Diff: encoding.c

Revision:

0:e4dad9e53f06

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/encoding.c	Wed Nov 04 09:58:41 2015 +0000
@@ -0,0 +1,46 @@
+#include "encoding.h"
+
+void encoding_streaming_decode_reset(EncodingStreamingContext *ctx) {
+  ctx->escape = false;
+}
+
+bool encoding_streaming_decode(EncodingStreamingContext *ctx, uint8_t *data, bool *should_store,
+                           bool *encoding_error) {
+  bool is_complete = false;
+  *encoding_error = false;
+  *should_store = false;
+  if (*data == ENCODING_FLAG) {
+    if (ctx->escape) {
+      // extra escape character before flag
+      ctx->escape = false;
+      *encoding_error = true;
+    }
+    // we've reached the end of the frame
+    is_complete = true;
+  } else if (*data == ENCODING_ESCAPE) {
+    if (ctx->escape) {
+      // invalid sequence
+      ctx->escape = false;
+      *encoding_error = true;
+    } else {
+      // ignore this character and escape the next one
+      ctx->escape = true;
+    }
+  } else {
+    if (ctx->escape) {
+      *data ^= ENCODING_ESCAPE_MASK;
+      ctx->escape = false;
+    }
+    *should_store = true;
+  }
+
+  return is_complete;
+}
+
+bool encoding_encode(uint8_t *data) {
+  if (*data == ENCODING_FLAG || *data == ENCODING_ESCAPE) {
+    *data ^= ENCODING_ESCAPE_MASK;
+    return true;
+  }
+  return false;
+}