// Copyright 2010 Google Inc.

//

// This code is licensed under the same terms as WebM:

// Software License Agreement: http://www.webmproject.org/license/software/

// Additional IP Rights Grant: http://www.webmproject.org/license/additional/

// -----------------------------------------------------------------------------

//

// Main decoding functions for WEBP images.

//

// Author: Skal (pascal.massimino@gmail.com)

#ifndef WEBP_WEBP_DECODE_H_

#define WEBP_WEBP_DECODE_H_

#include "./types.h"

#if defined(__cplusplus) || defined(c_plusplus)

extern "C" {

#endif

#define WEBP_DECODER_ABI_VERSION 0x0002

// Return the decoder's version number, packed in hexadecimal using 8bits for

// each of major/minor/revision. E.g: v2.5.7 is 0x020507.

WEBP_EXTERN(int) WebPGetDecoderVersion(void);

// Retrieve basic header information: width, height.

// This function will also validate the header and return 0 in

// case of formatting error.

// Pointers *width/*height can be passed NULL if deemed irrelevant.

WEBP_EXTERN(int) WebPGetInfo(const uint8_t* data, uint32_t data_size,

int* width, int* height);

// Decodes WEBP images pointed to by *data and returns RGB samples, along

// with the dimensions in *width and *height.

// The returned pointer should be deleted calling free().

// Returns NULL in case of error.

WEBP_EXTERN(uint8_t*) WebPDecodeRGB(const uint8_t* data, uint32_t data_size,

int* width, int* height);

// Same as WebPDecodeRGB, but returning RGBA data.

WEBP_EXTERN(uint8_t*) WebPDecodeRGBA(const uint8_t* data, uint32_t data_size,

int* width, int* height);

// Same as WebPDecodeRGBA, but returning ARGB data.

WEBP_EXTERN(uint8_t*) WebPDecodeARGB(const uint8_t* data, uint32_t data_size,

int* width, int* height);

// This variant decode to BGR instead of RGB.

WEBP_EXTERN(uint8_t*) WebPDecodeBGR(const uint8_t* data, uint32_t data_size,

int* width, int* height);

// This variant decodes to BGRA instead of RGBA.

WEBP_EXTERN(uint8_t*) WebPDecodeBGRA(const uint8_t* data, uint32_t data_size,

int* width, int* height);

// Decode WEBP images stored in *data in Y'UV format(*). The pointer returned is

// the Y samples buffer. Upon return, *u and *v will point to the U and V

// chroma data. These U and V buffers need NOT be free()'d, unlike the returned

// Y luma one. The dimension of the U and V planes are both (*width + 1) / 2

// and (*height + 1)/ 2.

// Upon return, the Y buffer has a stride returned as '*stride', while U and V

// have a common stride returned as '*uv_stride'.

// Return NULL in case of error.

// (*) Also named Y'CbCr. See: http://en.wikipedia.org/wiki/YCbCr

WEBP_EXTERN(uint8_t*) WebPDecodeYUV(const uint8_t* data, uint32_t data_size,

int* width, int* height,

uint8_t** u, uint8_t** v,

int* stride, int* uv_stride);

// These five functions are variants of the above ones, that decode the image

// directly into a pre-allocated buffer 'output_buffer'. The maximum storage

// available in this buffer is indicated by 'output_buffer_size'. If this

// storage is not sufficient (or an error occurred), NULL is returned.

// Otherwise, output_buffer is returned, for convenience.

// The parameter 'output_stride' specifies the distance (in bytes)

// between scanlines. Hence, output_buffer_size is expected to be at least

// output_stride x picture-height.

WEBP_EXTERN(uint8_t*) WebPDecodeRGBInto(

const uint8_t* data, uint32_t data_size,

uint8_t* output_buffer, int output_buffer_size, int output_stride);

WEBP_EXTERN(uint8_t*) WebPDecodeRGBAInto(

const uint8_t* data, uint32_t data_size,

uint8_t* output_buffer, int output_buffer_size, int output_stride);

WEBP_EXTERN(uint8_t*) WebPDecodeARGBInto(

const uint8_t* data, uint32_t data_size,

uint8_t* output_buffer, int output_buffer_size, int output_stride);

// BGR variants

WEBP_EXTERN(uint8_t*) WebPDecodeBGRInto(

const uint8_t* data, uint32_t data_size,

uint8_t* output_buffer, int output_buffer_size, int output_stride);

WEBP_EXTERN(uint8_t*) WebPDecodeBGRAInto(

const uint8_t* data, uint32_t data_size,

uint8_t* output_buffer, int output_buffer_size, int output_stride);

// WebPDecodeYUVInto() is a variant of WebPDecodeYUV() that operates directly

// into pre-allocated luma/chroma plane buffers. This function requires the

// strides to be passed: one for the luma plane and one for each of the

// chroma ones. The size of each plane buffer is passed as 'luma_size',

// 'u_size' and 'v_size' respectively.

// Pointer to the luma plane ('*luma') is returned or NULL if an error occurred

// during decoding (or because some buffers were found to be too small).

WEBP_EXTERN(uint8_t*) WebPDecodeYUVInto(

uint8_t* v, int v_size, int v_stride);

//------------------------------------------------------------------------------

// Output colorspaces and buffer

// Colorspaces

typedef enum { MODE_RGB = 0, MODE_RGBA = 1,

MODE_BGR = 2, MODE_BGRA = 3,

MODE_ARGB = 4, MODE_RGBA_4444 = 5,

MODE_RGB_565 = 6,

// YUV modes must come after RGB ones.

MODE_YUV = 7, MODE_YUVA = 8, // yuv 4:2:0

MODE_LAST = 9

} WEBP_CSP_MODE;

// Generic structure for describing the sample buffer.

typedef struct { // view as RGBA

uint8_t* rgba; // pointer to RGBA samples

int stride; // stride in bytes from one scanline to the next.

int size; // total size of the *rgba buffer.

} WebPRGBABuffer;

typedef struct { // view as YUVA

uint8_t* y, *u, *v, *a; // pointer to luma, chroma U/V, alpha samples

int y_stride; // luma stride

int u_stride, v_stride; // chroma strides

int a_stride; // alpha stride

int y_size; // luma plane size

int u_size, v_size; // chroma planes size

int a_size; // alpha-plane size

} WebPYUVABuffer;

// Output buffer

typedef struct {

WEBP_CSP_MODE colorspace; // Colorspace.

int width, height; // Dimensions.

int is_external_memory; // If true, 'internal_memory' pointer is not used.

union {

WebPRGBABuffer RGBA;

WebPYUVABuffer YUVA;

} u; // Nameless union of buffer parameters.

uint8_t* private_memory; // Internally allocated memory (only when

// is_external_memory is false). Should not be used

// externally, but accessed via the buffer union.

} WebPDecBuffer;

// Internal, version-checked, entry point

WEBP_EXTERN(int) WebPInitDecBufferInternal(WebPDecBuffer* const, int);

// Initialize the structure as empty. Must be called before any other use.

// Returns false in case of version mismatch

static WEBP_INLINE int WebPInitDecBuffer(WebPDecBuffer* const buffer) {

return WebPInitDecBufferInternal(buffer, WEBP_DECODER_ABI_VERSION);

}

// Free any memory associated with the buffer. Must always be called last.

// Note: doesn't free the 'buffer' structure itself.

WEBP_EXTERN(void) WebPFreeDecBuffer(WebPDecBuffer* const buffer);

//------------------------------------------------------------------------------

// Enumeration of the status codes

typedef enum {

VP8_STATUS_OK = 0,

VP8_STATUS_OUT_OF_MEMORY,

VP8_STATUS_INVALID_PARAM,

VP8_STATUS_BITSTREAM_ERROR,

VP8_STATUS_UNSUPPORTED_FEATURE,

VP8_STATUS_SUSPENDED,

VP8_STATUS_USER_ABORT,

VP8_STATUS_NOT_ENOUGH_DATA

} VP8StatusCode;

//------------------------------------------------------------------------------

// Incremental decoding

//

// This API allows streamlined decoding of partial data.

// Picture can be incrementally decoded as data become available thanks to the

// WebPIDecoder object. This object can be left in a SUSPENDED state if the

// picture is only partially decoded, pending additional input.

// Code example:

//

// WebPIDecoder* const idec = WebPINew(mode);

// while (has_more_data) {

// // ... (get additional data)

// status = WebPIAppend(idec, new_data, new_data_size);

// if (status != VP8_STATUS_SUSPENDED ||

// break;

// }

//

// // The above call decodes the current available buffer.

// // Part of the image can now be refreshed by calling to

// // WebPIDecGetRGB()/WebPIDecGetYUV() etc.

// }

// WebPIDelete(idec);

typedef struct WebPIDecoder WebPIDecoder;

// Creates a new incremental decoder with the supplied buffer parameter.

// This output_buffer can be passed NULL, in which case a default output buffer

// is used (with MODE_RGB). Otherwise, an internal reference to 'output_buffer'

// is kept, which means that the lifespan of 'output_buffer' must be larger than

// that of the returned WebPIDecoder object.

// Returns NULL if the allocation failed.

WEBP_EXTERN(WebPIDecoder*) WebPINewDecoder(WebPDecBuffer* const output_buffer);

// Creates a WebPIDecoder object. Returns NULL in case of failure.

// TODO(skal): DEPRECATED. Prefer using WebPINewDecoder().

WEBP_EXTERN(WebPIDecoder*) WebPINew(WEBP_CSP_MODE mode);

// This function allocates and initializes an incremental-decoder object, which

// will output the r/g/b(/a) samples specified by 'mode' into a preallocated

// buffer 'output_buffer'. The size of this buffer is at least

// 'output_buffer_size' and the stride (distance in bytes between two scanlines)

// is specified by 'output_stride'. Returns NULL if the allocation failed.

WEBP_EXTERN(WebPIDecoder*) WebPINewRGB(

WEBP_CSP_MODE mode,

uint8_t* output_buffer, int output_buffer_size, int output_stride);

// This function allocates and initializes an incremental-decoder object, which

// will output the raw luma/chroma samples into a preallocated planes. The luma

// plane is specified by its pointer 'luma', its size 'luma_size' and its stride

// 'luma_stride'. Similarly, the chroma-u plane is specified by the 'u',

// 'u_size' and 'u_stride' parameters, and the chroma-v plane by 'v', 'v_size'

// and 'v_size'.

// Returns NULL if the allocation failed.

WEBP_EXTERN(WebPIDecoder*) WebPINewYUV(

uint8_t* luma, int luma_size, int luma_stride,

uint8_t* u, int u_size, int u_stride,

uint8_t* v, int v_size, int v_stride);

// Deletes the WebPIDecoder object and associated memory. Must always be called

// if WebPINew, WebPINewRGB or WebPINewYUV succeeded.

WEBP_EXTERN(void) WebPIDelete(WebPIDecoder* const idec);

// Copies and decodes the next available data. Returns VP8_STATUS_OK when

// the image is successfully decoded. Returns VP8_STATUS_SUSPENDED when more

// data is expected. Returns error in other cases.

WEBP_EXTERN(VP8StatusCode) WebPIAppend(

WebPIDecoder* const idec, const uint8_t* data, uint32_t data_size);

// A variant of the above function to be used when data buffer contains

// partial data from the beginning. In this case data buffer is not copied

// to the internal memory.

// Note that the value of the 'data' pointer can change between calls to

// WebPIUpdate, for instance when the data buffer is resized to fit larger data.

WEBP_EXTERN(VP8StatusCode) WebPIUpdate(

WebPIDecoder* const idec, const uint8_t* data, uint32_t data_size);

// Returns the r/g/b/(a) image decoded so far. Returns NULL if output params

// are not initialized yet. The r/g/b/(a) output type corresponds to the mode

// specified in WebPINew()/WebPINewRGB(). *last_y is the index of last decoded

// row in raster scan order. Some pointers (*last_y, *width etc.) can be NULL if

// corresponding information is not needed.

WEBP_EXTERN(uint8_t*) WebPIDecGetRGB(

const WebPIDecoder* const idec, int* last_y,

int* width, int* height, int* stride);

// Same as above function to get YUV image. Returns pointer to the luma plane

// or NULL in case of error.

WEBP_EXTERN(uint8_t*) WebPIDecGetYUV(

const WebPIDecoder* const idec, int* last_y,

uint8_t** u, uint8_t** v,

int* width, int* height, int* stride, int* uv_stride);

// Generic call to retrieve information about the displayable area.

// If non NULL, the left/right/width/height pointers are filled with the visible

// rectangular area so far.

// Returns NULL in case the incremental decoder object is in an invalid state.

// Otherwise returns the pointer to the internal representation. This structure

// is read-only, tied to WebPIDecoder's lifespan and should not be modified.

WEBP_EXTERN(const WebPDecBuffer*) WebPIDecodedArea(

const WebPIDecoder* const idec,

int* const left, int* const top,

int* const width, int* const height);

//------------------------------------------------------------------------------

// Advanced decoding parametrization

//

// Code sample for using the advanced decoding API

/*

// A) Init a configuration object

WebPDecoderConfig config;

CHECK(WebPInitDecoderConfig(&config));

// B) optional: retrieve the bitstream's features.

CHECK(WebPGetFeatures(data, data_size, &config.input) == VP8_STATUS_OK);

// C) Adjust 'config', if needed

config.no_fancy = 1;

config.output.colorspace = MODE_BGRA;

// etc.

// Note that you can also make config.output point to an externally

// supplied memory buffer, provided it's big enough to store the decoded

// picture. Otherwise, config.output will just be used to allocate memory

// and store the decoded picture.

// D) Decode!

CHECK(WebPDecode(data, data_size, &config) == VP8_STATUS_OK);

// E) Decoded image is now in config.output (and config.output.u.RGBA)

// F) Reclaim memory allocated in config's object. It's safe to call

// this function even if the memory is external and wasn't allocated

// by WebPDecode().

WebPFreeDecBuffer(&config.output);

*/

// Features gathered from the bitstream

typedef struct {

int width; // the original width, as read from the bitstream

int height; // the original height, as read from the bitstream

int has_alpha; // true if bitstream contains an alpha channel

int no_incremental_decoding; // if true, using incremental decoding is not

// recommended.

int rotate; // TODO(later)

int uv_sampling; // should be 0 for now. TODO(later)

int bitstream_version; // should be 0 for now. TODO(later)

} WebPBitstreamFeatures;

// Internal, version-checked, entry point

WEBP_EXTERN(VP8StatusCode) WebPGetFeaturesInternal(

const uint8_t*, uint32_t, WebPBitstreamFeatures* const, int);

// Retrieve features from the bitstream. The *features structure is filled

// with information gathered from the bitstream.

// Returns false in case of error or version mismatch.

// In case of error, features->bitstream_status will reflect the error code.

static WEBP_INLINE VP8StatusCode WebPGetFeatures(

const uint8_t* data, uint32_t data_size,

WebPBitstreamFeatures* const features) {

return WebPGetFeaturesInternal(data, data_size, features,

WEBP_DECODER_ABI_VERSION);

}

// Decoding options

typedef struct {

int bypass_filtering; // if true, skip the in-loop filtering

int no_fancy_upsampling; // if true, use faster pointwise upsampler

int use_cropping; // if true, cropping is applied _first_

int crop_left, crop_top; // top-left position for cropping.

// Will be snapped to even values.

int crop_width, crop_height; // dimension of the cropping area

int use_scaling; // if true, scaling is applied _afterward_

int scaled_width, scaled_height; // final resolution

int force_rotation; // forced rotation (to be applied _last_)

int no_enhancement; // if true, discard enhancement layer

int use_threads; // if true, use multi-threaded decoding

} WebPDecoderOptions;

// Main object storing the configuration for advanced decoding.

typedef struct {

WebPBitstreamFeatures input; // Immutable bitstream features (optional)

WebPDecBuffer output; // Output buffer (can point to external mem)

WebPDecoderOptions options; // Decoding options

} WebPDecoderConfig;

// Internal, version-checked, entry point

WEBP_EXTERN(int) WebPInitDecoderConfigInternal(WebPDecoderConfig* const, int);

// Initialize the configuration as empty. This function must always be

// called first, unless WebPGetFeatures() is to be called.

// Returns false in case of mismatched version.

static WEBP_INLINE int WebPInitDecoderConfig(WebPDecoderConfig* const config) {

return WebPInitDecoderConfigInternal(config, WEBP_DECODER_ABI_VERSION);

}

// Instantiate a new incremental decoder object with requested configuration.

// The bitstream can be passed using *data and data_size parameter,

// in which case the features will be parsed and stored into config->input.

// Otherwise, 'data' can be NULL and now parsing will occur.

// Note that 'config' can be NULL too, in which case a default configuration is

// used.

// The return WebPIDecoder object must always be deleted calling WebPIDelete().

// Returns NULL in case of error (and config->status will then reflect

// the error condition).

WEBP_EXTERN(WebPIDecoder*) WebPIDecode(const uint8_t* data, uint32_t data_size,

WebPDecoderConfig* const config);

// Non-incremental version. This version decodes the full data at once, taking

// 'config' into account. Return decoding status (VP8_STATUS_OK if decoding

// was successful).

WEBP_EXTERN(VP8StatusCode) WebPDecode(const uint8_t* data, uint32_t data_size,

WebPDecoderConfig* const config);

#if defined(__cplusplus) || defined(c_plusplus)

} // extern "C"

#endif

#endif /* WEBP_WEBP_DECODE_H_ */