Initial commit

src/compressor.cpp

@@ -0,0 +1,71 @@
+#include "compressor.h"
+
+static constexpr uint8_t RLE_MARKER = 0xFF;
+
+bool compressBuffer(const uint8_t *in, size_t in_len, uint8_t *out, size_t out_max, size_t &out_len) {
+  out_len = 0;
+  if (!in || !out) {
+    return false;
+  }
+
+  size_t i = 0;
+  while (i < in_len) {
+    uint8_t value = in[i];
+    size_t run = 1;
+    while (i + run < in_len && in[i + run] == value && run < 255) {
+      run++;
+    }
+
+    if (value == RLE_MARKER || run >= 4) {
+      if (out_len + 3 > out_max) {
+        return false;
+      }
+      out[out_len++] = RLE_MARKER;
+      out[out_len++] = static_cast<uint8_t>(run);
+      out[out_len++] = value;
+    } else {
+      if (out_len + run > out_max) {
+        return false;
+      }
+      for (size_t j = 0; j < run; ++j) {
+        out[out_len++] = value;
+      }
+    }
+
+    i += run;
+  }
+
+  return true;
+}
+
+bool decompressBuffer(const uint8_t *in, size_t in_len, uint8_t *out, size_t out_max, size_t &out_len) {
+  out_len = 0;
+  if (!in || !out) {
+    return false;
+  }
+
+  size_t i = 0;
+  while (i < in_len) {
+    uint8_t value = in[i++];
+    if (value == RLE_MARKER) {
+      if (i + 1 >= in_len) {
+        return false;
+      }
+      uint8_t run = in[i++];
+      uint8_t data = in[i++];
+      if (out_len + run > out_max) {
+        return false;
+      }
+      for (uint8_t j = 0; j < run; ++j) {
+        out[out_len++] = data;
+      }
+    } else {
+      if (out_len + 1 > out_max) {
+        return false;
+      }
+      out[out_len++] = value;
+    }
+  }
+
+  return true;
+}