| commit | author | age | ||
| a6c014 | 1 | /* pb_decode.h: Functions to decode protocol buffers. Depends on pb_decode.c. |
| L | 2 | * The main function is pb_decode. You also need an input stream, and the |
| 3 | * field descriptions created by nanopb_generator.py. | |
| 4 | */ | |
| 5 | ||
| 6 | #ifndef PB_DECODE_H_INCLUDED | |
| 7 | #define PB_DECODE_H_INCLUDED | |
| 8 | ||
| 9 | #include "pb.h" | |
| 10 | ||
| 11 | #ifdef __cplusplus | |
| 12 | extern "C" { | |
| 13 | #endif | |
| 14 | ||
| 15 | /* Structure for defining custom input streams. You will need to provide | |
| 16 | * a callback function to read the bytes from your storage, which can be | |
| 17 | * for example a file or a network socket. | |
| 18 | * | |
| 19 | * The callback must conform to these rules: | |
| 20 | * | |
| 21 | * 1) Return false on IO errors. This will cause decoding to abort. | |
| 22 | * 2) You can use state to store your own data (e.g. buffer pointer), | |
| 23 | * and rely on pb_read to verify that no-body reads past bytes_left. | |
| 24 | * 3) Your callback may be used with substreams, in which case bytes_left | |
| 25 | * is different than from the main stream. Don't use bytes_left to compute | |
| 26 | * any pointers. | |
| 27 | */ | |
| 28 | struct pb_istream_s | |
| 29 | { | |
| 30 | #ifdef PB_BUFFER_ONLY | |
| 31 | /* Callback pointer is not used in buffer-only configuration. | |
| 32 | * Having an int pointer here allows binary compatibility but | |
| 33 | * gives an error if someone tries to assign callback function. | |
| 34 | */ | |
| 35 | int *callback; | |
| 36 | #else | |
| 37 | bool (*callback)(pb_istream_t *stream, pb_byte_t *buf, size_t count); | |
| 38 | #endif | |
| 39 | ||
| 40 | void *state; /* Free field for use by callback implementation */ | |
| 41 | size_t bytes_left; | |
| 42 | ||
| 43 | #ifndef PB_NO_ERRMSG | |
| 44 | const char *errmsg; | |
| 45 | #endif | |
| 46 | }; | |
| 47 | ||
| 48 | /*************************** | |
| 49 | * Main decoding functions * | |
| 50 | ***************************/ | |
| 51 | ||
| 52 | /* Decode a single protocol buffers message from input stream into a C structure. | |
| 53 | * Returns true on success, false on any failure. | |
| 54 | * The actual struct pointed to by dest must match the description in fields. | |
| 55 | * Callback fields of the destination structure must be initialized by caller. | |
| 56 | * All other fields will be initialized by this function. | |
| 57 | * | |
| 58 | * Example usage: | |
| 59 | * MyMessage msg = {}; | |
| 60 | * uint8_t buffer[64]; | |
| 61 | * pb_istream_t stream; | |
| 62 | * | |
| 63 | * // ... read some data into buffer ... | |
| 64 | * | |
| 65 | * stream = pb_istream_from_buffer(buffer, count); | |
| 66 | * pb_decode(&stream, MyMessage_fields, &msg); | |
| 67 | */ | |
| 68 | bool pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct); | |
| 69 | ||
| 70 | /* Same as pb_decode, except does not initialize the destination structure | |
| 71 | * to default values. This is slightly faster if you need no default values | |
| 72 | * and just do memset(struct, 0, sizeof(struct)) yourself. | |
| 73 | * | |
| 74 | * This can also be used for 'merging' two messages, i.e. update only the | |
| 75 | * fields that exist in the new message. | |
| 76 | * | |
| 77 | * Note: If this function returns with an error, it will not release any | |
| 78 | * dynamically allocated fields. You will need to call pb_release() yourself. | |
| 79 | */ | |
| 80 | bool pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct); | |
| 81 | ||
| 82 | /* Same as pb_decode, except expects the stream to start with the message size | |
| 83 | * encoded as varint. Corresponds to parseDelimitedFrom() in Google's | |
| 84 | * protobuf API. | |
| 85 | */ | |
| 86 | bool pb_decode_delimited(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct); | |
| 87 | ||
| 88 | /* Same as pb_decode_delimited, except that it does not initialize the destination structure. | |
| 89 | * See pb_decode_noinit | |
| 90 | */ | |
| 91 | bool pb_decode_delimited_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct); | |
| 92 | ||
| 93 | /* Same as pb_decode, except allows the message to be terminated with a null byte. | |
| 94 | * NOTE: Until nanopb-0.4.0, pb_decode() also allows null-termination. This behaviour | |
| 95 | * is not supported in most other protobuf implementations, so pb_decode_delimited() | |
| 96 | * is a better option for compatibility. | |
| 97 | */ | |
| 98 | bool pb_decode_nullterminated(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct); | |
| 99 | ||
| 100 | #ifdef PB_ENABLE_MALLOC | |
| 101 | /* Release any allocated pointer fields. If you use dynamic allocation, you should | |
| 102 | * call this for any successfully decoded message when you are done with it. If | |
| 103 | * pb_decode() returns with an error, the message is already released. | |
| 104 | */ | |
| 105 | void pb_release(const pb_field_t fields[], void *dest_struct); | |
| 106 | #endif | |
| 107 | ||
| 108 | ||
| 109 | /************************************** | |
| 110 | * Functions for manipulating streams * | |
| 111 | **************************************/ | |
| 112 | ||
| 113 | /* Create an input stream for reading from a memory buffer. | |
| 114 | * | |
| 115 | * Alternatively, you can use a custom stream that reads directly from e.g. | |
| 116 | * a file or a network socket. | |
| 117 | */ | |
| 118 | pb_istream_t pb_istream_from_buffer(const pb_byte_t *buf, size_t bufsize); | |
| 119 | ||
| 120 | /* Function to read from a pb_istream_t. You can use this if you need to | |
| 121 | * read some custom header data, or to read data in field callbacks. | |
| 122 | */ | |
| 123 | bool pb_read(pb_istream_t *stream, pb_byte_t *buf, size_t count); | |
| 124 | ||
| 125 | ||
| 126 | /************************************************ | |
| 127 | * Helper functions for writing field callbacks * | |
| 128 | ************************************************/ | |
| 129 | ||
| 130 | /* Decode the tag for the next field in the stream. Gives the wire type and | |
| 131 | * field tag. At end of the message, returns false and sets eof to true. */ | |
| 132 | bool pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof); | |
| 133 | ||
| 134 | /* Skip the field payload data, given the wire type. */ | |
| 135 | bool pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type); | |
| 136 | ||
| 137 | /* Decode an integer in the varint format. This works for enum, int32, | |
| 138 | * int64, uint32 and uint64 field types. */ | |
| 139 | #ifndef PB_WITHOUT_64BIT | |
| 140 | bool pb_decode_varint(pb_istream_t *stream, uint64_t *dest); | |
| 141 | #else | |
| 142 | #define pb_decode_varint pb_decode_varint32 | |
| 143 | #endif | |
| 144 | ||
| 145 | /* Decode an integer in the varint format. This works for enum, int32, | |
| 146 | * and uint32 field types. */ | |
| 147 | bool pb_decode_varint32(pb_istream_t *stream, uint32_t *dest); | |
| 148 | ||
| 149 | /* Decode a bool value in varint format. */ | |
| 150 | bool pb_decode_bool(pb_istream_t *stream, bool *dest); | |
| 151 | ||
| 152 | /* Decode an integer in the zig-zagged svarint format. This works for sint32 | |
| 153 | * and sint64. */ | |
| 154 | #ifndef PB_WITHOUT_64BIT | |
| 155 | bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest); | |
| 156 | #else | |
| 157 | bool pb_decode_svarint(pb_istream_t *stream, int32_t *dest); | |
| 158 | #endif | |
| 159 | ||
| 160 | /* Decode a fixed32, sfixed32 or float value. You need to pass a pointer to | |
| 161 | * a 4-byte wide C variable. */ | |
| 162 | bool pb_decode_fixed32(pb_istream_t *stream, void *dest); | |
| 163 | ||
| 164 | #ifndef PB_WITHOUT_64BIT | |
| 165 | /* Decode a fixed64, sfixed64 or double value. You need to pass a pointer to | |
| 166 | * a 8-byte wide C variable. */ | |
| 167 | bool pb_decode_fixed64(pb_istream_t *stream, void *dest); | |
| 168 | #endif | |
| 169 | ||
| 170 | /* Make a limited-length substream for reading a PB_WT_STRING field. */ | |
| 171 | bool pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream); | |
| 172 | bool pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream); | |
| 173 | ||
| 174 | #ifdef __cplusplus | |
| 175 | } /* extern "C" */ | |
| 176 | #endif | |
| 177 | ||
| 178 | #endif | |
