[phyrrus9]

For those of you who read my tutorial on RLE (link), here is some sample C code to accomplish it.

Code:

/* Run Length Encoder/Decoder * by Ethan Laur (phyrrus9) */ #include <stdio.h> int readuntilnext(FILE *in, unsigned char last, unsigned char *oops, unsigned char *n) { int nread; *n = 1; while ((nread = fread(oops, 1, 1, in)) > 0) //read { if (*oops != last || *n > 254) return 1; //return count if different ++*n; //add 1 to count } return 0; } void rleEncode(FILE *in, FILE *out, unsigned char flag) { unsigned char old = 0, buf, num; int i; readuntilnext(in, old, &buf, &num); //first time reads nothing... old = buf; while (readuntilnext(in, old, &buf, &num)) //read { if (num > 3) //then RLE that shit { fputc(flag, out); //place the flag fwrite(&num, 1, 1, out); //place the count fwrite(&old, 1, 1, out); //place the character } else fwrite(&old, 1, 1, out); //place the character old = buf; //do swap } fflush(out); //write caches } void rleDecode(FILE *in, FILE *out, unsigned char flag) { unsigned char buf, num; int i; while (fread(&buf, 1, 1, in) > 0) //while we read something { if (buf == flag) //if the character was the RLE flag { fread(&num, 1, 1, in); //get the number fread(&buf, 1, 1, in); //get the character for (i = 0; i < num; i++) //loop num times fwrite(&buf, 1, 1, out); //output character } else fwrite(&buf, 1, 1, out); //output character } fflush(out); //write any caches to disk } int main(int argc, char ** argv) { FILE *in = fopen(argv[2], "rb"); FILE *out = fopen(argv[3], "wb"); if (argv[1][0] == 'e') rleEncode(in, out, argv[1][1]); else if (argv[1][0] == 'd') rleDecode(in, out, argv[1][1]); fclose(in); fclose(out); }