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 /* Copyright 2013 Google Inc. All Rights Reserved.
 
    Distributed under MIT license.
    See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
 */
 
 /**
  * @file
  * API for Brotli compression.
  */
 
 #ifndef BROTLI_ENC_ENCODE_H_
 #define BROTLI_ENC_ENCODE_H_
 
 #include <brotli/port.h>
 #include <brotli/shared_dictionary.h>
 #include <brotli/types.h>  /* IWYU pragma: export */
 
 #if defined(__cplusplus) || defined(c_plusplus)
 extern "C" {
 #endif
 
 /** Minimal value for ::BROTLI_PARAM_LGWIN parameter. */
 #define BROTLI_MIN_WINDOW_BITS 10
 /**
  * Maximal value for ::BROTLI_PARAM_LGWIN parameter.
  *
  * @note equal to @c BROTLI_MAX_DISTANCE_BITS constant.
  */
 #define BROTLI_MAX_WINDOW_BITS 24
 /**
  * Maximal value for ::BROTLI_PARAM_LGWIN parameter
  * in "Large Window Brotli" (32-bit).
  */
 #define BROTLI_LARGE_MAX_WINDOW_BITS 30
 /** Minimal value for ::BROTLI_PARAM_LGBLOCK parameter. */
 #define BROTLI_MIN_INPUT_BLOCK_BITS 16
 /** Maximal value for ::BROTLI_PARAM_LGBLOCK parameter. */
 #define BROTLI_MAX_INPUT_BLOCK_BITS 24
 /** Minimal value for ::BROTLI_PARAM_QUALITY parameter. */
 #define BROTLI_MIN_QUALITY 0
 /** Maximal value for ::BROTLI_PARAM_QUALITY parameter. */
 #define BROTLI_MAX_QUALITY 11
 
 /** Options for ::BROTLI_PARAM_MODE parameter. */
 typedef enum BrotliEncoderMode {
   /**
    * Default compression mode.
    *
    * In this mode compressor does not know anything in advance about the
    * properties of the input.
    */
   BROTLI_MODE_GENERIC = 0,
   /** Compression mode for UTF-8 formatted text input. */
   BROTLI_MODE_TEXT = 1,
   /** Compression mode used in WOFF 2.0. */
   BROTLI_MODE_FONT = 2
 } BrotliEncoderMode;
 
 /** Default value for ::BROTLI_PARAM_QUALITY parameter. */
 #define BROTLI_DEFAULT_QUALITY 11
 /** Default value for ::BROTLI_PARAM_LGWIN parameter. */
 #define BROTLI_DEFAULT_WINDOW 22
 /** Default value for ::BROTLI_PARAM_MODE parameter. */
 #define BROTLI_DEFAULT_MODE BROTLI_MODE_GENERIC
 
 /** Operations that can be performed by streaming encoder. */
 typedef enum BrotliEncoderOperation {
   /**
    * Process input.
    *
    * Encoder may postpone producing output, until it has processed enough input.
    */
   BROTLI_OPERATION_PROCESS = 0,
   /**
    * 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 @p available_in becomes @c 0, and
    * ::BrotliEncoderHasMoreOutput returns ::BROTLI_FALSE. If output is acquired
    * via ::BrotliEncoderTakeOutput, then operation should be repeated after
    * output buffer is drained.
    *
    * @warning Until flush is complete, client @b SHOULD @b NOT swap,
    *          reduce or extend input stream.
    *
    * When flush is complete, output data will be sufficient for decoder to
    * reproduce all the given input.
    */
   BROTLI_OPERATION_FLUSH = 1,
   /**
    * 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 @p available_in becomes @c 0, and
    * ::BrotliEncoderHasMoreOutput returns ::BROTLI_FALSE. If output is acquired
    * via ::BrotliEncoderTakeOutput, then operation should be repeated after
    * output buffer is drained.
    *
    * @warning Until finalization is complete, client @b SHOULD @b NOT swap,
    *          reduce or extend input stream.
    *
    * Helper function ::BrotliEncoderIsFinished checks if stream is finalized and
    * output fully dumped.
    *
    * Adding more input data to finalized stream is impossible.
    */
   BROTLI_OPERATION_FINISH = 2,
   /**
    * 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.
    *
    * @note Encoder may emit empty metadata blocks internally, to pad encoded
    *       stream to byte boundary.
    *
    * @warning Until emitting metadata is complete client @b SHOULD @b NOT swap,
    *          reduce or extend input stream.
    *
    * @warning The whole content of input buffer is considered to be the content
    *          of metadata block. Do @b NOT @e append metadata to input stream,
    *          before it is depleted with other operations.
    *
    * Stream is soft-flushed before metadata block is emitted. Metadata block
    * @b MUST be no longer than than 16MiB.
    */
   BROTLI_OPERATION_EMIT_METADATA = 3
 } BrotliEncoderOperation;
 
 /** Options to be used with ::BrotliEncoderSetParameter. */
 typedef enum BrotliEncoderParameter {
   /**
    * Tune encoder for specific input.
    *
    * ::BrotliEncoderMode enumerates all available values.
    */
   BROTLI_PARAM_MODE = 0,
   /**
    * 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_QUALITY = 1,
   /**
    * Recommended sliding LZ77 window size.
    *
    * Encoder may reduce this value, e.g. if input is much smaller than
    * window size.
    *
    * Window size is `(1 << value) - 16`.
    *
    * Range is from ::BROTLI_MIN_WINDOW_BITS to ::BROTLI_MAX_WINDOW_BITS.
    */
   BROTLI_PARAM_LGWIN = 2,
   /**
    * 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.
    *
    * @note Bigger input block size allows better compression, but consumes more
    *       memory. \n The rough formula of memory used for temporary input
    *       storage is `3 << lgBlock`.
    */
   BROTLI_PARAM_LGBLOCK = 3,
   /**
    * Flag that affects usage of "literal context modeling" format feature.
    *
    * This flag is a "decoding-speed vs compression ratio" trade-off.
    */
   BROTLI_PARAM_DISABLE_LITERAL_CONTEXT_MODELING = 4,
   /**
    * Estimated total input size for all ::BrotliEncoderCompressStream calls.
    *
    * The default value is 0, which means that the total input size is unknown.
    */
   BROTLI_PARAM_SIZE_HINT = 5,
   /**
    * Flag that determines if "Large Window Brotli" is used.
    */
   BROTLI_PARAM_LARGE_WINDOW = 6,
   /**
    * Recommended number of postfix bits (NPOSTFIX).
    *
    * Encoder may change this value.
    *
    * Range is from 0 to ::BROTLI_MAX_NPOSTFIX.
    */
   BROTLI_PARAM_NPOSTFIX = 7,
   /**
    * 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_NDIRECT = 8,
   /**
    * Number of bytes of input stream already processed by a different instance.
    *
    * @note 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.
    *
    * 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_PARAM_STREAM_OFFSET = 9
 } BrotliEncoderParameter;
 
 /**
  * Opaque structure that holds encoder state.
  *
  * Allocated and initialized with ::BrotliEncoderCreateInstance.
  * Cleaned up and deallocated with ::BrotliEncoderDestroyInstance.
  */
 typedef struct BrotliEncoderStateStruct BrotliEncoderState;
 
 /**
  * Sets the specified parameter to the given encoder instance.
  *
  * @param state encoder instance
  * @param param parameter to set
  * @param value new parameter value
  * @returns ::BROTLI_FALSE if parameter is unrecognized, or value is invalid
  * @returns ::BROTLI_FALSE 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)
  * @returns ::BROTLI_TRUE if value is accepted
  * @warning invalid values might be accepted in case they would not break
  *          encoding process.
  */
 BROTLI_ENC_API BROTLI_BOOL BrotliEncoderSetParameter(
     BrotliEncoderState* state, BrotliEncoderParameter param, uint32_t value);
 
 /**
  * Creates an instance of ::BrotliEncoderState and initializes it.
  *
  * @p alloc_func and @p free_func @b MUST be both zero or both non-zero. In the
  * case they are both zero, default memory allocators are used. @p opaque is
  * passed to @p alloc_func and @p free_func when they are called. @p free_func
  * has to return without doing anything when asked to free a NULL pointer.
  *
  * @param alloc_func custom memory allocation function
  * @param free_func custom memory free function
  * @param opaque custom memory manager handle
  * @returns @c 0 if instance can not be allocated or initialized
  * @returns pointer to initialized ::BrotliEncoderState otherwise
  */
 BROTLI_ENC_API BrotliEncoderState* BrotliEncoderCreateInstance(
     brotli_alloc_func alloc_func, brotli_free_func free_func, void* opaque);
 
 /**
  * Deinitializes and frees ::BrotliEncoderState instance.
  *
  * @param state decoder instance to be cleaned up and deallocated
  */
 BROTLI_ENC_API void BrotliEncoderDestroyInstance(BrotliEncoderState* state);
 
 /* Opaque type for pointer to different possible internal structures containing
    dictionary prepared for the encoder */
 typedef struct BrotliEncoderPreparedDictionaryStruct
     BrotliEncoderPreparedDictionary;
 
 /**
  * Prepares a shared dictionary from the given file format for the encoder.
  *
  * @p alloc_func and @p free_func @b MUST be both zero or both non-zero. In the
  * case they are both zero, default memory allocators are used. @p opaque is
  * passed to @p alloc_func and @p free_func when they are called. @p free_func
  * has to return without doing anything when asked to free a NULL pointer.
  *
  * @warning Created instance is "lean"; it does not contain copy of @p data,
  *          rather it contains only pointer to it; therefore,
  *          @p data @b MUST outlive the created instance.
  *
  * @param type type of dictionary stored in data
  * @param data_size size of @p data buffer
  * @param data pointer to the dictionary data
  * @param quality the maximum Brotli quality to prepare the dictionary for,
  *        use BROTLI_MAX_QUALITY by default
  * @param alloc_func custom memory allocation function
  * @param free_func custom memory free function
  * @param opaque custom memory manager handle
  */
 BROTLI_ENC_API BrotliEncoderPreparedDictionary*
 BrotliEncoderPrepareDictionary(BrotliSharedDictionaryType type,
     size_t data_size, const uint8_t data[BROTLI_ARRAY_PARAM(data_size)],
     int quality,
     brotli_alloc_func alloc_func, brotli_free_func free_func, void* opaque);
 
 BROTLI_ENC_API void BrotliEncoderDestroyPreparedDictionary(
     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.
  *
  * @returns ::BROTLI_FALSE in case of error
  * @returns ::BROTLI_TRUE otherwise
  */
 BROTLI_ENC_API BROTLI_BOOL BrotliEncoderAttachPreparedDictionary(
     BrotliEncoderState* state,
     const BrotliEncoderPreparedDictionary* dictionary);
 
 /**
  * Calculates the output size bound for the given @p input_size.
  *
  * @warning Result is only valid if quality is at least @c 2 and, in
  *          case ::BrotliEncoderCompressStream was used, no flushes
  *          (::BROTLI_OPERATION_FLUSH) were performed.
  *
  * @param input_size size of projected input
  * @returns @c 0 if result does not fit @c size_t
  */
 BROTLI_ENC_API size_t BrotliEncoderMaxCompressedSize(size_t input_size);
 
 /**
  * Performs one-shot memory-to-memory compression.
  *
  * Compresses the data in @p input_buffer into @p encoded_buffer, and sets
  * @p *encoded_size to the compressed length.
  *
  * @note If ::BrotliEncoderMaxCompressedSize(@p input_size) returns non-zero
  *       value, then output is guaranteed to be no longer than that.
  *
  * @note If @p 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 = @c 1
  *
  * @param quality quality parameter value, e.g. ::BROTLI_DEFAULT_QUALITY
  * @param lgwin lgwin parameter value, e.g. ::BROTLI_DEFAULT_WINDOW
  * @param mode mode parameter value, e.g. ::BROTLI_DEFAULT_MODE
  * @param input_size size of @p input_buffer
  * @param input_buffer input data buffer with at least @p input_size
  *        addressable bytes
  * @param[in, out] encoded_size @b in: size of @p encoded_buffer; \n
  *                 @b out: length of compressed data written to
  *                 @p encoded_buffer, or @c 0 if compression fails
  * @param encoded_buffer compressed data destination buffer
  * @returns ::BROTLI_FALSE in case of compression error
  * @returns ::BROTLI_FALSE if output buffer is too small
  * @returns ::BROTLI_TRUE otherwise
  */
 BROTLI_ENC_API BROTLI_BOOL BrotliEncoderCompress(
     int quality, int lgwin, BrotliEncoderMode mode, size_t input_size,
     const uint8_t input_buffer[BROTLI_ARRAY_PARAM(input_size)],
     size_t* encoded_size,
     uint8_t encoded_buffer[BROTLI_ARRAY_PARAM(*encoded_size)]);
 
 /**
  * Compresses input stream to output stream.
  *
  * The values @p *available_in and @p *available_out must specify the number of
  * bytes addressable at @p *next_in and @p *next_out respectively.
  * When @p *available_out is @c 0, @p next_out is allowed to be @c NULL.
  *
  * After each call, @p *available_in will be decremented by the amount of input
  * bytes consumed, and the @p *next_in pointer will be incremented by that
  * amount. Similarly, @p *available_out will be decremented by the amount of
  * output bytes written, and the @p *next_out pointer will be incremented by
  * that amount.
  *
  * @p total_out, if it is not a null-pointer, will be set to the number
  * of bytes compressed since the last @p state initialization.
  *
  *
  *
  * Internally workflow consists of 3 tasks:
  *  -# (optionally) copy input data to internal buffer
  *  -# actually compress data and (optionally) store it to internal buffer
  *  -# (optionally) copy compressed bytes from internal buffer to output stream
  *
  * Whenever all 3 tasks can't move forward anymore, or error occurs, this
  * method returns the control flow to caller.
  *
  * @p 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 @p 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 @p 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.
  *
  * @warning When flushing and finishing, @p op should not change until operation
  *          is complete; input stream should not be swapped, reduced or
  *          extended as well.
  *
  * @param state encoder instance
  * @param op requested operation
  * @param[in, out] available_in @b in: amount of available input; \n
  *                 @b out: amount of unused input
  * @param[in, out] next_in pointer to the next input byte
  * @param[in, out] available_out @b in: length of output buffer; \n
  *                 @b out: remaining size of output buffer
  * @param[in, out] next_out compressed output buffer cursor;
  *                 can be @c NULL if @p available_out is @c 0
  * @param[out] total_out number of bytes produced so far; can be @c NULL
  * @returns ::BROTLI_FALSE if there was an error
  * @returns ::BROTLI_TRUE otherwise
  */
 BROTLI_ENC_API 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);
 
 /**
  * Checks if encoder instance reached the final state.
  *
  * @param state encoder instance
  * @returns ::BROTLI_TRUE if encoder is in a state where it reached the end of
  *          the input and produced all of the output
  * @returns ::BROTLI_FALSE otherwise
  */
 BROTLI_ENC_API BROTLI_BOOL BrotliEncoderIsFinished(BrotliEncoderState* state);
 
 /**
  * Checks if encoder has more output.
  *
  * @param state encoder instance
  * @returns ::BROTLI_TRUE, if encoder has some unconsumed output
  * @returns ::BROTLI_FALSE otherwise
  */
 BROTLI_ENC_API BROTLI_BOOL BrotliEncoderHasMoreOutput(
     BrotliEncoderState* state);
 
 /**
  * Acquires pointer to internal output buffer.
  *
  * This method is used to make language bindings easier and more efficient:
  *  -# push data to ::BrotliEncoderCompressStream,
  *     until ::BrotliEncoderHasMoreOutput returns BROTLI_TRUE
  *  -# use ::BrotliEncoderTakeOutput to peek bytes and copy to language-specific
  *     entity
  *
  * 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).
  *
  * @attention After every call to ::BrotliEncoderTakeOutput @p *size bytes of
  *            output are considered consumed for all consecutive calls to the
  *            instance methods; returned pointer becomes invalidated as well.
  *
  * @note Encoder output is not guaranteed to be contiguous. This means that
  *       after the size-unrestricted call to ::BrotliEncoderTakeOutput,
  *       immediate next call to ::BrotliEncoderTakeOutput may return more data.
  *
  * @param state encoder instance
  * @param[in, out] size @b in: number of bytes caller is ready to take, @c 0 if
  *                 any amount could be handled; \n
  *                 @b out: amount of data pointed by returned pointer and
  *                 considered consumed; \n
  *                 out value is never greater than in value, unless it is @c 0
  * @returns pointer to output data
  */
 BROTLI_ENC_API const uint8_t* BrotliEncoderTakeOutput(
     BrotliEncoderState* state, size_t* size);
 
 /* Returns the estimated peak memory usage (in bytes) of the BrotliCompress()
    function, not counting the memory needed for the input and output. */
 BROTLI_ENC_EXTRA_API size_t BrotliEncoderEstimatePeakMemoryUsage(
     int quality, int lgwin, size_t input_size);
 /* Returns 0 if dictionary is not valid; otherwise returns allocation size. */
 BROTLI_ENC_EXTRA_API size_t BrotliEncoderGetPreparedDictionarySize(
     const BrotliEncoderPreparedDictionary* dictionary);
 
 /**
  * Gets an encoder library version.
  *
  * Look at BROTLI_MAKE_HEX_VERSION for more information.
  */
 BROTLI_ENC_API uint32_t BrotliEncoderVersion(void);
 
 #if defined(__cplusplus) || defined(c_plusplus)
 }  /* extern "C" */
 #endif
 
 #endif  /* BROTLI_ENC_ENCODE_H_ */

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