/*
 *  pnglite.h - Interface for pnglite library
 *      Copyright (c) 2007 Daniel Karling
 *
 *      This software is provided 'as-is', without any express or implied
 *      warranty. In no event will the authors be held liable for any damages
 *      arising from the use of this software.
 *
 *      Permission is granted to anyone to use this software for any purpose,
 *      including commercial applications, and to alter it and redistribute it
 *      freely, subject to the following restrictions:
 *
 *      1. The origin of this software must not be misrepresented; you must not
 *         claim that you wrote the original software. If you use this software
 *         in a product, an acknowledgment in the product documentation would be
 *         appreciated but is not required.
 *
 *      2. Altered source versions must be plainly marked as such, and must not
 *         be misrepresented as being the original software.
 *
 *      3. This notice may not be removed or altered from any source
 *         distribution.
 *
 *      Daniel Karling
 *      daniel.karling@gmail.com
 */


#ifndef _PNGLITE_H_
#define _PNGLITE_H_

#include <string.h>

#ifdef __cplusplus
extern "C" {
#endif

/*
 *      Enumerations for pnglite.
 *      Negative numbers are error codes and 0 and up are okay responses.
 */

enum {
        PNG_DONE                        = 1,
        PNG_NO_ERROR                    = 0,
        PNG_FILE_ERROR                  = -1,
        PNG_HEADER_ERROR                = -2,
        PNG_IO_ERROR                    = -3,
        PNG_EOF_ERROR                   = -4,
        PNG_CRC_ERROR                   = -5,
        PNG_MEMORY_ERROR                = -6,
        PNG_ZLIB_ERROR                  = -7,
        PNG_UNKNOWN_FILTER              = -8,
        PNG_NOT_SUPPORTED               = -9,
        PNG_WRONG_ARGUMENTS             = -10
};

/*
 *      The five different kinds of color storage in PNG files.
 */

enum {
        PNG_GREYSCALE                   = 0,
        PNG_TRUECOLOR                   = 2,
        PNG_INDEXED                     = 3,
        PNG_GREYSCALE_ALPHA             = 4,
        PNG_TRUECOLOR_ALPHA             = 6
};

typedef struct {
        void                    *zs;            /* pointer to z_stream */
        int                     fd;
        unsigned char           *image;

        unsigned char           *png_data;
        unsigned                png_datalen;

        unsigned                width;
        unsigned                height;
        unsigned char           depth;
        unsigned char           color_type;
        unsigned char           compression_method;
        unsigned char           filter_method;
        unsigned char           interlace_method;
        unsigned char           bpp;

        unsigned char           *readbuf;
        unsigned                readbuflen;
} png_t;


/*
 *      Function: png_open
 *
 *      This function is used to open a png file with the internal file
 *      IO system.
 *
 *      Parameters:
 *              png - Empty png_t struct.
 *              filename - Filename of the file to be opened.
 *
 *      Returns:
 *              PNG_NO_ERROR on success, otherwise an error code.
 */

int png_open(png_t *png, const char *filename);

/*
 *      Function: png_print_info
 *
 *      This function prints some info about the opened png file to stdout.
 *
 *      Parameters:
 *              png - png struct to get info from.
 */

void png_print_info(png_t *png);

/*
 *      Function: png_error_string
 *
 *      This function translates an error code to a human readable string.
 *
 *      Parameters:
 *              error - Error code.
 *
 *      Returns:
 *              Pointer to string.
 */

char *png_error_string(int error);

/*
 *      Function: png_get_data
 *
 *      This function decodes the opened png file and stores the result in data.
 *      data should be big enough to hold the decoded png.
 *      Required size will be:
 *
 *      > width*height*(bytes per pixel)
 *
 *      Parameters:
 *              data - Where to store result.
 *
 *      Returns:
 *              PNG_NO_ERROR on success, otherwise an error code.
 */

int png_get_data(png_t *png, uint8_t *data);

/*
 *      Function: png_close
 *
 *      Closes an open png file pointer.
 *
 *      Parameters:
 *              png - png to close.
 *
 *      Returns:
 *              PNG_NO_ERROR
 */

int png_close(png_t *png);

#ifdef __cplusplus
}
#endif

#endif /* _PNGLITE_H_ */