API for Brotli compression. More...
Macros | |
#define | BROTLI_DEFAULT_MODE BROTLI_MODE_GENERIC |
Default value for BROTLI_PARAM_MODE parameter. More... | |
#define | BROTLI_DEFAULT_QUALITY 11 |
Default value for BROTLI_PARAM_QUALITY parameter. More... | |
#define | BROTLI_DEFAULT_WINDOW 22 |
Default value for BROTLI_PARAM_LGWIN parameter. More... | |
#define | BROTLI_LARGE_MAX_WINDOW_BITS 30 |
Maximal value for BROTLI_PARAM_LGWIN parameter in "Large Window Brotli" (32-bit). | |
#define | BROTLI_MAX_INPUT_BLOCK_BITS 24 |
Maximal value for BROTLI_PARAM_LGBLOCK parameter. More... | |
#define | BROTLI_MAX_QUALITY 11 |
Maximal value for BROTLI_PARAM_QUALITY parameter. More... | |
#define | BROTLI_MAX_WINDOW_BITS 24 |
Maximal value for BROTLI_PARAM_LGWIN parameter. More... | |
#define | BROTLI_MIN_INPUT_BLOCK_BITS 16 |
Minimal value for BROTLI_PARAM_LGBLOCK parameter. More... | |
#define | BROTLI_MIN_QUALITY 0 |
Minimal value for BROTLI_PARAM_QUALITY parameter. More... | |
#define | BROTLI_MIN_WINDOW_BITS 10 |
Minimal value for BROTLI_PARAM_LGWIN parameter. More... | |
Typedefs | |
typedef enum BrotliEncoderMode | BrotliEncoderMode |
Options for BROTLI_PARAM_MODE parameter. More... | |
typedef enum BrotliEncoderOperation | BrotliEncoderOperation |
Operations that can be performed by streaming encoder. More... | |
typedef enum BrotliEncoderParameter | BrotliEncoderParameter |
Options to be used with BrotliEncoderSetParameter. More... | |
typedef struct BrotliEncoderStateStruct | BrotliEncoderState |
Opaque structure that holds encoder state. More... | |
Enumerations |
Functions | |
BROTLI_BOOL | BrotliEncoderAttachPreparedDictionary (BrotliEncoderState *state, const BrotliEncoderPreparedDictionary *dictionary) |
Attaches a prepared dictionary of any type to the encoder. More... | |
BROTLI_BOOL | BrotliEncoderCompress (int quality, int lgwin, BrotliEncoderMode mode, size_t input_size, const uint8_t input_buffer[input_size], size_t *encoded_size, uint8_t encoded_buffer[*encoded_size]) |
Performs one-shot memory-to-memory compression. More... | |
BROTLI_BOOL | BrotliEncoderCompressStream (BrotliEncoderState *state, BrotliEncoderOperation op, size_t *available_in, const uint8_t **next_in, size_t *available_out, uint8_t **next_out, size_t *total_out) |
Compresses input stream to output stream. More... | |
BrotliEncoderState * | BrotliEncoderCreateInstance (brotli_alloc_func alloc_func, brotli_free_func free_func, void *opaque) |
Creates an instance of BrotliEncoderState and initializes it. More... | |
void | BrotliEncoderDestroyInstance (BrotliEncoderState *state) |
Deinitializes and frees BrotliEncoderState instance. More... | |
BROTLI_BOOL | BrotliEncoderHasMoreOutput (BrotliEncoderState *state) |
Checks if encoder has more output. More... | |
BROTLI_BOOL | BrotliEncoderIsFinished (BrotliEncoderState *state) |
Checks if encoder instance reached the final state. More... | |
size_t | BrotliEncoderMaxCompressedSize (size_t input_size) |
Calculates the output size bound for the given input_size . More... | |
BrotliEncoderPreparedDictionary * | BrotliEncoderPrepareDictionary (BrotliSharedDictionaryType type, size_t data_size, const uint8_t data[data_size], int quality, brotli_alloc_func alloc_func, brotli_free_func free_func, void *opaque) |
Prepares a shared dictionary from the given file format for the encoder. More... | |
BROTLI_BOOL | BrotliEncoderSetParameter (BrotliEncoderState *state, BrotliEncoderParameter param, uint32_t value) |
Sets the specified parameter to the given encoder instance. More... | |
const uint8_t * | BrotliEncoderTakeOutput (BrotliEncoderState *state, size_t *size) |
Acquires pointer to internal output buffer. More... | |
uint32_t | BrotliEncoderVersion (void) |
Gets an encoder library version. More... | |
API for Brotli compression.
#define BROTLI_DEFAULT_MODE BROTLI_MODE_GENERIC |
Default value for BROTLI_PARAM_MODE parameter.
#define BROTLI_DEFAULT_QUALITY 11 |
Default value for BROTLI_PARAM_QUALITY parameter.
#define BROTLI_DEFAULT_WINDOW 22 |
Default value for BROTLI_PARAM_LGWIN parameter.
#define BROTLI_MAX_INPUT_BLOCK_BITS 24 |
Maximal value for BROTLI_PARAM_LGBLOCK parameter.
#define BROTLI_MAX_QUALITY 11 |
Maximal value for BROTLI_PARAM_QUALITY parameter.
#define BROTLI_MAX_WINDOW_BITS 24 |
Maximal value for BROTLI_PARAM_LGWIN parameter.
BROTLI_MAX_DISTANCE_BITS
constant. #define BROTLI_MIN_INPUT_BLOCK_BITS 16 |
Minimal value for BROTLI_PARAM_LGBLOCK parameter.
#define BROTLI_MIN_QUALITY 0 |
Minimal value for BROTLI_PARAM_QUALITY parameter.
#define BROTLI_MIN_WINDOW_BITS 10 |
Minimal value for BROTLI_PARAM_LGWIN parameter.
typedef enum BrotliEncoderMode BrotliEncoderMode |
Options for BROTLI_PARAM_MODE parameter.
typedef enum BrotliEncoderOperation BrotliEncoderOperation |
Operations that can be performed by streaming encoder.
typedef enum BrotliEncoderParameter BrotliEncoderParameter |
Options to be used with BrotliEncoderSetParameter.
typedef struct BrotliEncoderStateStruct BrotliEncoderState |
Opaque structure that holds encoder state.
Allocated and initialized with BrotliEncoderCreateInstance. Cleaned up and deallocated with BrotliEncoderDestroyInstance.
enum BrotliEncoderMode |
Options for BROTLI_PARAM_MODE parameter.
Operations that can be performed by streaming encoder.
Enumerator | |
---|---|
BROTLI_OPERATION_PROCESS | Process input. Encoder may postpone producing output, until it has processed enough input. |
BROTLI_OPERATION_FLUSH | Produce output for all processed input. Actual flush is performed when input stream is depleted and there is enough space in output stream. This means that client should repeat BROTLI_OPERATION_FLUSH operation until
When flush is complete, output data will be sufficient for decoder to reproduce all the given input. |
BROTLI_OPERATION_FINISH | Finalize the stream. Actual finalization is performed when input stream is depleted and there is enough space in output stream. This means that client should repeat BROTLI_OPERATION_FINISH operation until
Helper function BrotliEncoderIsFinished checks if stream is finalized and output fully dumped. Adding more input data to finalized stream is impossible. |
BROTLI_OPERATION_EMIT_METADATA | Emit metadata block to stream. Metadata is opaque to Brotli: neither encoder, nor decoder processes this data or relies on it. It may be used to pass some extra information from encoder client to decoder client without interfering with main data stream.
Stream is soft-flushed before metadata block is emitted. Metadata block MUST be no longer than than 16MiB. |
Options to be used with BrotliEncoderSetParameter.
Enumerator | |
---|---|
BROTLI_PARAM_MODE | Tune encoder for specific input. BrotliEncoderMode enumerates all available values. |
BROTLI_PARAM_QUALITY | The main compression speed-density lever. The higher the quality, the slower the compression. Range is from BROTLI_MIN_QUALITY to BROTLI_MAX_QUALITY. |
BROTLI_PARAM_LGWIN | Recommended sliding LZ77 window size. Encoder may reduce this value, e.g. if input is much smaller than window size. Window size is Range is from BROTLI_MIN_WINDOW_BITS to BROTLI_MAX_WINDOW_BITS. |
BROTLI_PARAM_LGBLOCK | Recommended input block size. Encoder may reduce this value, e.g. if input is much smaller than input block size. Range is from BROTLI_MIN_INPUT_BLOCK_BITS to BROTLI_MAX_INPUT_BLOCK_BITS.
|
BROTLI_PARAM_DISABLE_LITERAL_CONTEXT_MODELING | Flag that affects usage of "literal context modeling" format feature. This flag is a "decoding-speed vs compression ratio" trade-off. |
BROTLI_PARAM_SIZE_HINT | Estimated total input size for all BrotliEncoderCompressStream calls. The default value is 0, which means that the total input size is unknown. |
BROTLI_PARAM_LARGE_WINDOW | Flag that determines if "Large Window Brotli" is used. |
BROTLI_PARAM_NPOSTFIX | Recommended number of postfix bits (NPOSTFIX). Encoder may change this value. Range is from 0 to BROTLI_MAX_NPOSTFIX. |
BROTLI_PARAM_NDIRECT | Recommended number of direct distance codes (NDIRECT). Encoder may change this value. Range is from 0 to (15 << NPOSTFIX) in steps of (1 << NPOSTFIX). |
BROTLI_PARAM_STREAM_OFFSET | Number of bytes of input stream already processed by a different instance.
If offset is not 0, then stream header is omitted. In any case output start is byte aligned, so for proper streams stitching "predecessor" stream must be flushed. Range is not artificially limited, but all the values greater or equal to maximal window size have the same effect. Values greater than 2**30 are not allowed. |
BROTLI_BOOL BrotliEncoderAttachPreparedDictionary | ( | BrotliEncoderState * | state, |
const BrotliEncoderPreparedDictionary * | dictionary | ||
) |
Attaches a prepared dictionary of any type to the encoder.
Can be used multiple times to attach multiple dictionaries. The dictionary type was determined by BrotliEncoderPrepareDictionary. Multiple raw prefix dictionaries and/or max 1 serialized dictionary with custom words can be attached.
BROTLI_BOOL BrotliEncoderCompress | ( | int | quality, |
int | lgwin, | ||
BrotliEncoderMode | mode, | ||
size_t | input_size, | ||
const uint8_t | input_buffer[input_size], | ||
size_t * | encoded_size, | ||
uint8_t | encoded_buffer[*encoded_size] | ||
) |
Performs one-shot memory-to-memory compression.
Compresses the data in input_buffer
into encoded_buffer
, and sets *encoded_size
to the compressed length.
input_size
) returns non-zero value, then output is guaranteed to be no longer than that.lgwin
is greater than BROTLI_MAX_WINDOW_BITS then resulting stream might be incompatible with RFC 7932; to decode such streams, decoder should be configured with BROTLI_DECODER_PARAM_LARGE_WINDOW = 1
quality | quality parameter value, e.g. BROTLI_DEFAULT_QUALITY | |
lgwin | lgwin parameter value, e.g. BROTLI_DEFAULT_WINDOW | |
mode | mode parameter value, e.g. BROTLI_DEFAULT_MODE | |
input_size | size of input_buffer | |
input_buffer | input data buffer with at least input_size addressable bytes | |
[in,out] | encoded_size | in: size of encoded_buffer ; out: length of compressed data written to encoded_buffer , or 0 if compression fails |
encoded_buffer | compressed data destination buffer |
BROTLI_BOOL BrotliEncoderCompressStream | ( | BrotliEncoderState * | state, |
BrotliEncoderOperation | op, | ||
size_t * | available_in, | ||
const uint8_t ** | next_in, | ||
size_t * | available_out, | ||
uint8_t ** | next_out, | ||
size_t * | total_out | ||
) |
Compresses input stream to output stream.
The values *available_in
and *available_out
must specify the number of bytes addressable at *next_in
and *next_out
respectively. When *available_out
is 0
, next_out
is allowed to be NULL
.
After each call, *available_in
will be decremented by the amount of input bytes consumed, and the *next_in
pointer will be incremented by that amount. Similarly, *available_out
will be decremented by the amount of output bytes written, and the *next_out
pointer will be incremented by that amount.
total_out
, if it is not a null-pointer, will be set to the number of bytes compressed since the last state
initialization.
Internally workflow consists of 3 tasks:
Whenever all 3 tasks can't move forward anymore, or error occurs, this method returns the control flow to caller.
op
is used to perform flush, finish the stream, or inject metadata block. See BrotliEncoderOperation for more information.
Flushing the stream means forcing encoding of all input passed to encoder and completing the current output block, so it could be fully decoded by stream decoder. To perform flush set op
to BROTLI_OPERATION_FLUSH. Under some circumstances (e.g. lack of output stream capacity) this operation would require several calls to BrotliEncoderCompressStream. The method must be called again until both input stream is depleted and encoder has no more output (see BrotliEncoderHasMoreOutput) after the method is called.
Finishing the stream means encoding of all input passed to encoder and adding specific "final" marks, so stream decoder could determine that stream is complete. To perform finish set op
to BROTLI_OPERATION_FINISH. Under some circumstances (e.g. lack of output stream capacity) this operation would require several calls to BrotliEncoderCompressStream. The method must be called again until both input stream is depleted and encoder has no more output (see BrotliEncoderHasMoreOutput) after the method is called.
op
should not change until operation is complete; input stream should not be swapped, reduced or extended as well.state | encoder instance | |
op | requested operation | |
[in,out] | available_in | in: amount of available input; out: amount of unused input |
[in,out] | next_in | pointer to the next input byte |
[in,out] | available_out | in: length of output buffer; out: remaining size of output buffer |
[in,out] | next_out | compressed output buffer cursor; can be NULL if available_out is 0 |
[out] | total_out | number of bytes produced so far; can be NULL |
BrotliEncoderState* BrotliEncoderCreateInstance | ( | brotli_alloc_func | alloc_func, |
brotli_free_func | free_func, | ||
void * | opaque | ||
) |
Creates an instance of BrotliEncoderState and initializes it.
alloc_func
and free_func
MUST be both zero or both non-zero. In the case they are both zero, default memory allocators are used. opaque
is passed to alloc_func
and free_func
when they are called. free_func
has to return without doing anything when asked to free a NULL pointer.
alloc_func | custom memory allocation function |
free_func | custom memory free function |
opaque | custom memory manager handle |
0
if instance can not be allocated or initialized void BrotliEncoderDestroyInstance | ( | BrotliEncoderState * | state | ) |
Deinitializes and frees BrotliEncoderState instance.
state | decoder instance to be cleaned up and deallocated |
BROTLI_BOOL BrotliEncoderHasMoreOutput | ( | BrotliEncoderState * | state | ) |
Checks if encoder has more output.
state | encoder instance |
BROTLI_BOOL BrotliEncoderIsFinished | ( | BrotliEncoderState * | state | ) |
Checks if encoder instance reached the final state.
state | encoder instance |
size_t BrotliEncoderMaxCompressedSize | ( | size_t | input_size | ) |
Calculates the output size bound for the given input_size
.
2
and, in case BrotliEncoderCompressStream was used, no flushes (BROTLI_OPERATION_FLUSH) were performed.input_size | size of projected input |
0
if result does not fit size_t
BrotliEncoderPreparedDictionary* BrotliEncoderPrepareDictionary | ( | BrotliSharedDictionaryType | type, |
size_t | data_size, | ||
const uint8_t | data[data_size], | ||
int | quality, | ||
brotli_alloc_func | alloc_func, | ||
brotli_free_func | free_func, | ||
void * | opaque | ||
) |
Prepares a shared dictionary from the given file format for the encoder.
alloc_func
and free_func
MUST be both zero or both non-zero. In the case they are both zero, default memory allocators are used. opaque
is passed to alloc_func
and free_func
when they are called. free_func
has to return without doing anything when asked to free a NULL pointer.
type | type of dictionary stored in data |
data_size | size of data buffer |
data | pointer to the dictionary data |
quality | the maximum Brotli quality to prepare the dictionary for, use BROTLI_MAX_QUALITY by default |
alloc_func | custom memory allocation function |
free_func | custom memory free function |
opaque | custom memory manager handle |
BROTLI_BOOL BrotliEncoderSetParameter | ( | BrotliEncoderState * | state, |
BrotliEncoderParameter | param, | ||
uint32_t | value | ||
) |
Sets the specified parameter to the given encoder instance.
state | encoder instance |
param | parameter to set |
value | new parameter value |
const uint8_t* BrotliEncoderTakeOutput | ( | BrotliEncoderState * | state, |
size_t * | size | ||
) |
Acquires pointer to internal output buffer.
This method is used to make language bindings easier and more efficient:
Also this could be useful if there is an output stream that is able to consume all the provided data (e.g. when data is saved to file system).
*size
bytes of output are considered consumed for all consecutive calls to the instance methods; returned pointer becomes invalidated as well.state | encoder instance | |
[in,out] | size | in: number of bytes caller is ready to take, 0 if any amount could be handled; out: amount of data pointed by returned pointer and considered consumed; out value is never greater than in value, unless it is 0 |
uint32_t BrotliEncoderVersion | ( | void | ) |
Gets an encoder library version.
Look at BROTLI_MAKE_HEX_VERSION for more information.