pngpread.c
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pngpread.c
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	/* pngpread.c - read a png file in push mode
	*
	* Last changed in libpng 1.2.25 [February 18, 2008]
	* For conditions of distribution and use, see copyright notice in png.h
	* Copyright (c) 1998-2008 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.)
	*/

	#define PNG_INTERNAL
	#include "png.h"

	#ifdef PNG_PROGRESSIVE_READ_SUPPORTED

	/* push model modes */
	#define PNG_READ_SIG_MODE 0
	#define PNG_READ_CHUNK_MODE 1
	#define PNG_READ_IDAT_MODE 2
	#define PNG_SKIP_MODE 3
	#define PNG_READ_tEXt_MODE 4
	#define PNG_READ_zTXt_MODE 5
	#define PNG_READ_DONE_MODE 6
	#define PNG_READ_iTXt_MODE 7
	#define PNG_ERROR_MODE 8

	void PNGAPI
	png_process_data(png_structp png_ptr, png_infop info_ptr,
	png_bytep buffer, png_size_t buffer_size)
	{
	if(png_ptr == NULL \|\| info_ptr == NULL) return;
	png_push_restore_buffer(png_ptr, buffer, buffer_size);

	while (png_ptr->buffer_size)
	{
	png_process_some_data(png_ptr, info_ptr);
	}
	}

	/* What we do with the incoming data depends on what we were previously
	* doing before we ran out of data...
	*/
	void /* PRIVATE */
	png_process_some_data(png_structp png_ptr, png_infop info_ptr)
	{
	if(png_ptr == NULL) return;
	switch (png_ptr->process_mode)
	{
	case PNG_READ_SIG_MODE:
	{
	png_push_read_sig(png_ptr, info_ptr);
	break;
	}
	case PNG_READ_CHUNK_MODE:
	{
	png_push_read_chunk(png_ptr, info_ptr);
	break;
	}
	case PNG_READ_IDAT_MODE:
	{
	png_push_read_IDAT(png_ptr);
	break;
	}
	#if defined(PNG_READ_tEXt_SUPPORTED)
	case PNG_READ_tEXt_MODE:
	{
	png_push_read_tEXt(png_ptr, info_ptr);
	break;
	}
	#endif
	#if defined(PNG_READ_zTXt_SUPPORTED)
	case PNG_READ_zTXt_MODE:
	{
	png_push_read_zTXt(png_ptr, info_ptr);
	break;
	}
	#endif
	#if defined(PNG_READ_iTXt_SUPPORTED)
	case PNG_READ_iTXt_MODE:
	{
	png_push_read_iTXt(png_ptr, info_ptr);
	break;
	}
	#endif
	case PNG_SKIP_MODE:
	{
	png_push_crc_finish(png_ptr);
	break;
	}
	default:
	{
	png_ptr->buffer_size = 0;
	break;
	}
	}
	}

	/* Read any remaining signature bytes from the stream and compare them with
	* the correct PNG signature. It is possible that this routine is called
	* with bytes already read from the signature, either because they have been
	* checked by the calling application, or because of multiple calls to this
	* routine.
	*/
	void /* PRIVATE */
	png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
	{
	png_size_t num_checked = png_ptr->sig_bytes,
	num_to_check = 8 - num_checked;

	if (png_ptr->buffer_size < num_to_check)
	{
	num_to_check = png_ptr->buffer_size;
	}

	png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
	num_to_check);
	png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes+num_to_check);

	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");
	}
	else
	{
	if (png_ptr->sig_bytes >= 8)
	{
	png_ptr->process_mode = PNG_READ_CHUNK_MODE;
	}
	}
	}

	void /* PRIVATE */
	png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
	{
	#ifdef PNG_USE_LOCAL_ARRAYS
	PNG_CONST PNG_IHDR;
	PNG_CONST PNG_IDAT;
	PNG_CONST PNG_IEND;
	PNG_CONST PNG_PLTE;
	#if defined(PNG_READ_bKGD_SUPPORTED)
	PNG_CONST PNG_bKGD;
	#endif
	#if defined(PNG_READ_cHRM_SUPPORTED)
	PNG_CONST PNG_cHRM;
	#endif
	#if defined(PNG_READ_gAMA_SUPPORTED)
	PNG_CONST PNG_gAMA;
	#endif
	#if defined(PNG_READ_hIST_SUPPORTED)
	PNG_CONST PNG_hIST;
	#endif
	#if defined(PNG_READ_iCCP_SUPPORTED)
	PNG_CONST PNG_iCCP;
	#endif
	#if defined(PNG_READ_iTXt_SUPPORTED)
	PNG_CONST PNG_iTXt;
	#endif
	#if defined(PNG_READ_oFFs_SUPPORTED)
	PNG_CONST PNG_oFFs;
	#endif
	#if defined(PNG_READ_pCAL_SUPPORTED)
	PNG_CONST PNG_pCAL;
	#endif
	#if defined(PNG_READ_pHYs_SUPPORTED)
	PNG_CONST PNG_pHYs;
	#endif
	#if defined(PNG_READ_sBIT_SUPPORTED)
	PNG_CONST PNG_sBIT;
	#endif
	#if defined(PNG_READ_sCAL_SUPPORTED)
	PNG_CONST PNG_sCAL;
	#endif
	#if defined(PNG_READ_sRGB_SUPPORTED)
	PNG_CONST PNG_sRGB;
	#endif
	#if defined(PNG_READ_sPLT_SUPPORTED)
	PNG_CONST PNG_sPLT;
	#endif
	#if defined(PNG_READ_tEXt_SUPPORTED)
	PNG_CONST PNG_tEXt;
	#endif
	#if defined(PNG_READ_tIME_SUPPORTED)
	PNG_CONST PNG_tIME;
	#endif
	#if defined(PNG_READ_tRNS_SUPPORTED)
	PNG_CONST PNG_tRNS;
	#endif
	#if defined(PNG_READ_zTXt_SUPPORTED)
	PNG_CONST PNG_zTXt;
	#endif
	#endif /* PNG_USE_LOCAL_ARRAYS */
	/* First we make sure we have enough data for the 4 byte chunk name
	* and the 4 byte chunk length before proceeding with decoding the
	* chunk data. To fully decode each of these chunks, we also make
	* sure we have enough data in the buffer for the 4 byte CRC at the
	* end of every chunk (except IDAT, which is handled separately).
	*/
	if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
	{
	png_byte chunk_length[4];

	if (png_ptr->buffer_size < 8)
	{
	png_push_save_buffer(png_ptr);
	return;
	}

	png_push_fill_buffer(png_ptr, chunk_length, 4);
	png_ptr->push_length = png_get_uint_31(png_ptr,chunk_length);
	png_reset_crc(png_ptr);
	png_crc_read(png_ptr, png_ptr->chunk_name, 4);
	png_ptr->mode \|= PNG_HAVE_CHUNK_HEADER;
	}

	if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
	if(png_ptr->mode & PNG_AFTER_IDAT)
	png_ptr->mode \|= PNG_HAVE_CHUNK_AFTER_IDAT;

	if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
	}
	else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);

	png_ptr->process_mode = PNG_READ_DONE_MODE;
	png_push_have_end(png_ptr, info_ptr);
	}
	#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
	else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
	png_ptr->mode \|= PNG_HAVE_IDAT;
	png_handle_unknown(png_ptr, info_ptr, png_ptr->push_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");
	}
	}
	#endif
	else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
	}
	else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
	{
	/* If we reach an IDAT chunk, this means we have read all of the
	* header chunks, and we can start reading the image (or if this
	* is called after the image has been read - we have an error).
	*/
	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");

	if (png_ptr->mode & PNG_HAVE_IDAT)
	{
	if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
	if (png_ptr->push_length == 0)
	return;

	if (png_ptr->mode & PNG_AFTER_IDAT)
	png_error(png_ptr, "Too many IDAT's found");
	}

	png_ptr->idat_size = png_ptr->push_length;
	png_ptr->mode \|= PNG_HAVE_IDAT;
	png_ptr->process_mode = PNG_READ_IDAT_MODE;
	png_push_have_info(png_ptr, info_ptr);
	png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
	png_ptr->zstream.next_out = png_ptr->row_buf;
	return;
	}
	#if defined(PNG_READ_gAMA_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_sBIT_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_cHRM_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_sRGB_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_iCCP_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_sPLT_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_tRNS_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_bKGD_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_hIST_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_pHYs_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_oFFs_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_pCAL_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_sCAL_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_tIME_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_tEXt_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_zTXt_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	#if defined(PNG_READ_iTXt_SUPPORTED)
	else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
	}
	#endif
	else
	{
	if (png_ptr->push_length + 4 > png_ptr->buffer_size)
	{
	png_push_save_buffer(png_ptr);
	return;
	}
	png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
	}

	png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
	}

	void /* PRIVATE */
	png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
	{
	png_ptr->process_mode = PNG_SKIP_MODE;
	png_ptr->skip_length = skip;
	}

	void /* PRIVATE */
	png_push_crc_finish(png_structp png_ptr)
	{
	if (png_ptr->skip_length && png_ptr->save_buffer_size)
	{
	png_size_t save_size;

	if (png_ptr->skip_length < (png_uint_32)png_ptr->save_buffer_size)
	save_size = (png_size_t)png_ptr->skip_length;
	else
	save_size = png_ptr->save_buffer_size;

	png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);

	png_ptr->skip_length -= save_size;
	png_ptr->buffer_size -= save_size;
	png_ptr->save_buffer_size -= save_size;
	png_ptr->save_buffer_ptr += save_size;
	}
	if (png_ptr->skip_length && png_ptr->current_buffer_size)
	{
	png_size_t save_size;

	if (png_ptr->skip_length < (png_uint_32)png_ptr->current_buffer_size)
	save_size = (png_size_t)png_ptr->skip_length;
	else
	save_size = png_ptr->current_buffer_size;

	png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);

	png_ptr->skip_length -= save_size;
	png_ptr->buffer_size -= save_size;
	png_ptr->current_buffer_size -= save_size;
	png_ptr->current_buffer_ptr += save_size;
	}
	if (!png_ptr->skip_length)
	{
	if (png_ptr->buffer_size < 4)
	{
	png_push_save_buffer(png_ptr);
	return;
	}

	png_crc_finish(png_ptr, 0);
	png_ptr->process_mode = PNG_READ_CHUNK_MODE;
	}
	}

	void PNGAPI
	png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
	{
	png_bytep ptr;

	if(png_ptr == NULL) return;
	ptr = buffer;
	if (png_ptr->save_buffer_size)
	{
	png_size_t save_size;

	if (length < png_ptr->save_buffer_size)
	save_size = length;
	else
	save_size = png_ptr->save_buffer_size;

	png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
	length -= save_size;
	ptr += save_size;
	png_ptr->buffer_size -= save_size;
	png_ptr->save_buffer_size -= save_size;
	png_ptr->save_buffer_ptr += save_size;
	}
	if (length && png_ptr->current_buffer_size)
	{
	png_size_t save_size;

	if (length < png_ptr->current_buffer_size)
	save_size = length;
	else
	save_size = png_ptr->current_buffer_size;

	png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
	png_ptr->buffer_size -= save_size;
	png_ptr->current_buffer_size -= save_size;
	png_ptr->current_buffer_ptr += save_size;
	}
	}

	void /* PRIVATE */
	png_push_save_buffer(png_structp png_ptr)
	{
	if (png_ptr->save_buffer_size)
	{
	if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
	{
	png_size_t i,istop;
	png_bytep sp;
	png_bytep dp;

	istop = png_ptr->save_buffer_size;
	for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
	i < istop; i++, sp++, dp++)
	{
	dp = sp;
	}
	}
	}
	if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
	png_ptr->save_buffer_max)
	{
	png_size_t new_max;
	png_bytep old_buffer;

	if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
	(png_ptr->current_buffer_size + 256))
	{
	png_error(png_ptr, "Potential overflow of save_buffer");
	}
	new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
	old_buffer = png_ptr->save_buffer;
	png_ptr->save_buffer = (png_bytep)png_malloc(png_ptr,
	(png_uint_32)new_max);
	png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
	png_free(png_ptr, old_buffer);
	png_ptr->save_buffer_max = new_max;
	}
	if (png_ptr->current_buffer_size)
	{
	png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
	png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
	png_ptr->save_buffer_size += png_ptr->current_buffer_size;
	png_ptr->current_buffer_size = 0;
	}
	png_ptr->save_buffer_ptr = png_ptr->save_buffer;
	png_ptr->buffer_size = 0;
	}

	void /* PRIVATE */
	png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
	png_size_t buffer_length)
	{
	png_ptr->current_buffer = buffer;
	png_ptr->current_buffer_size = buffer_length;
	png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
	png_ptr->current_buffer_ptr = png_ptr->current_buffer;
	}

	void /* PRIVATE */
	png_push_read_IDAT(png_structp png_ptr)
	{
	#ifdef PNG_USE_LOCAL_ARRAYS
	PNG_CONST PNG_IDAT;
	#endif
	if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
	{
	png_byte chunk_length[4];

	if (png_ptr->buffer_size < 8)
	{
	png_push_save_buffer(png_ptr);
	return;
	}

	png_push_fill_buffer(png_ptr, chunk_length, 4);
	png_ptr->push_length = png_get_uint_31(png_ptr,chunk_length);
	png_reset_crc(png_ptr);
	png_crc_read(png_ptr, png_ptr->chunk_name, 4);
	png_ptr->mode \|= PNG_HAVE_CHUNK_HEADER;

	if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
	{
	png_ptr->process_mode = PNG_READ_CHUNK_MODE;
	if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
	png_error(png_ptr, "Not enough compressed data");
	return;
	}

	png_ptr->idat_size = png_ptr->push_length;
	}
	if (png_ptr->idat_size && png_ptr->save_buffer_size)
	{
	png_size_t save_size;

	if (png_ptr->idat_size < (png_uint_32)png_ptr->save_buffer_size)
	{
	save_size = (png_size_t)png_ptr->idat_size;
	/* check for overflow */
	if((png_uint_32)save_size != png_ptr->idat_size)
	png_error(png_ptr, "save_size overflowed in pngpread");
	}
	else
	save_size = png_ptr->save_buffer_size;

	png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
	if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
	png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
	png_ptr->idat_size -= save_size;
	png_ptr->buffer_size -= save_size;
	png_ptr->save_buffer_size -= save_size;
	png_ptr->save_buffer_ptr += save_size;
	}
	if (png_ptr->idat_size && png_ptr->current_buffer_size)
	{
	png_size_t save_size;

	if (png_ptr->idat_size < (png_uint_32)png_ptr->current_buffer_size)
	{
	save_size = (png_size_t)png_ptr->idat_size;
	/* check for overflow */
	if((png_uint_32)save_size != png_ptr->idat_size)
	png_error(png_ptr, "save_size overflowed in pngpread");
	}
	else
	save_size = png_ptr->current_buffer_size;

	png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
	if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
	png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);

	png_ptr->idat_size -= save_size;
	png_ptr->buffer_size -= save_size;
	png_ptr->current_buffer_size -= save_size;
	png_ptr->current_buffer_ptr += save_size;
	}
	if (!png_ptr->idat_size)
	{
	if (png_ptr->buffer_size < 4)
	{
	png_push_save_buffer(png_ptr);
	return;
	}

	png_crc_finish(png_ptr, 0);
	png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
	png_ptr->mode \|= PNG_AFTER_IDAT;
	}
	}

	void /* PRIVATE */
	png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
	png_size_t buffer_length)
	{
	int ret;

	if ((png_ptr->flags & PNG_FLAG_ZLIB_FINISHED) && buffer_length)
	png_error(png_ptr, "Extra compression data");

	png_ptr->zstream.next_in = buffer;
	png_ptr->zstream.avail_in = (uInt)buffer_length;
	for(;;)
	{
	ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
	if (ret != Z_OK)
	{
	if (ret == Z_STREAM_END)
	{
	if (png_ptr->zstream.avail_in)
	png_error(png_ptr, "Extra compressed data");
	if (!(png_ptr->zstream.avail_out))
	{
	png_push_process_row(png_ptr);
	}

	png_ptr->mode \|= PNG_AFTER_IDAT;
	png_ptr->flags \|= PNG_FLAG_ZLIB_FINISHED;
	break;
	}
	else if (ret == Z_BUF_ERROR)
	break;
	else
	png_error(png_ptr, "Decompression Error");
	}
	if (!(png_ptr->zstream.avail_out))
	{
	if ((
	#if defined(PNG_READ_INTERLACING_SUPPORTED)
	png_ptr->interlaced && png_ptr->pass > 6) \|\|
	(!png_ptr->interlaced &&
	#endif
	png_ptr->row_number == png_ptr->num_rows))
	{
	if (png_ptr->zstream.avail_in)
	png_warning(png_ptr, "Too much data in IDAT chunks");
	png_ptr->flags \|= PNG_FLAG_ZLIB_FINISHED;
	break;
	}
	png_push_process_row(png_ptr);
	png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
	png_ptr->zstream.next_out = png_ptr->row_buf;
	}
	else
	break;
	}
	}

	void /* PRIVATE */
	png_push_process_row(png_structp png_ptr)
	{
	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_ROWBYTES(png_ptr->row_info.pixel_depth,
	png_ptr->row_info.width);

	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 (png_ptr->transformations \|\| (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
	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);

	switch (png_ptr->pass)
	{
	case 0:
	{
	int i;
	for (i = 0; i < 8 && png_ptr->pass == 0; i++)
	{
	png_push_have_row(png_ptr, png_ptr->row_buf + 1);
	png_read_push_finish_row(png_ptr); /* updates png_ptr->pass */
	}
	if (png_ptr->pass == 2) /* pass 1 might be empty */
	{
	for (i = 0; i < 4 && png_ptr->pass == 2; i++)
	{
	png_push_have_row(png_ptr, png_bytep_NULL);
	png_read_push_finish_row(png_ptr);
	}
	}
	if (png_ptr->pass == 4 && png_ptr->height <= 4)
	{
	for (i = 0; i < 2 && png_ptr->pass == 4; i++)
	{
	png_push_have_row(png_ptr, png_bytep_NULL);
	png_read_push_finish_row(png_ptr);
	}
	}
	if (png_ptr->pass == 6 && png_ptr->height <= 4)
	{
	png_push_have_row(png_ptr, png_bytep_NULL);
	png_read_push_finish_row(png_ptr);
	}
	break;
	}
	case 1:
	{
	int i;
	for (i = 0; i < 8 && png_ptr->pass == 1; i++)
	{
	png_push_have_row(png_ptr, png_ptr->row_buf + 1);
	png_read_push_finish_row(png_ptr);
	}
	if (png_ptr->pass == 2) /* skip top 4 generated rows */
	{
	for (i = 0; i < 4 && png_ptr->pass == 2; i++)
	{
	png_push_have_row(png_ptr, png_bytep_NULL);
	png_read_push_finish_row(png_ptr);
	}
	}
	break;
	}
	case 2:
	{
	int i;
	for (i = 0; i < 4 && png_ptr->pass == 2; i++)
	{
	png_push_have_row(png_ptr, png_ptr->row_buf + 1);
	png_read_push_finish_row(png_ptr);
	}
	for (i = 0; i < 4 && png_ptr->pass == 2; i++)
	{
	png_push_have_row(png_ptr, png_bytep_NULL);
	png_read_push_finish_row(png_ptr);
	}
	if (png_ptr->pass == 4) /* pass 3 might be empty */
	{
	for (i = 0; i < 2 && png_ptr->pass == 4; i++)
	{
	png_push_have_row(png_ptr, png_bytep_NULL);
	png_read_push_finish_row(png_ptr);
	}
	}
	break;
	}
	case 3:
	{
	int i;
	for (i = 0; i < 4 && png_ptr->pass == 3; i++)
	{
	png_push_have_row(png_ptr, png_ptr->row_buf + 1);
	png_read_push_finish_row(png_ptr);
	}
	if (png_ptr->pass == 4) /* skip top two generated rows */
	{
	for (i = 0; i < 2 && png_ptr->pass == 4; i++)
	{
	png_push_have_row(png_ptr, png_bytep_NULL);
	png_read_push_finish_row(png_ptr);
	}
	}
	break;
	}
	case 4:
	{
	int i;
	for (i = 0; i < 2 && png_ptr->pass == 4; i++)
	{
	png_push_have_row(png_ptr, png_ptr->row_buf + 1);
	png_read_push_finish_row(png_ptr);
	}
	for (i = 0; i < 2 && png_ptr->pass == 4; i++)
	{
	png_push_have_row(png_ptr, png_bytep_NULL);
	png_read_push_finish_row(png_ptr);
	}
	if (png_ptr->pass == 6) /* pass 5 might be empty */
	{
	png_push_have_row(png_ptr, png_bytep_NULL);
	png_read_push_finish_row(png_ptr);
	}
	break;
	}
	case 5:
	{
	int i;
	for (i = 0; i < 2 && png_ptr->pass == 5; i++)
	{
	png_push_have_row(png_ptr, png_ptr->row_buf + 1);
	png_read_push_finish_row(png_ptr);
	}
	if (png_ptr->pass == 6) /* skip top generated row */
	{
	png_push_have_row(png_ptr, png_bytep_NULL);
	png_read_push_finish_row(png_ptr);
	}
	break;
	}
	case 6:
	{
	png_push_have_row(png_ptr, png_ptr->row_buf + 1);
	png_read_push_finish_row(png_ptr);
	if (png_ptr->pass != 6)
	break;
	png_push_have_row(png_ptr, png_bytep_NULL);
	png_read_push_finish_row(png_ptr);
	}
	}
	}
	else
	#endif
	{
	png_push_have_row(png_ptr, png_ptr->row_buf + 1);
	png_read_push_finish_row(png_ptr);
	}
	}

	void /* PRIVATE */
	png_read_push_finish_row(png_structp png_ptr)
	{
	#ifdef PNG_USE_LOCAL_ARRAYS
	/* arrays to facilitate easy interlacing - use pass (0 - 6) as index */

	/* start of interlace block */
	PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};

	/* offset to next interlace block */
	PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};

	/* start of interlace block in the y direction */
	PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};

	/* offset to next interlace block in the y direction */
	PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};

	/* Height of interlace block. This is not currently used - if you need
	* it, uncomment it here and in png.h
	PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
	*/
	#endif

	png_ptr->row_number++;
	if (png_ptr->row_number < png_ptr->num_rows)
	return;

	if (png_ptr->interlaced)
	{
	png_ptr->row_number = 0;
	png_memset_check(png_ptr, png_ptr->prev_row, 0,
	png_ptr->rowbytes + 1);
	do
	{
	int pass;
	pass = png_ptr->pass;
	pass++;
	if ((pass == 1 && png_ptr->width < 5) \|\|
	(pass == 3 && png_ptr->width < 3) \|\|
	(pass == 5 && png_ptr->width < 2))
	pass++;

	if (pass > 7)
	pass--;
	png_ptr->pass = (png_byte) pass;
	if (pass < 7)
	{
	png_ptr->iwidth = (png_ptr->width +
	png_pass_inc[pass] - 1 -
	png_pass_start[pass]) /
	png_pass_inc[pass];

	png_ptr->irowbytes = PNG_ROWBYTES(png_ptr->pixel_depth,
	png_ptr->iwidth) + 1;

	if (png_ptr->transformations & PNG_INTERLACE)
	break;

	png_ptr->num_rows = (png_ptr->height +
	png_pass_yinc[pass] - 1 -
	png_pass_ystart[pass]) /
	png_pass_yinc[pass];
	}
	else
	break;

	} while (png_ptr->iwidth == 0 \|\| png_ptr->num_rows == 0);
	}
	}

	#if defined(PNG_READ_tEXt_SUPPORTED)
	void /* PRIVATE */
	png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
	length)
	{
	if (!(png_ptr->mode & PNG_HAVE_IHDR) \|\| (png_ptr->mode & PNG_HAVE_IEND))
	{
	png_error(png_ptr, "Out of place tEXt");
	info_ptr = info_ptr; /* to quiet some compiler warnings */
	}

	#ifdef PNG_MAX_MALLOC_64K
	png_ptr->skip_length = 0; /* This may not be necessary */

	if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
	{
	png_warning(png_ptr, "tEXt chunk too large to fit in memory");
	png_ptr->skip_length = length - (png_uint_32)65535L;
	length = (png_uint_32)65535L;
	}
	#endif

	png_ptr->current_text = (png_charp)png_malloc(png_ptr,
	(png_uint_32)(length+1));
	png_ptr->current_text[length] = '\0';
	png_ptr->current_text_ptr = png_ptr->current_text;
	png_ptr->current_text_size = (png_size_t)length;
	png_ptr->current_text_left = (png_size_t)length;
	png_ptr->process_mode = PNG_READ_tEXt_MODE;
	}

	void /* PRIVATE */
	png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
	{
	if (png_ptr->buffer_size && png_ptr->current_text_left)
	{
	png_size_t text_size;

	if (png_ptr->buffer_size < png_ptr->current_text_left)
	text_size = png_ptr->buffer_size;
	else
	text_size = png_ptr->current_text_left;
	png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
	png_ptr->current_text_left -= text_size;
	png_ptr->current_text_ptr += text_size;
	}
	if (!(png_ptr->current_text_left))
	{
	png_textp text_ptr;
	png_charp text;
	png_charp key;
	int ret;

	if (png_ptr->buffer_size < 4)
	{
	png_push_save_buffer(png_ptr);
	return;
	}

	png_push_crc_finish(png_ptr);

	#if defined(PNG_MAX_MALLOC_64K)
	if (png_ptr->skip_length)
	return;
	#endif

	key = png_ptr->current_text;

	for (text = key; *text; text++)
	/* empty loop */ ;

	if (text < key + png_ptr->current_text_size)
	text++;

	text_ptr = (png_textp)png_malloc(png_ptr,
	(png_uint_32)png_sizeof(png_text));
	text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
	text_ptr->key = key;
	#ifdef PNG_iTXt_SUPPORTED
	text_ptr->lang = NULL;
	text_ptr->lang_key = NULL;
	#endif
	text_ptr->text = text;

	ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);

	png_free(png_ptr, key);
	png_free(png_ptr, text_ptr);
	png_ptr->current_text = NULL;

	if (ret)
	png_warning(png_ptr, "Insufficient memory to store text chunk.");
	}
	}
	#endif

	#if defined(PNG_READ_zTXt_SUPPORTED)
	void /* PRIVATE */
	png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
	length)
	{
	if (!(png_ptr->mode & PNG_HAVE_IHDR) \|\| (png_ptr->mode & PNG_HAVE_IEND))
	{
	png_error(png_ptr, "Out of place zTXt");
	info_ptr = info_ptr; /* to quiet some compiler warnings */
	}

	#ifdef PNG_MAX_MALLOC_64K
	/* We can't handle zTXt chunks > 64K, since we don't have enough space
	* to be able to store the uncompressed data. Actually, the threshold
	* is probably around 32K, but it isn't as definite as 64K is.
	*/
	if (length > (png_uint_32)65535L)
	{
	png_warning(png_ptr, "zTXt chunk too large to fit in memory");
	png_push_crc_skip(png_ptr, length);
	return;
	}
	#endif

	png_ptr->current_text = (png_charp)png_malloc(png_ptr,
	(png_uint_32)(length+1));
	png_ptr->current_text[length] = '\0';
	png_ptr->current_text_ptr = png_ptr->current_text;
	png_ptr->current_text_size = (png_size_t)length;
	png_ptr->current_text_left = (png_size_t)length;
	png_ptr->process_mode = PNG_READ_zTXt_MODE;
	}

	void /* PRIVATE */
	png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
	{
	if (png_ptr->buffer_size && png_ptr->current_text_left)
	{
	png_size_t text_size;

	if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left)
	text_size = png_ptr->buffer_size;
	else
	text_size = png_ptr->current_text_left;
	png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
	png_ptr->current_text_left -= text_size;
	png_ptr->current_text_ptr += text_size;
	}
	if (!(png_ptr->current_text_left))
	{
	png_textp text_ptr;
	png_charp text;
	png_charp key;
	int ret;
	png_size_t text_size, key_size;

	if (png_ptr->buffer_size < 4)
	{
	png_push_save_buffer(png_ptr);
	return;
	}

	png_push_crc_finish(png_ptr);

	key = png_ptr->current_text;

	for (text = key; *text; text++)
	/* empty loop */ ;

	/* zTXt can't have zero text */
	if (text >= key + png_ptr->current_text_size)
	{
	png_ptr->current_text = NULL;
	png_free(png_ptr, key);
	return;
	}

	text++;

	if (text != PNG_TEXT_COMPRESSION_zTXt) / check compression byte */
	{
	png_ptr->current_text = NULL;
	png_free(png_ptr, key);
	return;
	}

	text++;

	png_ptr->zstream.next_in = (png_bytep )text;
	png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size -
	(text - key));
	png_ptr->zstream.next_out = png_ptr->zbuf;
	png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;

	key_size = text - key;
	text_size = 0;
	text = NULL;
	ret = Z_STREAM_END;

	while (png_ptr->zstream.avail_in)
	{
	ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
	if (ret != Z_OK && ret != Z_STREAM_END)
	{
	inflateReset(&png_ptr->zstream);
	png_ptr->zstream.avail_in = 0;
	png_ptr->current_text = NULL;
	png_free(png_ptr, key);
	png_free(png_ptr, text);
	return;
	}
	if (!(png_ptr->zstream.avail_out) \|\| ret == Z_STREAM_END)
	{
	if (text == NULL)
	{
	text = (png_charp)png_malloc(png_ptr,
	(png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
	+ key_size + 1));
	png_memcpy(text + key_size, png_ptr->zbuf,
	png_ptr->zbuf_size - png_ptr->zstream.avail_out);
	png_memcpy(text, key, key_size);
	text_size = key_size + png_ptr->zbuf_size -
	png_ptr->zstream.avail_out;
	*(text + text_size) = '\0';
	}
	else
	{
	png_charp tmp;

	tmp = text;
	text = (png_charp)png_malloc(png_ptr, text_size +
	(png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
	+ 1));
	png_memcpy(text, tmp, text_size);
	png_free(png_ptr, tmp);
	png_memcpy(text + text_size, png_ptr->zbuf,
	png_ptr->zbuf_size - png_ptr->zstream.avail_out);
	text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
	*(text + text_size) = '\0';
	}
	if (ret != Z_STREAM_END)
	{
	png_ptr->zstream.next_out = png_ptr->zbuf;
	png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
	}
	}
	else
	{
	break;
	}

	if (ret == Z_STREAM_END)
	break;
	}

	inflateReset(&png_ptr->zstream);
	png_ptr->zstream.avail_in = 0;

	if (ret != Z_STREAM_END)
	{
	png_ptr->current_text = NULL;
	png_free(png_ptr, key);
	png_free(png_ptr, text);
	return;
	}

	png_ptr->current_text = NULL;
	png_free(png_ptr, key);
	key = text;
	text += key_size;

	text_ptr = (png_textp)png_malloc(png_ptr,
	(png_uint_32)png_sizeof(png_text));
	text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
	text_ptr->key = key;
	#ifdef PNG_iTXt_SUPPORTED
	text_ptr->lang = NULL;
	text_ptr->lang_key = NULL;
	#endif
	text_ptr->text = text;

	ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);

	png_free(png_ptr, key);
	png_free(png_ptr, text_ptr);

	if (ret)
	png_warning(png_ptr, "Insufficient memory to store text chunk.");
	}
	}
	#endif

	#if defined(PNG_READ_iTXt_SUPPORTED)
	void /* PRIVATE */
	png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
	length)
	{
	if (!(png_ptr->mode & PNG_HAVE_IHDR) \|\| (png_ptr->mode & PNG_HAVE_IEND))
	{
	png_error(png_ptr, "Out of place iTXt");
	info_ptr = info_ptr; /* to quiet some compiler warnings */
	}

	#ifdef PNG_MAX_MALLOC_64K
	png_ptr->skip_length = 0; /* This may not be necessary */

	if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
	{
	png_warning(png_ptr, "iTXt chunk too large to fit in memory");
	png_ptr->skip_length = length - (png_uint_32)65535L;
	length = (png_uint_32)65535L;
	}
	#endif

	png_ptr->current_text = (png_charp)png_malloc(png_ptr,
	(png_uint_32)(length+1));
	png_ptr->current_text[length] = '\0';
	png_ptr->current_text_ptr = png_ptr->current_text;
	png_ptr->current_text_size = (png_size_t)length;
	png_ptr->current_text_left = (png_size_t)length;
	png_ptr->process_mode = PNG_READ_iTXt_MODE;
	}

	void /* PRIVATE */
	png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
	{

	if (png_ptr->buffer_size && png_ptr->current_text_left)
	{
	png_size_t text_size;

	if (png_ptr->buffer_size < png_ptr->current_text_left)
	text_size = png_ptr->buffer_size;
	else
	text_size = png_ptr->current_text_left;
	png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
	png_ptr->current_text_left -= text_size;
	png_ptr->current_text_ptr += text_size;
	}
	if (!(png_ptr->current_text_left))
	{
	png_textp text_ptr;
	png_charp key;
	int comp_flag;
	png_charp lang;
	png_charp lang_key;
	png_charp text;
	int ret;

	if (png_ptr->buffer_size < 4)
	{
	png_push_save_buffer(png_ptr);
	return;
	}

	png_push_crc_finish(png_ptr);

	#if defined(PNG_MAX_MALLOC_64K)
	if (png_ptr->skip_length)
	return;
	#endif

	key = png_ptr->current_text;

	for (lang = key; *lang; lang++)
	/* empty loop */ ;

	if (lang < key + png_ptr->current_text_size - 3)
	lang++;

	comp_flag = *lang++;
	lang++; /* skip comp_type, always zero */

	for (lang_key = lang; *lang_key; lang_key++)
	/* empty loop */ ;
	lang_key++; /* skip NUL separator */

	text=lang_key;
	if (lang_key < key + png_ptr->current_text_size - 1)
	{
	for (; *text; text++)
	/* empty loop */ ;
	}

	if (text < key + png_ptr->current_text_size)
	text++;

	text_ptr = (png_textp)png_malloc(png_ptr,
	(png_uint_32)png_sizeof(png_text));
	text_ptr->compression = comp_flag + 2;
	text_ptr->key = key;
	text_ptr->lang = lang;
	text_ptr->lang_key = lang_key;
	text_ptr->text = text;
	text_ptr->text_length = 0;
	text_ptr->itxt_length = png_strlen(text);

	ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);

	png_ptr->current_text = NULL;

	png_free(png_ptr, text_ptr);
	if (ret)
	png_warning(png_ptr, "Insufficient memory to store iTXt chunk.");
	}
	}
	#endif

	/* This function is called when we haven't found a handler for this
	* chunk. If there isn't a problem with the chunk itself (ie a bad chunk
	* name or a critical chunk), the chunk is (currently) silently ignored.
	*/
	void /* PRIVATE */
	png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
	length)
	{
	png_uint_32 skip=0;
	png_check_chunk_name(png_ptr, png_ptr->chunk_name);

	if (!(png_ptr->chunk_name[0] & 0x20))
	{
	#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
	if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
	PNG_HANDLE_CHUNK_ALWAYS
	#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
	&& png_ptr->read_user_chunk_fn == NULL
	#endif
	)
	#endif
	png_chunk_error(png_ptr, "unknown critical chunk");

	info_ptr = info_ptr; /* to quiet some compiler warnings */
	}

	#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
	if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
	{
	#ifdef PNG_MAX_MALLOC_64K
	if (length > (png_uint_32)65535L)
	{
	png_warning(png_ptr, "unknown chunk too large to fit in memory");
	skip = length - (png_uint_32)65535L;
	length = (png_uint_32)65535L;
	}
	#endif
	png_memcpy((png_charp)png_ptr->unknown_chunk.name,
	(png_charp)png_ptr->chunk_name,
	png_sizeof(png_ptr->unknown_chunk.name));
	png_ptr->unknown_chunk.name[png_sizeof(png_ptr->unknown_chunk.name)-1]='\0';

	png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length);
	png_ptr->unknown_chunk.size = (png_size_t)length;
	png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
	#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
	if(png_ptr->read_user_chunk_fn != NULL)
	{
	/* callback to user unknown chunk handler */
	int ret;
	ret = (*(png_ptr->read_user_chunk_fn))
	(png_ptr, &png_ptr->unknown_chunk);
	if (ret < 0)
	png_chunk_error(png_ptr, "error in user chunk");
	if (ret == 0)
	{
	if (!(png_ptr->chunk_name[0] & 0x20))
	if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
	PNG_HANDLE_CHUNK_ALWAYS)
	png_chunk_error(png_ptr, "unknown critical chunk");
	png_set_unknown_chunks(png_ptr, info_ptr,
	&png_ptr->unknown_chunk, 1);
	}
	}
	else
	#endif
	png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
	png_free(png_ptr, png_ptr->unknown_chunk.data);
	png_ptr->unknown_chunk.data = NULL;
	}
	else
	#endif
	skip=length;
	png_push_crc_skip(png_ptr, skip);
	}

	void /* PRIVATE */
	png_push_have_info(png_structp png_ptr, png_infop info_ptr)
	{
	if (png_ptr->info_fn != NULL)
	(*(png_ptr->info_fn))(png_ptr, info_ptr);
	}

	void /* PRIVATE */
	png_push_have_end(png_structp png_ptr, png_infop info_ptr)
	{
	if (png_ptr->end_fn != NULL)
	(*(png_ptr->end_fn))(png_ptr, info_ptr);
	}

	void /* PRIVATE */
	png_push_have_row(png_structp png_ptr, png_bytep row)
	{
	if (png_ptr->row_fn != NULL)
	(*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
	(int)png_ptr->pass);
	}

	void PNGAPI
	png_progressive_combine_row (png_structp png_ptr,
	png_bytep old_row, png_bytep new_row)
	{
	#ifdef PNG_USE_LOCAL_ARRAYS
	PNG_CONST int FARDATA png_pass_dsp_mask[7] =
	{0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
	#endif
	if(png_ptr == NULL) return;
	if (new_row != NULL) /* new_row must == png_ptr->row_buf here. */
	png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
	}

	void PNGAPI
	png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
	png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
	png_progressive_end_ptr end_fn)
	{
	if(png_ptr == NULL) return;
	png_ptr->info_fn = info_fn;
	png_ptr->row_fn = row_fn;
	png_ptr->end_fn = end_fn;

	png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
	}

	png_voidp PNGAPI
	png_get_progressive_ptr(png_structp png_ptr)
	{
	if(png_ptr == NULL) return (NULL);
	return png_ptr->io_ptr;
	}
	#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */

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