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- /* Copyright (c) the JPEG XL Project Authors. All rights reserved.
- *
- * Use of this source code is governed by a BSD-style
- * license that can be found in the LICENSE file.
- */
- /** @addtogroup libjxl_metadata
- * @{
- * @file gain_map.h
- * @brief Utility functions to manipulate jhgm (gain map) boxes.
- */
- #ifndef JXL_GAIN_MAP_H_
- #define JXL_GAIN_MAP_H_
- #include <jxl/color_encoding.h>
- #include <jxl/jxl_export.h>
- #include <jxl/types.h>
- #ifdef __cplusplus
- extern "C" {
- #endif
- /**
- * Gain map bundle
- *
- * This structure is used to serialize gain map data to and from an input
- * buffer. It holds pointers to sections within the buffer, and different parts
- * of the gain map data such as metadata, ICC profile data, and the gain map
- * itself.
- *
- * The pointers in this structure do not take ownership of the memory they point
- * to. Instead, they reference specific locations within the provided buffer. It
- * is the caller's responsibility to ensure that the buffer remains valid and is
- * not deallocated as long as these pointers are in use. The structure should be
- * considered as providing a view into the buffer, not as an owner of the data.
- */
- typedef struct {
- /** Version number of the gain map bundle. */
- uint8_t jhgm_version;
- /** Size of the gain map metadata in bytes. */
- uint16_t gain_map_metadata_size;
- /** Pointer to the gain map metadata, which is a binary
- * blob following ISO 21496-1. This pointer references data within the input
- * buffer. */
- const uint8_t* gain_map_metadata;
- /** Indicates whether a color encoding is present. */
- JXL_BOOL has_color_encoding;
- /** If has_color_encoding is true, this field contains the
- * uncompressed color encoding data. */
- JxlColorEncoding color_encoding;
- /** Size of the alternative ICC profile in bytes (compressed
- * size). */
- uint32_t alt_icc_size;
- /** Pointer to the compressed ICC profile. This pointer references
- * data within the input buffer. */
- const uint8_t* alt_icc;
- /** Size of the gain map in bytes. */
- uint32_t gain_map_size;
- /** Pointer to the gain map data, which is a JPEG XL naked
- * codestream. This pointer references data within the input buffer.*/
- const uint8_t* gain_map;
- } JxlGainMapBundle;
- /**
- * Calculates the total size required to serialize the gain map bundle into a
- * binary buffer. This function accounts for all the necessary space to
- * serialize fields such as gain map metadata, color encoding, compressed ICC
- * profile data, and the gain map itself.
- *
- * @param[in] map_bundle Pointer to the JxlGainMapBundle containing all
- * necessary data to compute the size.
- * @param[out] bundle_size The size in bytes required to serialize the bundle.
- * @return Whether setting the size was successful.
- */
- JXL_EXPORT JXL_BOOL JxlGainMapGetBundleSize(const JxlGainMapBundle* map_bundle,
- size_t* bundle_size);
- /**
- * Serializes the gain map bundle into a preallocated buffer. The function
- * ensures that all parts of the bundle such as metadata, color encoding,
- * compressed ICC profile, and the gain map are correctly encoded into the
- * buffer. First call `JxlGainMapGetBundleSize` to get the size needed for
- * the buffer.
- *
- * @param[in] map_bundle Pointer to the `JxlGainMapBundle` to serialize.
- * @param[out] output_buffer Pointer to the buffer where the serialized data
- * will be written.
- * @param[in] output_buffer_size The size of the output buffer in bytes. Must be
- * large enough to hold the entire serialized data.
- * @param[out] bytes_written The number of bytes written to the output buffer.
- * @return Whether writing the bundle was successful.
- */
- JXL_EXPORT JXL_BOOL JxlGainMapWriteBundle(const JxlGainMapBundle* map_bundle,
- uint8_t* output_buffer,
- size_t output_buffer_size,
- size_t* bytes_written);
- /**
- * Deserializes a gain map bundle from a provided buffer and populates a
- * `JxlGainMapBundle` structure with the data extracted. This function assumes
- * the buffer contains a valid serialized gain map bundle. After successful
- * execution, the `JxlGainMapBundle` structure will reference three different
- * sections within the buffer:
- * - gain_map_metadata
- * - alt_icc
- * - gain_map
- * These sections will be accompanied by their respective sizes. Users must
- * ensure that the buffer remains valid as long as these pointers are in use.
- * @param[in,out] map_bundle Pointer to a preallocated `JxlGainMapBundle` where
- * the deserialized data will be stored.
- * @param[in] input_buffer Pointer to the buffer containing the serialized gain
- * map bundle data.
- * @param[in] input_buffer_size The size of the input buffer in bytes.
- * @param[out] bytes_read The number of bytes read from the input buffer.
- * @return Whether reading the bundle was successful.
- */
- JXL_EXPORT JXL_BOOL JxlGainMapReadBundle(JxlGainMapBundle* map_bundle,
- const uint8_t* input_buffer,
- size_t input_buffer_size,
- size_t* bytes_read);
- #ifdef __cplusplus
- }
- #endif
- #endif /* JXL_GAIN_MAP_H_ */
- /** @} */
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