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- #include <stdio.h>
- #include <fcntl.h>
- #include <stdint.h>
- #define LEN_THRESH (3)
- FILE *in, *out;
- uint8_t data, datalast;
- uint16_t len, first=1;
- size_t off;
- uint16_t getrunlength(uint8_t data) {
- uint16_t count=1;
- while(fgetc(in)==data && count<65535) {
- if(feof(in))break;
- count++;
- }
- return count;
- }
- void writerle(uint8_t data, uint16_t len) {
- if(len<256) {
- fputc(0x5b, out);
- fputc(data, out);
- fputc(len & 0xff, out);
- } else {
- fputc(0x77, out);
- fputc(data, out);
- fputc(len & 0xff, out);
- fputc(len >> 8, out);
- }
- }
- void writeliteral(uint8_t data) {
- if(data==0x5b || data==0x77 || data==0x9b) {
- fputc(0x9b, out);
- }
- fputc(data, out);
- }
- int main(int argc, char** argv) {
- if((in=fopen(argv[1], "rb"))==NULL) {
- perror("could not open input file");
- return 1;
- }
- if((out=fopen(argv[2], "wb"))==NULL) {
- perror("could not open output file");
- fclose(in);
- return 1;
- }
- len=0;
- while(!feof(in)) {
- data=fgetc(in);
- if(feof(in))break;
- off=ftell(in);
- if((len=getrunlength(data)) > LEN_THRESH) {
- writerle(data, len);
- fseek(in, -1, SEEK_CUR);
- } else {
- fseek(in, off, SEEK_SET);
- writeliteral(data);
- }
- }
- fclose(out);
- fclose(in);
- return 0;
- }
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