hex/hex.c

/* This file is part of HEX, the hex dump utility
 * ============================================================
 * HEX is free software and comes with NO WARRANTY - 
 * read the file COPYING for details
 */
 
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#ifndef WINDOWS
#include <sysexits.h>
#else
  #define EX_OK 0
  #define EX_USAGE -1
  #define EX_DATAERR -1
  #define EX_NOINPUT -1
  #define EX_IOERR -1
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <fcntl.h>
#include <unistd.h>

#define PROGRAM_NAME "hex"

#define VERSION "1.00"

int verbose=0;
char ifilename[128];

static void intro() {
  puts("*********************************\n"
         "*     " PROGRAM_NAME "     V." VERSION "            *\n"
         "* (c) Markus Hoffmann 1997-2021 *\n"
         "*                               *\n"
         "*********************************\n");
}



static void usage() {
  printf(
    "Usage: %s [-h -v -q] <filename> \n\n"
    "  -h, --help\t---\tUsage, Display this information\n"
    "  -v\t\t---\tbe more verbose\n"
    "  -q\t\t---\tbe more quiet\n"
    ,PROGRAM_NAME);
}

static void kommandozeile(int anzahl, char *argumente[]) {
  int count,quitflag=0;

  /* Kommandozeile bearbeiten   */
  for(count=1;count<anzahl;count++) {
    if(!strcmp(argumente[count],"--help") || !strcmp(argumente[count],"-h")) {
      intro();
      usage();
      quitflag=1;
    } 
    else if(!strcmp(argumente[count],"-v"))           verbose++;
    else if(!strcmp(argumente[count],"-q"))           verbose--;
    else strcpy(ifilename,argumente[count]);
   }
   if(quitflag) exit(EX_OK);
}

/* Helper functions for File I/O */

/* Return 0 if file does not exist. */

static int exist(const char *filename) {
  struct stat fstats;
  int retc=stat(filename, &fstats);
  if(retc==-1) return(0);
  return(!0);
}

/* Returns the length of the open file n */

size_t lof(FILE *n) {	
  long position=ftell(n);
  if(position==-1) {
    perror("lof");
    return(0);
  }
  if(fseek(n,0,SEEK_END)==0) {
    long laenge=ftell(n);
    if(laenge<0) perror("ftell");
    if(fseek(n,position,0)<0) perror("fseek"); 
    return(laenge);
  } else perror("fseek");
  return(0);
}

/* loads the file with filename name to a memory location at address adr.
   the whole file is read. 
   RETURNS the number of read bytes or 0 on error.
 */

size_t bload(const char *name,char **adr) {	
  FILE *fdis=fopen(name,"rb");
  if(fdis==NULL) return(0);
  size_t len=lof(fdis);
  *adr=realloc(*adr,len);
  if(len>0) len=fread(*adr,1,len,fdis);
  fclose(fdis);
  return(len);
}

/* This is a handy helper function which prints out a 
   hex dump of the memory area pointed to by adr of length l
   The output is in magenta and fits on a 80 char screen.
   (c) by Markus Hoffmann 1997 */

void memdump(const unsigned char *adr,int l) {
  int i,ii;
  printf("\033[35m");
  ii=0;
  while(l>16) {
    printf("%08x: ",ii);	
    for(i=0;i<16;i++) printf("%02x ",adr[i]);
    putchar(' ');
    for(i=0;i<16;i++) {
      if(adr[i]>31) putchar(adr[i]);
      else putchar('.');
    }
    putchar('\n');
    adr+=16;
    l-=16;
    ii+=16;
  }
  if(l>0) {
    printf("%08x: ",ii);
    for(i=0;i<16;i++) {
      if(i<l) printf("%02x ",adr[i]);
      else printf("   ");
    }
    putchar(' ');
    for(i=0;i<l;i++) {
      if(adr[i]>31) putchar(adr[i]);
      else putchar('.');
    }
    putchar('\n');
  }
  printf("\033[m");
}

int main(int anzahl, char *argumente[]) {
  if(anzahl<2) {    /* Kommandomodus */
    intro();
    usage();
    exit(EX_OK);
  } else kommandozeile(anzahl, argumente);    /* Kommandozeile bearbeiten */
  
  if(!exist(ifilename)) {
    perror(ifilename);
    return(EX_NOINPUT);
  }
  char *adr=NULL;
  if(verbose) printf("<-- %s \n",ifilename);
  size_t len=bload(ifilename,&adr);
  memdump((unsigned char *)adr,(int)len);
  return(EX_OK);
}