/* File: dcodrle2.c   Author: David Bourgin   Creation date: 1/2/94   Last update: 22/5/94   Purpose: Example of RLE type 2 decoding with a file source to decompress.*/#include <stdio.h>/* For routines printf,fgetc and fputc */#include <stdlib.h>/* For routine exit *//* Error codes sent to the caller */#define NO_ERROR      0#define BAD_FILE_NAME 1#define BAD_ARGUMENT  2/* Useful constants */#define FALSE 0#define TRUE  1/* Global variables */FILE *source_file,*dest_file;                             /* Being that fgetc=EOF only after an access                                then 'byte_stored_status' is 'TRUE' if a byte has been stored by 'fgetc'                                or 'FALSE' if there's no valid byte not already read and not handled in 'val_byte_stored' */int byte_stored_status=FALSE;int val_byte_stored;/* Pseudo procedures */#define end_of_data()  (byte_stored_status?FALSE:!(byte_stored_status=((val_byte_stored=fgetc(source_file))!=EOF)))#define read_byte()  (byte_stored_status?byte_stored_status=FALSE,(unsigned char)val_byte_stored:(unsigned char)fgetc(source_file))#define write_byte(byte)  ((void)fputc((byte),dest_file))void rle2decoding()/* Returned parameters: None   Action: Decompresses with RLE type 2 method all bytes read by the function read_byte   Errors: An input/output error could disturb the running of the program*/{ unsigned char header_byte,byte_read,byte_to_repeat;  register unsigned int i;  if (!end_of_data())     { header_byte=read_byte();       do {                  /* Being that header byte is present, then there are bytes to decompress */            if ((byte_read=read_byte())==header_byte)               { byte_read=read_byte();                 if (byte_read<3)                    byte_to_repeat=header_byte;                 else byte_to_repeat=read_byte();                 for (i=0;i<=byte_read;i++)                     write_byte(byte_to_repeat);               }            else write_byte(byte_read);          }       while (!end_of_data());     }}void help()/* Returned parameters: None   Action: Displays the help of the program and then stops its running   Errors: None*/{ printf("This utility enables you to decompress a file by using RLE type 2 method\n");  printf("as given in 'La Video et Les Imprimantes sur PC'\n");  printf("\nUse: dcodrle2 source target\n");  printf("source: Name of the file to decompress\n");  printf("target: Name of the restored file\n");}int main(argc,argv)/* Returned parameters: Returns an error code (0=None)   Action: Main procedure   Errors: Detected, handled and an error code is returned, if any*/int argc;char *argv[];{ if (argc!=3)     { help();       exit(BAD_ARGUMENT);     }  else if ((source_file=fopen(argv[1],"rb"))==NULL)          { help();            exit(BAD_FILE_NAME);          }       else if ((dest_file=fopen(argv[2],"wb"))==NULL)               { help();                 exit(BAD_FILE_NAME);               }            else { rle2decoding();                   fclose(source_file);                   fclose(dest_file);                 }  printf("Execution of dcodrle2 completed.\n");  return (NO_ERROR);}