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/*
dictionary compression for images based on fastlz (http://www.fastlz.org/)
(Distributed under MIT license).
*/
#ifndef __LZ_H
#define __LZ_H
#include "lz_common.h"
#include "lz_config.h"
#include "draw.h"
typedef void *LzContext;
typedef struct LzUsrContext LzUsrContext;
struct LzUsrContext {
void (*error)(LzUsrContext *usr, const char *fmt, ...);
void (*warn)(LzUsrContext *usr, const char *fmt, ...);
void (*info)(LzUsrContext *usr, const char *fmt, ...);
void *(*malloc)(LzUsrContext *usr, int size);
void (*free)(LzUsrContext *usr, void *ptr);
int (*more_space)(LzUsrContext *usr, uint8_t **io_ptr); // get the next chunk of the
// compressed buffer. return
// number of bytes in the chunk.
int (*more_lines)(LzUsrContext *usr, uint8_t **lines); // get the next chunk of the
// original image. If the image
// is down to top, return it from
// the last line to the first one
// (stride should always be
// positive)
};
/*
assumes width is in pixels and stride is in bytes
return: the number of bytes in the compressed data
TODO : determine size limit for the first segment and each chunk. check validity
of the segment or go to literal copy.
TODO : currently support only rgb images in which width*bytes_per_pixel = stride OR
paletter images in which stride eqauls the min number of bytes to
hold a line. stride is not necessary for now. just for sanity check.
stride should be > 0
*/
int lz_encode(LzContext *lz, LzImageType type, int width, int height, int top_down,
uint8_t *lines, unsigned int num_lines, int stride,
uint8_t *io_ptr, unsigned int num_io_bytes);
/*
prepare encoder and read lz magic.
out_n_pixels number of compressed pixels. May differ from Width*height in plt1/4.
Use it for allocation the decompressed buffer.
*/
void lz_decode_begin(LzContext *lz, uint8_t *io_ptr, unsigned int num_io_bytes,
LzImageType *out_type, int *out_width, int *out_height,
int *out_n_pixels, int *out_top_down, const Palette *palette);
/*
to_type = the image output type.
We assume the buffer is consecutive. i.e. width = stride
Improtant: if the image is plt1/4 and to_type is rgb32, the image
will decompressed including the last bits in each line. This means buffer should be
larger than width*height if neede and you shoud use stride to fix it.
Note: If the image is down to top, set the stride in the cairo surface to negative.
use cairo_image_surface_create_for_data to create the surface and
cairo_surface_set_user_data in order to free the data in the destroy callback.
*/
void lz_decode(LzContext *lz, LzImageType to_type, uint8_t *buf);
LzContext *lz_create(LzUsrContext *usr);
void lz_destroy(LzContext *lz);
#endif // __LZ_H
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