CWebRender pt2

gfx/wr/wr_frame_packet.c

@@ -0,0 +1,59 @@
+#include "webrender.h"
+
+#include <stdint.h>
+#include <string.h>
+
+static int
+wr_packet_size_mul_overflow(size_t a, size_t b)
+{
+  return b != 0 && a > SIZE_MAX / b;
+}
+
+size_t
+wr_frame_packet_size(const wr_frame* frame)
+{
+  size_t size;
+
+  if (!frame || frame->quad_count > UINT32_MAX ||
+      frame->batch_count > UINT32_MAX ||
+      (frame->quad_count && !frame->quads) ||
+      (frame->batch_count && !frame->batches))
+    return 0;
+
+  size = sizeof(wr_frame_packet_header);
+  if (wr_packet_size_mul_overflow(frame->quad_count, sizeof(*frame->quads)) ||
+      wr_packet_size_mul_overflow(frame->batch_count, sizeof(*frame->batches)))
+    return 0;
+  if (size > SIZE_MAX - frame->quad_count * sizeof(*frame->quads))
+    return 0;
+  size += frame->quad_count * sizeof(*frame->quads);
+  if (size > SIZE_MAX - frame->batch_count * sizeof(*frame->batches))
+    return 0;
+  return size + frame->batch_count * sizeof(*frame->batches);
+}
+
+int
+wr_frame_serialize(const wr_frame* frame, void* buffer, size_t buffer_size)
+{
+  wr_frame_packet_header header;
+  size_t required = wr_frame_packet_size(frame);
+  unsigned char* output = (unsigned char*)buffer;
+
+  if (!required || !buffer || buffer_size < required)
+    return 0;
+  header.version = WR_FRAME_PACKET_VERSION;
+  header.quad_count = (uint32_t)frame->quad_count;
+  header.batch_count = (uint32_t)frame->batch_count;
+  memcpy(output, &header, sizeof(header));
+  output += sizeof(header);
+  if (frame->quad_count) {
+    memcpy(output, frame->quads,
+           frame->quad_count * sizeof(*frame->quads));
+    output += frame->quad_count * sizeof(*frame->quads);
+  }
+  if (frame->batch_count) {
+    memcpy(output, frame->batches,
+           frame->batch_count * sizeof(*frame->batches));
+  }
+  return 1;
+}