Ollie Matthews / Nanopb

Nanopb files

Dependents:   nanopb_V2 Message_generator LEX_Threaded_Programming_V3

pb_decode.h@3:67ee10c4ae98, 2019-08-19 (annotated)

Committer:
omatthews
Date:
Mon Aug 19 15:23:39 2019 +0000
Revision:
3:67ee10c4ae98
Parent:
2:d2c61a9be078 
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intrinseca 0:c7beea49fc91 1 /* pb_decode.h: Functions to decode protocol buffers. Depends on pb_decode.c.
omatthews 2:d2c61a9be078 2 * The main function is pb_decode. You also need an input stream, and the
omatthews 2:d2c61a9be078 3 * field descriptions created by nanopb_generator.py.
intrinseca 0:c7beea49fc91 4 */
intrinseca 0:c7beea49fc91 5
omatthews 2:d2c61a9be078 6 #ifndef PB_DECODE_H_INCLUDED
omatthews 2:d2c61a9be078 7 #define PB_DECODE_H_INCLUDED
omatthews 2:d2c61a9be078 8
intrinseca 0:c7beea49fc91 9 #include "pb.h"
intrinseca 0:c7beea49fc91 10
intrinseca 0:c7beea49fc91 11 #ifdef __cplusplus
intrinseca 0:c7beea49fc91 12 extern "C" {
intrinseca 0:c7beea49fc91 13 #endif
intrinseca 0:c7beea49fc91 14
omatthews 2:d2c61a9be078 15 /* Structure for defining custom input streams. You will need to provide
omatthews 2:d2c61a9be078 16 * a callback function to read the bytes from your storage, which can be
omatthews 2:d2c61a9be078 17 * for example a file or a network socket.
intrinseca 0:c7beea49fc91 18 *
omatthews 2:d2c61a9be078 19 * The callback must conform to these rules:
omatthews 2:d2c61a9be078 20 *
intrinseca 0:c7beea49fc91 21 * 1) Return false on IO errors. This will cause decoding to abort.
intrinseca 0:c7beea49fc91 22 * 2) You can use state to store your own data (e.g. buffer pointer),
omatthews 2:d2c61a9be078 23 * and rely on pb_read to verify that no-body reads past bytes_left.
intrinseca 0:c7beea49fc91 24 * 3) Your callback may be used with substreams, in which case bytes_left
omatthews 2:d2c61a9be078 25 * is different than from the main stream. Don't use bytes_left to compute
omatthews 2:d2c61a9be078 26 * any pointers.
intrinseca 0:c7beea49fc91 27 */
omatthews 2:d2c61a9be078 28 struct pb_istream_s
intrinseca 0:c7beea49fc91 29 {
intrinseca 0:c7beea49fc91 30 #ifdef PB_BUFFER_ONLY
intrinseca 0:c7beea49fc91 31 /* Callback pointer is not used in buffer-only configuration.
intrinseca 0:c7beea49fc91 32 * Having an int pointer here allows binary compatibility but
intrinseca 0:c7beea49fc91 33 * gives an error if someone tries to assign callback function.
intrinseca 0:c7beea49fc91 34 */
intrinseca 0:c7beea49fc91 35 int *callback;
intrinseca 0:c7beea49fc91 36 #else
omatthews 2:d2c61a9be078 37 bool (*callback)(pb_istream_t *stream, pb_byte_t *buf, size_t count);
intrinseca 0:c7beea49fc91 38 #endif
intrinseca 0:c7beea49fc91 39
intrinseca 0:c7beea49fc91 40 void *state; /* Free field for use by callback implementation */
intrinseca 0:c7beea49fc91 41 size_t bytes_left;
intrinseca 0:c7beea49fc91 42
intrinseca 0:c7beea49fc91 43 #ifndef PB_NO_ERRMSG
intrinseca 0:c7beea49fc91 44 const char *errmsg;
intrinseca 0:c7beea49fc91 45 #endif
intrinseca 0:c7beea49fc91 46 };
intrinseca 0:c7beea49fc91 47
omatthews 2:d2c61a9be078 48 /***************************
omatthews 2:d2c61a9be078 49 * Main decoding functions *
omatthews 2:d2c61a9be078 50 ***************************/
omatthews 2:d2c61a9be078 51
omatthews 2:d2c61a9be078 52 /* Decode a single protocol buffers message from input stream into a C structure.
intrinseca 0:c7beea49fc91 53 * Returns true on success, false on any failure.
intrinseca 0:c7beea49fc91 54 * The actual struct pointed to by dest must match the description in fields.
omatthews 2:d2c61a9be078 55 * Callback fields of the destination structure must be initialized by caller.
omatthews 2:d2c61a9be078 56 * All other fields will be initialized by this function.
omatthews 2:d2c61a9be078 57 *
omatthews 2:d2c61a9be078 58 * Example usage:
omatthews 2:d2c61a9be078 59 * MyMessage msg = {};
omatthews 2:d2c61a9be078 60 * uint8_t buffer[64];
omatthews 2:d2c61a9be078 61 * pb_istream_t stream;
omatthews 2:d2c61a9be078 62 *
omatthews 2:d2c61a9be078 63 * // ... read some data into buffer ...
omatthews 2:d2c61a9be078 64 *
omatthews 2:d2c61a9be078 65 * stream = pb_istream_from_buffer(buffer, count);
omatthews 2:d2c61a9be078 66 * pb_decode(&stream, MyMessage_fields, &msg);
intrinseca 0:c7beea49fc91 67 */
intrinseca 0:c7beea49fc91 68 bool pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
intrinseca 0:c7beea49fc91 69
intrinseca 0:c7beea49fc91 70 /* Same as pb_decode, except does not initialize the destination structure
intrinseca 0:c7beea49fc91 71 * to default values. This is slightly faster if you need no default values
intrinseca 0:c7beea49fc91 72 * and just do memset(struct, 0, sizeof(struct)) yourself.
omatthews 2:d2c61a9be078 73 *
omatthews 2:d2c61a9be078 74 * This can also be used for 'merging' two messages, i.e. update only the
omatthews 2:d2c61a9be078 75 * fields that exist in the new message.
omatthews 2:d2c61a9be078 76 *
omatthews 2:d2c61a9be078 77 * Note: If this function returns with an error, it will not release any
omatthews 2:d2c61a9be078 78 * dynamically allocated fields. You will need to call pb_release() yourself.
intrinseca 0:c7beea49fc91 79 */
intrinseca 0:c7beea49fc91 80 bool pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
intrinseca 0:c7beea49fc91 81
omatthews 2:d2c61a9be078 82 /* Same as pb_decode, except expects the stream to start with the message size
omatthews 2:d2c61a9be078 83 * encoded as varint. Corresponds to parseDelimitedFrom() in Google's
omatthews 2:d2c61a9be078 84 * protobuf API.
omatthews 2:d2c61a9be078 85 */
omatthews 2:d2c61a9be078 86 bool pb_decode_delimited(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
omatthews 2:d2c61a9be078 87
omatthews 2:d2c61a9be078 88 /* Same as pb_decode_delimited, except that it does not initialize the destination structure.
omatthews 2:d2c61a9be078 89 * See pb_decode_noinit
omatthews 2:d2c61a9be078 90 */
omatthews 2:d2c61a9be078 91 bool pb_decode_delimited_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
omatthews 2:d2c61a9be078 92
omatthews 2:d2c61a9be078 93 /* Same as pb_decode, except allows the message to be terminated with a null byte.
omatthews 2:d2c61a9be078 94 * NOTE: Until nanopb-0.4.0, pb_decode() also allows null-termination. This behaviour
omatthews 2:d2c61a9be078 95 * is not supported in most other protobuf implementations, so pb_decode_delimited()
omatthews 2:d2c61a9be078 96 * is a better option for compatibility.
omatthews 2:d2c61a9be078 97 */
omatthews 2:d2c61a9be078 98 bool pb_decode_nullterminated(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
omatthews 2:d2c61a9be078 99
omatthews 2:d2c61a9be078 100 #ifdef PB_ENABLE_MALLOC
omatthews 2:d2c61a9be078 101 /* Release any allocated pointer fields. If you use dynamic allocation, you should
omatthews 2:d2c61a9be078 102 * call this for any successfully decoded message when you are done with it. If
omatthews 2:d2c61a9be078 103 * pb_decode() returns with an error, the message is already released.
intrinseca 0:c7beea49fc91 104 */
omatthews 2:d2c61a9be078 105 void pb_release(const pb_field_t fields[], void *dest_struct);
omatthews 2:d2c61a9be078 106 #endif
omatthews 2:d2c61a9be078 107
omatthews 2:d2c61a9be078 108
omatthews 2:d2c61a9be078 109 /**************************************
omatthews 2:d2c61a9be078 110 * Functions for manipulating streams *
omatthews 2:d2c61a9be078 111 **************************************/
omatthews 2:d2c61a9be078 112
omatthews 2:d2c61a9be078 113 /* Create an input stream for reading from a memory buffer.
omatthews 2:d2c61a9be078 114 *
omatthews 2:d2c61a9be078 115 * Alternatively, you can use a custom stream that reads directly from e.g.
omatthews 2:d2c61a9be078 116 * a file or a network socket.
omatthews 2:d2c61a9be078 117 */
omatthews 2:d2c61a9be078 118 pb_istream_t pb_istream_from_buffer(const pb_byte_t *buf, size_t bufsize);
omatthews 2:d2c61a9be078 119
omatthews 2:d2c61a9be078 120 /* Function to read from a pb_istream_t. You can use this if you need to
omatthews 2:d2c61a9be078 121 * read some custom header data, or to read data in field callbacks.
omatthews 2:d2c61a9be078 122 */
omatthews 2:d2c61a9be078 123 bool pb_read(pb_istream_t *stream, pb_byte_t *buf, size_t count);
omatthews 2:d2c61a9be078 124
omatthews 2:d2c61a9be078 125
omatthews 2:d2c61a9be078 126 /************************************************
omatthews 2:d2c61a9be078 127 * Helper functions for writing field callbacks *
omatthews 2:d2c61a9be078 128 ************************************************/
intrinseca 0:c7beea49fc91 129
intrinseca 0:c7beea49fc91 130 /* Decode the tag for the next field in the stream. Gives the wire type and
intrinseca 0:c7beea49fc91 131 * field tag. At end of the message, returns false and sets eof to true. */
intrinseca 0:c7beea49fc91 132 bool pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof);
intrinseca 0:c7beea49fc91 133
intrinseca 0:c7beea49fc91 134 /* Skip the field payload data, given the wire type. */
intrinseca 0:c7beea49fc91 135 bool pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type);
intrinseca 0:c7beea49fc91 136
intrinseca 0:c7beea49fc91 137 /* Decode an integer in the varint format. This works for bool, enum, int32,
intrinseca 0:c7beea49fc91 138 * int64, uint32 and uint64 field types. */
omatthews 2:d2c61a9be078 139 #ifndef PB_WITHOUT_64BIT
intrinseca 0:c7beea49fc91 140 bool pb_decode_varint(pb_istream_t *stream, uint64_t *dest);
omatthews 2:d2c61a9be078 141 #else
omatthews 2:d2c61a9be078 142 #define pb_decode_varint pb_decode_varint32
omatthews 2:d2c61a9be078 143 #endif
omatthews 2:d2c61a9be078 144
omatthews 2:d2c61a9be078 145 /* Decode an integer in the varint format. This works for bool, enum, int32,
omatthews 2:d2c61a9be078 146 * and uint32 field types. */
omatthews 2:d2c61a9be078 147 bool pb_decode_varint32(pb_istream_t *stream, uint32_t *dest);
intrinseca 0:c7beea49fc91 148
intrinseca 0:c7beea49fc91 149 /* Decode an integer in the zig-zagged svarint format. This works for sint32
intrinseca 0:c7beea49fc91 150 * and sint64. */
omatthews 2:d2c61a9be078 151 #ifndef PB_WITHOUT_64BIT
intrinseca 0:c7beea49fc91 152 bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest);
omatthews 2:d2c61a9be078 153 #else
omatthews 2:d2c61a9be078 154 bool pb_decode_svarint(pb_istream_t *stream, int32_t *dest);
omatthews 2:d2c61a9be078 155 #endif
intrinseca 0:c7beea49fc91 156
intrinseca 0:c7beea49fc91 157 /* Decode a fixed32, sfixed32 or float value. You need to pass a pointer to
intrinseca 0:c7beea49fc91 158 * a 4-byte wide C variable. */
intrinseca 0:c7beea49fc91 159 bool pb_decode_fixed32(pb_istream_t *stream, void *dest);
intrinseca 0:c7beea49fc91 160
omatthews 2:d2c61a9be078 161 #ifndef PB_WITHOUT_64BIT
intrinseca 0:c7beea49fc91 162 /* Decode a fixed64, sfixed64 or double value. You need to pass a pointer to
intrinseca 0:c7beea49fc91 163 * a 8-byte wide C variable. */
intrinseca 0:c7beea49fc91 164 bool pb_decode_fixed64(pb_istream_t *stream, void *dest);
omatthews 2:d2c61a9be078 165 #endif
intrinseca 0:c7beea49fc91 166
intrinseca 0:c7beea49fc91 167 /* Make a limited-length substream for reading a PB_WT_STRING field. */
intrinseca 0:c7beea49fc91 168 bool pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream);
omatthews 2:d2c61a9be078 169 bool pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream);
intrinseca 0:c7beea49fc91 170
intrinseca 0:c7beea49fc91 171 #ifdef __cplusplus
intrinseca 0:c7beea49fc91 172 } /* extern "C" */
intrinseca 0:c7beea49fc91 173 #endif
intrinseca 0:c7beea49fc91 174
omatthews 2:d2c61a9be078 175 #endif