |
|
/*values in encoded vector are those used by deflate: |
|
0-255: literal bytes |
|
256: end |
|
257-285: length/distance pair (length code, followed by extra length bits, distance code, extra distance bits) |
|
286-287: invalid*/ |
|
|
|
unsigned length_code = (unsigned)searchCodeIndex(LENGTHBASE, 29, length); |
|
unsigned extra_length = (unsigned)(length - LENGTHBASE[length_code]); |
|
unsigned dist_code = (unsigned)searchCodeIndex(DISTANCEBASE, 30, distance); |
|
unsigned extra_distance = (unsigned)(distance - DISTANCEBASE[dist_code]); |
|
|
|
uivector_push_back(values, length_code + FIRST_LENGTH_CODE_INDEX); |
|
uivector_push_back(values, extra_length); |
|
uivector_push_back(values, dist_code); |
|
uivector_push_back(values, extra_distance); |
|
} |
|
|
|
static const unsigned HASH_BIT_MASK = 65535; |
|
static const unsigned HASH_NUM_VALUES = 65536; |
|
static const unsigned HASH_NUM_CHARACTERS = 3; |
|
static const unsigned HASH_SHIFT = 2; |
|
/* |
|
The HASH_NUM_CHARACTERS value is used to make encoding faster by using longer |
|
sequences to generate a hash value from the stream bytes. Setting it to 3 |
|
gives exactly the same compression as the brute force method, since deflate's |
|
run length encoding starts with lengths of 3. Setting it to higher values, |
|
like 6, can make the encoding faster (not always though!), but will cause the |
|
encoding to miss any length between 3 and this value, so that the compression |
|
may be worse (but this can vary too depending on the image, sometimes it is |
|
even a bit better instead). |
|
The HASH_NUM_VALUES is the amount of unique possible hash values that |
|
combinations of bytes can give, the higher it is the more memory is needed, but |
|
if it's too low the advantage of hashing is gone. |
|
*/ |
|
|
|
typedef struct Hash |
|
{ |
|
int* head; /*hash value to head circular pos*/ |
|
int* val; /*circular pos to hash value*/ |
|
/*circular pos to prev circular pos*/ |
|
unsigned short* chain; |
|
unsigned short* zeros; |
|
} Hash; |
|
|
|
static unsigned hash_init(Hash* hash, unsigned windowsize) |
|
{ |
|
unsigned i; |
|
hash->head = (int*)lodepng_malloc(sizeof(int) * HASH_NUM_VALUES); |
|
hash->val = (int*)lodepng_malloc(sizeof(int) * windowsize); |
|
hash->chain = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize); |
|
hash->zeros = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize); |
|
|
|
if(!hash->head || !hash->val || !hash->chain || !hash->zeros) return 83; /*alloc fail*/ |
|
|
|
/*initialize hash table*/ |
|
for(i = 0; i < HASH_NUM_VALUES; i++) hash->head[i] = -1; |
|
for(i = 0; i < windowsize; i++) hash->val[i] = -1; |
|
for(i = 0; i < windowsize; i++) hash->chain[i] = i; /*same value as index indicates uninitialized*/ |
|
|
|
return 0; |
|
} |
|
|
|
static void hash_cleanup(Hash* hash) |
|
{ |
|
lodepng_free(hash->head); |
|
lodepng_free(hash->val); |
|
lodepng_free(hash->chain); |
|
lodepng_free(hash->zeros); |
|
} |
|
|
|
static unsigned getHash(const unsigned char* data, size_t size, size_t pos) |
|
{ |
|
unsigned result = 0; |
|
if (HASH_NUM_CHARACTERS == 3 && pos + 2 < size) { |
|
result ^= (data[pos + 0] << (0 * HASH_SHIFT)); |
|
result ^= (data[pos + 1] << (1 * HASH_SHIFT)); |
|
result ^= (data[pos + 2] << (2 * HASH_SHIFT)); |
|
} else { |
|
size_t amount, i; |
|
if(pos >= size) return 0; |
|
amount = HASH_NUM_CHARACTERS; |
|
if(pos + amount >= size) amount = size - pos; |
|
for(i = 0; i < amount; i++) result ^= (data[pos + i] << (i * HASH_SHIFT)); |
|
} |
|
return result & HASH_BIT_MASK; |
|
} |
|
|
|
static unsigned countZeros(const unsigned char* data, size_t size, size_t pos) |
|
{ |
|
const unsigned char* start = data + pos; |
|
const unsigned char* end = start + MAX_SUPPORTED_DEFLATE_LENGTH; |
|
if(end > data + size) end = data + size; |
|
data = start; |
|
while (data != end && *data == 0) data++; |
|
/*subtracting two addresses returned as 32-bit number (max value is MAX_SUPPORTED_DEFLATE_LENGTH)*/ |
|
return (unsigned)(data - start); |
|
} |
|
|
|
/*wpos = pos & (windowsize - 1)*/ |
|
static void updateHashChain(Hash* hash, size_t wpos, int hashval) |
|
{ |
|
hash->val[wpos] = hashval; |
|
if(hash->head[hashval] != -1) hash->chain[wpos] = hash->head[hashval]; |
|
hash->head[hashval] = wpos; |
|
} |
|
|
|
/* |
|
LZ77-encode the data. Return value is error code. The input are raw bytes, the output |
|
is in the form of unsigned integers with codes representing for example literal bytes, or |
|
length/distance pairs. |
|
It uses a hash table technique to let it encode faster. When doing LZ77 encoding, a |
|
sliding window (of windowsize) is used, and all past bytes in that window can be used as |
|
the "dictionary". A brute force search through all possible distances would be slow, and |
|
this hash technique is one out of several ways to speed this up. |
|
*/ |
|
static unsigned encodeLZ77(uivector* out, Hash* hash, |
|
const unsigned char* in, size_t inpos, size_t insize, unsigned windowsize, |
|
unsigned minmatch, unsigned nicematch, unsigned lazymatching) |
|
{ |
|
unsigned pos, i, error = 0; |
|
/*for large window lengths, assume the user wants no compression loss. Otherwise, max hash chain length speedup.*/ |
|
unsigned maxchainlength = windowsize >= 8192 ? windowsize : windowsize / 8; |
|
unsigned maxlazymatch = windowsize >= 8192 ? MAX_SUPPORTED_DEFLATE_LENGTH : 64; |
|
|
|
unsigned usezeros = 1; /*not sure if setting it to false for windowsize < 8192 is better or worse*/ |
|
unsigned numzeros = 0; |
|
|
|
unsigned offset; /*the offset represents the distance in LZ77 terminology*/ |
|
unsigned length; |
|
unsigned lazy = 0; |
|
unsigned lazylength = 0, lazyoffset = 0; |
|
unsigned hashval; |
|
unsigned current_offset, current_length; |
|
const unsigned char *lastptr, *foreptr, *backptr; |
|
unsigned hashpos, prevpos; |
|
|
|
if(windowsize <= 0 || windowsize > 32768) return 60; /*error: windowsize smaller/larger than allowed*/ |
|
if((windowsize & (windowsize - 1)) != 0) return 90; /*error: must be power of two*/ |
|
|
|
if(nicematch > MAX_SUPPORTED_DEFLATE_LENGTH) nicematch = MAX_SUPPORTED_DEFLATE_LENGTH; |
|
|
|
for(pos = inpos; pos < insize; pos++) |
|
{ |
|
size_t wpos = pos & (windowsize - 1); /*position for in 'circular' hash buffers*/ |
|
unsigned chainlength = 0; |
|
|
|
hashval = getHash(in, insize, pos); |
|
updateHashChain(hash, wpos, hashval); |
|
|
|
if(usezeros && hashval == 0) |
|
{ |
|
if (numzeros == 0) numzeros = countZeros(in, insize, pos); |
|
else if (pos + numzeros >= insize || in[pos + numzeros - 1] != 0) numzeros--; |
|
hash->zeros[wpos] = numzeros; |
|
} |
|
else |
|
{ |
|
numzeros = 0; |
|
} |
|
|
|
/*the length and offset found for the current position*/ |
|
length = 0; |
|
offset = 0; |
|
|
|
prevpos = hash->head[hashval]; |
|
hashpos = hash->chain[prevpos]; |
|
|
|
lastptr = &in[insize < pos + MAX_SUPPORTED_DEFLATE_LENGTH ? insize : pos + MAX_SUPPORTED_DEFLATE_LENGTH]; |
|
|
|
/*search for the longest string*/ |
|
for(;;) |
|
{ |
|
/*stop when went completely around the circular buffer*/ |
|
if(prevpos < wpos && hashpos > prevpos && hashpos <= wpos) break; |
|
if(prevpos > wpos && (hashpos <= wpos || hashpos > prevpos)) break; |
|
if(chainlength++ >= maxchainlength) break; |
|
|
|
current_offset = hashpos <= wpos ? wpos - hashpos : wpos - hashpos + windowsize; |
|
if(current_offset > 0) |
|
{ |
|
/*test the next characters*/ |
|
foreptr = &in[pos]; |
|
backptr = &in[pos - current_offset]; |
|
|
|
/*common case in PNGs is lots of zeros. Quickly skip over them as a speedup*/ |
|
if(usezeros && hashval == 0 && hash->val[hashpos] == 0 /*hashval[hashpos] may be out of date*/) |
|
{ |
|
unsigned skip = hash->zeros[hashpos]; |
|
if(skip > numzeros) skip = numzeros; |
|
backptr += skip; |
|
foreptr += skip; |
|
} |
|
|
|
while(foreptr != lastptr && *backptr == *foreptr) /*maximum supported length by deflate is max length*/ |
|
{ |
|
++backptr; |
|
++foreptr; |
|
} |
|
current_length = (unsigned)(foreptr - &in[pos]); |
|
|
|
if(current_length > length) |
|
{ |
|
length = current_length; /*the longest length*/ |
|
offset = current_offset; /*the offset that is related to this longest length*/ |
|
/*jump out once a length of max length is found (speed gain). This also jumps |
|
out if length is MAX_SUPPORTED_DEFLATE_LENGTH*/ |
|
if(current_length >= nicematch) break; |
|
} |
|
} |
|
|
|
if(hashpos == hash->chain[hashpos]) break; |
|
|
|
prevpos = hashpos; |
|
hashpos = hash->chain[hashpos]; |
|
} |
|
|
|
if(lazymatching) |
|
{ |
|
if(!lazy && length >= 3 && length <= maxlazymatch && length < MAX_SUPPORTED_DEFLATE_LENGTH) |
|
{ |
|
lazy = 1; |
|
lazylength = length; |
|
lazyoffset = offset; |
|
continue; /*try the next byte*/ |
|
} |
|
if(lazy) |
|
{ |
|
lazy = 0; |
|
if(pos == 0) ERROR_BREAK(81); |
|
if(length > lazylength + 1) |
|
{ |
|
/*push the previous character as literal*/ |
|
if(!uivector_push_back(out, in[pos - 1])) ERROR_BREAK(83 /*alloc fail*/); |
|
} |
|
else |
|
{ |
|
length = lazylength; |
|
offset = lazyoffset; |
|
hash->head[hashval] = -1; /*the same hashchain update will be done, this ensures no wrong alteration*/ |
|
pos--; |
|
} |
|
} |
|
} |
|
if(length >= 3 && offset > windowsize) ERROR_BREAK(86 /*too big (or overflown negative) offset*/); |
|
|
|
/*encode it as length/distance pair or literal value*/ |
|
if(length < 3) /*only lengths of 3 or higher are supported as length/distance pair*/ |
|
{ |
|
if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/); |
|
} |
|
else if(length < minmatch || (length == 3 && offset > 4096)) |
|
{ |
|
/*compensate for the fact that longer offsets have more extra bits, a |
|
length of only 3 may be not worth it then*/ |
|
if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/); |
|
} |
|
else |
|
{ |
|
addLengthDistance(out, length, offset); |
|
for(i = 1; i < length; i++) |
|
{ |
|
pos++; |
|
wpos = pos & (windowsize - 1); |
|
hashval = getHash(in, insize, pos); |
|
updateHashChain(hash, wpos, hashval); |
|
if(usezeros && hashval == 0) |
|
{ |
|
if (numzeros == 0) numzeros = countZeros(in, insize, pos); |
|
else if (pos + numzeros >= insize || in[pos + numzeros - 1] != 0) numzeros--; |
|
hash->zeros[wpos] = numzeros; |
|
} |
|
else |
|
{ |
|
numzeros = 0; |
|
} |
|
} |
|
} |
|
} /*end of the loop through each character of input*/ |
|
|
|
return error; |
|
} |
|
|
|
/* /////////////////////////////////////////////////////////////////////////// */ |
|
|
|
static unsigned deflateNoCompression(ucvector* out, const unsigned char* data, size_t datasize) |
|
{ |
|
/*non compressed deflate block data: 1 bit BFINAL,2 bits BTYPE,(5 bits): it jumps to start of next byte, |
|
2 bytes LEN, 2 bytes NLEN, LEN bytes literal DATA*/ |
|
|
|
size_t i, j, numdeflateblocks = (datasize + 65534) / 65535; |
|
unsigned datapos = 0; |
|
for(i = 0; i < numdeflateblocks; i++) |
|
{ |
|
unsigned BFINAL, BTYPE, LEN, NLEN; |
|
unsigned char firstbyte; |
|
|
|
BFINAL = (i == numdeflateblocks - 1); |
|
BTYPE = 0; |
|
|
|
firstbyte = (unsigned char)(BFINAL + ((BTYPE & 1) << 1) + ((BTYPE & 2) << 1)); |
|
ucvector_push_back(out, firstbyte); |
|
|
|
LEN = 65535; |
|
if(datasize - datapos < 65535) LEN = (unsigned)datasize - datapos; |
|
NLEN = 65535 - LEN; |
|
|
|
ucvector_push_back(out, (unsigned char)(LEN % 256)); |
|
ucvector_push_back(out, (unsigned char)(LEN / 256)); |
|
ucvector_push_back(out, (unsigned char)(NLEN % 256)); |
|
ucvector_push_back(out, (unsigned char)(NLEN / 256)); |
|
|
|
/*Decompressed data*/ |
|
for(j = 0; j < 65535 && datapos < datasize; j++) |
|
{ |
|
ucvector_push_back(out, data[datapos++]); |
|
} |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
write the lz77-encoded data, which has lit, len and dist codes, to compressed stream using huffman trees. |
|
tree_ll: the tree for lit and len codes. |
|
tree_d: the tree for distance codes. |
|
*/ |
|
static void writeLZ77data(size_t* bp, ucvector* out, const uivector* lz77_encoded, |
|
const HuffmanTree* tree_ll, const HuffmanTree* tree_d) |
|
{ |
|
size_t i = 0; |
|
for(i = 0; i < lz77_encoded->size; i++) |
|
{ |
|
unsigned val = lz77_encoded->data[i]; |
|
addHuffmanSymbol(bp, out, HuffmanTree_getCode(tree_ll, val), HuffmanTree_getLength(tree_ll, val)); |
|
if(val > 256) /*for a length code, 3 more things have to be added*/ |
|
{ |
|
unsigned length_index = val - FIRST_LENGTH_CODE_INDEX; |
|
unsigned n_length_extra_bits = LENGTHEXTRA[length_index]; |
|
unsigned length_extra_bits = lz77_encoded->data[++i]; |
|
|
|
unsigned distance_code = lz77_encoded->data[++i]; |
|
|
|
unsigned distance_index = distance_code; |
|
unsigned n_distance_extra_bits = DISTANCEEXTRA[distance_index]; |
|
unsigned distance_extra_bits = lz77_encoded->data[++i]; |
|
|
|
addBitsToStream(bp, out, length_extra_bits, n_length_extra_bits); |
|
addHuffmanSymbol(bp, out, HuffmanTree_getCode(tree_d, distance_code), |
|
HuffmanTree_getLength(tree_d, distance_code)); |
|
addBitsToStream(bp, out, distance_extra_bits, n_distance_extra_bits); |
|
} |
|
} |
|
} |
|
|
|
/*Deflate for a block of type "dynamic", that is, with freely, optimally, created huffman trees*/ |
|
static unsigned deflateDynamic(ucvector* out, size_t* bp, Hash* hash, |
|
const unsigned char* data, size_t datapos, size_t dataend, |
|
const LodePNGCompressSettings* settings, int final) |
|
{ |
|
unsigned error = 0; |
|
|
|
/* |
|
A block is compressed as follows: The PNG data is lz77 encoded, resulting in |
|
literal bytes and length/distance pairs. This is then huffman compressed with |
|
two huffman trees. One huffman tree is used for the lit and len values ("ll"), |
|
another huffman tree is used for the dist values ("d"). These two trees are |
|
stored using their code lengths, and to compress even more these code lengths |
|
are also run-length encoded and huffman compressed. This gives a huffman tree |
|
of code lengths "cl". The code lenghts used to describe this third tree are |
|
the code length code lengths ("clcl"). |
|
*/ |
|
|
|
/*The lz77 encoded data, represented with integers since there will also be length and distance codes in it*/ |
|
uivector lz77_encoded; |
|
HuffmanTree tree_ll; /*tree for lit,len values*/ |
|
HuffmanTree tree_d; /*tree for distance codes*/ |
|
HuffmanTree tree_cl; /*tree for encoding the code lengths representing tree_ll and tree_d*/ |
|
uivector frequencies_ll; /*frequency of lit,len codes*/ |
|
uivector frequencies_d; /*frequency of dist codes*/ |
|
uivector frequencies_cl; /*frequency of code length codes*/ |
|
uivector bitlen_lld; /*lit,len,dist code lenghts (int bits), literally (without repeat codes).*/ |
|
uivector bitlen_lld_e; /*bitlen_lld encoded with repeat codes (this is a rudemtary run length compression)*/ |
|
/*bitlen_cl is the code length code lengths ("clcl"). The bit lengths of codes to represent tree_cl |
|
(these are written as is in the file, it would be crazy to compress these using yet another huffman |
|
tree that needs to be represented by yet another set of code lengths)*/ |
|
uivector bitlen_cl; |
|
size_t datasize = dataend - datapos; |
|
|
|
/* |
|
Due to the huffman compression of huffman tree representations ("two levels"), there are some anologies: |
|
bitlen_lld is to tree_cl what data is to tree_ll and tree_d. |
|
bitlen_lld_e is to bitlen_lld what lz77_encoded is to data. |
|
bitlen_cl is to bitlen_lld_e what bitlen_lld is to lz77_encoded. |
|
*/ |
|
|
|
unsigned BFINAL = final; |
|
size_t numcodes_ll, numcodes_d, i; |
|
unsigned HLIT, HDIST, HCLEN; |
|
|
|
uivector_init(&lz77_encoded); |
|
HuffmanTree_init(&tree_ll); |
|
HuffmanTree_init(&tree_d); |
|
HuffmanTree_init(&tree_cl); |
|
uivector_init(&frequencies_ll); |
|
uivector_init(&frequencies_d); |
|
uivector_init(&frequencies_cl); |
|
uivector_init(&bitlen_lld); |
|
uivector_init(&bitlen_lld_e); |
|
uivector_init(&bitlen_cl); |
|
|
|
/*This while loop never loops due to a break at the end, it is here to |
|
allow breaking out of it to the cleanup phase on error conditions.*/ |
|
while(!error) |
|
{ |
|
if(settings->use_lz77) |
|
{ |
|
error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings->windowsize, |
|
settings->minmatch, settings->nicematch, settings->lazymatching); |
|
if(error) break; |
|
} |
|
else |
|
{ |
|
if(!uivector_resize(&lz77_encoded, datasize)) ERROR_BREAK(83 /*alloc fail*/); |
|
for(i = datapos; i < dataend; i++) lz77_encoded.data[i] = data[i]; /*no LZ77, but still will be Huffman compressed*/ |
|
} |
|
|
|
if(!uivector_resizev(&frequencies_ll, 286, 0)) ERROR_BREAK(83 /*alloc fail*/); |
|
if(!uivector_resizev(&frequencies_d, 30, 0)) ERROR_BREAK(83 /*alloc fail*/); |
|
|
|
/*Count the frequencies of lit, len and dist codes*/ |
|
for(i = 0; i < lz77_encoded.size; i++) |
|
{ |
|
unsigned symbol = lz77_encoded.data[i]; |
|
frequencies_ll.data[symbol]++; |
|
if(symbol > 256) |
|
{ |
|
unsigned dist = lz77_encoded.data[i + 2]; |
|
frequencies_d.data[dist]++; |
|
i += 3; |
|
} |
|
} |
|
frequencies_ll.data[256] = 1; /*there will be exactly 1 end code, at the end of the block*/ |
|
|
|
/*Make both huffman trees, one for the lit and len codes, one for the dist codes*/ |
|
error = HuffmanTree_makeFromFrequencies(&tree_ll, frequencies_ll.data, 257, frequencies_ll.size, 15); |
|
if(error) break; |
|
/*2, not 1, is chosen for mincodes: some buggy PNG decoders require at least 2 symbols in the dist tree*/ |
|
error = HuffmanTree_makeFromFrequencies(&tree_d, frequencies_d.data, 2, frequencies_d.size, 15); |
|
if(error) break; |
|
|
|
numcodes_ll = tree_ll.numcodes; if(numcodes_ll > 286) numcodes_ll = 286; |
|
numcodes_d = tree_d.numcodes; if(numcodes_d > 30) numcodes_d = 30; |
|
/*store the code lengths of both generated trees in bitlen_lld*/ |
|
for(i = 0; i < numcodes_ll; i++) uivector_push_back(&bitlen_lld, HuffmanTree_getLength(&tree_ll, (unsigned)i)); |
|
for(i = 0; i < numcodes_d; i++) uivector_push_back(&bitlen_lld, HuffmanTree_getLength(&tree_d, (unsigned)i)); |
|
|
|
/*run-length compress bitlen_ldd into bitlen_lld_e by using repeat codes 16 (copy length 3-6 times), |
|
17 (3-10 zeroes), 18 (11-138 zeroes)*/ |
|
for(i = 0; i < (unsigned)bitlen_lld.size; i++) |
|
{ |
|
unsigned j = 0; /*amount of repititions*/ |
|
while(i + j + 1 < (unsigned)bitlen_lld.size && bitlen_lld.data[i + j + 1] == bitlen_lld.data[i]) j++; |
|
|
|
if(bitlen_lld.data[i] == 0 && j >= 2) /*repeat code for zeroes*/ |
|
{ |
|
j++; /*include the first zero*/ |
|
if(j <= 10) /*repeat code 17 supports max 10 zeroes*/ |
|
{ |
|
uivector_push_back(&bitlen_lld_e, 17); |
|
uivector_push_back(&bitlen_lld_e, j - 3); |
|
} |
|
else /*repeat code 18 supports max 138 zeroes*/ |
|
{ |
|
if(j > 138) j = 138; |
|
uivector_push_back(&bitlen_lld_e, 18); |
|
uivector_push_back(&bitlen_lld_e, j - 11); |
|
} |
|
i += (j - 1); |
|
} |
|
else if(j >= 3) /*repeat code for value other than zero*/ |
|
{ |
|
size_t k; |
|
unsigned num = j / 6, rest = j % 6; |
|
uivector_push_back(&bitlen_lld_e, bitlen_lld.data[i]); |
|
for(k = 0; k < num; k++) |
|
{ |
|
uivector_push_back(&bitlen_lld_e, 16); |
|
uivector_push_back(&bitlen_lld_e, 6 - 3); |
|
} |
|
if(rest >= 3) |
|
{ |
|
uivector_push_back(&bitlen_lld_e, 16); |
|
uivector_push_back(&bitlen_lld_e, rest - 3); |
|
} |
|
else j -= rest; |
|
i += j; |
|
} |
|
else /*too short to benefit from repeat code*/ |
|
{ |
|
uivector_push_back(&bitlen_lld_e, bitlen_lld.data[i]); |
|
} |
|
} |
|
|
|
/*generate tree_cl, the huffmantree of huffmantrees*/ |
|
|
|
if(!uivector_resizev(&frequencies_cl, NUM_CODE_LENGTH_CODES, 0)) ERROR_BREAK(83 /*alloc fail*/); |
|
for(i = 0; i < bitlen_lld_e.size; i++) |
|
{ |
|
frequencies_cl.data[bitlen_lld_e.data[i]]++; |
|
/*after a repeat code come the bits that specify the number of repetitions, |
|
those don't need to be in the frequencies_cl calculation*/ |
|
if(bitlen_lld_e.data[i] >= 16) i++; |
|
} |
|
|
|
error = HuffmanTree_makeFromFrequencies(&tree_cl, frequencies_cl.data, |
|
frequencies_cl.size, frequencies_cl.size, 7); |
|
if(error) break; |
|
|
|
if(!uivector_resize(&bitlen_cl, tree_cl.numcodes)) ERROR_BREAK(83 /*alloc fail*/); |
|
for(i = 0; i < tree_cl.numcodes; i++) |
|
{ |
|
/*lenghts of code length tree is in the order as specified by deflate*/ |
|
bitlen_cl.data[i] = HuffmanTree_getLength(&tree_cl, CLCL_ORDER[i]); |
|
} |
|
while(bitlen_cl.data[bitlen_cl.size - 1] == 0 && bitlen_cl.size > 4) |
|
{ |
|
/*remove zeros at the end, but minimum size must be 4*/ |
|
if(!uivector_resize(&bitlen_cl, bitlen_cl.size - 1)) ERROR_BREAK(83 /*alloc fail*/); |
|
} |
|
if(error) break; |
|
|
|
/* |
|
Write everything into the output |
|
|
|
After the BFINAL and BTYPE, the dynamic block consists out of the following: |
|
- 5 bits HLIT, 5 bits HDIST, 4 bits HCLEN |
|
- (HCLEN+4)*3 bits code lengths of code length alphabet |
|
- HLIT + 257 code lenghts of lit/length alphabet (encoded using the code length |
|
alphabet, + possible repetition codes 16, 17, 18) |
|
- HDIST + 1 code lengths of distance alphabet (encoded using the code length |
|
alphabet, + possible repetition codes 16, 17, 18) |
|
- compressed data |
|
- 256 (end code) |
|
*/ |
|
|
|
/*Write block type*/ |
|
addBitToStream(bp, out, BFINAL); |
|
addBitToStream(bp, out, 0); /*first bit of BTYPE "dynamic"*/ |
|
addBitToStream(bp, out, 1); /*second bit of BTYPE "dynamic"*/ |
|
|
|
/*write the HLIT, HDIST and HCLEN values*/ |
|
HLIT = (unsigned)(numcodes_ll - 257); |
|
HDIST = (unsigned)(numcodes_d - 1); |
|
HCLEN = (unsigned)bitlen_cl.size - 4; |
|
/*trim zeroes for HCLEN. HLIT and HDIST were already trimmed at tree creation*/ |
|
while(!bitlen_cl.data[HCLEN + 4 - 1] && HCLEN > 0) HCLEN--; |
|
addBitsToStream(bp, out, HLIT, 5); |
|
addBitsToStream(bp, out, HDIST, 5); |
|
addBitsToStream(bp, out, HCLEN, 4); |
|
|
|
/*write the code lenghts of the code length alphabet*/ |
|
for(i = 0; i < HCLEN + 4; i++) addBitsToStream(bp, out, bitlen_cl.data[i], 3); |
|
|
|
/*write the lenghts of the lit/len AND the dist alphabet*/ |
|
for(i = 0; i < bitlen_lld_e.size; i++) |
|
{ |
|
addHuffmanSymbol(bp, out, HuffmanTree_getCode(&tree_cl, bitlen_lld_e.data[i]), |
|
HuffmanTree_getLength(&tree_cl, bitlen_lld_e.data[i])); |
|
/*extra bits of repeat codes*/ |
|
if(bitlen_lld_e.data[i] == 16) addBitsToStream(bp, out, bitlen_lld_e.data[++i], 2); |
|
else if(bitlen_lld_e.data[i] == 17) addBitsToStream(bp, out, bitlen_lld_e.data[++i], 3); |
|
else if(bitlen_lld_e.data[i] == 18) addBitsToStream(bp, out, bitlen_lld_e.data[++i], 7); |
|
} |
|
|
|
/*write the compressed data symbols*/ |
|
writeLZ77data(bp, out, &lz77_encoded, &tree_ll, &tree_d); |
|
/*error: the length of the end code 256 must be larger than 0*/ |
|
if(HuffmanTree_getLength(&tree_ll, 256) == 0) ERROR_BREAK(64); |
|
|
|
/*write the end code*/ |
|
addHuffmanSymbol(bp, out, HuffmanTree_getCode(&tree_ll, 256), HuffmanTree_getLength(&tree_ll, 256)); |
|
|
|
break; /*end of error-while*/ |
|
} |
|
|
|
/*cleanup*/ |
|
uivector_cleanup(&lz77_encoded); |
|
HuffmanTree_cleanup(&tree_ll); |
|
HuffmanTree_cleanup(&tree_d); |
|
HuffmanTree_cleanup(&tree_cl); |
|
uivector_cleanup(&frequencies_ll); |
|
uivector_cleanup(&frequencies_d); |
|
uivector_cleanup(&frequencies_cl); |
|
uivector_cleanup(&bitlen_lld_e); |
|
uivector_cleanup(&bitlen_lld); |
|
uivector_cleanup(&bitlen_cl); |
|
|
|
return error; |
|
} |
|
|
|
static unsigned deflateFixed(ucvector* out, size_t* bp, Hash* hash, |
|
const unsigned char* data, |
|
size_t datapos, size_t dataend, |
|
const LodePNGCompressSettings* settings, int final) |
|
{ |
|
HuffmanTree tree_ll; /*tree for literal values and length codes*/ |
|
HuffmanTree tree_d; /*tree for distance codes*/ |
|
|
|
unsigned BFINAL = final; |
|
unsigned error = 0; |
|
size_t i; |
|
|
|
HuffmanTree_init(&tree_ll); |
|
HuffmanTree_init(&tree_d); |
|
|
|
generateFixedLitLenTree(&tree_ll); |
|
generateFixedDistanceTree(&tree_d); |
|
|
|
addBitToStream(bp, out, BFINAL); |
|
addBitToStream(bp, out, 1); /*first bit of BTYPE*/ |
|
addBitToStream(bp, out, 0); /*second bit of BTYPE*/ |
|
|
|
if(settings->use_lz77) /*LZ77 encoded*/ |
|
{ |
|
uivector lz77_encoded; |
|
uivector_init(&lz77_encoded); |
|
error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings->windowsize, |
|
settings->minmatch, settings->nicematch, settings->lazymatching); |
|
if(!error) writeLZ77data(bp, out, &lz77_encoded, &tree_ll, &tree_d); |
|
uivector_cleanup(&lz77_encoded); |
|
} |
|
else /*no LZ77, but still will be Huffman compressed*/ |
|
{ |
|
for(i = datapos; i < dataend; i++) |
|
{ |
|
addHuffmanSymbol(bp, out, HuffmanTree_getCode(&tree_ll, data[i]), HuffmanTree_getLength(&tree_ll, data[i])); |
|
} |
|
} |
|
/*add END code*/ |
|
if(!error) addHuffmanSymbol(bp, out, HuffmanTree_getCode(&tree_ll, 256), HuffmanTree_getLength(&tree_ll, 256)); |
|
|
|
/*cleanup*/ |
|
HuffmanTree_cleanup(&tree_ll); |
|
HuffmanTree_cleanup(&tree_d); |
|
|
|
return error; |
|
} |
|
|
|
static unsigned lodepng_deflatev(ucvector* out, const unsigned char* in, size_t insize, |
|
const LodePNGCompressSettings* settings) |
|
{ |
|
unsigned error = 0; |
|
size_t i, blocksize, numdeflateblocks; |
|
size_t bp = 0; /*the bit pointer*/ |
|
Hash hash; |
|
|
|
if(settings->btype > 2) return 61; |
|
else if(settings->btype == 0) return deflateNoCompression(out, in, insize); |
|
else if(settings->btype == 1) blocksize = insize; |
|
else /*if(settings->btype == 2)*/ |
|
{ |
|
blocksize = insize / 8 + 8; |
|
if(blocksize < 65535) blocksize = 65535; |
|
} |
|
|
|
numdeflateblocks = (insize + blocksize - 1) / blocksize; |
|
if(numdeflateblocks == 0) numdeflateblocks = 1; |
|
|
|
error = hash_init(&hash, settings->windowsize); |
|
if(error) return error; |
|
|
|
for(i = 0; i < numdeflateblocks && !error; i++) |
|
{ |
|
int final = i == numdeflateblocks - 1; |
|
size_t start = i * blocksize; |
|
size_t end = start + blocksize; |
|
if(end > insize) end = insize; |
|
|
|
if(settings->btype == 1) error = deflateFixed(out, &bp, &hash, in, start, end, settings, final); |
|
else if(settings->btype == 2) error = deflateDynamic(out, &bp, &hash, in, start, end, settings, final); |
|
} |
|
|
|
hash_cleanup(&hash); |
|
|
|
return error; |
|
} |
|
|
|
unsigned lodepng_deflate(unsigned char** out, size_t* outsize, |
|
const unsigned char* in, size_t insize, |
|
const LodePNGCompressSettings* settings) |
|
{ |
|
unsigned error; |
|
ucvector v; |
|
ucvector_init_buffer(&v, *out, *outsize); |
|
error = lodepng_deflatev(&v, in, insize, settings); |
|
*out = v.data; |
|
*outsize = v.size; |
|
return error; |
|
} |
|
|
|
static unsigned deflate(unsigned char** out, size_t* outsize, |
|
const unsigned char* in, size_t insize, |
|
const LodePNGCompressSettings* settings) |
|
{ |
|
if(settings->custom_deflate) |
|
{ |
|
return settings->custom_deflate(out, outsize, in, insize, settings); |
|
} |
|
else |
|
{ |
|
return lodepng_deflate(out, outsize, in, insize, settings); |
|
} |
|
} |
|
|
|
#endif /*LODEPNG_COMPILE_DECODER*/ |
|
|
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
/* / Adler32 */ |
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
|
|
static unsigned update_adler32(unsigned adler, const unsigned char* data, unsigned len) |
|
{ |
|
unsigned s1 = adler & 0xffff; |
|
unsigned s2 = (adler >> 16) & 0xffff; |
|
|
|
while(len > 0) |
|
{ |
|
/*at least 5550 sums can be done before the sums overflow, saving a lot of module divisions*/ |
|
unsigned amount = len > 5550 ? 5550 : len; |
|
len -= amount; |
|
while(amount > 0) |
|
{ |
|
s1 += (*data++); |
|
s2 += s1; |
|
amount--; |
|
} |
|
s1 %= 65521; |
|
s2 %= 65521; |
|
} |
|
|
|
return (s2 << 16) | s1; |
|
} |
|
|
|
/*Return the adler32 of the bytes data[0..len-1]*/ |
|
static unsigned adler32(const unsigned char* data, unsigned len) |
|
{ |
|
return update_adler32(1L, data, len); |
|
} |
|
|
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
/* / Zlib / */ |
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
|
|
#ifdef LODEPNG_COMPILE_DECODER |
|
|
|
unsigned lodepng_zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in, |
|
size_t insize, const LodePNGDecompressSettings* settings) |
|
{ |
|
unsigned error = 0; |
|
unsigned CM, CINFO, FDICT; |
|
|
|
if(insize < 2) return 53; /*error, size of zlib data too small*/ |
|
/*read information from zlib header*/ |
|
if((in[0] * 256 + in[1]) % 31 != 0) |
|
{ |
|
/*error: 256 * in[0] + in[1] must be a multiple of 31, the FCHECK value is supposed to be made that way*/ |
|
return 24; |
|
} |
|
|
|
CM = in[0] & 15; |
|
CINFO = (in[0] >> 4) & 15; |
|
/*FCHECK = in[1] & 31;*/ /*FCHECK is already tested above*/ |
|
FDICT = (in[1] >> 5) & 1; |
|
/*FLEVEL = (in[1] >> 6) & 3;*/ /*FLEVEL is not used here*/ |
|
|
|
if(CM != 8 || CINFO > 7) |
|
{ |
|
/*error: only compression method 8: inflate with sliding window of 32k is supported by the PNG spec*/ |
|
return 25; |
|
} |
|
if(FDICT != 0) |
|
{ |
|
/*error: the specification of PNG says about the zlib stream: |
|
"The additional flags shall not specify a preset dictionary."*/ |
|
return 26; |
|
} |
|
|
|
error = inflate(out, outsize, in + 2, insize - 2, settings); |
|
if(error) return error; |
|
|
|
if(!settings->ignore_adler32) |
|
{ |
|
unsigned ADLER32 = lodepng_read32bitInt(&in[insize - 4]); |
|
unsigned checksum = adler32(*out, (unsigned)(*outsize)); |
|
if(checksum != ADLER32) return 58; /*error, adler checksum not correct, data must be corrupted*/ |
|
} |
|
|
|
return 0; /*no error*/ |
|
} |
|
|
|
static unsigned zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in, |
|
size_t insize, const LodePNGDecompressSettings* settings) |
|
{ |
|
if(settings->custom_zlib) |
|
{ |
|
return settings->custom_zlib(out, outsize, in, insize, settings); |
|
} |
|
else |
|
{ |
|
return lodepng_zlib_decompress(out, outsize, in, insize, settings); |
|
} |
|
} |
|
|
|
#endif /*LODEPNG_COMPILE_DECODER*/ |
|
|
|
#ifdef LODEPNG_COMPILE_ENCODER |
|
|
|
unsigned lodepng_zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, |
|
size_t insize, const LodePNGCompressSettings* settings) |
|
{ |
|
/*initially, *out must be NULL and outsize 0, if you just give some random *out |
|
that's pointing to a non allocated buffer, this'll crash*/ |
|
ucvector outv; |
|
size_t i; |
|
unsigned error; |
|
unsigned char* deflatedata = 0; |
|
size_t deflatesize = 0; |
|
|
|
unsigned ADLER32; |
|
/*zlib data: 1 byte CMF (CM+CINFO), 1 byte FLG, deflate data, 4 byte ADLER32 checksum of the Decompressed data*/ |
|
unsigned CMF = 120; /*0b01111000: CM 8, CINFO 7. With CINFO 7, any window size up to 32768 can be used.*/ |
|
unsigned FLEVEL = 0; |
|
unsigned FDICT = 0; |
|
unsigned CMFFLG = 256 * CMF + FDICT * 32 + FLEVEL * 64; |
|
unsigned FCHECK = 31 - CMFFLG % 31; |
|
CMFFLG += FCHECK; |
|
|
|
/*ucvector-controlled version of the output buffer, for dynamic array*/ |
|
ucvector_init_buffer(&outv, *out, *outsize); |
|
|
|
ucvector_push_back(&outv, (unsigned char)(CMFFLG / 256)); |
|
ucvector_push_back(&outv, (unsigned char)(CMFFLG % 256)); |
|
|
|
error = deflate(&deflatedata, &deflatesize, in, insize, settings); |
|
|
|
if(!error) |
|
{ |
|
ADLER32 = adler32(in, (unsigned)insize); |
|
for(i = 0; i < deflatesize; i++) ucvector_push_back(&outv, deflatedata[i]); |
|
lodepng_free(deflatedata); |
|
lodepng_add32bitInt(&outv, ADLER32); |
|
} |
|
|
|
*out = outv.data; |
|
*outsize = outv.size; |
|
|
|
return error; |
|
} |
|
|
|
/* compress using the default or custom zlib function */ |
|
static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, |
|
size_t insize, const LodePNGCompressSettings* settings) |
|
{ |
|
if(settings->custom_zlib) |
|
{ |
|
return settings->custom_zlib(out, outsize, in, insize, settings); |
|
} |
|
else |
|
{ |
|
return lodepng_zlib_compress(out, outsize, in, insize, settings); |
|
} |
|
} |
|
|
|
#endif /*LODEPNG_COMPILE_ENCODER*/ |
|
|
|
#else /*no LODEPNG_COMPILE_ZLIB*/ |
|
|
|
#ifdef LODEPNG_COMPILE_DECODER |
|
static unsigned zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in, |
|
size_t insize, const LodePNGDecompressSettings* settings) |
|
{ |
|
if (!settings->custom_zlib) return 87; /*no custom zlib function provided */ |
|
return settings->custom_zlib(out, outsize, in, insize, settings); |
|
} |
|
#endif /*LODEPNG_COMPILE_DECODER*/ |
|
#ifdef LODEPNG_COMPILE_ENCODER |
|
static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, |
|
size_t insize, const LodePNGCompressSettings* settings) |
|
{ |
|
if (!settings->custom_zlib) return 87; /*no custom zlib function provided */ |
|
return settings->custom_zlib(out, outsize, in, insize, settings); |
|
} |
|
#endif /*LODEPNG_COMPILE_ENCODER*/ |
|
|
|
#endif /*LODEPNG_COMPILE_ZLIB*/ |
|
|
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
|
|
#ifdef LODEPNG_COMPILE_ENCODER |
|
|
|
/*this is a good tradeoff between speed and compression ratio*/ |
|
#define DEFAULT_WINDOWSIZE 2048 |
|
|
|
void lodepng_compress_settings_init(LodePNGCompressSettings* settings) |
|
{ |
|
/*compress with dynamic huffman tree (not in the mathematical sense, just not the predefined one)*/ |
|
settings->btype = 2; |
|
settings->use_lz77 = 1; |
|
settings->windowsize = DEFAULT_WINDOWSIZE; |
|
settings->minmatch = 3; |
|
settings->nicematch = 128; |
|
settings->lazymatching = 1; |
|
|
|
settings->custom_zlib = 0; |
|
settings->custom_deflate = 0; |
|
settings->custom_context = 0; |
|
} |
|
|
|
const LodePNGCompressSettings lodepng_default_compress_settings = {2, 1, DEFAULT_WINDOWSIZE, 3, 128, 1, 0, 0, 0}; |
|
|
|
|
|
#endif /*LODEPNG_COMPILE_ENCODER*/ |
|
|
|
#ifdef LODEPNG_COMPILE_DECODER |
|
|
|
void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings) |
|
{ |
|
settings->ignore_adler32 = 0; |
|
|
|
settings->custom_zlib = 0; |
|
settings->custom_inflate = 0; |
|
settings->custom_context = 0; |
|
} |
|
|
|
const LodePNGDecompressSettings lodepng_default_decompress_settings = {0, 0, 0, 0}; |
|
|
|
#endif /*LODEPNG_COMPILE_DECODER*/ |
|
|
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
/* // End of Zlib related code. Begin of PNG related code. // */ |
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
|
|
#ifdef LODEPNG_COMPILE_PNG |
|
|
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
/* / CRC32 / */ |
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
|
|
/* CRC polynomial: 0xedb88320 */ |
|
static unsigned lodepng_crc32_table[256] = { |
|
0u, 1996959894u, 3993919788u, 2567524794u, 124634137u, 1886057615u, 3915621685u, 2657392035u, |
|
249268274u, 2044508324u, 3772115230u, 2547177864u, 162941995u, 2125561021u, 3887607047u, 2428444049u, |
|
498536548u, 1789927666u, 4089016648u, 2227061214u, 450548861u, 1843258603u, 4107580753u, 2211677639u, |
|
325883990u, 1684777152u, 4251122042u, 2321926636u, 335633487u, 1661365465u, 4195302755u, 2366115317u, |
|
997073096u, 1281953886u, 3579855332u, 2724688242u, 1006888145u, 1258607687u, 3524101629u, 2768942443u, |
|
901097722u, 1119000684u, 3686517206u, 2898065728u, 853044451u, 1172266101u, 3705015759u, 2882616665u, |
|
651767980u, 1373503546u, 3369554304u, 3218104598u, 565507253u, 1454621731u, 3485111705u, 3099436303u, |
|
671266974u, 1594198024u, 3322730930u, 2970347812u, 795835527u, 1483230225u, 3244367275u, 3060149565u, |
|
1994146192u, 31158534u, 2563907772u, 4023717930u, 1907459465u, 112637215u, 2680153253u, 3904427059u, |
|
2013776290u, 251722036u, 2517215374u, 3775830040u, 2137656763u, 141376813u, 2439277719u, 3865271297u, |
|
1802195444u, 476864866u, 2238001368u, 4066508878u, 1812370925u, 453092731u, 2181625025u, 4111451223u, |
|
1706088902u, 314042704u, 2344532202u, 4240017532u, 1658658271u, 366619977u, 2362670323u, 4224994405u, |
|
1303535960u, 984961486u, 2747007092u, 3569037538u, 1256170817u, 1037604311u, 2765210733u, 3554079995u, |
|
1131014506u, 879679996u, 2909243462u, 3663771856u, 1141124467u, 855842277u, 2852801631u, 3708648649u, |
|
1342533948u, 654459306u, 3188396048u, 3373015174u, 1466479909u, 544179635u, 3110523913u, 3462522015u, |
|
1591671054u, 702138776u, 2966460450u, 3352799412u, 1504918807u, 783551873u, 3082640443u, 3233442989u, |
|
3988292384u, 2596254646u, 62317068u, 1957810842u, 3939845945u, 2647816111u, 81470997u, 1943803523u, |
|
3814918930u, 2489596804u, 225274430u, 2053790376u, 3826175755u, 2466906013u, 167816743u, 2097651377u, |
|
4027552580u, 2265490386u, 503444072u, 1762050814u, 4150417245u, 2154129355u, 426522225u, 1852507879u, |
|
4275313526u, 2312317920u, 282753626u, 1742555852u, 4189708143u, 2394877945u, 397917763u, 1622183637u, |
|
3604390888u, 2714866558u, 953729732u, 1340076626u, 3518719985u, 2797360999u, 1068828381u, 1219638859u, |
|
3624741850u, 2936675148u, 906185462u, 1090812512u, 3747672003u, 2825379669u, 829329135u, 1181335161u, |
|
3412177804u, 3160834842u, 628085408u, 1382605366u, 3423369109u, 3138078467u, 570562233u, 1426400815u, |
|
3317316542u, 2998733608u, 733239954u, 1555261956u, 3268935591u, 3050360625u, 752459403u, 1541320221u, |
|
2607071920u, 3965973030u, 1969922972u, 40735498u, 2617837225u, 3943577151u, 1913087877u, 83908371u, |
|
2512341634u, 3803740692u, 2075208622u, 213261112u, 2463272603u, 3855990285u, 2094854071u, 198958881u, |
|
2262029012u, 4057260610u, 1759359992u, 534414190u, 2176718541u, 4139329115u, 1873836001u, 414664567u, |
|
2282248934u, 4279200368u, 1711684554u, 285281116u, 2405801727u, 4167216745u, 1634467795u, 376229701u, |
|
2685067896u, 3608007406u, 1308918612u, 956543938u, 2808555105u, 3495958263u, 1231636301u, 1047427035u, |
|
2932959818u, 3654703836u, 1088359270u, 936918000u, 2847714899u, 3736837829u, 1202900863u, 817233897u, |
|
3183342108u, 3401237130u, 1404277552u, 615818150u, 3134207493u, 3453421203u, 1423857449u, 601450431u, |
|
3009837614u, 3294710456u, 1567103746u, 711928724u, 3020668471u, 3272380065u, 1510334235u, 755167117u |
|
}; |
|
|
|
/*Return the CRC of the bytes buf[0..len-1].*/ |
|
unsigned lodepng_crc32(const unsigned char* buf, size_t len) |
|
{ |
|
unsigned c = 0xffffffffL; |
|
size_t n; |
|
|
|
for(n = 0; n < len; n++) |
|
{ |
|
c = lodepng_crc32_table[(c ^ buf[n]) & 0xff] ^ (c >> 8); |
|
} |
|
return c ^ 0xffffffffL; |
|
} |
|
|
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
/* / Reading and writing single bits and bytes from/to stream for LodePNG / */ |
|
/* ////////////////////////////////////////////////////////////////////////// */ |
|
|
|
static unsigned char readBitFromReversedStream(size_t* bitpointer, const unsigned char* bitstream) |
|
{ |
|
unsigned char result = (unsigned char)((bitstream[(*bitpointer) >> 3] >> (7 - ((*bitpointer) & 0x7))) & 1); |
|
(*bitpointer)++; |
|
return result; |
|
} |
|
|
|
static unsigned readBitsFromReversedStream(size_t* bitpointer, const unsigned char* bitstream, size_t nbits) |
|
{ |
|
unsigned result = 0; |
|
size_t i; |
|
for(i = nbits - 1; i < nbits; i--) |
|
{ |
|
result += (unsigned)readBitFromReversedStream(bitpointer, bitstream) << i |