Diff: pb_decode.h

Revision:

0:c7beea49fc91

Child:

2:d2c61a9be078

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pb_decode.h	Tue Feb 19 20:03:29 2013 +0000
@@ -0,0 +1,122 @@
+#ifndef _PB_DECODE_H_
+#define _PB_DECODE_H_
+
+/* pb_decode.h: Functions to decode protocol buffers. Depends on pb_decode.c.
+ * The main function is pb_decode. You will also need to create an input
+ * stream, which is easiest to do with pb_istream_from_buffer().
+ * 
+ * You also need structures and their corresponding pb_field_t descriptions.
+ * These are usually generated from .proto-files with a script.
+ */
+
+#include <stdbool.h>
+#include "pb.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Lightweight input stream.
+ * You can provide a callback function for reading or use
+ * pb_istream_from_buffer.
+ * 
+ * Rules for callback:
+ * 1) Return false on IO errors. This will cause decoding to abort.
+ * 
+ * 2) You can use state to store your own data (e.g. buffer pointer),
+ * and rely on pb_read to verify that no-body reads past bytes_left.
+ * 
+ * 3) Your callback may be used with substreams, in which case bytes_left
+ * is different than from the main stream. Don't use bytes_left to compute
+ * any pointers.
+ */
+struct _pb_istream_t
+{
+#ifdef PB_BUFFER_ONLY
+    /* Callback pointer is not used in buffer-only configuration.
+     * Having an int pointer here allows binary compatibility but
+     * gives an error if someone tries to assign callback function.
+     */
+    int *callback;
+#else
+    bool (*callback)(pb_istream_t *stream, uint8_t *buf, size_t count);
+#endif
+
+    void *state; /* Free field for use by callback implementation */
+    size_t bytes_left;
+    
+#ifndef PB_NO_ERRMSG
+    const char *errmsg;
+#endif
+};
+
+pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize);
+bool pb_read(pb_istream_t *stream, uint8_t *buf, size_t count);
+
+/* Decode from stream to destination struct.
+ * Returns true on success, false on any failure.
+ * The actual struct pointed to by dest must match the description in fields.
+ */
+bool pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
+
+/* Same as pb_decode, except does not initialize the destination structure
+ * to default values. This is slightly faster if you need no default values
+ * and just do memset(struct, 0, sizeof(struct)) yourself.
+ */
+bool pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
+
+/* --- Helper functions ---
+ * You may want to use these from your caller or callbacks.
+ */
+
+/* Decode the tag for the next field in the stream. Gives the wire type and
+ * field tag. At end of the message, returns false and sets eof to true. */
+bool pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof);
+
+/* Skip the field payload data, given the wire type. */
+bool pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type);
+
+/* Decode an integer in the varint format. This works for bool, enum, int32,
+ * int64, uint32 and uint64 field types. */
+bool pb_decode_varint(pb_istream_t *stream, uint64_t *dest);
+
+/* Decode an integer in the zig-zagged svarint format. This works for sint32
+ * and sint64. */
+bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest);
+
+/* Decode a fixed32, sfixed32 or float value. You need to pass a pointer to
+ * a 4-byte wide C variable. */
+bool pb_decode_fixed32(pb_istream_t *stream, void *dest);
+
+/* Decode a fixed64, sfixed64 or double value. You need to pass a pointer to
+ * a 8-byte wide C variable. */
+bool pb_decode_fixed64(pb_istream_t *stream, void *dest);
+
+/* Make a limited-length substream for reading a PB_WT_STRING field. */
+bool pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream);
+void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream);
+
+/* --- Internal functions ---
+ * These functions are not terribly useful for the average library user, but
+ * are exported to make the unit testing and extending nanopb easier.
+ */
+
+#ifdef NANOPB_INTERNALS
+bool pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest);
+bool pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest);
+bool pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest);
+bool pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest);
+
+bool pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest);
+bool pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest);
+bool pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest);
+
+bool pb_skip_varint(pb_istream_t *stream);
+bool pb_skip_string(pb_istream_t *stream);
+#endif
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif