#if _MSC_VER >= 1400

#define _CRT_SECURE_NO_DEPRECATE 1

#endif

/* pngread.c - read a PNG file

 *

 * libpng 1.2.4 - July 8, 2002

 * For conditions of distribution and use, see copyright notice in png.h

 * Copyright (c) 1998-2002 Glenn Randers-Pehrson

 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)

 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)

 *

 * This file contains routines that an application calls directly to

 * read a PNG file or stream.

 */

#define PNG_INTERNAL

#include "png.h"

/* Create a PNG structure for reading, and allocate any memory needed. */

png_structp PNGAPI

png_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr,

					   png_error_ptr error_fn, png_error_ptr warn_fn)

{

#ifdef PNG_USER_MEM_SUPPORTED

	return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,

									 warn_fn, png_voidp_NULL, png_malloc_ptr_NULL, png_free_ptr_NULL));

}

/* Alternate create PNG structure for reading, and allocate any memory needed. */

png_structp PNGAPI

png_create_read_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,

						 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,

						 png_malloc_ptr malloc_fn, png_free_ptr free_fn)

{

#endif /* PNG_USER_MEM_SUPPORTED */

	png_structp png_ptr;

#ifdef PNG_SETJMP_SUPPORTED

#ifdef USE_FAR_KEYWORD

	jmp_buf jmpbuf;

#endif

#endif

	int i;

	png_debug(1, "in png_create_read_struct\n");

#ifdef PNG_USER_MEM_SUPPORTED

	png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,

											   (png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);

#else

	png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);

#endif

	if (png_ptr == NULL)

		return (NULL);

	png_ptr->m_canDelete = 1;

#if !defined(PNG_1_0_X)

#ifdef PNG_ASSEMBLER_CODE_SUPPORTED

	png_init_mmx_flags(png_ptr); /* 1.2.0 addition */

#endif

#endif /* PNG_1_0_X */

#ifdef PNG_SETJMP_SUPPORTED

#ifdef USE_FAR_KEYWORD

	if (setjmp(jmpbuf))

#else

	if (setjmp(png_ptr->jmpbuf))

#endif

	{

		png_free(png_ptr, png_ptr->zbuf);

		png_ptr->zbuf = NULL;

#ifdef PNG_USER_MEM_SUPPORTED

		png_destroy_struct_2((png_voidp)png_ptr,

							 (png_free_ptr)free_fn, (png_voidp)mem_ptr);

#else

		png_destroy_struct((png_voidp)png_ptr);

#endif

		return (NULL);

	}

#ifdef USE_FAR_KEYWORD

	png_memcpy(png_ptr->jmpbuf, jmpbuf, sizeof(jmp_buf));

#endif

#endif

#ifdef PNG_USER_MEM_SUPPORTED

	png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);

#endif

	png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);

	i = 0;

	do {

		if (user_png_ver[i] != png_libpng_ver[i])

			png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;

	} while (png_libpng_ver[i++]);

	if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH) {

		/* Libpng 0.90 and later are binary incompatible with libpng 0.89, so

      * we must recompile any applications that use any older library version.

      * For versions after libpng 1.0, we will be compatible, so we need

      * only check the first digit.

      */

		if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||

			(user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||

			(user_png_ver[0] == '0' && user_png_ver[2] < '9')) {

#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)

			char msg[80];

			if (user_png_ver) {

				sprintf(msg, "Application was compiled with png.h from libpng-%.20s",

						user_png_ver);

				png_warning(png_ptr, msg);

			}

			sprintf(msg, "Application  is  running with png.c from libpng-%.20s",

					png_libpng_ver);

			png_warning(png_ptr, msg);

#endif

#ifdef PNG_ERROR_NUMBERS_SUPPORTED

			png_ptr->flags = 0;

#endif

			png_error(png_ptr,

					  "Incompatible libpng version in application and library");

		}

	}

	/* initialize zbuf - compression buffer */

	png_ptr->zbuf_size = PNG_ZBUF_SIZE;

	png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,

										  (png_uint_32)png_ptr->zbuf_size);

	png_ptr->zstream.zalloc = png_zalloc;

	png_ptr->zstream.zfree = png_zfree;

	png_ptr->zstream.opaque = (voidpf)png_ptr;

	switch (inflateInit(&png_ptr->zstream)) {

	case Z_OK: /* Do nothing */

		break;

	case Z_MEM_ERROR:

	case Z_STREAM_ERROR:

		png_error(png_ptr, "zlib memory error");

		break;

	case Z_VERSION_ERROR:

		png_error(png_ptr, "zlib version error");

		break;

	default:

		png_error(png_ptr, "Unknown zlib error");

	}

	png_ptr->zstream.next_out = png_ptr->zbuf;

	png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;

	png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);

#ifdef PNG_SETJMP_SUPPORTED

/* Applications that neglect to set up their own setjmp() and then encounter

   a png_error() will longjmp here.  Since the jmpbuf is then meaningless we

   abort instead of returning. */

#ifdef USE_FAR_KEYWORD

	if (setjmp(jmpbuf))

		PNG_ABORT();

	png_memcpy(png_ptr->jmpbuf, jmpbuf, sizeof(jmp_buf));

#else

	if (setjmp(png_ptr->jmpbuf))

		PNG_ABORT();

#endif

#endif

	return (png_ptr);

}

/* Initialize PNG structure for reading, and allocate any memory needed.

   This interface is deprecated in favour of the png_create_read_struct(),

   and it will eventually disappear. */

#undef png_read_init

void PNGAPI

png_read_init(png_structp png_ptr)

{

	/* We only come here via pre-1.0.7-compiled applications */

	png_read_init_2(png_ptr, "1.0.6 or earlier", 0, 0);

}

void PNGAPI

png_read_init_2(png_structp png_ptr, png_const_charp user_png_ver,

				png_size_t png_struct_size, png_size_t png_info_size)

{

/* We only come here via pre-1.0.12-compiled applications */

#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)

	if (sizeof(png_struct) > png_struct_size || sizeof(png_info) > png_info_size) {

		char msg[80];

		png_ptr->warning_fn = NULL;

		if (user_png_ver) {

			sprintf(msg, "Application was compiled with png.h from libpng-%.20s",

					user_png_ver);

			png_warning(png_ptr, msg);

		}

		sprintf(msg, "Application  is  running with png.c from libpng-%.20s",

				png_libpng_ver);

		png_warning(png_ptr, msg);

	}

#endif

	if (sizeof(png_struct) > png_struct_size) {

		png_ptr->error_fn = NULL;

#ifdef PNG_ERROR_NUMBERS_SUPPORTED

		png_ptr->flags = 0;

#endif

		png_error(png_ptr,

				  "The png struct allocated by the application for reading is too small.");

	}

	if (sizeof(png_info) > png_info_size) {

		png_ptr->error_fn = NULL;

#ifdef PNG_ERROR_NUMBERS_SUPPORTED

		png_ptr->flags = 0;

#endif

		png_error(png_ptr,

				  "The info struct allocated by application for reading is too small.");

	}

	png_read_init_3(&png_ptr, user_png_ver, png_struct_size);

}

void PNGAPI

png_read_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,

				png_size_t png_struct_size)

{

#ifdef PNG_SETJMP_SUPPORTED

	jmp_buf tmp_jmp; /* to save current jump buffer */

#endif

	int i = 0;

	png_structp png_ptr = *ptr_ptr;

	do {

		if (user_png_ver[i] != png_libpng_ver[i]) {

#ifdef PNG_LEGACY_SUPPORTED

			png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;

#else

			png_ptr->warning_fn = NULL;

			png_warning(png_ptr,

						"Application uses deprecated png_read_init() and should be recompiled.");

			break;

#endif

		}

	} while (png_libpng_ver[i++]);

	png_debug(1, "in png_read_init_3\n");

#ifdef PNG_SETJMP_SUPPORTED

	/* save jump buffer and error functions */

	png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof(jmp_buf));

#endif

	if (sizeof(png_struct) > png_struct_size) {

		png_destroy_struct(png_ptr);

		*ptr_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);

		png_ptr = *ptr_ptr;

	}

	/* reset all variables to 0 */

	png_memset(png_ptr, 0, sizeof(png_struct));

#ifdef PNG_SETJMP_SUPPORTED

	/* restore jump buffer */

	png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof(jmp_buf));

#endif

	/* initialize zbuf - compression buffer */

	png_ptr->zbuf_size = PNG_ZBUF_SIZE;

	png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,

										  (png_uint_32)png_ptr->zbuf_size);

	png_ptr->zstream.zalloc = png_zalloc;

	png_ptr->zstream.zfree = png_zfree;

	png_ptr->zstream.opaque = (voidpf)png_ptr;

	switch (inflateInit(&png_ptr->zstream)) {

	case Z_OK: /* Do nothing */

		break;

	case Z_MEM_ERROR:

	case Z_STREAM_ERROR:

		png_error(png_ptr, "zlib memory");

		break;

	case Z_VERSION_ERROR:

		png_error(png_ptr, "zlib version");

		break;

	default:

		png_error(png_ptr, "Unknown zlib error");

	}

	png_ptr->zstream.next_out = png_ptr->zbuf;

	png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;

	png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);

}

/* Read the information before the actual image data.  This has been

 * changed in v0.90 to allow reading a file that already has the magic

 * bytes read from the stream.  You can tell libpng how many bytes have

 * been read from the beginning of the stream (up to the maximum of 8)

 * via png_set_sig_bytes(), and we will only check the remaining bytes

 * here.  The application can then have access to the signature bytes we

 * read if it is determined that this isn't a valid PNG file.

 */

void PNGAPI

png_read_info(png_structp png_ptr, png_infop info_ptr)

{

	png_debug(1, "in png_read_info\n");

	/* If we haven't checked all of the PNG signature bytes, do so now. */

	if (png_ptr->sig_bytes < 8) {

		png_size_t num_checked = png_ptr->sig_bytes,

				   num_to_check = 8 - num_checked;

		png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);

		png_ptr->sig_bytes = 8;

		if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check)) {

			if (num_checked < 4 &&

				png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))

				png_error(png_ptr, "Not a PNG file");

			else

				png_error(png_ptr, "PNG file corrupted by ASCII conversion");

		}

		if (num_checked < 3)

			png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;

	}

	for (;;) {

#ifdef PNG_USE_LOCAL_ARRAYS

		PNG_IHDR;

		PNG_IDAT;

		PNG_IEND;

		PNG_PLTE;

#if defined(PNG_READ_bKGD_SUPPORTED)

		PNG_bKGD;

#endif

#if defined(PNG_READ_cHRM_SUPPORTED)

		PNG_cHRM;

#endif

#if defined(PNG_READ_gAMA_SUPPORTED)

		PNG_gAMA;

#endif

#if defined(PNG_READ_hIST_SUPPORTED)

		PNG_hIST;

#endif

#if defined(PNG_READ_iCCP_SUPPORTED)

		PNG_iCCP;

#endif

#if defined(PNG_READ_iTXt_SUPPORTED)

		PNG_iTXt;

#endif

#if defined(PNG_READ_oFFs_SUPPORTED)

		PNG_oFFs;

#endif

#if defined(PNG_READ_pCAL_SUPPORTED)

		PNG_pCAL;

#endif

#if defined(PNG_READ_pHYs_SUPPORTED)

		PNG_pHYs;

#endif

#if defined(PNG_READ_sBIT_SUPPORTED)

		PNG_sBIT;

#endif

#if defined(PNG_READ_sCAL_SUPPORTED)

		PNG_sCAL;

#endif

#if defined(PNG_READ_sPLT_SUPPORTED)

		PNG_sPLT;

#endif

#if defined(PNG_READ_sRGB_SUPPORTED)

		PNG_sRGB;

#endif

#if defined(PNG_READ_tEXt_SUPPORTED)

		PNG_tEXt;

#endif

#if defined(PNG_READ_tIME_SUPPORTED)

		PNG_tIME;

#endif

#if defined(PNG_READ_tRNS_SUPPORTED)

		PNG_tRNS;

#endif

#if defined(PNG_READ_zTXt_SUPPORTED)

		PNG_zTXt;

#endif

#endif /* PNG_GLOBAL_ARRAYS */

		png_byte chunk_length[4];

		png_uint_32 length;

		png_read_data(png_ptr, chunk_length, 4);

		length = png_get_uint_32(chunk_length);

		png_reset_crc(png_ptr);

		png_crc_read(png_ptr, png_ptr->chunk_name, 4);

		png_debug2(0, "Reading %s chunk, length=%lu.\n", png_ptr->chunk_name,

				   length);

		if (length > PNG_MAX_UINT)

			png_error(png_ptr, "Invalid chunk length.");

		/* This should be a binary subdivision search or a hash for

       * matching the chunk name rather than a linear search.

       */

		if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))

			png_handle_IHDR(png_ptr, info_ptr, length);

		else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))

			png_handle_IEND(png_ptr, info_ptr, length);

#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED

		else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name)) {

			if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))

				png_ptr->mode |= PNG_HAVE_IDAT;

			png_handle_unknown(png_ptr, info_ptr, length);

			if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))

				png_ptr->mode |= PNG_HAVE_PLTE;

			else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4)) {

				if (!(png_ptr->mode & PNG_HAVE_IHDR))

					png_error(png_ptr, "Missing IHDR before IDAT");

				else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&

						 !(png_ptr->mode & PNG_HAVE_PLTE))

					png_error(png_ptr, "Missing PLTE before IDAT");

				break;

			}

		}

#endif

		else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))

			png_handle_PLTE(png_ptr, info_ptr, length);

		else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4)) {

			if (!(png_ptr->mode & PNG_HAVE_IHDR))

				png_error(png_ptr, "Missing IHDR before IDAT");

			else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&

					 !(png_ptr->mode & PNG_HAVE_PLTE))

				png_error(png_ptr, "Missing PLTE before IDAT");

			png_ptr->idat_size = length;

			png_ptr->mode |= PNG_HAVE_IDAT;

			break;

		}

#if defined(PNG_READ_bKGD_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))

			png_handle_bKGD(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_cHRM_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))

			png_handle_cHRM(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_gAMA_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))

			png_handle_gAMA(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_hIST_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))

			png_handle_hIST(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_oFFs_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))

			png_handle_oFFs(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_pCAL_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))

			png_handle_pCAL(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_sCAL_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))

			png_handle_sCAL(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_pHYs_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))

			png_handle_pHYs(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_sBIT_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))

			png_handle_sBIT(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_sRGB_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))

			png_handle_sRGB(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_iCCP_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))

			png_handle_iCCP(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_sPLT_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))

			png_handle_sPLT(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_tEXt_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))

			png_handle_tEXt(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_tIME_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))

			png_handle_tIME(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_tRNS_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))

			png_handle_tRNS(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_zTXt_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))

			png_handle_zTXt(png_ptr, info_ptr, length);

#endif

#if defined(PNG_READ_iTXt_SUPPORTED)

		else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))

			png_handle_iTXt(png_ptr, info_ptr, length);

#endif

		else

			png_handle_unknown(png_ptr, info_ptr, length);

	}

}

/* optional call to update the users info_ptr structure */

void PNGAPI

png_read_update_info(png_structp png_ptr, png_infop info_ptr)

{

	png_debug(1, "in png_read_update_info\n");

	if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))

		png_read_start_row(png_ptr);

	else

		png_warning(png_ptr,

					"Ignoring extra png_read_update_info() call; row buffer not reallocated");

	png_read_transform_info(png_ptr, info_ptr);

}

/* Initialize palette, background, etc, after transformations

 * are set, but before any reading takes place.  This allows

 * the user to obtain a gamma-corrected palette, for example.

 * If the user doesn't call this, we will do it ourselves.

 */

void PNGAPI

png_start_read_image(png_structp png_ptr)

{

	png_debug(1, "in png_start_read_image\n");

	if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))

		png_read_start_row(png_ptr);

}

void PNGAPI

png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)

{

#ifdef PNG_USE_LOCAL_ARRAYS

	PNG_IDAT;

	const int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};

	const int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};

#endif

	int ret;

	png_debug2(1, "in png_read_row (row %lu, pass %d)\n",

			   png_ptr->row_number, png_ptr->pass);

	if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))

		png_read_start_row(png_ptr);

	if (png_ptr->row_number == 0 && png_ptr->pass == 0) {

/* check for transforms that have been set but were defined out */

#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)

		if (png_ptr->transformations & PNG_INVERT_MONO)

			png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined.");

#endif

#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)

		if (png_ptr->transformations & PNG_FILLER)

			png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined.");

#endif

#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && !defined(PNG_READ_PACKSWAP_SUPPORTED)

		if (png_ptr->transformations & PNG_PACKSWAP)

			png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined.");

#endif

#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)

		if (png_ptr->transformations & PNG_PACK)

			png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined.");

#endif

#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)

		if (png_ptr->transformations & PNG_SHIFT)

			png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined.");

#endif

#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)

		if (png_ptr->transformations & PNG_BGR)

			png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined.");

#endif

#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)

		if (png_ptr->transformations & PNG_SWAP_BYTES)

			png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined.");

#endif

	}

#if defined(PNG_READ_INTERLACING_SUPPORTED)

	/* if interlaced and we do not need a new row, combine row and return */

	if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE)) {

		switch (png_ptr->pass) {

		case 0:

			if (png_ptr->row_number & 0x07) {

				if (dsp_row != NULL)

					png_combine_row(png_ptr, dsp_row,

									png_pass_dsp_mask[png_ptr->pass]);

				png_read_finish_row(png_ptr);

				return;

			}

			break;

		case 1:

			if ((png_ptr->row_number & 0x07) || png_ptr->width < 5) {

				if (dsp_row != NULL)

					png_combine_row(png_ptr, dsp_row,

									png_pass_dsp_mask[png_ptr->pass]);

				png_read_finish_row(png_ptr);

				return;

			}

			break;

		case 2:

			if ((png_ptr->row_number & 0x07) != 4) {

				if (dsp_row != NULL && (png_ptr->row_number & 4))

					png_combine_row(png_ptr, dsp_row,

									png_pass_dsp_mask[png_ptr->pass]);

				png_read_finish_row(png_ptr);

				return;

			}

			break;

		case 3:

			if ((png_ptr->row_number & 3) || png_ptr->width < 3) {

				if (dsp_row != NULL)

					png_combine_row(png_ptr, dsp_row,

									png_pass_dsp_mask[png_ptr->pass]);

				png_read_finish_row(png_ptr);

				return;

			}

			break;

		case 4:

			if ((png_ptr->row_number & 3) != 2) {

				if (dsp_row != NULL && (png_ptr->row_number & 2))

					png_combine_row(png_ptr, dsp_row,

									png_pass_dsp_mask[png_ptr->pass]);

				png_read_finish_row(png_ptr);

				return;

			}

			break;

		case 5:

			if ((png_ptr->row_number & 1) || png_ptr->width < 2) {

				if (dsp_row != NULL)

					png_combine_row(png_ptr, dsp_row,

									png_pass_dsp_mask[png_ptr->pass]);

				png_read_finish_row(png_ptr);

				return;

			}

			break;

		case 6:

			if (!(png_ptr->row_number & 1)) {

				png_read_finish_row(png_ptr);

				return;

			}

			break;

		}

	}

#endif

	if (!(png_ptr->mode & PNG_HAVE_IDAT))

		png_error(png_ptr, "Invalid attempt to read row data");

	png_ptr->zstream.next_out = png_ptr->row_buf;

	png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;

	do {

		if (!(png_ptr->zstream.avail_in)) {

			while (!png_ptr->idat_size) {

				png_byte chunk_length[4];

				png_crc_finish(png_ptr, 0);

				png_read_data(png_ptr, chunk_length, 4);

				png_ptr->idat_size = png_get_uint_32(chunk_length);

				if (png_ptr->idat_size > PNG_MAX_UINT)

					png_error(png_ptr, "Invalid chunk length.");

				png_reset_crc(png_ptr);

				png_crc_read(png_ptr, png_ptr->chunk_name, 4);

				if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))

					png_error(png_ptr, "Not enough image data");

			}

			png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;

			png_ptr->zstream.next_in = png_ptr->zbuf;

			if (png_ptr->zbuf_size > png_ptr->idat_size)

				png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;

			png_crc_read(png_ptr, png_ptr->zbuf,

						 (png_size_t)png_ptr->zstream.avail_in);

			png_ptr->idat_size -= png_ptr->zstream.avail_in;

		}

		ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);

		if (ret == Z_STREAM_END) {

			if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||

				png_ptr->idat_size)

				png_error(png_ptr, "Extra compressed data");

			png_ptr->mode |= PNG_AFTER_IDAT;

			png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;

			break;

		}

		if (ret != Z_OK)

			png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg : "Decompression error");

	} while (png_ptr->zstream.avail_out);

	png_ptr->row_info.color_type = png_ptr->color_type;

	png_ptr->row_info.width = png_ptr->iwidth;

	png_ptr->row_info.channels = png_ptr->channels;

	png_ptr->row_info.bit_depth = png_ptr->bit_depth;

	png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;

	png_ptr->row_info.rowbytes = ((png_ptr->row_info.width *

									   (png_uint_32)png_ptr->row_info.pixel_depth +

								   7) >>

								  3);

	if (png_ptr->row_buf[0])

		png_read_filter_row(png_ptr, &(png_ptr->row_info),

							png_ptr->row_buf + 1, png_ptr->prev_row + 1,

							(int)(png_ptr->row_buf[0]));

	png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,

					 png_ptr->rowbytes + 1);

#if defined(PNG_MNG_FEATURES_SUPPORTED)

	if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&

		(png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING)) {

		/* Intrapixel differencing */

		png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);

	}

#endif

	if (png_ptr->transformations)

		png_do_read_transformations(png_ptr);

#if defined(PNG_READ_INTERLACING_SUPPORTED)

	/* blow up interlaced rows to full size */

	if (png_ptr->interlaced &&

		(png_ptr->transformations & PNG_INTERLACE)) {

		if (png_ptr->pass < 6)

			/*       old interface (pre-1.0.9):

         png_do_read_interlace(&(png_ptr->row_info),

            png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);

 */

			png_do_read_interlace(png_ptr);

		if (dsp_row != NULL)

			png_combine_row(png_ptr, dsp_row,

							png_pass_dsp_mask[png_ptr->pass]);

		if (row != NULL)

			png_combine_row(png_ptr, row,

							png_pass_mask[png_ptr->pass]);

	} else

#endif

	{

		if (row != NULL)

			png_combine_row(png_ptr, row, 0xff);

		if (dsp_row != NULL)

			png_combine_row(png_ptr, dsp_row, 0xff);

	}

	png_read_finish_row(png_ptr);

	if (png_ptr->read_row_fn != NULL)

		(*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);

}

/* Read one or more rows of image data.  If the image is interlaced,

 * and png_set_interlace_handling() has been called, the rows need to

 * contain the contents of the rows from the previous pass.  If the

 * image has alpha or transparency, and png_handle_alpha()[*] has been

 * called, the rows contents must be initialized to the contents of the

 * screen.

 *

 * "row" holds the actual image, and pixels are placed in it

 * as they arrive.  If the image is displayed after each pass, it will

 * appear to "sparkle" in.  "display_row" can be used to display a

 * "chunky" progressive image, with finer detail added as it becomes

 * available.  If you do not want this "chunky" display, you may pass

 * NULL for display_row.  If you do not want the sparkle display, and

 * you have not called png_handle_alpha(), you may pass NULL for rows.

 * If you have called png_handle_alpha(), and the image has either an

 * alpha channel or a transparency chunk, you must provide a buffer for

 * rows.  In this case, you do not have to provide a display_row buffer

 * also, but you may.  If the image is not interlaced, or if you have

 * not called png_set_interlace_handling(), the display_row buffer will

 * be ignored, so pass NULL to it.

 *

 * [*] png_handle_alpha() does not exist yet, as of libpng version 1.2.4

 */

void PNGAPI

png_read_rows(png_structp png_ptr, png_bytepp row,

			  png_bytepp display_row, png_uint_32 num_rows)

{

	png_uint_32 i;

	png_bytepp rp;

	png_bytepp dp;

	png_debug(1, "in png_read_rows\n");

	rp = row;

	dp = display_row;

	if (rp != NULL && dp != NULL)

		for (i = 0; i < num_rows; i++) {

			png_bytep rptr = *rp++;

			png_bytep dptr = *dp++;

			png_read_row(png_ptr, rptr, dptr);

		}

	else if (rp != NULL)

		for (i = 0; i < num_rows; i++) {

			png_bytep rptr = *rp;

			png_read_row(png_ptr, rptr, png_bytep_NULL);

			rp++;

		}

	else if (dp != NULL)

		for (i = 0; i < num_rows; i++) {

			png_bytep dptr = *dp;

			png_read_row(png_ptr, png_bytep_NULL, dptr);

			dp++;

		}

}

/* Read the entire image.  If the image has an alpha channel or a tRNS

 * chunk, and you have called png_handle_alpha()[*], you will need to

 * initialize the image to the current image that PNG will be overlaying.

 * We set the num_rows again here, in case it was incorrectly set in

 * png_read_start_row() by a call to png_read_update_info() or

 * png_start_read_image() if png_set_interlace_handling() wasn't called

 * prior to either of these functions like it should have been.  You can

 * only call this function once.  If you desire to have an image for

 * each pass of a interlaced image, use png_read_rows() instead.

 *

 * [*] png_handle_alpha() does not exist yet, as of libpng version 1.2.4

 */

void PNGAPI

png_read_image(png_structp png_ptr, png_bytepp image)

{

	png_uint_32 i, image_height;

	int pass, j;

	png_bytepp rp;

	png_debug(1, "in png_read_image\n");

#ifdef PNG_READ_INTERLACING_SUPPORTED

	pass = png_set_interlace_handling(png_ptr);

#else

	if (png_ptr->interlaced)

		png_error(png_ptr,

				  "Cannot read interlaced image -- interlace handler disabled.");

	pass = 1;

#endif

	image_height = png_ptr->height;

	png_ptr->num_rows = image_height; /* Make sure this is set correctly */

	for (j = 0; j < pass; j++) {

		rp = image;

		for (i = 0; i < image_height; i++) {

			png_read_row(png_ptr, *rp, png_bytep_NULL);

			rp++;

		}

	}

}

/* Read the end of the PNG file.  Will not read past the end of the

 * file, will verify the end is accurate, and will read any comments

 * or time information at the end of the file, if info is not NULL.

 */

void PNGAPI

png_read_end(png_structp png_ptr, png_infop info_ptr)

{

	png_byte chunk_length[4];

	png_uint_32 length;

	png_debug(1, "in png_read_end\n");

	if (png_crc_finish(png_ptr, 0) != 0)

		return;

	/* Finish off CRC from last IDAT chunk */

	do {

#ifdef PNG_USE_LOCAL_ARRAYS

		PNG_IHDR;

		PNG_IDAT;

		PNG_IEND;

		PNG_PLTE;

#if defined(PNG_READ_bKGD_SUPPORTED)

		PNG_bKGD;

#endif

#if defined(PNG_READ_cHRM_SUPPORTED)

		PNG_cHRM;

#endif

#if defined(PNG_READ_gAMA_SUPPORTED)

		PNG_gAMA;

#endif