1/* Copyright 2013 Google Inc. All Rights Reserved.
2
3 Distributed under MIT license.
4 See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
5*/
6
7/**
8 * @file
9 * API for Brotli decompression.
10 */
11
12#ifndef BROTLI_DEC_DECODE_H_
13#define BROTLI_DEC_DECODE_H_
14
15#include <brotli/port.h>
16#include <brotli/types.h>
17
18#if defined(__cplusplus) || defined(c_plusplus)
19extern "C" {
20#endif
21
22/**
23 * Opaque structure that holds decoder state.
24 *
25 * Allocated and initialized with ::BrotliDecoderCreateInstance.
26 * Cleaned up and deallocated with ::BrotliDecoderDestroyInstance.
27 */
28typedef struct BrotliDecoderStateStruct BrotliDecoderState;
29
30/**
31 * Result type for ::BrotliDecoderDecompress and
32 * ::BrotliDecoderDecompressStream functions.
33 */
34typedef enum {
35 /** Decoding error, e.g. corrupted input or memory allocation problem. */
36 BROTLI_DECODER_RESULT_ERROR = 0,
37 /** Decoding successfully completed. */
38 BROTLI_DECODER_RESULT_SUCCESS = 1,
39 /** Partially done; should be called again with more input. */
40 BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT = 2,
41 /** Partially done; should be called again with more output. */
42 BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT = 3
43} BrotliDecoderResult;
44
45/**
46 * Template that evaluates items of ::BrotliDecoderErrorCode.
47 *
48 * Example: @code {.cpp}
49 * // Log Brotli error code.
50 * switch (brotliDecoderErrorCode) {
51 * #define CASE_(PREFIX, NAME, CODE) \
52 * case BROTLI_DECODER ## PREFIX ## NAME: \
53 * LOG(INFO) << "error code:" << #NAME; \
54 * break;
55 * #define NEWLINE_
56 * BROTLI_DECODER_ERROR_CODES_LIST(CASE_, NEWLINE_)
57 * #undef CASE_
58 * #undef NEWLINE_
59 * default: LOG(FATAL) << "unknown brotli error code";
60 * }
61 * @endcode
62 */
63#define BROTLI_DECODER_ERROR_CODES_LIST(BROTLI_ERROR_CODE, SEPARATOR) \
64 BROTLI_ERROR_CODE(_, NO_ERROR, 0) SEPARATOR \
65 /* Same as BrotliDecoderResult values */ \
66 BROTLI_ERROR_CODE(_, SUCCESS, 1) SEPARATOR \
67 BROTLI_ERROR_CODE(_, NEEDS_MORE_INPUT, 2) SEPARATOR \
68 BROTLI_ERROR_CODE(_, NEEDS_MORE_OUTPUT, 3) SEPARATOR \
69 \
70 /* Errors caused by invalid input */ \
71 BROTLI_ERROR_CODE(_ERROR_FORMAT_, EXUBERANT_NIBBLE, -1) SEPARATOR \
72 BROTLI_ERROR_CODE(_ERROR_FORMAT_, RESERVED, -2) SEPARATOR \
73 BROTLI_ERROR_CODE(_ERROR_FORMAT_, EXUBERANT_META_NIBBLE, -3) SEPARATOR \
74 BROTLI_ERROR_CODE(_ERROR_FORMAT_, SIMPLE_HUFFMAN_ALPHABET, -4) SEPARATOR \
75 BROTLI_ERROR_CODE(_ERROR_FORMAT_, SIMPLE_HUFFMAN_SAME, -5) SEPARATOR \
76 BROTLI_ERROR_CODE(_ERROR_FORMAT_, CL_SPACE, -6) SEPARATOR \
77 BROTLI_ERROR_CODE(_ERROR_FORMAT_, HUFFMAN_SPACE, -7) SEPARATOR \
78 BROTLI_ERROR_CODE(_ERROR_FORMAT_, CONTEXT_MAP_REPEAT, -8) SEPARATOR \
79 BROTLI_ERROR_CODE(_ERROR_FORMAT_, BLOCK_LENGTH_1, -9) SEPARATOR \
80 BROTLI_ERROR_CODE(_ERROR_FORMAT_, BLOCK_LENGTH_2, -10) SEPARATOR \
81 BROTLI_ERROR_CODE(_ERROR_FORMAT_, TRANSFORM, -11) SEPARATOR \
82 BROTLI_ERROR_CODE(_ERROR_FORMAT_, DICTIONARY, -12) SEPARATOR \
83 BROTLI_ERROR_CODE(_ERROR_FORMAT_, WINDOW_BITS, -13) SEPARATOR \
84 BROTLI_ERROR_CODE(_ERROR_FORMAT_, PADDING_1, -14) SEPARATOR \
85 BROTLI_ERROR_CODE(_ERROR_FORMAT_, PADDING_2, -15) SEPARATOR \
86 BROTLI_ERROR_CODE(_ERROR_FORMAT_, DISTANCE, -16) SEPARATOR \
87 \
88 /* -17..-18 codes are reserved */ \
89 \
90 BROTLI_ERROR_CODE(_ERROR_, DICTIONARY_NOT_SET, -19) SEPARATOR \
91 BROTLI_ERROR_CODE(_ERROR_, INVALID_ARGUMENTS, -20) SEPARATOR \
92 \
93 /* Memory allocation problems */ \
94 BROTLI_ERROR_CODE(_ERROR_ALLOC_, CONTEXT_MODES, -21) SEPARATOR \
95 /* Literal, insert and distance trees together */ \
96 BROTLI_ERROR_CODE(_ERROR_ALLOC_, TREE_GROUPS, -22) SEPARATOR \
97 /* -23..-24 codes are reserved for distinct tree groups */ \
98 BROTLI_ERROR_CODE(_ERROR_ALLOC_, CONTEXT_MAP, -25) SEPARATOR \
99 BROTLI_ERROR_CODE(_ERROR_ALLOC_, RING_BUFFER_1, -26) SEPARATOR \
100 BROTLI_ERROR_CODE(_ERROR_ALLOC_, RING_BUFFER_2, -27) SEPARATOR \
101 /* -28..-29 codes are reserved for dynamic ring-buffer allocation */ \
102 BROTLI_ERROR_CODE(_ERROR_ALLOC_, BLOCK_TYPE_TREES, -30) SEPARATOR \
103 \
104 /* "Impossible" states */ \
105 BROTLI_ERROR_CODE(_ERROR_, UNREACHABLE, -31)
106
107/**
108 * Error code for detailed logging / production debugging.
109 *
110 * See ::BrotliDecoderGetErrorCode and ::BROTLI_LAST_ERROR_CODE.
111 */
112typedef enum {
113#define BROTLI_COMMA_ ,
114#define BROTLI_ERROR_CODE_ENUM_ITEM_(PREFIX, NAME, CODE) \
115 BROTLI_DECODER ## PREFIX ## NAME = CODE
116 BROTLI_DECODER_ERROR_CODES_LIST(BROTLI_ERROR_CODE_ENUM_ITEM_, BROTLI_COMMA_)
117} BrotliDecoderErrorCode;
118#undef BROTLI_ERROR_CODE_ENUM_ITEM_
119#undef BROTLI_COMMA_
120
121/**
122 * The value of the last error code, negative integer.
123 *
124 * All other error code values are in the range from ::BROTLI_LAST_ERROR_CODE
125 * to @c -1. There are also 4 other possible non-error codes @c 0 .. @c 3 in
126 * ::BrotliDecoderErrorCode enumeration.
127 */
128#define BROTLI_LAST_ERROR_CODE BROTLI_DECODER_ERROR_UNREACHABLE
129
130/** Options to be used with ::BrotliDecoderSetParameter. */
131typedef enum BrotliDecoderParameter {
132 /**
133 * Disable "canny" ring buffer allocation strategy.
134 *
135 * Ring buffer is allocated according to window size, despite the real size of
136 * the content.
137 */
138 BROTLI_DECODER_PARAM_DISABLE_RING_BUFFER_REALLOCATION = 0,
139 /**
140 * Flag that determines if "Large Window Brotli" is used.
141 */
142 BROTLI_DECODER_PARAM_LARGE_WINDOW = 1
143} BrotliDecoderParameter;
144
145/**
146 * Sets the specified parameter to the given decoder instance.
147 *
148 * @param state decoder instance
149 * @param param parameter to set
150 * @param value new parameter value
151 * @returns ::BROTLI_FALSE if parameter is unrecognized, or value is invalid
152 * @returns ::BROTLI_TRUE if value is accepted
153 */
154BROTLI_DEC_API BROTLI_BOOL BrotliDecoderSetParameter(
155 BrotliDecoderState* state, BrotliDecoderParameter param, uint32_t value);
156
157/**
158 * Creates an instance of ::BrotliDecoderState and initializes it.
159 *
160 * The instance can be used once for decoding and should then be destroyed with
161 * ::BrotliDecoderDestroyInstance, it cannot be reused for a new decoding
162 * session.
163 *
164 * @p alloc_func and @p free_func @b MUST be both zero or both non-zero. In the
165 * case they are both zero, default memory allocators are used. @p opaque is
166 * passed to @p alloc_func and @p free_func when they are called. @p free_func
167 * has to return without doing anything when asked to free a NULL pointer.
168 *
169 * @param alloc_func custom memory allocation function
170 * @param free_func custom memory free function
171 * @param opaque custom memory manager handle
172 * @returns @c 0 if instance can not be allocated or initialized
173 * @returns pointer to initialized ::BrotliDecoderState otherwise
174 */
175BROTLI_DEC_API BrotliDecoderState* BrotliDecoderCreateInstance(
176 brotli_alloc_func alloc_func, brotli_free_func free_func, void* opaque);
177
178/**
179 * Deinitializes and frees ::BrotliDecoderState instance.
180 *
181 * @param state decoder instance to be cleaned up and deallocated
182 */
183BROTLI_DEC_API void BrotliDecoderDestroyInstance(BrotliDecoderState* state);
184
185/**
186 * Performs one-shot memory-to-memory decompression.
187 *
188 * Decompresses the data in @p encoded_buffer into @p decoded_buffer, and sets
189 * @p *decoded_size to the decompressed length.
190 *
191 * @param encoded_size size of @p encoded_buffer
192 * @param encoded_buffer compressed data buffer with at least @p encoded_size
193 * addressable bytes
194 * @param[in, out] decoded_size @b in: size of @p decoded_buffer; \n
195 * @b out: length of decompressed data written to
196 * @p decoded_buffer
197 * @param decoded_buffer decompressed data destination buffer
198 * @returns ::BROTLI_DECODER_RESULT_ERROR if input is corrupted, memory
199 * allocation failed, or @p decoded_buffer is not large enough;
200 * @returns ::BROTLI_DECODER_RESULT_SUCCESS otherwise
201 */
202BROTLI_DEC_API BrotliDecoderResult BrotliDecoderDecompress(
203 size_t encoded_size,
204 const uint8_t encoded_buffer[BROTLI_ARRAY_PARAM(encoded_size)],
205 size_t* decoded_size,
206 uint8_t decoded_buffer[BROTLI_ARRAY_PARAM(*decoded_size)]);
207
208/**
209 * Decompresses the input stream to the output stream.
210 *
211 * The values @p *available_in and @p *available_out must specify the number of
212 * bytes addressable at @p *next_in and @p *next_out respectively.
213 * When @p *available_out is @c 0, @p next_out is allowed to be @c NULL.
214 *
215 * After each call, @p *available_in will be decremented by the amount of input
216 * bytes consumed, and the @p *next_in pointer will be incremented by that
217 * amount. Similarly, @p *available_out will be decremented by the amount of
218 * output bytes written, and the @p *next_out pointer will be incremented by
219 * that amount.
220 *
221 * @p total_out, if it is not a null-pointer, will be set to the number
222 * of bytes decompressed since the last @p state initialization.
223 *
224 * @note Input is never overconsumed, so @p next_in and @p available_in could be
225 * passed to the next consumer after decoding is complete.
226 *
227 * @param state decoder instance
228 * @param[in, out] available_in @b in: amount of available input; \n
229 * @b out: amount of unused input
230 * @param[in, out] next_in pointer to the next compressed byte
231 * @param[in, out] available_out @b in: length of output buffer; \n
232 * @b out: remaining size of output buffer
233 * @param[in, out] next_out output buffer cursor;
234 * can be @c NULL if @p available_out is @c 0
235 * @param[out] total_out number of bytes decompressed so far; can be @c NULL
236 * @returns ::BROTLI_DECODER_RESULT_ERROR if input is corrupted, memory
237 * allocation failed, arguments were invalid, etc.;
238 * use ::BrotliDecoderGetErrorCode to get detailed error code
239 * @returns ::BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT decoding is blocked until
240 * more input data is provided
241 * @returns ::BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT decoding is blocked until
242 * more output space is provided
243 * @returns ::BROTLI_DECODER_RESULT_SUCCESS decoding is finished, no more
244 * input might be consumed and no more output will be produced
245 */
246BROTLI_DEC_API BrotliDecoderResult BrotliDecoderDecompressStream(
247 BrotliDecoderState* state, size_t* available_in, const uint8_t** next_in,
248 size_t* available_out, uint8_t** next_out, size_t* total_out);
249
250/**
251 * Checks if decoder has more output.
252 *
253 * @param state decoder instance
254 * @returns ::BROTLI_TRUE, if decoder has some unconsumed output
255 * @returns ::BROTLI_FALSE otherwise
256 */
257BROTLI_DEC_API BROTLI_BOOL BrotliDecoderHasMoreOutput(
258 const BrotliDecoderState* state);
259
260/**
261 * Acquires pointer to internal output buffer.
262 *
263 * This method is used to make language bindings easier and more efficient:
264 * -# push data to ::BrotliDecoderDecompressStream,
265 * until ::BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT is reported
266 * -# use ::BrotliDecoderTakeOutput to peek bytes and copy to language-specific
267 * entity
268 *
269 * Also this could be useful if there is an output stream that is able to
270 * consume all the provided data (e.g. when data is saved to file system).
271 *
272 * @attention After every call to ::BrotliDecoderTakeOutput @p *size bytes of
273 * output are considered consumed for all consecutive calls to the
274 * instance methods; returned pointer becomes invalidated as well.
275 *
276 * @note Decoder output is not guaranteed to be contiguous. This means that
277 * after the size-unrestricted call to ::BrotliDecoderTakeOutput,
278 * immediate next call to ::BrotliDecoderTakeOutput may return more data.
279 *
280 * @param state decoder instance
281 * @param[in, out] size @b in: number of bytes caller is ready to take, @c 0 if
282 * any amount could be handled; \n
283 * @b out: amount of data pointed by returned pointer and
284 * considered consumed; \n
285 * out value is never greater than in value, unless it is @c 0
286 * @returns pointer to output data
287 */
288BROTLI_DEC_API const uint8_t* BrotliDecoderTakeOutput(
289 BrotliDecoderState* state, size_t* size);
290
291/**
292 * Checks if instance has already consumed input.
293 *
294 * Instance that returns ::BROTLI_FALSE is considered "fresh" and could be
295 * reused.
296 *
297 * @param state decoder instance
298 * @returns ::BROTLI_TRUE if decoder has already used some input bytes
299 * @returns ::BROTLI_FALSE otherwise
300 */
301BROTLI_DEC_API BROTLI_BOOL BrotliDecoderIsUsed(const BrotliDecoderState* state);
302
303/**
304 * Checks if decoder instance reached the final state.
305 *
306 * @param state decoder instance
307 * @returns ::BROTLI_TRUE if decoder is in a state where it reached the end of
308 * the input and produced all of the output
309 * @returns ::BROTLI_FALSE otherwise
310 */
311BROTLI_DEC_API BROTLI_BOOL BrotliDecoderIsFinished(
312 const BrotliDecoderState* state);
313
314/**
315 * Acquires a detailed error code.
316 *
317 * Should be used only after ::BrotliDecoderDecompressStream returns
318 * ::BROTLI_DECODER_RESULT_ERROR.
319 *
320 * See also ::BrotliDecoderErrorString
321 *
322 * @param state decoder instance
323 * @returns last saved error code
324 */
325BROTLI_DEC_API BrotliDecoderErrorCode BrotliDecoderGetErrorCode(
326 const BrotliDecoderState* state);
327
328/**
329 * Converts error code to a c-string.
330 */
331BROTLI_DEC_API const char* BrotliDecoderErrorString(BrotliDecoderErrorCode c);
332
333/**
334 * Gets a decoder library version.
335 *
336 * Look at BROTLI_VERSION for more information.
337 */
338BROTLI_DEC_API uint32_t BrotliDecoderVersion(void);
339
340#if defined(__cplusplus) || defined(c_plusplus)
341} /* extern "C" */
342#endif
343
344#endif /* BROTLI_DEC_DECODE_H_ */
345

source code of include/brotli/decode.h