RLE tools

utils/derle.c

@@ -0,0 +1,45 @@
+#include <stdio.h>
+#include <fcntl.h>
+#include <stdint.h>
+
+FILE *in, *out;
+uint8_t data;
+uint16_t len;
+
+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;
+    switch(data) {
+      case 0x9b:
+        fputc(fgetc(in), out);
+        break;
+      case 0x5b:
+        data=fgetc(in);
+        len=fgetc(in);
+        while(len--)fputc(data, out);
+        break;
+      case 0x77:
+        data=fgetc(in);
+        len = fgetc(in);
+        len |= fgetc(in) << 8;
+        while(len--)fputc(data, out);
+        break;
+      default:
+        fputc(data, out);
+    }
+  }
+  fclose(out);
+  fclose(in);
+  return 0;
+}

utils/rle.c

@@ -0,0 +1,67 @@
+#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;
+}