Merge pull request rebol#156 from hostilefork/fix-cc-2068

Free intermediate buffers used by do-codec (CC #2068)

src/core/n-system.c

@@ -450,14 +450,18 @@ REBYTE *evoke_help = "Evoke values:\n"
 		memcpy(BIN_HEAD(ser), codi.data, codi.len);
 		Set_Binary(D_RET, ser);
 		if (result != CODI_BINARY) VAL_SET(D_RET, REB_STRING);
-		// Free the binary!
+
+		// See notice in reb-codec.h on reb_codec_image 
+		Free_Mem(codi.data, codi.len);
 		break;
 
 	case CODI_IMAGE:
 		ser = Make_Image(codi.w, codi.h, TRUE); // Puts it into RETURN stack position
 		memcpy(IMG_DATA(ser), codi.bits, codi.w * codi.h * 4);
 		SET_IMAGE(D_RET, ser);
-		// Free the image!
+
+		// See notice in reb-codec.h on reb_codec_image 
+		Free_Mem(codi.bits, codi.w * codi.h * 4);
 		break;
 
 	case CODI_BLOCK:

src/include/reb-codec.h

@@ -29,6 +29,17 @@
 #define CODI_DEFINED
 
 // Codec image interface:
+//
+// If your codec routine returns CODI_IMAGE, it is expected that the
+// ->bits field contains a block of memory allocated with Make_Mem
+// of size (->w * ->h * 4).  This will be freed by the
+// REBNATIVE(do_codec) in n-system.c
+//
+// If your codec routine returns CODI_BINARY or CODI_TEXT, it is
+// expected that the ->data field contains a block of memory
+// allocated with Make_Mem of size ->len.  This will be freed by
+// the REBNATIVE(do_codec) in n-system.c
+//
 typedef struct reb_codec_image {
 	int action;
 	int w;