Change reader and parser initializer prototype (#8)

Author: onkwon

CHANGELOG.md

@@ -1,3 +1,7 @@
-## v0.1.0 - August 24, 2022
+## v0.2.0 - August 24, 2022
+- **Breaking Change**: Change the reader and the parser initializer prototypes
+  - `cbor_reader_init()` and `cbor_parse()`
+  - Now a reader can be reusable to different messages
 
+## v0.1.0 - August 24, 2022
 The initial release.

README.md

@@ -61,8 +61,8 @@ cbor_reader_t reader;
 cbor_item_t items[MAX_ITEMS];
 size_t n;
 
-cbor_reader_init(&reader, cbor_message, sizeof(cbor_message));
-cbor_parse(&reader, items, MAX_ITEMS, &n);
+cbor_reader_init(&reader, items, sizeof(items) / sizeof(*items));
+cbor_parse(&reader, cbor_message, cbor_message_len, &n);
 
 for (i = 0; i < n; i++) {
 	printf("item: %s, size: %zu\n",

examples/complex.c

@@ -162,8 +162,8 @@ void complex_example(void const *data, size_t datasize, void *udt)
 	cbor_item_t items[32];
 	size_t n;
 
-	cbor_reader_init(&reader, data, datasize);
-	cbor_error_t err = cbor_parse(&reader, items, sizeof(items) / sizeof(items[0]), &n);
+	cbor_reader_init(&reader, items, sizeof(items) / sizeof(*items));
+	cbor_error_t err = cbor_parse(&reader, data, datasize, &n);
 	if (err == CBOR_SUCCESS || err == CBOR_BREAK) {
 		cbor_iterate(&reader, items, n, 0, convert, udt);
 	}

examples/example.h

@@ -28,9 +28,9 @@ struct udt {
 	} data;
 };
 
-typedef void (*example_writer)(void const *data, size_t datasize);
+typedef void (*example_printer_t)(void const *data, size_t datasize);
 
-void simple_example(example_writer print);
+void simple_example(example_printer_t print);
 void complex_example(void const *data, size_t datasize, void *udt);
 
 #if defined(__cplusplus)

examples/simple.c

@@ -20,7 +20,7 @@ union cbor_value {
 	uint8_t str_copy[16];
 };
 
-static void print_cbor(cbor_reader_t const *reader, cbor_item_t const *item, example_writer print)
+static void print_cbor(cbor_reader_t const *reader, cbor_item_t const *item, example_printer_t print)
 {
 	union cbor_value val;
 
@@ -55,21 +55,21 @@ static size_t encode_simple_data(void *buf, size_t bufsize)
 	return cbor_writer_len(&writer);
 }
 
-static void decode_simple_data(void const *data, size_t datasize, example_writer print)
+static void decode_simple_data(void const *data, size_t datasize, example_printer_t print)
 {
 	cbor_reader_t reader;
 	cbor_item_t items[16];
 	size_t n;
 
-	cbor_reader_init(&reader, data, datasize);
-	cbor_parse(&reader, items, sizeof(items) / sizeof(items[0]), &n);
+	cbor_reader_init(&reader, items, sizeof(items) / sizeof(items[0]));
+	cbor_parse(&reader, data, datasize, &n);
 
 	for (size_t i = 0; i < n; i++) {
 		print_cbor(&reader, &items[i], print);
 	}
 }
 
-void simple_example(example_writer print)
+void simple_example(example_printer_t print)
 {
 	uint8_t buf[32];
 	size_t len = encode_simple_data(buf, sizeof(buf));

include/cbor/cbor.h

@@ -51,6 +51,10 @@ typedef struct {
 	uint8_t const *msg;
 	size_t msgsize;
 	size_t msgidx;
+
+	cbor_item_t *items;
+	size_t itemidx;
+	size_t maxitems;
 } cbor_reader_t;
 
 typedef struct {
@@ -59,7 +63,14 @@ typedef struct {
 	size_t bufidx;
 } cbor_writer_t;
 
-void cbor_reader_init(cbor_reader_t *reader, void const *msg, size_t msgsize);
+/**
+ * Initialize the reader for CBOR encoded messages.
+ *
+ * @param[in,out] reader reader context for the actual encoded message
+ * @param[out] items a pointer to item buffers
+ * @param[in] maxitems the maximum number of items to be stored in @p items
+ */
+void cbor_reader_init(cbor_reader_t *reader, cbor_item_t *items, size_t maxitems);
 void cbor_writer_init(cbor_writer_t *writer, void *buf, size_t bufsize);
 size_t cbor_writer_len(cbor_writer_t const *writer);
 uint8_t const *cbor_writer_get_encoded(cbor_writer_t const *writer);

include/cbor/parser.h

@@ -11,14 +11,14 @@ extern "C" {
  * Parse the encoded CBOR messages into items.
  *
  * @param[in,out] reader reader context for the actual encoded message
- * @param[out] items a pointer to item buffers
- * @param[in] maxitems the maximum number of items to be stored in @p items
+ * @param[in] msg CBOR encoded message
+ * @param[in] msgsize the @p msg size in bytes
  * @param[out] nitems_parsed the number of items parsed gets stored if not null
  *
  * @return a code of @ref cbor_error_t
  */
-cbor_error_t cbor_parse(cbor_reader_t *reader,
-		cbor_item_t *items, size_t maxitems, size_t *nitems_parsed);
+cbor_error_t cbor_parse(cbor_reader_t *reader, void const *msg, size_t msgsize,
+		size_t *nitems_parsed);
 
 #if defined(__cplusplus)
 }

src/common.c

@@ -59,20 +59,19 @@ size_t cbor_get_item_size(cbor_item_t const *item)
 	return item->size;
 }
 
-void cbor_reader_init(cbor_reader_t *reader, void const *msg, size_t msgsize)
+void cbor_reader_init(cbor_reader_t *reader, cbor_item_t *items, size_t maxitems)
 {
-	assert(parser != NULL);
-	assert(msg != NULL);
+	assert(reader != NULL);
 
-	reader->msg = (uint8_t const *)msg;
-	reader->msgsize = msgsize;
-	reader->msgidx = 0;
+	reader->items = items;
+	reader->maxitems = maxitems;
+	reader->itemidx = 0;
 }
 
 void cbor_writer_init(cbor_writer_t *writer, void *buf, size_t bufsize)
 {
-	assert(parser != NULL);
-	assert(msg != NULL);
+	assert(writer != NULL);
+	assert(buf != NULL);
 
 	writer->buf = (uint8_t *)buf;
 	writer->bufsize = bufsize;

src/parser.c

@@ -11,10 +11,6 @@
 struct parser_context {
 	cbor_reader_t *reader;
 
-	cbor_item_t *items;
-	size_t itemidx;
-	size_t maxitems;
-
 	uint8_t major_type;
 	uint8_t additional_info;
 	uint8_t following_bytes;
@@ -93,8 +89,9 @@ static cbor_error_t parse(struct parser_context *ctx, size_t maxitems)
 		return CBOR_EXCESSIVE;
 	}
 
-	for (size_t i = 0; i < maxitems && ctx->itemidx < ctx->maxitems
-			&& ctx->reader->msgidx < ctx->reader->msgsize; i++) {
+	for (size_t i = 0; i < maxitems &&
+			ctx->reader->itemidx < ctx->reader->maxitems &&
+			ctx->reader->msgidx < ctx->reader->msgsize; i++) {
 		uint8_t val = ctx->reader->msg[ctx->reader->msgidx];
 		ctx->major_type = get_cbor_major_type(val);
 		ctx->additional_info = get_cbor_additional_info(val);
@@ -131,44 +128,44 @@ static cbor_error_t do_integer(struct parser_context *ctx)
 		return CBOR_ILLEGAL;
 	}
 
-	cbor_item_t *item = &ctx->items[ctx->itemidx];
+	cbor_item_t *item = &ctx->reader->items[ctx->reader->itemidx];
 	item->type = CBOR_ITEM_INTEGER;
 	item->size = (size_t)ctx->following_bytes;
 	item->offset = ctx->reader->msgidx;
 
 	ctx->reader->msgidx += (size_t)(ctx->following_bytes + 1);
-	ctx->itemidx++;
+	ctx->reader->itemidx++;
 
 	return CBOR_SUCCESS;
 }
 
 static cbor_error_t do_string(struct parser_context *ctx)
 {
-	cbor_item_t *item = &ctx->items[ctx->itemidx];
+	cbor_item_t *item = &ctx->reader->items[ctx->reader->itemidx];
 	size_t len = go_get_item_length(ctx);
 
 	item->type = CBOR_ITEM_STRING;
 	item->size = len;
 	item->offset = ctx->reader->msgidx;
 
 	if (len == (size_t)CBOR_INDEFINITE_VALUE) {
-		ctx->itemidx++;
-		return parse(ctx, ctx->maxitems - ctx->itemidx);
+		ctx->reader->itemidx++;
+		return parse(ctx, ctx->reader->maxitems - ctx->reader->itemidx);
 	}
 	if (len > ctx->reader->msgsize - ctx->reader->msgidx) {
 		return CBOR_ILLEGAL;
 	}
 
 	ctx->reader->msgidx += len;
-	ctx->itemidx++;
+	ctx->reader->itemidx++;
 
 	return CBOR_SUCCESS;
 }
 
 static cbor_error_t do_recursive(struct parser_context *ctx)
 {
-	size_t current_item_index = ctx->itemidx;
-	cbor_item_t *item = &ctx->items[current_item_index];
+	size_t current_item_index = ctx->reader->itemidx;
+	cbor_item_t *item = &ctx->reader->items[current_item_index];
 	size_t len = go_get_item_length(ctx);
 
 	item->type = (cbor_item_data_t)(ctx->major_type - 1);
@@ -179,9 +176,9 @@ static cbor_error_t do_recursive(struct parser_context *ctx)
 		return CBOR_ILLEGAL;
 	}
 
-	ctx->itemidx++;
+	ctx->reader->itemidx++;
 
-	return parse(ctx, MIN(len, ctx->maxitems - ctx->itemidx));
+	return parse(ctx, MIN(len, ctx->reader->maxitems - ctx->reader->itemidx));
 }
 
 /* TODO: Implement tag */
@@ -193,7 +190,7 @@ static cbor_error_t do_tag(struct parser_context *ctx)
 
 static cbor_error_t do_float_and_other(struct parser_context *ctx)
 {
-	cbor_item_t *item = &ctx->items[ctx->itemidx];
+	cbor_item_t *item = &ctx->reader->items[ctx->reader->itemidx];
 	cbor_error_t err = CBOR_SUCCESS;
 
 	item->type = CBOR_ITEM_FLOAT;
@@ -202,7 +199,7 @@ static cbor_error_t do_float_and_other(struct parser_context *ctx)
 
 	if (ctx->following_bytes == (uint8_t)CBOR_INDEFINITE_VALUE) {
 		ctx->reader->msgidx++;
-		ctx->itemidx++;
+		ctx->reader->itemidx++;
 		return CBOR_BREAK;
 	} else if (!has_valid_following_bytes(ctx, &err)) {
 		return err;
@@ -211,29 +208,33 @@ static cbor_error_t do_float_and_other(struct parser_context *ctx)
 	}
 
 	ctx->reader->msgidx += item->size + 1;
-	ctx->itemidx++;
+	ctx->reader->itemidx++;
 
 	return err;
 }
 
-cbor_error_t cbor_parse(cbor_reader_t *reader,
-		cbor_item_t *items, size_t maxitems, size_t *items_parsed)
+cbor_error_t cbor_parse(cbor_reader_t *reader, void const *msg, size_t msgsize,
+		size_t *nitems_parsed)
 {
+	assert(reader->items != NULL);
+	reader->itemidx = 0;
+
+	reader->msg = (uint8_t const *)msg;
+	reader->msgsize = msgsize;
+	reader->msgidx = 0;
+
 	struct parser_context ctx = {
 		.reader = reader,
-		.items = items,
-		.itemidx = 0,
-		.maxitems = maxitems,
 	};
 
-	cbor_error_t err = parse(&ctx, maxitems);
+	cbor_error_t err = parse(&ctx, reader->maxitems);
 
 	if (err == CBOR_SUCCESS && reader->msgidx < reader->msgsize) {
 		err = CBOR_OVERRUN;
 	}
 
-	if (items_parsed != NULL) {
-		*items_parsed = ctx.itemidx;
+	if (nitems_parsed != NULL) {
+		*nitems_parsed = reader->itemidx;
 	}
 
 	return err;