Import of the watch repository from Pebble

third_party/nanopb/pb_decode.h

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+/* pb_decode.h: Functions to decode protocol buffers. Depends on pb_decode.c.
+ * The main function is pb_decode. You also need an input stream, and the
+ * field descriptions created by nanopb_generator.py.
+ */
+
+#ifndef PB_DECODE_H_INCLUDED
+#define PB_DECODE_H_INCLUDED
+
+#include "pb.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Structure for defining custom input streams. You will need to provide
+ * a callback function to read the bytes from your storage, which can be
+ * for example a file or a network socket.
+ * 
+ * The callback must conform to these rules:
+ *
+ * 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_s
+{
+#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, pb_byte_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
+};
+
+#ifndef PB_NO_ERRMSG
+#define PB_ISTREAM_EMPTY {0,0,0,0}
+#else
+#define PB_ISTREAM_EMPTY {0,0,0}
+#endif
+
+/***************************
+ * Main decoding functions *
+ ***************************/
+ 
+/* Decode a single protocol buffers message from input stream into a C structure.
+ * Returns true on success, false on any failure.
+ * The actual struct pointed to by dest must match the description in fields.
+ * Callback fields of the destination structure must be initialized by caller.
+ * All other fields will be initialized by this function.
+ *
+ * Example usage:
+ *    MyMessage msg = {};
+ *    uint8_t buffer[64];
+ *    pb_istream_t stream;
+ *    
+ *    // ... read some data into buffer ...
+ *
+ *    stream = pb_istream_from_buffer(buffer, count);
+ *    pb_decode(&stream, MyMessage_fields, &msg);
+ */
+bool pb_decode(pb_istream_t *stream, const pb_msgdesc_t *fields, void *dest_struct);
+
+/* Extended version of pb_decode, with several options to control
+ * the decoding process:
+ *
+ * PB_DECODE_NOINIT:         Do not initialize the fields to default values.
+ *                           This is slightly faster if you do not need the default
+ *                           values and instead initialize the structure to 0 using
+ *                           e.g. memset(). This can also be used for merging two
+ *                           messages, i.e. combine already existing data with new
+ *                           values.
+ *
+ * PB_DECODE_DELIMITED:      Input message starts with the message size as varint.
+ *                           Corresponds to parseDelimitedFrom() in Google's
+ *                           protobuf API.
+ *
+ * PB_DECODE_NULLTERMINATED: Stop reading when field tag is read as 0. This allows
+ *                           reading null terminated messages.
+ *                           NOTE: Until nanopb-0.4.0, pb_decode() also allows
+ *                           null-termination. This behaviour is not supported in
+ *                           most other protobuf implementations, so PB_DECODE_DELIMITED
+ *                           is a better option for compatibility.
+ *
+ * Multiple flags can be combined with bitwise or (| operator)
+ */
+#define PB_DECODE_NOINIT          0x01U
+#define PB_DECODE_DELIMITED       0x02U
+#define PB_DECODE_NULLTERMINATED  0x04U
+bool pb_decode_ex(pb_istream_t *stream, const pb_msgdesc_t *fields, void *dest_struct, unsigned int flags);
+
+/* Defines for backwards compatibility with code written before nanopb-0.4.0 */
+#define pb_decode_noinit(s,f,d) pb_decode_ex(s,f,d, PB_DECODE_NOINIT)
+#define pb_decode_delimited(s,f,d) pb_decode_ex(s,f,d, PB_DECODE_DELIMITED)
+#define pb_decode_delimited_noinit(s,f,d) pb_decode_ex(s,f,d, PB_DECODE_DELIMITED | PB_DECODE_NOINIT)
+#define pb_decode_nullterminated(s,f,d) pb_decode_ex(s,f,d, PB_DECODE_NULLTERMINATED)
+
+#ifdef PB_ENABLE_MALLOC
+/* Release any allocated pointer fields. If you use dynamic allocation, you should
+ * call this for any successfully decoded message when you are done with it. If
+ * pb_decode() returns with an error, the message is already released.
+ */
+void pb_release(const pb_msgdesc_t *fields, void *dest_struct);
+#else
+/* Allocation is not supported, so release is no-op */
+#define pb_release(fields, dest_struct) PB_UNUSED(fields); PB_UNUSED(dest_struct);
+#endif
+
+
+/**************************************
+ * Functions for manipulating streams *
+ **************************************/
+
+/* Create an input stream for reading from a memory buffer.
+ *
+ * msglen should be the actual length of the message, not the full size of
+ * allocated buffer.
+ *
+ * Alternatively, you can use a custom stream that reads directly from e.g.
+ * a file or a network socket.
+ */
+pb_istream_t pb_istream_from_buffer(const pb_byte_t *buf, size_t msglen);
+
+/* Function to read from a pb_istream_t. You can use this if you need to
+ * read some custom header data, or to read data in field callbacks.
+ */
+bool pb_read(pb_istream_t *stream, pb_byte_t *buf, size_t count);
+
+
+/************************************************
+ * Helper functions for writing field 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 enum, int32,
+ * int64, uint32 and uint64 field types. */
+#ifndef PB_WITHOUT_64BIT
+bool pb_decode_varint(pb_istream_t *stream, uint64_t *dest);
+#else
+#define pb_decode_varint pb_decode_varint32
+#endif
+
+/* Decode an integer in the varint format. This works for enum, int32,
+ * and uint32 field types. */
+bool pb_decode_varint32(pb_istream_t *stream, uint32_t *dest);
+
+/* Decode a bool value in varint format. */
+bool pb_decode_bool(pb_istream_t *stream, bool *dest);
+
+/* Decode an integer in the zig-zagged svarint format. This works for sint32
+ * and sint64. */
+#ifndef PB_WITHOUT_64BIT
+bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest);
+#else
+bool pb_decode_svarint(pb_istream_t *stream, int32_t *dest);
+#endif
+
+/* 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);
+
+#ifndef PB_WITHOUT_64BIT
+/* 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);
+#endif
+
+#ifdef PB_CONVERT_DOUBLE_FLOAT
+/* Decode a double value into float variable. */
+bool pb_decode_double_as_float(pb_istream_t *stream, float *dest);
+#endif
+
+/* 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);
+bool pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif