mirror of
https://github.com/google/brotli.git
synced 2024-11-08 13:20:05 +00:00
0e42caf359
Not all combinations are migrated to the initial configuration; corresponding TODOs added. Drive-by: additional combinations uncovered minor portability problems -> fixed Drive-by: remove no-longer used "script" files. Co-authored-by: Eugene Kliuchnikov <eustas@chromium.org>
631 lines
24 KiB
Groff
631 lines
24 KiB
Groff
.TH "encode.h" 3 "August 2021" "Brotli" \" -*- nroff -*-
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.ad l
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.nh
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.SH NAME
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encode.h \- API for Brotli compression\&.
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.SH SYNOPSIS
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.br
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.PP
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.SS "Macros"
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.in +1c
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.ti -1c
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.RI "#define \fBBROTLI_DEFAULT_MODE\fP \fBBROTLI_MODE_GENERIC\fP"
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.br
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.RI "\fIDefault value for \fBBROTLI_PARAM_MODE\fP parameter\&. \fP"
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.ti -1c
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.RI "#define \fBBROTLI_DEFAULT_QUALITY\fP 11"
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.br
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.RI "\fIDefault value for \fBBROTLI_PARAM_QUALITY\fP parameter\&. \fP"
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.ti -1c
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.RI "#define \fBBROTLI_DEFAULT_WINDOW\fP 22"
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.br
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.RI "\fIDefault value for \fBBROTLI_PARAM_LGWIN\fP parameter\&. \fP"
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.ti -1c
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.RI "#define \fBBROTLI_LARGE_MAX_WINDOW_BITS\fP 30"
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.br
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.RI "\fIMaximal value for \fBBROTLI_PARAM_LGWIN\fP parameter in 'Large Window Brotli' (32-bit)\&. \fP"
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.ti -1c
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.RI "#define \fBBROTLI_MAX_INPUT_BLOCK_BITS\fP 24"
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.br
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.RI "\fIMaximal value for \fBBROTLI_PARAM_LGBLOCK\fP parameter\&. \fP"
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.ti -1c
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.RI "#define \fBBROTLI_MAX_QUALITY\fP 11"
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.br
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.RI "\fIMaximal value for \fBBROTLI_PARAM_QUALITY\fP parameter\&. \fP"
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.ti -1c
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.RI "#define \fBBROTLI_MAX_WINDOW_BITS\fP 24"
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.br
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.RI "\fIMaximal value for \fBBROTLI_PARAM_LGWIN\fP parameter\&. \fP"
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.ti -1c
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.RI "#define \fBBROTLI_MIN_INPUT_BLOCK_BITS\fP 16"
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.br
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.RI "\fIMinimal value for \fBBROTLI_PARAM_LGBLOCK\fP parameter\&. \fP"
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.ti -1c
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.RI "#define \fBBROTLI_MIN_QUALITY\fP 0"
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.br
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.RI "\fIMinimal value for \fBBROTLI_PARAM_QUALITY\fP parameter\&. \fP"
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.ti -1c
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.RI "#define \fBBROTLI_MIN_WINDOW_BITS\fP 10"
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.br
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.RI "\fIMinimal value for \fBBROTLI_PARAM_LGWIN\fP parameter\&. \fP"
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.in -1c
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.SS "Typedefs"
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.in +1c
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.ti -1c
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.RI "typedef enum \fBBrotliEncoderMode\fP \fBBrotliEncoderMode\fP"
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.br
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.RI "\fIOptions for \fBBROTLI_PARAM_MODE\fP parameter\&. \fP"
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.ti -1c
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.RI "typedef enum \fBBrotliEncoderOperation\fP \fBBrotliEncoderOperation\fP"
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.br
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.RI "\fIOperations that can be performed by streaming encoder\&. \fP"
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.ti -1c
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.RI "typedef enum \fBBrotliEncoderParameter\fP \fBBrotliEncoderParameter\fP"
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.br
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.RI "\fIOptions to be used with \fBBrotliEncoderSetParameter\fP\&. \fP"
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.ti -1c
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.RI "typedef struct BrotliEncoderStateStruct \fBBrotliEncoderState\fP"
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.br
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.RI "\fIOpaque structure that holds encoder state\&. \fP"
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.in -1c
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.SS "Enumerations"
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.SS "Functions"
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.in +1c
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.ti -1c
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.RI "\fBBROTLI_BOOL\fP \fBBrotliEncoderAttachPreparedDictionary\fP (\fBBrotliEncoderState\fP *state, const BrotliEncoderPreparedDictionary *dictionary)"
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.br
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.RI "\fIAttaches a prepared dictionary of any type to the encoder\&. \fP"
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.ti -1c
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.RI "\fBBROTLI_BOOL\fP \fBBrotliEncoderCompress\fP (int quality, int lgwin, \fBBrotliEncoderMode\fP mode, size_t input_size, const uint8_t input_buffer[input_size], size_t *encoded_size, uint8_t encoded_buffer[*encoded_size])"
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.br
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.RI "\fIPerforms one-shot memory-to-memory compression\&. \fP"
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.ti -1c
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.RI "\fBBROTLI_BOOL\fP \fBBrotliEncoderCompressStream\fP (\fBBrotliEncoderState\fP *state, \fBBrotliEncoderOperation\fP op, size_t *available_in, const uint8_t **next_in, size_t *available_out, uint8_t **next_out, size_t *total_out)"
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.br
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.RI "\fICompresses input stream to output stream\&. \fP"
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.ti -1c
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.RI "\fBBrotliEncoderState\fP * \fBBrotliEncoderCreateInstance\fP (\fBbrotli_alloc_func\fP alloc_func, \fBbrotli_free_func\fP free_func, void *opaque)"
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.br
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.RI "\fICreates an instance of \fBBrotliEncoderState\fP and initializes it\&. \fP"
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.ti -1c
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.RI "void \fBBrotliEncoderDestroyInstance\fP (\fBBrotliEncoderState\fP *state)"
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.br
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.RI "\fIDeinitializes and frees \fBBrotliEncoderState\fP instance\&. \fP"
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.ti -1c
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.RI "\fBBROTLI_BOOL\fP \fBBrotliEncoderHasMoreOutput\fP (\fBBrotliEncoderState\fP *state)"
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.br
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.RI "\fIChecks if encoder has more output\&. \fP"
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.ti -1c
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.RI "\fBBROTLI_BOOL\fP \fBBrotliEncoderIsFinished\fP (\fBBrotliEncoderState\fP *state)"
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.br
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.RI "\fIChecks if encoder instance reached the final state\&. \fP"
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.ti -1c
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.RI "size_t \fBBrotliEncoderMaxCompressedSize\fP (size_t input_size)"
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.br
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.RI "\fICalculates the output size bound for the given \fCinput_size\fP\&. \fP"
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.ti -1c
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.RI "BrotliEncoderPreparedDictionary * \fBBrotliEncoderPrepareDictionary\fP (BrotliSharedDictionaryType type, size_t data_size, const uint8_t data[data_size], int quality, \fBbrotli_alloc_func\fP alloc_func, \fBbrotli_free_func\fP free_func, void *opaque)"
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.br
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.RI "\fIPrepares a shared dictionary from the given file format for the encoder\&. \fP"
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.ti -1c
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.RI "\fBBROTLI_BOOL\fP \fBBrotliEncoderSetParameter\fP (\fBBrotliEncoderState\fP *state, \fBBrotliEncoderParameter\fP param, uint32_t value)"
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.br
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.RI "\fISets the specified parameter to the given encoder instance\&. \fP"
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.ti -1c
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.RI "const uint8_t * \fBBrotliEncoderTakeOutput\fP (\fBBrotliEncoderState\fP *state, size_t *size)"
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.br
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.RI "\fIAcquires pointer to internal output buffer\&. \fP"
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.ti -1c
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.RI "uint32_t \fBBrotliEncoderVersion\fP (void)"
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.br
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.RI "\fIGets an encoder library version\&. \fP"
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.in -1c
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.SH "Detailed Description"
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.PP
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API for Brotli compression\&.
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.SH "Macro Definition Documentation"
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.PP
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.SS "#define BROTLI_DEFAULT_MODE \fBBROTLI_MODE_GENERIC\fP"
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.PP
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Default value for \fBBROTLI_PARAM_MODE\fP parameter\&.
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.SS "#define BROTLI_DEFAULT_QUALITY 11"
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.PP
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Default value for \fBBROTLI_PARAM_QUALITY\fP parameter\&.
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.SS "#define BROTLI_DEFAULT_WINDOW 22"
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.PP
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Default value for \fBBROTLI_PARAM_LGWIN\fP parameter\&.
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.SS "#define BROTLI_MAX_INPUT_BLOCK_BITS 24"
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.PP
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Maximal value for \fBBROTLI_PARAM_LGBLOCK\fP parameter\&.
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.SS "#define BROTLI_MAX_QUALITY 11"
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.PP
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Maximal value for \fBBROTLI_PARAM_QUALITY\fP parameter\&.
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.SS "#define BROTLI_MAX_WINDOW_BITS 24"
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.PP
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Maximal value for \fBBROTLI_PARAM_LGWIN\fP parameter\&.
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.PP
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\fBNote:\fP
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.RS 4
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equal to \fCBROTLI_MAX_DISTANCE_BITS\fP constant\&.
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.RE
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.PP
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.SS "#define BROTLI_MIN_INPUT_BLOCK_BITS 16"
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.PP
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Minimal value for \fBBROTLI_PARAM_LGBLOCK\fP parameter\&.
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.SS "#define BROTLI_MIN_QUALITY 0"
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.PP
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Minimal value for \fBBROTLI_PARAM_QUALITY\fP parameter\&.
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.SS "#define BROTLI_MIN_WINDOW_BITS 10"
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.PP
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Minimal value for \fBBROTLI_PARAM_LGWIN\fP parameter\&.
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.SH "Typedef Documentation"
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.PP
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.SS "typedef enum \fBBrotliEncoderMode\fP \fBBrotliEncoderMode\fP"
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.PP
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Options for \fBBROTLI_PARAM_MODE\fP parameter\&.
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.SS "typedef enum \fBBrotliEncoderOperation\fP \fBBrotliEncoderOperation\fP"
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.PP
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Operations that can be performed by streaming encoder\&.
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.SS "typedef enum \fBBrotliEncoderParameter\fP \fBBrotliEncoderParameter\fP"
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.PP
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Options to be used with \fBBrotliEncoderSetParameter\fP\&.
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.SS "typedef struct BrotliEncoderStateStruct \fBBrotliEncoderState\fP"
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.PP
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Opaque structure that holds encoder state\&. Allocated and initialized with \fBBrotliEncoderCreateInstance\fP\&. Cleaned up and deallocated with \fBBrotliEncoderDestroyInstance\fP\&.
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.SH "Enumeration Type Documentation"
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.PP
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.SS "enum \fBBrotliEncoderMode\fP"
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.PP
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Options for \fBBROTLI_PARAM_MODE\fP parameter\&.
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.PP
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\fBEnumerator\fP
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.in +1c
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.TP
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\fB\fIBROTLI_MODE_GENERIC \fP\fP
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Default compression mode\&. In this mode compressor does not know anything in advance about the properties of the input\&.
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.TP
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\fB\fIBROTLI_MODE_TEXT \fP\fP
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Compression mode for UTF-8 formatted text input\&.
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.TP
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\fB\fIBROTLI_MODE_FONT \fP\fP
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Compression mode used in WOFF 2\&.0\&.
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.SS "enum \fBBrotliEncoderOperation\fP"
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.PP
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Operations that can be performed by streaming encoder\&.
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.PP
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\fBEnumerator\fP
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.in +1c
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.TP
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\fB\fIBROTLI_OPERATION_PROCESS \fP\fP
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Process input\&. Encoder may postpone producing output, until it has processed enough input\&.
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.TP
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\fB\fIBROTLI_OPERATION_FLUSH \fP\fP
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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 \fBBROTLI_OPERATION_FLUSH\fP operation until \fCavailable_in\fP becomes \fC0\fP, and \fBBrotliEncoderHasMoreOutput\fP returns \fBBROTLI_FALSE\fP\&. If output is acquired via \fBBrotliEncoderTakeOutput\fP, then operation should be repeated after output buffer is drained\&.
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.PP
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\fBWarning:\fP
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.RS 4
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Until flush is complete, client \fBSHOULD\fP \fBNOT\fP swap, reduce or extend input stream\&.
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.RE
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.PP
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When flush is complete, output data will be sufficient for decoder to reproduce all the given input\&.
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.TP
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\fB\fIBROTLI_OPERATION_FINISH \fP\fP
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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 \fBBROTLI_OPERATION_FINISH\fP operation until \fCavailable_in\fP becomes \fC0\fP, and \fBBrotliEncoderHasMoreOutput\fP returns \fBBROTLI_FALSE\fP\&. If output is acquired via \fBBrotliEncoderTakeOutput\fP, then operation should be repeated after output buffer is drained\&.
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.PP
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\fBWarning:\fP
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.RS 4
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Until finalization is complete, client \fBSHOULD\fP \fBNOT\fP swap, reduce or extend input stream\&.
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.RE
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.PP
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Helper function \fBBrotliEncoderIsFinished\fP checks if stream is finalized and output fully dumped\&.
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.PP
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Adding more input data to finalized stream is impossible\&.
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.TP
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\fB\fIBROTLI_OPERATION_EMIT_METADATA \fP\fP
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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\&.
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.PP
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\fBNote:\fP
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.RS 4
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Encoder may emit empty metadata blocks internally, to pad encoded stream to byte boundary\&.
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.RE
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.PP
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\fBWarning:\fP
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.RS 4
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Until emitting metadata is complete client \fBSHOULD\fP \fBNOT\fP swap, reduce or extend input stream\&.
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.PP
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The whole content of input buffer is considered to be the content of metadata block\&. Do \fBNOT\fP \fIappend\fP metadata to input stream, before it is depleted with other operations\&.
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.RE
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.PP
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Stream is soft-flushed before metadata block is emitted\&. Metadata block \fBMUST\fP be no longer than than 16MiB\&.
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.SS "enum \fBBrotliEncoderParameter\fP"
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.PP
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Options to be used with \fBBrotliEncoderSetParameter\fP\&.
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.PP
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\fBEnumerator\fP
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.in +1c
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.TP
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\fB\fIBROTLI_PARAM_MODE \fP\fP
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Tune encoder for specific input\&. \fBBrotliEncoderMode\fP enumerates all available values\&.
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.TP
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\fB\fIBROTLI_PARAM_QUALITY \fP\fP
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The main compression speed-density lever\&. The higher the quality, the slower the compression\&. Range is from \fBBROTLI_MIN_QUALITY\fP to \fBBROTLI_MAX_QUALITY\fP\&.
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.TP
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\fB\fIBROTLI_PARAM_LGWIN \fP\fP
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Recommended sliding LZ77 window size\&. Encoder may reduce this value, e\&.g\&. if input is much smaller than window size\&.
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.PP
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Window size is \fC(1 << value) - 16\fP\&.
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.PP
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Range is from \fBBROTLI_MIN_WINDOW_BITS\fP to \fBBROTLI_MAX_WINDOW_BITS\fP\&.
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.TP
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\fB\fIBROTLI_PARAM_LGBLOCK \fP\fP
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Recommended input block size\&. Encoder may reduce this value, e\&.g\&. if input is much smaller than input block size\&.
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.PP
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Range is from \fBBROTLI_MIN_INPUT_BLOCK_BITS\fP to \fBBROTLI_MAX_INPUT_BLOCK_BITS\fP\&.
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.PP
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\fBNote:\fP
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.RS 4
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Bigger input block size allows better compression, but consumes more memory\&.
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.br
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The rough formula of memory used for temporary input storage is \fC3 << lgBlock\fP\&.
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.RE
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.PP
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.TP
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\fB\fIBROTLI_PARAM_DISABLE_LITERAL_CONTEXT_MODELING \fP\fP
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Flag that affects usage of 'literal context modeling' format feature\&. This flag is a 'decoding-speed vs compression ratio' trade-off\&.
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.TP
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\fB\fIBROTLI_PARAM_SIZE_HINT \fP\fP
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Estimated total input size for all \fBBrotliEncoderCompressStream\fP calls\&. The default value is 0, which means that the total input size is unknown\&.
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.TP
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\fB\fIBROTLI_PARAM_LARGE_WINDOW \fP\fP
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Flag that determines if 'Large Window Brotli' is used\&.
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.TP
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\fB\fIBROTLI_PARAM_NPOSTFIX \fP\fP
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Recommended number of postfix bits (NPOSTFIX)\&. Encoder may change this value\&.
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.PP
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Range is from 0 to \fBBROTLI_MAX_NPOSTFIX\fP\&.
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.TP
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\fB\fIBROTLI_PARAM_NDIRECT \fP\fP
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Recommended number of direct distance codes (NDIRECT)\&. Encoder may change this value\&.
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.PP
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Range is from 0 to (15 << NPOSTFIX) in steps of (1 << NPOSTFIX)\&.
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.TP
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\fB\fIBROTLI_PARAM_STREAM_OFFSET \fP\fP
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Number of bytes of input stream already processed by a different instance\&.
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.PP
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\fBNote:\fP
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.RS 4
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It is important to configure all the encoder instances with same parameters (except this one) in order to allow all the encoded parts obey the same restrictions implied by header\&.
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.RE
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.PP
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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\&.
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.PP
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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\&.
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.SH "Function Documentation"
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.PP
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.SS "\fBBROTLI_BOOL\fP BrotliEncoderAttachPreparedDictionary (\fBBrotliEncoderState\fP * state, const BrotliEncoderPreparedDictionary * dictionary)"
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.PP
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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\&.
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.PP
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\fBReturns:\fP
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.RS 4
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\fBBROTLI_FALSE\fP in case of error
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.PP
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\fBBROTLI_TRUE\fP otherwise
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.RE
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.PP
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.SS "\fBBROTLI_BOOL\fP BrotliEncoderCompress (int quality, int lgwin, \fBBrotliEncoderMode\fP mode, size_t input_size, const uint8_t input_buffer[input_size], size_t * encoded_size, uint8_t encoded_buffer[*encoded_size])"
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.PP
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Performs one-shot memory-to-memory compression\&. Compresses the data in \fCinput_buffer\fP into \fCencoded_buffer\fP, and sets \fC*encoded_size\fP to the compressed length\&.
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.PP
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\fBNote:\fP
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.RS 4
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If \fBBrotliEncoderMaxCompressedSize\fP(\fCinput_size\fP) returns non-zero value, then output is guaranteed to be no longer than that\&.
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.PP
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If \fClgwin\fP is greater than \fBBROTLI_MAX_WINDOW_BITS\fP then resulting stream might be incompatible with RFC 7932; to decode such streams, decoder should be configured with \fBBROTLI_DECODER_PARAM_LARGE_WINDOW\fP = \fC1\fP
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.RE
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.PP
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\fBParameters:\fP
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.RS 4
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\fIquality\fP quality parameter value, e\&.g\&. \fBBROTLI_DEFAULT_QUALITY\fP
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.br
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\fIlgwin\fP lgwin parameter value, e\&.g\&. \fBBROTLI_DEFAULT_WINDOW\fP
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.br
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\fImode\fP mode parameter value, e\&.g\&. \fBBROTLI_DEFAULT_MODE\fP
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.br
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\fIinput_size\fP size of \fCinput_buffer\fP
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.br
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\fIinput_buffer\fP input data buffer with at least \fCinput_size\fP addressable bytes
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.br
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\fIencoded_size\fP \fBin:\fP size of \fCencoded_buffer\fP;
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.br
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\fBout:\fP length of compressed data written to \fCencoded_buffer\fP, or \fC0\fP if compression fails
|
|
.br
|
|
\fIencoded_buffer\fP compressed data destination buffer
|
|
.RE
|
|
.PP
|
|
\fBReturns:\fP
|
|
.RS 4
|
|
\fBBROTLI_FALSE\fP in case of compression error
|
|
.PP
|
|
\fBBROTLI_FALSE\fP if output buffer is too small
|
|
.PP
|
|
\fBBROTLI_TRUE\fP otherwise
|
|
.RE
|
|
.PP
|
|
|
|
.SS "\fBBROTLI_BOOL\fP BrotliEncoderCompressStream (\fBBrotliEncoderState\fP * state, \fBBrotliEncoderOperation\fP op, size_t * available_in, const uint8_t ** next_in, size_t * available_out, uint8_t ** next_out, size_t * total_out)"
|
|
|
|
.PP
|
|
Compresses input stream to output stream\&. The values \fC*available_in\fP and \fC*available_out\fP must specify the number of bytes addressable at \fC*next_in\fP and \fC*next_out\fP respectively\&. When \fC*available_out\fP is \fC0\fP, \fCnext_out\fP is allowed to be \fCNULL\fP\&.
|
|
.PP
|
|
After each call, \fC*available_in\fP will be decremented by the amount of input bytes consumed, and the \fC*next_in\fP pointer will be incremented by that amount\&. Similarly, \fC*available_out\fP will be decremented by the amount of output bytes written, and the \fC*next_out\fP pointer will be incremented by that amount\&.
|
|
.PP
|
|
\fCtotal_out\fP, if it is not a null-pointer, will be set to the number of bytes compressed since the last \fCstate\fP initialization\&.
|
|
.PP
|
|
Internally workflow consists of 3 tasks:
|
|
.IP "1." 4
|
|
(optionally) copy input data to internal buffer
|
|
.IP "2." 4
|
|
actually compress data and (optionally) store it to internal buffer
|
|
.IP "3." 4
|
|
(optionally) copy compressed bytes from internal buffer to output stream
|
|
.PP
|
|
.PP
|
|
Whenever all 3 tasks can't move forward anymore, or error occurs, this method returns the control flow to caller\&.
|
|
.PP
|
|
\fCop\fP is used to perform flush, finish the stream, or inject metadata block\&. See \fBBrotliEncoderOperation\fP for more information\&.
|
|
.PP
|
|
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 \fCop\fP to \fBBROTLI_OPERATION_FLUSH\fP\&. Under some circumstances (e\&.g\&. lack of output stream capacity) this operation would require several calls to \fBBrotliEncoderCompressStream\fP\&. The method must be called again until both input stream is depleted and encoder has no more output (see \fBBrotliEncoderHasMoreOutput\fP) after the method is called\&.
|
|
.PP
|
|
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 \fCop\fP to \fBBROTLI_OPERATION_FINISH\fP\&. Under some circumstances (e\&.g\&. lack of output stream capacity) this operation would require several calls to \fBBrotliEncoderCompressStream\fP\&. The method must be called again until both input stream is depleted and encoder has no more output (see \fBBrotliEncoderHasMoreOutput\fP) after the method is called\&.
|
|
.PP
|
|
\fBWarning:\fP
|
|
.RS 4
|
|
When flushing and finishing, \fCop\fP should not change until operation is complete; input stream should not be swapped, reduced or extended as well\&.
|
|
.RE
|
|
.PP
|
|
\fBParameters:\fP
|
|
.RS 4
|
|
\fIstate\fP encoder instance
|
|
.br
|
|
\fIop\fP requested operation
|
|
.br
|
|
\fIavailable_in\fP \fBin:\fP amount of available input;
|
|
.br
|
|
\fBout:\fP amount of unused input
|
|
.br
|
|
\fInext_in\fP pointer to the next input byte
|
|
.br
|
|
\fIavailable_out\fP \fBin:\fP length of output buffer;
|
|
.br
|
|
\fBout:\fP remaining size of output buffer
|
|
.br
|
|
\fInext_out\fP compressed output buffer cursor; can be \fCNULL\fP if \fCavailable_out\fP is \fC0\fP
|
|
.br
|
|
\fItotal_out\fP number of bytes produced so far; can be \fCNULL\fP
|
|
.RE
|
|
.PP
|
|
\fBReturns:\fP
|
|
.RS 4
|
|
\fBBROTLI_FALSE\fP if there was an error
|
|
.PP
|
|
\fBBROTLI_TRUE\fP otherwise
|
|
.RE
|
|
.PP
|
|
|
|
.SS "\fBBrotliEncoderState\fP* BrotliEncoderCreateInstance (\fBbrotli_alloc_func\fP alloc_func, \fBbrotli_free_func\fP free_func, void * opaque)"
|
|
|
|
.PP
|
|
Creates an instance of \fBBrotliEncoderState\fP and initializes it\&. \fCalloc_func\fP and \fCfree_func\fP \fBMUST\fP be both zero or both non-zero\&. In the case they are both zero, default memory allocators are used\&. \fCopaque\fP is passed to \fCalloc_func\fP and \fCfree_func\fP when they are called\&. \fCfree_func\fP has to return without doing anything when asked to free a NULL pointer\&.
|
|
.PP
|
|
\fBParameters:\fP
|
|
.RS 4
|
|
\fIalloc_func\fP custom memory allocation function
|
|
.br
|
|
\fIfree_func\fP custom memory free function
|
|
.br
|
|
\fIopaque\fP custom memory manager handle
|
|
.RE
|
|
.PP
|
|
\fBReturns:\fP
|
|
.RS 4
|
|
\fC0\fP if instance can not be allocated or initialized
|
|
.PP
|
|
pointer to initialized \fBBrotliEncoderState\fP otherwise
|
|
.RE
|
|
.PP
|
|
|
|
.SS "void BrotliEncoderDestroyInstance (\fBBrotliEncoderState\fP * state)"
|
|
|
|
.PP
|
|
Deinitializes and frees \fBBrotliEncoderState\fP instance\&.
|
|
.PP
|
|
\fBParameters:\fP
|
|
.RS 4
|
|
\fIstate\fP decoder instance to be cleaned up and deallocated
|
|
.RE
|
|
.PP
|
|
|
|
.SS "\fBBROTLI_BOOL\fP BrotliEncoderHasMoreOutput (\fBBrotliEncoderState\fP * state)"
|
|
|
|
.PP
|
|
Checks if encoder has more output\&.
|
|
.PP
|
|
\fBParameters:\fP
|
|
.RS 4
|
|
\fIstate\fP encoder instance
|
|
.RE
|
|
.PP
|
|
\fBReturns:\fP
|
|
.RS 4
|
|
\fBBROTLI_TRUE\fP, if encoder has some unconsumed output
|
|
.PP
|
|
\fBBROTLI_FALSE\fP otherwise
|
|
.RE
|
|
.PP
|
|
|
|
.SS "\fBBROTLI_BOOL\fP BrotliEncoderIsFinished (\fBBrotliEncoderState\fP * state)"
|
|
|
|
.PP
|
|
Checks if encoder instance reached the final state\&.
|
|
.PP
|
|
\fBParameters:\fP
|
|
.RS 4
|
|
\fIstate\fP encoder instance
|
|
.RE
|
|
.PP
|
|
\fBReturns:\fP
|
|
.RS 4
|
|
\fBBROTLI_TRUE\fP if encoder is in a state where it reached the end of the input and produced all of the output
|
|
.PP
|
|
\fBBROTLI_FALSE\fP otherwise
|
|
.RE
|
|
.PP
|
|
|
|
.SS "size_t BrotliEncoderMaxCompressedSize (size_t input_size)"
|
|
|
|
.PP
|
|
Calculates the output size bound for the given \fCinput_size\fP\&.
|
|
.PP
|
|
\fBWarning:\fP
|
|
.RS 4
|
|
Result is only valid if quality is at least \fC2\fP and, in case \fBBrotliEncoderCompressStream\fP was used, no flushes (\fBBROTLI_OPERATION_FLUSH\fP) were performed\&.
|
|
.RE
|
|
.PP
|
|
\fBParameters:\fP
|
|
.RS 4
|
|
\fIinput_size\fP size of projected input
|
|
.RE
|
|
.PP
|
|
\fBReturns:\fP
|
|
.RS 4
|
|
\fC0\fP if result does not fit \fCsize_t\fP
|
|
.RE
|
|
.PP
|
|
|
|
.SS "BrotliEncoderPreparedDictionary* BrotliEncoderPrepareDictionary (BrotliSharedDictionaryType type, size_t data_size, const uint8_t data[data_size], int quality, \fBbrotli_alloc_func\fP alloc_func, \fBbrotli_free_func\fP free_func, void * opaque)"
|
|
|
|
.PP
|
|
Prepares a shared dictionary from the given file format for the encoder\&. \fCalloc_func\fP and \fCfree_func\fP \fBMUST\fP be both zero or both non-zero\&. In the case they are both zero, default memory allocators are used\&. \fCopaque\fP is passed to \fCalloc_func\fP and \fCfree_func\fP when they are called\&. \fCfree_func\fP has to return without doing anything when asked to free a NULL pointer\&.
|
|
.PP
|
|
\fBParameters:\fP
|
|
.RS 4
|
|
\fItype\fP type of dictionary stored in data
|
|
.br
|
|
\fIdata_size\fP size of \fCdata\fP buffer
|
|
.br
|
|
\fIdata\fP pointer to the dictionary data
|
|
.br
|
|
\fIquality\fP the maximum Brotli quality to prepare the dictionary for, use BROTLI_MAX_QUALITY by default
|
|
.br
|
|
\fIalloc_func\fP custom memory allocation function
|
|
.br
|
|
\fIfree_func\fP custom memory free function
|
|
.br
|
|
\fIopaque\fP custom memory manager handle
|
|
.RE
|
|
.PP
|
|
|
|
.SS "\fBBROTLI_BOOL\fP BrotliEncoderSetParameter (\fBBrotliEncoderState\fP * state, \fBBrotliEncoderParameter\fP param, uint32_t value)"
|
|
|
|
.PP
|
|
Sets the specified parameter to the given encoder instance\&.
|
|
.PP
|
|
\fBParameters:\fP
|
|
.RS 4
|
|
\fIstate\fP encoder instance
|
|
.br
|
|
\fIparam\fP parameter to set
|
|
.br
|
|
\fIvalue\fP new parameter value
|
|
.RE
|
|
.PP
|
|
\fBReturns:\fP
|
|
.RS 4
|
|
\fBBROTLI_FALSE\fP if parameter is unrecognized, or value is invalid
|
|
.PP
|
|
\fBBROTLI_FALSE\fP if value of parameter can not be changed at current encoder state (e\&.g\&. when encoding is started, window size might be already encoded and therefore it is impossible to change it)
|
|
.PP
|
|
\fBBROTLI_TRUE\fP if value is accepted
|
|
.RE
|
|
.PP
|
|
\fBWarning:\fP
|
|
.RS 4
|
|
invalid values might be accepted in case they would not break encoding process\&.
|
|
.RE
|
|
.PP
|
|
|
|
.SS "const uint8_t* BrotliEncoderTakeOutput (\fBBrotliEncoderState\fP * state, size_t * size)"
|
|
|
|
.PP
|
|
Acquires pointer to internal output buffer\&. This method is used to make language bindings easier and more efficient:
|
|
.IP "1." 4
|
|
push data to \fBBrotliEncoderCompressStream\fP, until \fBBrotliEncoderHasMoreOutput\fP returns BROTL_TRUE
|
|
.IP "2." 4
|
|
use \fBBrotliEncoderTakeOutput\fP to peek bytes and copy to language-specific entity
|
|
.PP
|
|
.PP
|
|
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)\&.
|
|
.PP
|
|
\fBAttention:\fP
|
|
.RS 4
|
|
After every call to \fBBrotliEncoderTakeOutput\fP \fC*size\fP bytes of output are considered consumed for all consecutive calls to the instance methods; returned pointer becomes invalidated as well\&.
|
|
.RE
|
|
.PP
|
|
\fBNote:\fP
|
|
.RS 4
|
|
Encoder output is not guaranteed to be contiguous\&. This means that after the size-unrestricted call to \fBBrotliEncoderTakeOutput\fP, immediate next call to \fBBrotliEncoderTakeOutput\fP may return more data\&.
|
|
.RE
|
|
.PP
|
|
\fBParameters:\fP
|
|
.RS 4
|
|
\fIstate\fP encoder instance
|
|
.br
|
|
\fIsize\fP \fBin:\fP number of bytes caller is ready to take, \fC0\fP if any amount could be handled;
|
|
.br
|
|
\fBout:\fP amount of data pointed by returned pointer and considered consumed;
|
|
.br
|
|
out value is never greater than in value, unless it is \fC0\fP
|
|
.RE
|
|
.PP
|
|
\fBReturns:\fP
|
|
.RS 4
|
|
pointer to output data
|
|
.RE
|
|
.PP
|
|
|
|
.SS "uint32_t BrotliEncoderVersion (void)"
|
|
|
|
.PP
|
|
Gets an encoder library version\&. Look at BROTLI_VERSION for more information\&.
|
|
.SH "Author"
|
|
.PP
|
|
Generated automatically by Doxygen for Brotli from the source code\&.
|