rle module moved to coders package

2024-04-15 02:57:42 +03:00
parent 4a32b33bf3
commit d2a2f0e8ae
5 changed files with 108 additions and 108 deletions
@@ -0,0 +1,90 @@
+#include "rle.h"
+
+size_t rle::decode(const ubyte* src, size_t srclen, ubyte* dst) {
+    size_t offset = 0;
+    for (size_t i = 0; i < srclen;) {
+        ubyte len = src[i++];
+        ubyte c = src[i++];
+        for (size_t j = 0; j <= len; j++) {
+            dst[offset++] = c;
+        }
+    }
+    return offset;
+}
+
+size_t rle::encode(const ubyte* src, size_t srclen, ubyte* dst) {
+    if (srclen == 0) {
+        return 0;
+    }
+    size_t offset = 0;
+    ubyte counter = 0;
+    ubyte c = src[0];
+    for (size_t i = 1; i < srclen; i++) {
+        ubyte cnext = src[i];
+        if (cnext != c || counter == 255) {
+            dst[offset++] = counter;
+            dst[offset++] = c;
+            c = cnext;
+            counter = 0;
+        }
+        else {
+            counter++;
+        }
+    }
+    dst[offset++] = counter;
+    dst[offset++] = c;
+    return offset;
+}
+
+
+size_t extrle::decode(const ubyte* src, size_t srclen, ubyte* dst) {
+    size_t offset = 0;
+    for (size_t i = 0; i < srclen;) {
+        uint len = src[i++];
+        if (len & 0x80) {
+            len &= 0x7F;
+            len |= ((uint)src[i++]) << 7;
+        }
+        ubyte c = src[i++];
+        for (size_t j = 0; j <= len; j++) {
+            dst[offset++] = c;
+        }
+    }
+    return offset;
+}
+
+size_t extrle::encode(const ubyte* src, size_t srclen, ubyte* dst) {
+    if (srclen == 0) {
+        return 0;
+    }
+    size_t offset = 0;
+    uint counter = 0;
+    ubyte c = src[0];
+    for (size_t i = 1; i < srclen; i++) {
+        ubyte cnext = src[i];
+        if (cnext != c || counter == max_sequence) {
+            if (counter >= 0x80) {
+                dst[offset++] = 0x80 | (counter & 0x7F);
+                dst[offset++] = counter >> 7;
+            }
+            else {
+                dst[offset++] = counter;
+            }
+            dst[offset++] = c;
+            c = cnext;
+            counter = 0;
+        }
+        else {
+            counter++;
+        }
+    }
+    if (counter >= 0x80) {
+        dst[offset++] = 0x80 | (counter & 0x7F);
+        dst[offset++] = counter >> 7;
+    }
+    else {
+        dst[offset++] = counter;
+    }
+    dst[offset++] = c;
+    return offset;
+}