add util::Buffer, rle::encode16, rle::decode16

src/coders/rle.cpp

@@ -35,6 +35,45 @@ size_t rle::encode(const ubyte* src, size_t srclen, ubyte* dst) {
     return offset;
 }
 
+size_t rle::decode16(const ubyte* src, size_t srclen, ubyte* dst) {
+    auto src16 = reinterpret_cast<const uint16_t*>(src);
+    auto dst16 = reinterpret_cast<uint16_t*>(dst);
+    size_t offset = 0;
+    for (size_t i = 0; i < srclen / 2;) {
+        uint16_t len = src16[i++];
+        uint16_t c = src16[i++];
+        for (size_t j = 0; j <= len; j++) {
+            dst16[offset++] = c;
+        }
+    }
+    return offset * 2;
+}
+
+size_t rle::encode16(const ubyte* src, size_t srclen, ubyte* dst) {
+    if (srclen == 0) {
+        return 0;
+    }
+    auto src16 = reinterpret_cast<const uint16_t*>(src);
+    auto dst16 = reinterpret_cast<uint16_t*>(dst);
+    size_t offset = 0;
+    uint16_t counter = 0;
+    uint16_t c = src16[0];
+    for (size_t i = 1; i < srclen / 2; i++) {
+        uint16_t cnext = src16[i];
+        if (cnext != c || counter == 0xFFFF) {
+            dst16[offset++] = counter;
+            dst16[offset++] = c;
+            c = cnext;
+            counter = 0;
+        } else {
+            counter++;
+        }
+    }
+    dst16[offset++] = counter;
+    dst16[offset++] = c;
+    return offset * 2;
+}
+
 size_t extrle::decode(const ubyte* src, size_t srclen, ubyte* dst) {
     size_t offset = 0;
     for (size_t i = 0; i < srclen;) {