fife-parpg: ext/libpng-1.2.29/pngrutil.c comparison

comparison ext/libpng-1.2.29/pngrutil.c @ 0:4a0efb7baf70

* Datasets becomes the new trunk and retires after that :-)

author	mvbarracuda@33b003aa-7bff-0310-803a-e67f0ece8222
date	Sun, 29 Jun 2008 18:44:17 +0000
parents
children

comparison

equal deleted inserted replaced

--1:000000000000
+:4a0efb7baf70
+/* pngrutil.c - utilities to read a PNG file
+*
+* Last changed in libpng 1.2.27 [April 29, 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.)
+*
+* This file contains routines that are only called from within
+* libpng itself during the course of reading an image.
+*/
+#define PNG_INTERNAL
+#include "png.h"
+#if defined(PNG_READ_SUPPORTED)
+#if defined(_WIN32_WCE) && (_WIN32_WCE<0x500)
+#  define WIN32_WCE_OLD
+#endif
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+#  if defined(WIN32_WCE_OLD)
+/* strtod() function is not supported on WindowsCE */
+__inline double png_strtod(png_structp png_ptr, PNG_CONST char *nptr, char **endptr)
+{
+double result = 0;
+int len;
+wchar_t *str, *end;
+len = MultiByteToWideChar(CP_ACP, 0, nptr, -1, NULL, 0);
+str = (wchar_t *)png_malloc(png_ptr, len * sizeof(wchar_t));
+if ( NULL != str )
+{
+MultiByteToWideChar(CP_ACP, 0, nptr, -1, str, len);
+result = wcstod(str, &end);
+len = WideCharToMultiByte(CP_ACP, 0, end, -1, NULL, 0, NULL, NULL);
+*endptr = (char *)nptr + (png_strlen(nptr) - len + 1);
+png_free(png_ptr, str);
+}
+return result;
+}
+#  else
+#    define png_strtod(p,a,b) strtod(a,b)
+#  endif
+#endif
+png_uint_32 PNGAPI
+png_get_uint_31(png_structp png_ptr, png_bytep buf)
+{
+png_uint_32 i = png_get_uint_32(buf);
+if (i > PNG_UINT_31_MAX)
+png_error(png_ptr, "PNG unsigned integer out of range.");
+return (i);
+}
+#ifndef PNG_READ_BIG_ENDIAN_SUPPORTED
+/* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
+png_uint_32 PNGAPI
+png_get_uint_32(png_bytep buf)
+{
+png_uint_32 i = ((png_uint_32)(*buf) << 24) +
+((png_uint_32)(*(buf + 1)) << 16) +
+((png_uint_32)(*(buf + 2)) << 8) +
+(png_uint_32)(*(buf + 3));
+return (i);
+}
+/* Grab a signed 32-bit integer from a buffer in big-endian format.  The
+* data is stored in the PNG file in two's complement format, and it is
+* assumed that the machine format for signed integers is the same. */
+png_int_32 PNGAPI
+png_get_int_32(png_bytep buf)
+{
+png_int_32 i = ((png_int_32)(*buf) << 24) +
+((png_int_32)(*(buf + 1)) << 16) +
+((png_int_32)(*(buf + 2)) << 8) +
+(png_int_32)(*(buf + 3));
+return (i);
+}
+/* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
+png_uint_16 PNGAPI
+png_get_uint_16(png_bytep buf)
+{
+png_uint_16 i = (png_uint_16)(((png_uint_16)(*buf) << 8) +
+(png_uint_16)(*(buf + 1)));
+return (i);
+}
+#endif /* PNG_READ_BIG_ENDIAN_SUPPORTED */
+/* Read data, and (optionally) run it through the CRC. */
+void /* PRIVATE */
+png_crc_read(png_structp png_ptr, png_bytep buf, png_size_t length)
+{
+if(png_ptr == NULL) return;
+png_read_data(png_ptr, buf, length);
+png_calculate_crc(png_ptr, buf, length);
+}
+/* Optionally skip data and then check the CRC.  Depending on whether we
+are reading a ancillary or critical chunk, and how the program has set
+things up, we may calculate the CRC on the data and print a message.
+Returns '1' if there was a CRC error, '0' otherwise. */
+int /* PRIVATE */
+png_crc_finish(png_structp png_ptr, png_uint_32 skip)
+{
+png_size_t i;
+png_size_t istop = png_ptr->zbuf_size;
+for (i = (png_size_t)skip; i > istop; i -= istop)
+{
+png_crc_read(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
+}
+if (i)
+{
+png_crc_read(png_ptr, png_ptr->zbuf, i);
+}
+if (png_crc_error(png_ptr))
+{
+if (((png_ptr->chunk_name[0] & 0x20) &&                /* Ancillary */
+!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)) ||
+(!(png_ptr->chunk_name[0] & 0x20) &&             /* Critical  */
+(png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE)))
+{
+png_chunk_warning(png_ptr, "CRC error");
+}
+else
+{
+png_chunk_error(png_ptr, "CRC error");
+}
+return (1);
+}
+return (0);
+}
+/* Compare the CRC stored in the PNG file with that calculated by libpng from
+the data it has read thus far. */
+int /* PRIVATE */
+png_crc_error(png_structp png_ptr)
+{
+png_byte crc_bytes[4];
+png_uint_32 crc;
+int need_crc = 1;
+if (png_ptr->chunk_name[0] & 0x20)                     /* ancillary */
+{
+if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
+(PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
+need_crc = 0;
+}
+else                                                    /* critical */
+{
+if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
+need_crc = 0;
+}
+png_read_data(png_ptr, crc_bytes, 4);
+if (need_crc)
+{
+crc = png_get_uint_32(crc_bytes);
+return ((int)(crc != png_ptr->crc));
+}
+else
+return (0);
+}
+#if defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) || \
+defined(PNG_READ_iCCP_SUPPORTED)
+/*
+* Decompress trailing data in a chunk.  The assumption is that chunkdata
+* points at an allocated area holding the contents of a chunk with a
+* trailing compressed part.  What we get back is an allocated area
+* holding the original prefix part and an uncompressed version of the
+* trailing part (the malloc area passed in is freed).
+*/
+png_charp /* PRIVATE */
+png_decompress_chunk(png_structp png_ptr, int comp_type,
+png_charp chunkdata, png_size_t chunklength,
+png_size_t prefix_size, png_size_t *newlength)
+{
+static PNG_CONST char msg[] = "Error decoding compressed text";
+png_charp text;
+png_size_t text_size;
+if (comp_type == PNG_COMPRESSION_TYPE_BASE)
+{
+int ret = Z_OK;
+png_ptr->zstream.next_in = (png_bytep)(chunkdata + prefix_size);
+png_ptr->zstream.avail_in = (uInt)(chunklength - prefix_size);
+png_ptr->zstream.next_out = png_ptr->zbuf;
+png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+text_size = 0;
+text = NULL;
+while (png_ptr->zstream.avail_in)
+{
+ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
+if (ret != Z_OK && ret != Z_STREAM_END)
+{
+if (png_ptr->zstream.msg != NULL)
+png_warning(png_ptr, png_ptr->zstream.msg);
+else
+png_warning(png_ptr, msg);
+inflateReset(&png_ptr->zstream);
+png_ptr->zstream.avail_in = 0;
+if (text ==  NULL)
+{
+text_size = prefix_size + png_sizeof(msg) + 1;
+text = (png_charp)png_malloc_warn(png_ptr, text_size);
+if (text ==  NULL)
+{
+png_free(png_ptr,chunkdata);
+png_error(png_ptr,"Not enough memory to decompress chunk");
+}
+png_memcpy(text, chunkdata, prefix_size);
+}
+text[text_size - 1] = 0x00;
+/* Copy what we can of the error message into the text chunk */
+text_size = (png_size_t)(chunklength - (text - chunkdata) - 1);
+text_size = png_sizeof(msg) > text_size ? text_size :
+png_sizeof(msg);
+png_memcpy(text + prefix_size, msg, text_size);
+break;
+}
+if (!png_ptr->zstream.avail_out || ret == Z_STREAM_END)
+{
+if (text == NULL)
+{
+text_size = prefix_size +
+png_ptr->zbuf_size - png_ptr->zstream.avail_out;
+text = (png_charp)png_malloc_warn(png_ptr, text_size + 1);
+if (text ==  NULL)
+{
+png_free(png_ptr,chunkdata);
+png_error(png_ptr,"Not enough memory to decompress chunk.");
+}
+png_memcpy(text + prefix_size, png_ptr->zbuf,
+text_size - prefix_size);
+png_memcpy(text, chunkdata, prefix_size);
+*(text + text_size) = 0x00;
+}
+else
+{
+png_charp tmp;
+tmp = text;
+text = (png_charp)png_malloc_warn(png_ptr,
+(png_uint_32)(text_size +
+png_ptr->zbuf_size - png_ptr->zstream.avail_out + 1));
+if (text == NULL)
+{
+png_free(png_ptr, tmp);
+png_free(png_ptr, chunkdata);
+png_error(png_ptr,"Not enough memory to decompress chunk..");
+}
+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) = 0x00;
+}
+if (ret == Z_STREAM_END)
+break;
+else
+{
+png_ptr->zstream.next_out = png_ptr->zbuf;
+png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+}
+}
+}
+if (ret != Z_STREAM_END)
+{
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+char umsg[52];
+if (ret == Z_BUF_ERROR)
+png_snprintf(umsg, 52,
+"Buffer error in compressed datastream in %s chunk",
+png_ptr->chunk_name);
+else if (ret == Z_DATA_ERROR)
+png_snprintf(umsg, 52,
+"Data error in compressed datastream in %s chunk",
+png_ptr->chunk_name);
+else
+png_snprintf(umsg, 52,
+"Incomplete compressed datastream in %s chunk",
+png_ptr->chunk_name);
+png_warning(png_ptr, umsg);
+#else
+png_warning(png_ptr,
+"Incomplete compressed datastream in chunk other than IDAT");
+#endif
+text_size=prefix_size;
+if (text ==  NULL)
+{
+text = (png_charp)png_malloc_warn(png_ptr, text_size+1);
+if (text == NULL)
+{
+png_free(png_ptr, chunkdata);
+png_error(png_ptr,"Not enough memory for text.");
+}
+png_memcpy(text, chunkdata, prefix_size);
+}
+*(text + text_size) = 0x00;
+}
+inflateReset(&png_ptr->zstream);
+png_ptr->zstream.avail_in = 0;
+png_free(png_ptr, chunkdata);
+chunkdata = text;
+*newlength=text_size;
+}
+else /* if (comp_type != PNG_COMPRESSION_TYPE_BASE) */
+{
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+char umsg[50];
+png_snprintf(umsg, 50,
+"Unknown zTXt compression type %d", comp_type);
+png_warning(png_ptr, umsg);
+#else
+png_warning(png_ptr, "Unknown zTXt compression type");
+#endif
+*(chunkdata + prefix_size) = 0x00;
+*newlength=prefix_size;
+}
+return chunkdata;
+}
+#endif
+/* read and check the IDHR chunk */
+void /* PRIVATE */
+png_handle_IHDR(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_byte buf[13];
+png_uint_32 width, height;
+int bit_depth, color_type, compression_type, filter_type;
+int interlace_type;
+png_debug(1, "in png_handle_IHDR\n");
+if (png_ptr->mode & PNG_HAVE_IHDR)
+png_error(png_ptr, "Out of place IHDR");
+/* check the length */
+if (length != 13)
+png_error(png_ptr, "Invalid IHDR chunk");
+png_ptr->mode |= PNG_HAVE_IHDR;
+png_crc_read(png_ptr, buf, 13);
+png_crc_finish(png_ptr, 0);
+width = png_get_uint_31(png_ptr, buf);
+height = png_get_uint_31(png_ptr, buf + 4);
+bit_depth = buf[8];
+color_type = buf[9];
+compression_type = buf[10];
+filter_type = buf[11];
+interlace_type = buf[12];
+/* set internal variables */
+png_ptr->width = width;
+png_ptr->height = height;
+png_ptr->bit_depth = (png_byte)bit_depth;
+png_ptr->interlaced = (png_byte)interlace_type;
+png_ptr->color_type = (png_byte)color_type;
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+png_ptr->filter_type = (png_byte)filter_type;
+#endif
+png_ptr->compression_type = (png_byte)compression_type;
+/* find number of channels */
+switch (png_ptr->color_type)
+{
+case PNG_COLOR_TYPE_GRAY:
+case PNG_COLOR_TYPE_PALETTE:
+png_ptr->channels = 1;
+break;
+case PNG_COLOR_TYPE_RGB:
+png_ptr->channels = 3;
+break;
+case PNG_COLOR_TYPE_GRAY_ALPHA:
+png_ptr->channels = 2;
+break;
+case PNG_COLOR_TYPE_RGB_ALPHA:
+png_ptr->channels = 4;
+break;
+}
+/* set up other useful info */
+png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth *
+png_ptr->channels);
+png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth,png_ptr->width);
+png_debug1(3,"bit_depth = %d\n", png_ptr->bit_depth);
+png_debug1(3,"channels = %d\n", png_ptr->channels);
+png_debug1(3,"rowbytes = %lu\n", png_ptr->rowbytes);
+png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
+color_type, interlace_type, compression_type, filter_type);
+}
+/* read and check the palette */
+void /* PRIVATE */
+png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_color palette[PNG_MAX_PALETTE_LENGTH];
+int num, i;
+#ifndef PNG_NO_POINTER_INDEXING
+png_colorp pal_ptr;
+#endif
+png_debug(1, "in png_handle_PLTE\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before PLTE");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid PLTE after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (png_ptr->mode & PNG_HAVE_PLTE)
+png_error(png_ptr, "Duplicate PLTE chunk");
+png_ptr->mode |= PNG_HAVE_PLTE;
+if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
+{
+png_warning(png_ptr,
+"Ignoring PLTE chunk in grayscale PNG");
+png_crc_finish(png_ptr, length);
+return;
+}
+#if !defined(PNG_READ_OPT_PLTE_SUPPORTED)
+if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+{
+png_crc_finish(png_ptr, length);
+return;
+}
+#endif
+if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
+{
+if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+{
+png_warning(png_ptr, "Invalid palette chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+else
+{
+png_error(png_ptr, "Invalid palette chunk");
+}
+}
+num = (int)length / 3;
+#ifndef PNG_NO_POINTER_INDEXING
+for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
+{
+png_byte buf[3];
+png_crc_read(png_ptr, buf, 3);
+pal_ptr->red = buf[0];
+pal_ptr->green = buf[1];
+pal_ptr->blue = buf[2];
+}
+#else
+for (i = 0; i < num; i++)
+{
+png_byte buf[3];
+png_crc_read(png_ptr, buf, 3);
+/* don't depend upon png_color being any order */
+palette[i].red = buf[0];
+palette[i].green = buf[1];
+palette[i].blue = buf[2];
+}
+#endif
+/* If we actually NEED the PLTE chunk (ie for a paletted image), we do
+whatever the normal CRC configuration tells us.  However, if we
+have an RGB image, the PLTE can be considered ancillary, so
+we will act as though it is. */
+#if !defined(PNG_READ_OPT_PLTE_SUPPORTED)
+if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+#endif
+{
+png_crc_finish(png_ptr, 0);
+}
+#if !defined(PNG_READ_OPT_PLTE_SUPPORTED)
+else if (png_crc_error(png_ptr))  /* Only if we have a CRC error */
+{
+/* If we don't want to use the data from an ancillary chunk,
+we have two options: an error abort, or a warning and we
+ignore the data in this chunk (which should be OK, since
+it's considered ancillary for a RGB or RGBA image). */
+if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE))
+{
+if (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)
+{
+png_chunk_error(png_ptr, "CRC error");
+}
+else
+{
+png_chunk_warning(png_ptr, "CRC error");
+return;
+}
+}
+/* Otherwise, we (optionally) emit a warning and use the chunk. */
+else if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN))
+{
+png_chunk_warning(png_ptr, "CRC error");
+}
+}
+#endif
+png_set_PLTE(png_ptr, info_ptr, palette, num);
+#if defined(PNG_READ_tRNS_SUPPORTED)
+if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+{
+if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
+{
+if (png_ptr->num_trans > (png_uint_16)num)
+{
+png_warning(png_ptr, "Truncating incorrect tRNS chunk length");
+png_ptr->num_trans = (png_uint_16)num;
+}
+if (info_ptr->num_trans > (png_uint_16)num)
+{
+png_warning(png_ptr, "Truncating incorrect info tRNS chunk length");
+info_ptr->num_trans = (png_uint_16)num;
+}
+}
+}
+#endif
+}
+void /* PRIVATE */
+png_handle_IEND(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_debug(1, "in png_handle_IEND\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR) || !(png_ptr->mode & PNG_HAVE_IDAT))
+{
+png_error(png_ptr, "No image in file");
+}
+png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
+if (length != 0)
+{
+png_warning(png_ptr, "Incorrect IEND chunk length");
+}
+png_crc_finish(png_ptr, length);
+info_ptr =info_ptr; /* quiet compiler warnings about unused info_ptr */
+}
+#if defined(PNG_READ_gAMA_SUPPORTED)
+void /* PRIVATE */
+png_handle_gAMA(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_fixed_point igamma;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+float file_gamma;
+#endif
+png_byte buf[4];
+png_debug(1, "in png_handle_gAMA\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before gAMA");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid gAMA after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (png_ptr->mode & PNG_HAVE_PLTE)
+/* Should be an error, but we can cope with it */
+png_warning(png_ptr, "Out of place gAMA chunk");
+if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)
+#if defined(PNG_READ_sRGB_SUPPORTED)
+&& !(info_ptr->valid & PNG_INFO_sRGB)
+#endif
+)
+{
+png_warning(png_ptr, "Duplicate gAMA chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+if (length != 4)
+{
+png_warning(png_ptr, "Incorrect gAMA chunk length");
+png_crc_finish(png_ptr, length);
+return;
+}
+png_crc_read(png_ptr, buf, 4);
+if (png_crc_finish(png_ptr, 0))
+return;
+igamma = (png_fixed_point)png_get_uint_32(buf);
+/* check for zero gamma */
+if (igamma == 0)
+{
+png_warning(png_ptr,
+"Ignoring gAMA chunk with gamma=0");
+return;
+}
+#if defined(PNG_READ_sRGB_SUPPORTED)
+if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB))
+if (PNG_OUT_OF_RANGE(igamma, 45500L, 500))
+{
+png_warning(png_ptr,
+"Ignoring incorrect gAMA value when sRGB is also present");
+#ifndef PNG_NO_CONSOLE_IO
+fprintf(stderr, "gamma = (%d/100000)\n", (int)igamma);
+#endif
+return;
+}
+#endif /* PNG_READ_sRGB_SUPPORTED */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+file_gamma = (float)igamma / (float)100000.0;
+#  ifdef PNG_READ_GAMMA_SUPPORTED
+png_ptr->gamma = file_gamma;
+#  endif
+png_set_gAMA(png_ptr, info_ptr, file_gamma);
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_set_gAMA_fixed(png_ptr, info_ptr, igamma);
+#endif
+}
+#endif
+#if defined(PNG_READ_sBIT_SUPPORTED)
+void /* PRIVATE */
+png_handle_sBIT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_size_t truelen;
+png_byte buf[4];
+png_debug(1, "in png_handle_sBIT\n");
+buf[0] = buf[1] = buf[2] = buf[3] = 0;
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before sBIT");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid sBIT after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (png_ptr->mode & PNG_HAVE_PLTE)
+{
+/* Should be an error, but we can cope with it */
+png_warning(png_ptr, "Out of place sBIT chunk");
+}
+if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT))
+{
+png_warning(png_ptr, "Duplicate sBIT chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+truelen = 3;
+else
+truelen = (png_size_t)png_ptr->channels;
+if (length != truelen || length > 4)
+{
+png_warning(png_ptr, "Incorrect sBIT chunk length");
+png_crc_finish(png_ptr, length);
+return;
+}
+png_crc_read(png_ptr, buf, truelen);
+if (png_crc_finish(png_ptr, 0))
+return;
+if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
+{
+png_ptr->sig_bit.red = buf[0];
+png_ptr->sig_bit.green = buf[1];
+png_ptr->sig_bit.blue = buf[2];
+png_ptr->sig_bit.alpha = buf[3];
+}
+else
+{
+png_ptr->sig_bit.gray = buf[0];
+png_ptr->sig_bit.red = buf[0];
+png_ptr->sig_bit.green = buf[0];
+png_ptr->sig_bit.blue = buf[0];
+png_ptr->sig_bit.alpha = buf[1];
+}
+png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
+}
+#endif
+#if defined(PNG_READ_cHRM_SUPPORTED)
+void /* PRIVATE */
+png_handle_cHRM(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_byte buf[4];
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+float white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y;
+#endif
+png_fixed_point int_x_white, int_y_white, int_x_red, int_y_red, int_x_green,
+int_y_green, int_x_blue, int_y_blue;
+png_uint_32 uint_x, uint_y;
+png_debug(1, "in png_handle_cHRM\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before cHRM");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid cHRM after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (png_ptr->mode & PNG_HAVE_PLTE)
+/* Should be an error, but we can cope with it */
+png_warning(png_ptr, "Missing PLTE before cHRM");
+if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM)
+#if defined(PNG_READ_sRGB_SUPPORTED)
+&& !(info_ptr->valid & PNG_INFO_sRGB)
+#endif
+)
+{
+png_warning(png_ptr, "Duplicate cHRM chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+if (length != 32)
+{
+png_warning(png_ptr, "Incorrect cHRM chunk length");
+png_crc_finish(png_ptr, length);
+return;
+}
+png_crc_read(png_ptr, buf, 4);
+uint_x = png_get_uint_32(buf);
+png_crc_read(png_ptr, buf, 4);
+uint_y = png_get_uint_32(buf);
+if (uint_x > 80000L || uint_y > 80000L ||
+uint_x + uint_y > 100000L)
+{
+png_warning(png_ptr, "Invalid cHRM white point");
+png_crc_finish(png_ptr, 24);
+return;
+}
+int_x_white = (png_fixed_point)uint_x;
+int_y_white = (png_fixed_point)uint_y;
+png_crc_read(png_ptr, buf, 4);
+uint_x = png_get_uint_32(buf);
+png_crc_read(png_ptr, buf, 4);
+uint_y = png_get_uint_32(buf);
+if (uint_x + uint_y > 100000L)
+{
+png_warning(png_ptr, "Invalid cHRM red point");
+png_crc_finish(png_ptr, 16);
+return;
+}
+int_x_red = (png_fixed_point)uint_x;
+int_y_red = (png_fixed_point)uint_y;
+png_crc_read(png_ptr, buf, 4);
+uint_x = png_get_uint_32(buf);
+png_crc_read(png_ptr, buf, 4);
+uint_y = png_get_uint_32(buf);
+if (uint_x + uint_y > 100000L)
+{
+png_warning(png_ptr, "Invalid cHRM green point");
+png_crc_finish(png_ptr, 8);
+return;
+}
+int_x_green = (png_fixed_point)uint_x;
+int_y_green = (png_fixed_point)uint_y;
+png_crc_read(png_ptr, buf, 4);
+uint_x = png_get_uint_32(buf);
+png_crc_read(png_ptr, buf, 4);
+uint_y = png_get_uint_32(buf);
+if (uint_x + uint_y > 100000L)
+{
+png_warning(png_ptr, "Invalid cHRM blue point");
+png_crc_finish(png_ptr, 0);
+return;
+}
+int_x_blue = (png_fixed_point)uint_x;
+int_y_blue = (png_fixed_point)uint_y;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+white_x = (float)int_x_white / (float)100000.0;
+white_y = (float)int_y_white / (float)100000.0;
+red_x   = (float)int_x_red   / (float)100000.0;
+red_y   = (float)int_y_red   / (float)100000.0;
+green_x = (float)int_x_green / (float)100000.0;
+green_y = (float)int_y_green / (float)100000.0;
+blue_x  = (float)int_x_blue  / (float)100000.0;
+blue_y  = (float)int_y_blue  / (float)100000.0;
+#endif
+#if defined(PNG_READ_sRGB_SUPPORTED)
+if ((info_ptr != NULL) && (info_ptr->valid & PNG_INFO_sRGB))
+{
+if (PNG_OUT_OF_RANGE(int_x_white, 31270,  1000) ||
+PNG_OUT_OF_RANGE(int_y_white, 32900,  1000) ||
+PNG_OUT_OF_RANGE(int_x_red,   64000L, 1000) ||
+PNG_OUT_OF_RANGE(int_y_red,   33000,  1000) ||
+PNG_OUT_OF_RANGE(int_x_green, 30000,  1000) ||
+PNG_OUT_OF_RANGE(int_y_green, 60000L, 1000) ||
+PNG_OUT_OF_RANGE(int_x_blue,  15000,  1000) ||
+PNG_OUT_OF_RANGE(int_y_blue,   6000,  1000))
+{
+png_warning(png_ptr,
+"Ignoring incorrect cHRM value when sRGB is also present");
+#ifndef PNG_NO_CONSOLE_IO
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+fprintf(stderr,"wx=%f, wy=%f, rx=%f, ry=%f\n",
+white_x, white_y, red_x, red_y);
+fprintf(stderr,"gx=%f, gy=%f, bx=%f, by=%f\n",
+green_x, green_y, blue_x, blue_y);
+#else
+fprintf(stderr,"wx=%ld, wy=%ld, rx=%ld, ry=%ld\n",
+int_x_white, int_y_white, int_x_red, int_y_red);
+fprintf(stderr,"gx=%ld, gy=%ld, bx=%ld, by=%ld\n",
+int_x_green, int_y_green, int_x_blue, int_y_blue);
+#endif
+#endif /* PNG_NO_CONSOLE_IO */
+}
+png_crc_finish(png_ptr, 0);
+return;
+}
+#endif /* PNG_READ_sRGB_SUPPORTED */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+png_set_cHRM(png_ptr, info_ptr,
+white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y);
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_set_cHRM_fixed(png_ptr, info_ptr,
+int_x_white, int_y_white, int_x_red, int_y_red, int_x_green,
+int_y_green, int_x_blue, int_y_blue);
+#endif
+if (png_crc_finish(png_ptr, 0))
+return;
+}
+#endif
+#if defined(PNG_READ_sRGB_SUPPORTED)
+void /* PRIVATE */
+png_handle_sRGB(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+int intent;
+png_byte buf[1];
+png_debug(1, "in png_handle_sRGB\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before sRGB");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid sRGB after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (png_ptr->mode & PNG_HAVE_PLTE)
+/* Should be an error, but we can cope with it */
+png_warning(png_ptr, "Out of place sRGB chunk");
+if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB))
+{
+png_warning(png_ptr, "Duplicate sRGB chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+if (length != 1)
+{
+png_warning(png_ptr, "Incorrect sRGB chunk length");
+png_crc_finish(png_ptr, length);
+return;
+}
+png_crc_read(png_ptr, buf, 1);
+if (png_crc_finish(png_ptr, 0))
+return;
+intent = buf[0];
+/* check for bad intent */
+if (intent >= PNG_sRGB_INTENT_LAST)
+{
+png_warning(png_ptr, "Unknown sRGB intent");
+return;
+}
+#if defined(PNG_READ_gAMA_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
+if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA))
+{
+png_fixed_point igamma;
+#ifdef PNG_FIXED_POINT_SUPPORTED
+igamma=info_ptr->int_gamma;
+#else
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+igamma=(png_fixed_point)(info_ptr->gamma * 100000.);
+#  endif
+#endif
+if (PNG_OUT_OF_RANGE(igamma, 45500L, 500))
+{
+png_warning(png_ptr,
+"Ignoring incorrect gAMA value when sRGB is also present");
+#ifndef PNG_NO_CONSOLE_IO
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+fprintf(stderr,"incorrect gamma=(%d/100000)\n",(int)png_ptr->int_gamma);
+#  else
+#    ifdef PNG_FLOATING_POINT_SUPPORTED
+fprintf(stderr,"incorrect gamma=%f\n",png_ptr->gamma);
+#    endif
+#  endif
+#endif
+}
+}
+#endif /* PNG_READ_gAMA_SUPPORTED */
+#ifdef PNG_READ_cHRM_SUPPORTED
+#ifdef PNG_FIXED_POINT_SUPPORTED
+if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
+if (PNG_OUT_OF_RANGE(info_ptr->int_x_white, 31270,  1000) ||
+PNG_OUT_OF_RANGE(info_ptr->int_y_white, 32900,  1000) ||
+PNG_OUT_OF_RANGE(info_ptr->int_x_red,   64000L, 1000) ||
+PNG_OUT_OF_RANGE(info_ptr->int_y_red,   33000,  1000) ||
+PNG_OUT_OF_RANGE(info_ptr->int_x_green, 30000,  1000) ||
+PNG_OUT_OF_RANGE(info_ptr->int_y_green, 60000L, 1000) ||
+PNG_OUT_OF_RANGE(info_ptr->int_x_blue,  15000,  1000) ||
+PNG_OUT_OF_RANGE(info_ptr->int_y_blue,   6000,  1000))
+{
+png_warning(png_ptr,
+"Ignoring incorrect cHRM value when sRGB is also present");
+}
+#endif /* PNG_FIXED_POINT_SUPPORTED */
+#endif /* PNG_READ_cHRM_SUPPORTED */
+png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr, intent);
+}
+#endif /* PNG_READ_sRGB_SUPPORTED */
+#if defined(PNG_READ_iCCP_SUPPORTED)
+void /* PRIVATE */
+png_handle_iCCP(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+/* Note: this does not properly handle chunks that are > 64K under DOS */
+{
+png_charp chunkdata;
+png_byte compression_type;
+png_bytep pC;
+png_charp profile;
+png_uint_32 skip = 0;
+png_uint_32 profile_size, profile_length;
+png_size_t slength, prefix_length, data_length;
+png_debug(1, "in png_handle_iCCP\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before iCCP");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid iCCP after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (png_ptr->mode & PNG_HAVE_PLTE)
+/* Should be an error, but we can cope with it */
+png_warning(png_ptr, "Out of place iCCP chunk");
+if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP))
+{
+png_warning(png_ptr, "Duplicate iCCP chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+#ifdef PNG_MAX_MALLOC_64K
+if (length > (png_uint_32)65535L)
+{
+png_warning(png_ptr, "iCCP chunk too large to fit in memory");
+skip = length - (png_uint_32)65535L;
+length = (png_uint_32)65535L;
+}
+#endif
+chunkdata = (png_charp)png_malloc(png_ptr, length + 1);
+slength = (png_size_t)length;
+png_crc_read(png_ptr, (png_bytep)chunkdata, slength);
+if (png_crc_finish(png_ptr, skip))
+{
+png_free(png_ptr, chunkdata);
+return;
+}
+chunkdata[slength] = 0x00;
+for (profile = chunkdata; *profile; profile++)
+/* empty loop to find end of name */ ;
+++profile;
+/* there should be at least one zero (the compression type byte)
+following the separator, and we should be on it  */
+if ( profile >= chunkdata + slength - 1)
+{
+png_free(png_ptr, chunkdata);
+png_warning(png_ptr, "Malformed iCCP chunk");
+return;
+}
+/* compression_type should always be zero */
+compression_type = *profile++;
+if (compression_type)
+{
+png_warning(png_ptr, "Ignoring nonzero compression type in iCCP chunk");
+compression_type=0x00;  /* Reset it to zero (libpng-1.0.6 through 1.0.8
+wrote nonzero) */
+}
+prefix_length = profile - chunkdata;
+chunkdata = png_decompress_chunk(png_ptr, compression_type, chunkdata,
+slength, prefix_length, &data_length);
+profile_length = data_length - prefix_length;
+if ( prefix_length > data_length || profile_length < 4)
+{
+png_free(png_ptr, chunkdata);
+png_warning(png_ptr, "Profile size field missing from iCCP chunk");
+return;
+}
+/* Check the profile_size recorded in the first 32 bits of the ICC profile */
+pC = (png_bytep)(chunkdata+prefix_length);
+profile_size = ((*(pC  ))<<24) |
+((*(pC+1))<<16) |
+((*(pC+2))<< 8) |
+((*(pC+3))    );
+if(profile_size < profile_length)
+profile_length = profile_size;
+if(profile_size > profile_length)
+{
+png_free(png_ptr, chunkdata);
+png_warning(png_ptr, "Ignoring truncated iCCP profile.");
+return;
+}
+png_set_iCCP(png_ptr, info_ptr, chunkdata, compression_type,
+chunkdata + prefix_length, profile_length);
+png_free(png_ptr, chunkdata);
+}
+#endif /* PNG_READ_iCCP_SUPPORTED */
+#if defined(PNG_READ_sPLT_SUPPORTED)
+void /* PRIVATE */
+png_handle_sPLT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+/* Note: this does not properly handle chunks that are > 64K under DOS */
+{
+png_bytep chunkdata;
+png_bytep entry_start;
+png_sPLT_t new_palette;
+#ifdef PNG_NO_POINTER_INDEXING
+png_sPLT_entryp pp;
+#endif
+int data_length, entry_size, i;
+png_uint_32 skip = 0;
+png_size_t slength;
+png_debug(1, "in png_handle_sPLT\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before sPLT");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid sPLT after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+#ifdef PNG_MAX_MALLOC_64K
+if (length > (png_uint_32)65535L)
+{
+png_warning(png_ptr, "sPLT chunk too large to fit in memory");
+skip = length - (png_uint_32)65535L;
+length = (png_uint_32)65535L;
+}
+#endif
+chunkdata = (png_bytep)png_malloc(png_ptr, length + 1);
+slength = (png_size_t)length;
+png_crc_read(png_ptr, (png_bytep)chunkdata, slength);
+if (png_crc_finish(png_ptr, skip))
+{
+png_free(png_ptr, chunkdata);
+return;
+}
+chunkdata[slength] = 0x00;
+for (entry_start = chunkdata; *entry_start; entry_start++)
+/* empty loop to find end of name */ ;
+++entry_start;
+/* a sample depth should follow the separator, and we should be on it  */
+if (entry_start > chunkdata + slength - 2)
+{
+png_free(png_ptr, chunkdata);
+png_warning(png_ptr, "malformed sPLT chunk");
+return;
+}
+new_palette.depth = *entry_start++;
+entry_size = (new_palette.depth == 8 ? 6 : 10);
+data_length = (slength - (entry_start - chunkdata));
+/* integrity-check the data length */
+if (data_length % entry_size)
+{
+png_free(png_ptr, chunkdata);
+png_warning(png_ptr, "sPLT chunk has bad length");
+return;
+}
+new_palette.nentries = (png_int_32) ( data_length / entry_size);
+if ((png_uint_32) new_palette.nentries > (png_uint_32) (PNG_SIZE_MAX /
+png_sizeof(png_sPLT_entry)))
+{
+png_warning(png_ptr, "sPLT chunk too long");
+return;
+}
+new_palette.entries = (png_sPLT_entryp)png_malloc_warn(
+png_ptr, new_palette.nentries * png_sizeof(png_sPLT_entry));
+if (new_palette.entries == NULL)
+{
+png_warning(png_ptr, "sPLT chunk requires too much memory");
+return;
+}
+#ifndef PNG_NO_POINTER_INDEXING
+for (i = 0; i < new_palette.nentries; i++)
+{
+png_sPLT_entryp pp = new_palette.entries + i;
+if (new_palette.depth == 8)
+{
+pp->red = *entry_start++;
+pp->green = *entry_start++;
+pp->blue = *entry_start++;
+pp->alpha = *entry_start++;
+}
+else
+{
+pp->red   = png_get_uint_16(entry_start); entry_start += 2;
+pp->green = png_get_uint_16(entry_start); entry_start += 2;
+pp->blue  = png_get_uint_16(entry_start); entry_start += 2;
+pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
+}
+pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
+}
+#else
+pp = new_palette.entries;
+for (i = 0; i < new_palette.nentries; i++)
+{
+if (new_palette.depth == 8)
+{
+pp[i].red   = *entry_start++;
+pp[i].green = *entry_start++;
+pp[i].blue  = *entry_start++;
+pp[i].alpha = *entry_start++;
+}
+else
+{
+pp[i].red   = png_get_uint_16(entry_start); entry_start += 2;
+pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
+pp[i].blue  = png_get_uint_16(entry_start); entry_start += 2;
+pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
+}
+pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
+}
+#endif
+/* discard all chunk data except the name and stash that */
+new_palette.name = (png_charp)chunkdata;
+png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
+png_free(png_ptr, chunkdata);
+png_free(png_ptr, new_palette.entries);
+}
+#endif /* PNG_READ_sPLT_SUPPORTED */
+#if defined(PNG_READ_tRNS_SUPPORTED)
+void /* PRIVATE */
+png_handle_tRNS(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
+png_debug(1, "in png_handle_tRNS\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before tRNS");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid tRNS after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
+{
+png_warning(png_ptr, "Duplicate tRNS chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+{
+png_byte buf[2];
+if (length != 2)
+{
+png_warning(png_ptr, "Incorrect tRNS chunk length");
+png_crc_finish(png_ptr, length);
+return;
+}
+png_crc_read(png_ptr, buf, 2);
+png_ptr->num_trans = 1;
+png_ptr->trans_values.gray = png_get_uint_16(buf);
+}
+else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+{
+png_byte buf[6];
+if (length != 6)
+{
+png_warning(png_ptr, "Incorrect tRNS chunk length");
+png_crc_finish(png_ptr, length);
+return;
+}
+png_crc_read(png_ptr, buf, (png_size_t)length);
+png_ptr->num_trans = 1;
+png_ptr->trans_values.red = png_get_uint_16(buf);
+png_ptr->trans_values.green = png_get_uint_16(buf + 2);
+png_ptr->trans_values.blue = png_get_uint_16(buf + 4);
+}
+else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+{
+if (!(png_ptr->mode & PNG_HAVE_PLTE))
+{
+/* Should be an error, but we can cope with it. */
+png_warning(png_ptr, "Missing PLTE before tRNS");
+}
+if (length > (png_uint_32)png_ptr->num_palette ||
+length > PNG_MAX_PALETTE_LENGTH)
+{
+png_warning(png_ptr, "Incorrect tRNS chunk length");
+png_crc_finish(png_ptr, length);
+return;
+}
+if (length == 0)
+{
+png_warning(png_ptr, "Zero length tRNS chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+png_crc_read(png_ptr, readbuf, (png_size_t)length);
+png_ptr->num_trans = (png_uint_16)length;
+}
+else
+{
+png_warning(png_ptr, "tRNS chunk not allowed with alpha channel");
+png_crc_finish(png_ptr, length);
+return;
+}
+if (png_crc_finish(png_ptr, 0))
+{
+png_ptr->num_trans = 0;
+return;
+}
+png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
+&(png_ptr->trans_values));
+}
+#endif
+#if defined(PNG_READ_bKGD_SUPPORTED)
+void /* PRIVATE */
+png_handle_bKGD(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_size_t truelen;
+png_byte buf[6];
+png_debug(1, "in png_handle_bKGD\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before bKGD");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid bKGD after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+!(png_ptr->mode & PNG_HAVE_PLTE))
+{
+png_warning(png_ptr, "Missing PLTE before bKGD");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD))
+{
+png_warning(png_ptr, "Duplicate bKGD chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+truelen = 1;
+else if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
+truelen = 6;
+else
+truelen = 2;
+if (length != truelen)
+{
+png_warning(png_ptr, "Incorrect bKGD chunk length");
+png_crc_finish(png_ptr, length);
+return;
+}
+png_crc_read(png_ptr, buf, truelen);
+if (png_crc_finish(png_ptr, 0))
+return;
+/* We convert the index value into RGB components so that we can allow
+* arbitrary RGB values for background when we have transparency, and
+* so it is easy to determine the RGB values of the background color
+* from the info_ptr struct. */
+if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+{
+png_ptr->background.index = buf[0];
+if (info_ptr && info_ptr->num_palette)
+{
+if(buf[0] > info_ptr->num_palette)
+{
+png_warning(png_ptr, "Incorrect bKGD chunk index value");
+return;
+}
+png_ptr->background.red =
+(png_uint_16)png_ptr->palette[buf[0]].red;
+png_ptr->background.green =
+(png_uint_16)png_ptr->palette[buf[0]].green;
+png_ptr->background.blue =
+(png_uint_16)png_ptr->palette[buf[0]].blue;
+}
+}
+else if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) /* GRAY */
+{
+png_ptr->background.red =
+png_ptr->background.green =
+png_ptr->background.blue =
+png_ptr->background.gray = png_get_uint_16(buf);
+}
+else
+{
+png_ptr->background.red = png_get_uint_16(buf);
+png_ptr->background.green = png_get_uint_16(buf + 2);
+png_ptr->background.blue = png_get_uint_16(buf + 4);
+}
+png_set_bKGD(png_ptr, info_ptr, &(png_ptr->background));
+}
+#endif
+#if defined(PNG_READ_hIST_SUPPORTED)
+void /* PRIVATE */
+png_handle_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+unsigned int num, i;
+png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
+png_debug(1, "in png_handle_hIST\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before hIST");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid hIST after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (!(png_ptr->mode & PNG_HAVE_PLTE))
+{
+png_warning(png_ptr, "Missing PLTE before hIST");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST))
+{
+png_warning(png_ptr, "Duplicate hIST chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+num = length / 2 ;
+if (num != (unsigned int) png_ptr->num_palette || num >
+(unsigned int) PNG_MAX_PALETTE_LENGTH)
+{
+png_warning(png_ptr, "Incorrect hIST chunk length");
+png_crc_finish(png_ptr, length);
+return;
+}
+for (i = 0; i < num; i++)
+{
+png_byte buf[2];
+png_crc_read(png_ptr, buf, 2);
+readbuf[i] = png_get_uint_16(buf);
+}
+if (png_crc_finish(png_ptr, 0))
+return;
+png_set_hIST(png_ptr, info_ptr, readbuf);
+}
+#endif
+#if defined(PNG_READ_pHYs_SUPPORTED)
+void /* PRIVATE */
+png_handle_pHYs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_byte buf[9];
+png_uint_32 res_x, res_y;
+int unit_type;
+png_debug(1, "in png_handle_pHYs\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before pHYs");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid pHYs after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+{
+png_warning(png_ptr, "Duplicate pHYs chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+if (length != 9)
+{
+png_warning(png_ptr, "Incorrect pHYs chunk length");
+png_crc_finish(png_ptr, length);
+return;
+}
+png_crc_read(png_ptr, buf, 9);
+if (png_crc_finish(png_ptr, 0))
+return;
+res_x = png_get_uint_32(buf);
+res_y = png_get_uint_32(buf + 4);
+unit_type = buf[8];
+png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
+}
+#endif
+#if defined(PNG_READ_oFFs_SUPPORTED)
+void /* PRIVATE */
+png_handle_oFFs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_byte buf[9];
+png_int_32 offset_x, offset_y;
+int unit_type;
+png_debug(1, "in png_handle_oFFs\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before oFFs");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid oFFs after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+{
+png_warning(png_ptr, "Duplicate oFFs chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+if (length != 9)
+{
+png_warning(png_ptr, "Incorrect oFFs chunk length");
+png_crc_finish(png_ptr, length);
+return;
+}
+png_crc_read(png_ptr, buf, 9);
+if (png_crc_finish(png_ptr, 0))
+return;
+offset_x = png_get_int_32(buf);
+offset_y = png_get_int_32(buf + 4);
+unit_type = buf[8];
+png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
+}
+#endif
+#if defined(PNG_READ_pCAL_SUPPORTED)
+/* read the pCAL chunk (described in the PNG Extensions document) */
+void /* PRIVATE */
+png_handle_pCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_charp purpose;
+png_int_32 X0, X1;
+png_byte type, nparams;
+png_charp buf, units, endptr;
+png_charpp params;
+png_size_t slength;
+int i;
+png_debug(1, "in png_handle_pCAL\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before pCAL");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid pCAL after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL))
+{
+png_warning(png_ptr, "Duplicate pCAL chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+png_debug1(2, "Allocating and reading pCAL chunk data (%lu bytes)\n",
+length + 1);
+purpose = (png_charp)png_malloc_warn(png_ptr, length + 1);
+if (purpose == NULL)
+{
+png_warning(png_ptr, "No memory for pCAL purpose.");
+return;
+}
+slength = (png_size_t)length;
+png_crc_read(png_ptr, (png_bytep)purpose, slength);
+if (png_crc_finish(png_ptr, 0))
+{
+png_free(png_ptr, purpose);
+return;
+}
+purpose[slength] = 0x00; /* null terminate the last string */
+png_debug(3, "Finding end of pCAL purpose string\n");
+for (buf = purpose; *buf; buf++)
+/* empty loop */ ;
+endptr = purpose + slength;
+/* We need to have at least 12 bytes after the purpose string
+in order to get the parameter information. */
+if (endptr <= buf + 12)
+{
+png_warning(png_ptr, "Invalid pCAL data");
+png_free(png_ptr, purpose);
+return;
+}
+png_debug(3, "Reading pCAL X0, X1, type, nparams, and units\n");
+X0 = png_get_int_32((png_bytep)buf+1);
+X1 = png_get_int_32((png_bytep)buf+5);
+type = buf[9];
+nparams = buf[10];
+units = buf + 11;
+png_debug(3, "Checking pCAL equation type and number of parameters\n");
+/* Check that we have the right number of parameters for known
+equation types. */
+if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
+(type == PNG_EQUATION_BASE_E && nparams != 3) ||
+(type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
+(type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
+{
+png_warning(png_ptr, "Invalid pCAL parameters for equation type");
+png_free(png_ptr, purpose);
+return;
+}
+else if (type >= PNG_EQUATION_LAST)
+{
+png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
+}
+for (buf = units; *buf; buf++)
+/* Empty loop to move past the units string. */ ;
+png_debug(3, "Allocating pCAL parameters array\n");
+params = (png_charpp)png_malloc_warn(png_ptr, (png_uint_32)(nparams
+*png_sizeof(png_charp))) ;
+if (params == NULL)
+{
+png_free(png_ptr, purpose);
+png_warning(png_ptr, "No memory for pCAL params.");
+return;
+}
+/* Get pointers to the start of each parameter string. */
+for (i = 0; i < (int)nparams; i++)
+{
+buf++; /* Skip the null string terminator from previous parameter. */
+png_debug1(3, "Reading pCAL parameter %d\n", i);
+for (params[i] = buf; buf <= endptr && *buf != 0x00; buf++)
+/* Empty loop to move past each parameter string */ ;
+/* Make sure we haven't run out of data yet */
+if (buf > endptr)
+{
+png_warning(png_ptr, "Invalid pCAL data");
+png_free(png_ptr, purpose);
+png_free(png_ptr, params);
+return;
+}
+}
+png_set_pCAL(png_ptr, info_ptr, purpose, X0, X1, type, nparams,
+units, params);
+png_free(png_ptr, purpose);
+png_free(png_ptr, params);
+}
+#endif
+#if defined(PNG_READ_sCAL_SUPPORTED)
+/* read the sCAL chunk */
+void /* PRIVATE */
+png_handle_sCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_charp buffer, ep;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+double width, height;
+png_charp vp;
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_charp swidth, sheight;
+#endif
+#endif
+png_size_t slength;
+png_debug(1, "in png_handle_sCAL\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before sCAL");
+else if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+png_warning(png_ptr, "Invalid sCAL after IDAT");
+png_crc_finish(png_ptr, length);
+return;
+}
+else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL))
+{
+png_warning(png_ptr, "Duplicate sCAL chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+png_debug1(2, "Allocating and reading sCAL chunk data (%lu bytes)\n",
+length + 1);
+buffer = (png_charp)png_malloc_warn(png_ptr, length + 1);
+if (buffer == NULL)
+{
+png_warning(png_ptr, "Out of memory while processing sCAL chunk");
+return;
+}
+slength = (png_size_t)length;
+png_crc_read(png_ptr, (png_bytep)buffer, slength);
+if (png_crc_finish(png_ptr, 0))
+{
+png_free(png_ptr, buffer);
+return;
+}
+buffer[slength] = 0x00; /* null terminate the last string */
+ep = buffer + 1;        /* skip unit byte */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+width = png_strtod(png_ptr, ep, &vp);
+if (*vp)
+{
+png_warning(png_ptr, "malformed width string in sCAL chunk");
+return;
+}
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+swidth = (png_charp)png_malloc_warn(png_ptr, png_strlen(ep) + 1);
+if (swidth == NULL)
+{
+png_warning(png_ptr, "Out of memory while processing sCAL chunk width");
+return;
+}
+png_memcpy(swidth, ep, (png_size_t)png_strlen(ep));
+#endif
+#endif
+for (ep = buffer; *ep; ep++)
+/* empty loop */ ;
+ep++;
+if (buffer + slength < ep)
+{
+png_warning(png_ptr, "Truncated sCAL chunk");
+#if defined(PNG_FIXED_POINT_SUPPORTED) && \
+!defined(PNG_FLOATING_POINT_SUPPORTED)
+png_free(png_ptr, swidth);
+#endif
+png_free(png_ptr, buffer);
+return;
+}
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+height = png_strtod(png_ptr, ep, &vp);
+if (*vp)
+{
+png_warning(png_ptr, "malformed height string in sCAL chunk");
+return;
+}
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+sheight = (png_charp)png_malloc_warn(png_ptr, png_strlen(ep) + 1);
+if (sheight == NULL)
+{
+png_warning(png_ptr, "Out of memory while processing sCAL chunk height");
+return;
+}
+png_memcpy(sheight, ep, (png_size_t)png_strlen(ep));
+#endif
+#endif
+if (buffer + slength < ep
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+|| width <= 0. || height <= 0.
+#endif
+)
+{
+png_warning(png_ptr, "Invalid sCAL data");
+png_free(png_ptr, buffer);
+#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
+png_free(png_ptr, swidth);
+png_free(png_ptr, sheight);
+#endif
+return;
+}
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+png_set_sCAL(png_ptr, info_ptr, buffer[0], width, height);
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_set_sCAL_s(png_ptr, info_ptr, buffer[0], swidth, sheight);
+#endif
+#endif
+png_free(png_ptr, buffer);
+#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
+png_free(png_ptr, swidth);
+png_free(png_ptr, sheight);
+#endif
+}
+#endif
+#if defined(PNG_READ_tIME_SUPPORTED)
+void /* PRIVATE */
+png_handle_tIME(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_byte buf[7];
+png_time mod_time;
+png_debug(1, "in png_handle_tIME\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Out of place tIME chunk");
+else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME))
+{
+png_warning(png_ptr, "Duplicate tIME chunk");
+png_crc_finish(png_ptr, length);
+return;
+}
+if (png_ptr->mode & PNG_HAVE_IDAT)
+png_ptr->mode |= PNG_AFTER_IDAT;
+if (length != 7)
+{
+png_warning(png_ptr, "Incorrect tIME chunk length");
+png_crc_finish(png_ptr, length);
+return;
+}
+png_crc_read(png_ptr, buf, 7);
+if (png_crc_finish(png_ptr, 0))
+return;
+mod_time.second = buf[6];
+mod_time.minute = buf[5];
+mod_time.hour = buf[4];
+mod_time.day = buf[3];
+mod_time.month = buf[2];
+mod_time.year = png_get_uint_16(buf);
+png_set_tIME(png_ptr, info_ptr, &mod_time);
+}
+#endif
+#if defined(PNG_READ_tEXt_SUPPORTED)
+/* Note: this does not properly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_textp text_ptr;
+png_charp key;
+png_charp text;
+png_uint_32 skip = 0;
+png_size_t slength;
+int ret;
+png_debug(1, "in png_handle_tEXt\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before tEXt");
+if (png_ptr->mode & PNG_HAVE_IDAT)
+png_ptr->mode |= PNG_AFTER_IDAT;
+#ifdef PNG_MAX_MALLOC_64K
+if (length > (png_uint_32)65535L)
+{
+png_warning(png_ptr, "tEXt chunk too large to fit in memory");
+skip = length - (png_uint_32)65535L;
+length = (png_uint_32)65535L;
+}
+#endif
+key = (png_charp)png_malloc_warn(png_ptr, length + 1);
+if (key == NULL)
+{
+png_warning(png_ptr, "No memory to process text chunk.");
+return;
+}
+slength = (png_size_t)length;
+png_crc_read(png_ptr, (png_bytep)key, slength);
+if (png_crc_finish(png_ptr, skip))
+{
+png_free(png_ptr, key);
+return;
+}
+key[slength] = 0x00;
+for (text = key; *text; text++)
+/* empty loop to find end of key */ ;
+if (text != key + slength)
+text++;
+text_ptr = (png_textp)png_malloc_warn(png_ptr,
+(png_uint_32)png_sizeof(png_text));
+if (text_ptr == NULL)
+{
+png_warning(png_ptr, "Not enough memory to process text chunk.");
+png_free(png_ptr, key);
+return;
+}
+text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
+text_ptr->key = key;
+#ifdef PNG_iTXt_SUPPORTED
+text_ptr->lang = NULL;
+text_ptr->lang_key = NULL;
+text_ptr->itxt_length = 0;
+#endif
+text_ptr->text = text;
+text_ptr->text_length = png_strlen(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 process text chunk.");
+}
+#endif
+#if defined(PNG_READ_zTXt_SUPPORTED)
+/* note: this does not correctly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_textp text_ptr;
+png_charp chunkdata;
+png_charp text;
+int comp_type;
+int ret;
+png_size_t slength, prefix_len, data_len;
+png_debug(1, "in png_handle_zTXt\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before zTXt");
+if (png_ptr->mode & PNG_HAVE_IDAT)
+png_ptr->mode |= PNG_AFTER_IDAT;
+#ifdef PNG_MAX_MALLOC_64K
+/* We will no doubt have problems with chunks even half this size, but
+there is no hard and fast rule to tell us where to stop. */
+if (length > (png_uint_32)65535L)
+{
+png_warning(png_ptr,"zTXt chunk too large to fit in memory");
+png_crc_finish(png_ptr, length);
+return;
+}
+#endif
+chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
+if (chunkdata == NULL)
+{
+png_warning(png_ptr,"Out of memory processing zTXt chunk.");
+return;
+}
+slength = (png_size_t)length;
+png_crc_read(png_ptr, (png_bytep)chunkdata, slength);
+if (png_crc_finish(png_ptr, 0))
+{
+png_free(png_ptr, chunkdata);
+return;
+}
+chunkdata[slength] = 0x00;
+for (text = chunkdata; *text; text++)
+/* empty loop */ ;
+/* zTXt must have some text after the chunkdataword */
+if (text >= chunkdata + slength - 2)
+{
+png_warning(png_ptr, "Truncated zTXt chunk");
+png_free(png_ptr, chunkdata);
+return;
+}
+else
+{
+comp_type = *(++text);
+if (comp_type != PNG_TEXT_COMPRESSION_zTXt)
+{
+png_warning(png_ptr, "Unknown compression type in zTXt chunk");
+comp_type = PNG_TEXT_COMPRESSION_zTXt;
+}
+text++;        /* skip the compression_method byte */
+}
+prefix_len = text - chunkdata;
+chunkdata = (png_charp)png_decompress_chunk(png_ptr, comp_type, chunkdata,
+(png_size_t)length, prefix_len, &data_len);
+text_ptr = (png_textp)png_malloc_warn(png_ptr,
+(png_uint_32)png_sizeof(png_text));
+if (text_ptr == NULL)
+{
+png_warning(png_ptr,"Not enough memory to process zTXt chunk.");
+png_free(png_ptr, chunkdata);
+return;
+}
+text_ptr->compression = comp_type;
+text_ptr->key = chunkdata;
+#ifdef PNG_iTXt_SUPPORTED
+text_ptr->lang = NULL;
+text_ptr->lang_key = NULL;
+text_ptr->itxt_length = 0;
+#endif
+text_ptr->text = chunkdata + prefix_len;
+text_ptr->text_length = data_len;
+ret=png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
+png_free(png_ptr, text_ptr);
+png_free(png_ptr, chunkdata);
+if (ret)
+png_error(png_ptr, "Insufficient memory to store zTXt chunk.");
+}
+#endif
+#if defined(PNG_READ_iTXt_SUPPORTED)
+/* note: this does not correctly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_textp text_ptr;
+png_charp chunkdata;
+png_charp key, lang, text, lang_key;
+int comp_flag;
+int comp_type = 0;
+int ret;
+png_size_t slength, prefix_len, data_len;
+png_debug(1, "in png_handle_iTXt\n");
+if (!(png_ptr->mode & PNG_HAVE_IHDR))
+png_error(png_ptr, "Missing IHDR before iTXt");
+if (png_ptr->mode & PNG_HAVE_IDAT)
+png_ptr->mode |= PNG_AFTER_IDAT;
+#ifdef PNG_MAX_MALLOC_64K
+/* We will no doubt have problems with chunks even half this size, but
+there is no hard and fast rule to tell us where to stop. */
+if (length > (png_uint_32)65535L)
+{
+png_warning(png_ptr,"iTXt chunk too large to fit in memory");
+png_crc_finish(png_ptr, length);
+return;
+}
+#endif
+chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
+if (chunkdata == NULL)
+{
+png_warning(png_ptr, "No memory to process iTXt chunk.");
+return;
+}
+slength = (png_size_t)length;
+png_crc_read(png_ptr, (png_bytep)chunkdata, slength);
+if (png_crc_finish(png_ptr, 0))
+{
+png_free(png_ptr, chunkdata);
+return;
+}
+chunkdata[slength] = 0x00;
+for (lang = chunkdata; *lang; lang++)
+/* empty loop */ ;
+lang++;        /* skip NUL separator */
+/* iTXt must have a language tag (possibly empty), two compression bytes,
+translated keyword (possibly empty), and possibly some text after the
+keyword */
+if (lang >= chunkdata + slength - 3)
+{
+png_warning(png_ptr, "Truncated iTXt chunk");
+png_free(png_ptr, chunkdata);
+return;
+}
+else
+{
+comp_flag = *lang++;
+comp_type = *lang++;
+}
+for (lang_key = lang; *lang_key; lang_key++)
+/* empty loop */ ;
+lang_key++;        /* skip NUL separator */
+if (lang_key >= chunkdata + slength)
+{
+png_warning(png_ptr, "Truncated iTXt chunk");
+png_free(png_ptr, chunkdata);
+return;
+}
+for (text = lang_key; *text; text++)
+/* empty loop */ ;
+text++;        /* skip NUL separator */
+if (text >= chunkdata + slength)
+{
+png_warning(png_ptr, "Malformed iTXt chunk");
+png_free(png_ptr, chunkdata);
+return;
+}
+prefix_len = text - chunkdata;
+key=chunkdata;
+if (comp_flag)
+chunkdata = png_decompress_chunk(png_ptr, comp_type, chunkdata,
+(size_t)length, prefix_len, &data_len);
+else
+data_len=png_strlen(chunkdata + prefix_len);
+text_ptr = (png_textp)png_malloc_warn(png_ptr,
+(png_uint_32)png_sizeof(png_text));
+if (text_ptr == NULL)
+{
+png_warning(png_ptr,"Not enough memory to process iTXt chunk.");
+png_free(png_ptr, chunkdata);
+return;
+}
+text_ptr->compression = (int)comp_flag + 1;
+text_ptr->lang_key = chunkdata+(lang_key-key);
+text_ptr->lang = chunkdata+(lang-key);
+text_ptr->itxt_length = data_len;
+text_ptr->text_length = 0;
+text_ptr->key = chunkdata;
+text_ptr->text = chunkdata + prefix_len;
+ret=png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
+png_free(png_ptr, text_ptr);
+png_free(png_ptr, chunkdata);
+if (ret)
+png_error(png_ptr, "Insufficient memory to store iTXt chunk.");
+}
+#endif
+/* This function is called when we haven't found a handler for a
+chunk.  If there isn't a problem with the chunk itself (ie bad
+chunk name, CRC, or a critical chunk), the chunk is silently ignored
+-- unless the PNG_FLAG_UNKNOWN_CHUNKS_SUPPORTED flag is on in which
+case it will be saved away to be written out later. */
+void /* PRIVATE */
+png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+png_uint_32 skip = 0;
+png_debug(1, "in png_handle_unknown\n");
+if (png_ptr->mode & PNG_HAVE_IDAT)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+PNG_CONST PNG_IDAT;
+#endif
+if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))  /* not an IDAT */
+png_ptr->mode |= PNG_AFTER_IDAT;
+}
+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");
+}
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+if ((png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS) ||
+(png_ptr->read_user_chunk_fn != NULL))
+{
+#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.size = (png_size_t)length;
+if (length == 0)
+png_ptr->unknown_chunk.data = NULL;
+else
+{
+png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, 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_crc_finish(png_ptr, skip);
+#if !defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+info_ptr = info_ptr; /* quiet compiler warnings about unused info_ptr */
+#endif
+}
+/* This function is called to verify that a chunk name is valid.
+This function can't have the "critical chunk check" incorporated
+into it, since in the future we will need to be able to call user
+functions to handle unknown critical chunks after we check that
+the chunk name itself is valid. */
+#define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
+void /* PRIVATE */
+png_check_chunk_name(png_structp png_ptr, png_bytep chunk_name)
+{
+png_debug(1, "in png_check_chunk_name\n");
+if (isnonalpha(chunk_name[0]) || isnonalpha(chunk_name[1]) ||
+isnonalpha(chunk_name[2]) || isnonalpha(chunk_name[3]))
+{
+png_chunk_error(png_ptr, "invalid chunk type");
+}
+}
+/* Combines the row recently read in with the existing pixels in the
+row.  This routine takes care of alpha and transparency if requested.
+This routine also handles the two methods of progressive display
+of interlaced images, depending on the mask value.
+The mask value describes which pixels are to be combined with
+the row.  The pattern always repeats every 8 pixels, so just 8
+bits are needed.  A one indicates the pixel is to be combined,
+a zero indicates the pixel is to be skipped.  This is in addition
+to any alpha or transparency value associated with the pixel.  If
+you want all pixels to be combined, pass 0xff (255) in mask.  */
+void /* PRIVATE */
+png_combine_row(png_structp png_ptr, png_bytep row, int mask)
+{
+png_debug(1,"in png_combine_row\n");
+if (mask == 0xff)
+{
+png_memcpy(row, png_ptr->row_buf + 1,
+PNG_ROWBYTES(png_ptr->row_info.pixel_depth, png_ptr->width));
+}
+else
+{
+switch (png_ptr->row_info.pixel_depth)
+{
+case 1:
+{
+png_bytep sp = png_ptr->row_buf + 1;
+png_bytep dp = row;
+int s_inc, s_start, s_end;
+int m = 0x80;
+int shift;
+png_uint_32 i;
+png_uint_32 row_width = png_ptr->width;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+if (png_ptr->transformations & PNG_PACKSWAP)
+{
+s_start = 0;
+s_end = 7;
+s_inc = 1;
+}
+else
+#endif
+{
+s_start = 7;
+s_end = 0;
+s_inc = -1;
+}
+shift = s_start;
+for (i = 0; i < row_width; i++)
+{
+if (m & mask)
+{
+int value;
+value = (*sp >> shift) & 0x01;
+*dp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
+*dp |= (png_byte)(value << shift);
+}
+if (shift == s_end)
+{
+shift = s_start;
+sp++;
+dp++;
+}
+else
+shift += s_inc;
+if (m == 1)
+m = 0x80;
+else
+m >>= 1;
+}
+break;
+}
+case 2:
+{
+png_bytep sp = png_ptr->row_buf + 1;
+png_bytep dp = row;
+int s_start, s_end, s_inc;
+int m = 0x80;
+int shift;
+png_uint_32 i;
+png_uint_32 row_width = png_ptr->width;
+int value;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+if (png_ptr->transformations & PNG_PACKSWAP)
+{
+s_start = 0;
+s_end = 6;
+s_inc = 2;
+}
+else
+#endif
+{
+s_start = 6;
+s_end = 0;
+s_inc = -2;
+}
+shift = s_start;
+for (i = 0; i < row_width; i++)
+{
+if (m & mask)
+{
+value = (*sp >> shift) & 0x03;
+*dp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
+*dp |= (png_byte)(value << shift);
+}
+if (shift == s_end)
+{
+shift = s_start;
+sp++;
+dp++;
+}
+else
+shift += s_inc;
+if (m == 1)
+m = 0x80;
+else
+m >>= 1;
+}
+break;
+}
+case 4:
+{
+png_bytep sp = png_ptr->row_buf + 1;
+png_bytep dp = row;
+int s_start, s_end, s_inc;
+int m = 0x80;
+int shift;
+png_uint_32 i;
+png_uint_32 row_width = png_ptr->width;
+int value;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+if (png_ptr->transformations & PNG_PACKSWAP)
+{
+s_start = 0;
+s_end = 4;
+s_inc = 4;
+}
+else
+#endif
+{
+s_start = 4;
+s_end = 0;
+s_inc = -4;
+}
+shift = s_start;
+for (i = 0; i < row_width; i++)
+{
+if (m & mask)
+{
+value = (*sp >> shift) & 0xf;
+*dp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
+*dp |= (png_byte)(value << shift);
+}
+if (shift == s_end)
+{
+shift = s_start;
+sp++;
+dp++;
+}
+else
+shift += s_inc;
+if (m == 1)
+m = 0x80;
+else
+m >>= 1;
+}
+break;
+}
+default:
+{
+png_bytep sp = png_ptr->row_buf + 1;
+png_bytep dp = row;
+png_size_t pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+png_uint_32 i;
+png_uint_32 row_width = png_ptr->width;
+png_byte m = 0x80;
+for (i = 0; i < row_width; i++)
+{
+if (m & mask)
+{
+png_memcpy(dp, sp, pixel_bytes);
+}
+sp += pixel_bytes;
+dp += pixel_bytes;
+if (m == 1)
+m = 0x80;
+else
+m >>= 1;
+}
+break;
+}
+}
+}
+}
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+/* OLD pre-1.0.9 interface:
+void png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
+png_uint_32 transformations)
+*/
+void /* PRIVATE */
+png_do_read_interlace(png_structp png_ptr)
+{
+png_row_infop row_info = &(png_ptr->row_info);
+png_bytep row = png_ptr->row_buf + 1;
+int pass = png_ptr->pass;
+png_uint_32 transformations = png_ptr->transformations;
+#ifdef PNG_USE_LOCAL_ARRAYS
+/* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+/* offset to next interlace block */
+PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+#endif
+png_debug(1,"in png_do_read_interlace\n");
+if (row != NULL && row_info != NULL)
+{
+png_uint_32 final_width;
+final_width = row_info->width * png_pass_inc[pass];
+switch (row_info->pixel_depth)
+{
+case 1:
+{
+png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
+png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
+int sshift, dshift;
+int s_start, s_end, s_inc;
+int jstop = png_pass_inc[pass];
+png_byte v;
+png_uint_32 i;
+int j;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+if (transformations & PNG_PACKSWAP)
+{
+sshift = (int)((row_info->width + 7) & 0x07);
+dshift = (int)((final_width + 7) & 0x07);
+s_start = 7;
+s_end = 0;
+s_inc = -1;
+}
+else
+#endif
+{
+sshift = 7 - (int)((row_info->width + 7) & 0x07);
+dshift = 7 - (int)((final_width + 7) & 0x07);
+s_start = 0;
+s_end = 7;
+s_inc = 1;
+}
+for (i = 0; i < row_info->width; i++)
+{
+v = (png_byte)((*sp >> sshift) & 0x01);
+for (j = 0; j < jstop; j++)
+{
+*dp &= (png_byte)((0x7f7f >> (7 - dshift)) & 0xff);
+*dp |= (png_byte)(v << dshift);
+if (dshift == s_end)
+{
+dshift = s_start;
+dp--;
+}
+else
+dshift += s_inc;
+}
+if (sshift == s_end)
+{
+sshift = s_start;
+sp--;
+}
+else
+sshift += s_inc;
+}
+break;
+}
+case 2:
+{
+png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
+png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
+int sshift, dshift;
+int s_start, s_end, s_inc;
+int jstop = png_pass_inc[pass];
+png_uint_32 i;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+if (transformations & PNG_PACKSWAP)
+{
+sshift = (int)(((row_info->width + 3) & 0x03) << 1);
+dshift = (int)(((final_width + 3) & 0x03) << 1);
+s_start = 6;
+s_end = 0;
+s_inc = -2;
+}
+else
+#endif
+{
+sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1);
+dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1);
+s_start = 0;
+s_end = 6;
+s_inc = 2;
+}
+for (i = 0; i < row_info->width; i++)
+{
+png_byte v;
+int j;
+v = (png_byte)((*sp >> sshift) & 0x03);
+for (j = 0; j < jstop; j++)
+{
+*dp &= (png_byte)((0x3f3f >> (6 - dshift)) & 0xff);
+*dp |= (png_byte)(v << dshift);
+if (dshift == s_end)
+{
+dshift = s_start;
+dp--;
+}
+else
+dshift += s_inc;
+}
+if (sshift == s_end)
+{
+sshift = s_start;
+sp--;
+}
+else
+sshift += s_inc;
+}
+break;
+}
+case 4:
+{
+png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
+png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
+int sshift, dshift;
+int s_start, s_end, s_inc;
+png_uint_32 i;
+int jstop = png_pass_inc[pass];
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+if (transformations & PNG_PACKSWAP)
+{
+sshift = (int)(((row_info->width + 1) & 0x01) << 2);
+dshift = (int)(((final_width + 1) & 0x01) << 2);
+s_start = 4;
+s_end = 0;
+s_inc = -4;
+}
+else
+#endif
+{
+sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2);
+dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2);
+s_start = 0;
+s_end = 4;
+s_inc = 4;
+}
+for (i = 0; i < row_info->width; i++)
+{
+png_byte v = (png_byte)((*sp >> sshift) & 0xf);
+int j;
+for (j = 0; j < jstop; j++)
+{
+*dp &= (png_byte)((0xf0f >> (4 - dshift)) & 0xff);
+*dp |= (png_byte)(v << dshift);
+if (dshift == s_end)
+{
+dshift = s_start;
+dp--;
+}
+else
+dshift += s_inc;
+}
+if (sshift == s_end)
+{
+sshift = s_start;
+sp--;
+}
+else
+sshift += s_inc;
+}
+break;
+}
+default:
+{
+png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
+png_bytep sp = row + (png_size_t)(row_info->width - 1) * pixel_bytes;
+png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;
+int jstop = png_pass_inc[pass];
+png_uint_32 i;
+for (i = 0; i < row_info->width; i++)
+{
+png_byte v[8];
+int j;
+png_memcpy(v, sp, pixel_bytes);
+for (j = 0; j < jstop; j++)
+{
+png_memcpy(dp, v, pixel_bytes);
+dp -= pixel_bytes;
+}
+sp -= pixel_bytes;
+}
+break;
+}
+}
+row_info->width = final_width;
+row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,final_width);
+}
+#if !defined(PNG_READ_PACKSWAP_SUPPORTED)
+transformations = transformations; /* silence compiler warning */
+#endif
+}
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
+void /* PRIVATE */
+png_read_filter_row(png_structp png_ptr, png_row_infop row_info, png_bytep row,
+png_bytep prev_row, int filter)
+{
+png_debug(1, "in png_read_filter_row\n");
+png_debug2(2,"row = %lu, filter = %d\n", png_ptr->row_number, filter);
+switch (filter)
+{
+case PNG_FILTER_VALUE_NONE:
+break;
+case PNG_FILTER_VALUE_SUB:
+{
+png_uint_32 i;
+png_uint_32 istop = row_info->rowbytes;
+png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+png_bytep rp = row + bpp;
+png_bytep lp = row;
+for (i = bpp; i < istop; i++)
+{
+*rp = (png_byte)(((int)(*rp) + (int)(*lp++)) & 0xff);
+rp++;
+}
+break;
+}
+case PNG_FILTER_VALUE_UP:
+{
+png_uint_32 i;
+png_uint_32 istop = row_info->rowbytes;
+png_bytep rp = row;
+png_bytep pp = prev_row;
+for (i = 0; i < istop; i++)
+{
+*rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+rp++;
+}
+break;
+}
+case PNG_FILTER_VALUE_AVG:
+{
+png_uint_32 i;
+png_bytep rp = row;
+png_bytep pp = prev_row;
+png_bytep lp = row;
+png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+png_uint_32 istop = row_info->rowbytes - bpp;
+for (i = 0; i < bpp; i++)
+{
+*rp = (png_byte)(((int)(*rp) +
+((int)(*pp++) / 2 )) & 0xff);
+rp++;
+}
+for (i = 0; i < istop; i++)
+{
+*rp = (png_byte)(((int)(*rp) +
+(int)(*pp++ + *lp++) / 2 ) & 0xff);
+rp++;
+}
+break;
+}
+case PNG_FILTER_VALUE_PAETH:
+{
+png_uint_32 i;
+png_bytep rp = row;
+png_bytep pp = prev_row;
+png_bytep lp = row;
+png_bytep cp = prev_row;
+png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+png_uint_32 istop=row_info->rowbytes - bpp;
+for (i = 0; i < bpp; i++)
+{
+*rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+rp++;
+}
+for (i = 0; i < istop; i++)   /* use leftover rp,pp */
+{
+int a, b, c, pa, pb, pc, p;
+a = *lp++;
+b = *pp++;
+c = *cp++;
+p = b - c;
+pc = a - c;
+#ifdef PNG_USE_ABS
+pa = abs(p);
+pb = abs(pc);
+pc = abs(p + pc);
+#else
+pa = p < 0 ? -p : p;
+pb = pc < 0 ? -pc : pc;
+pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+/*
+if (pa <= pb && pa <= pc)
+p = a;
+else if (pb <= pc)
+p = b;
+else
+p = c;
+*/
+p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+*rp = (png_byte)(((int)(*rp) + p) & 0xff);
+rp++;
+}
+break;
+}
+default:
+png_warning(png_ptr, "Ignoring bad adaptive filter type");
+*row=0;
+break;
+}
+}
+void /* PRIVATE */
+png_read_finish_row(png_structp png_ptr)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+/* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+/* start of interlace block */
+PNG_CONST int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+/* offset to next interlace block */
+PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+/* start of interlace block in the y direction */
+PNG_CONST int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+/* offset to next interlace block in the y direction */
+PNG_CONST int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
+#endif
+png_debug(1, "in png_read_finish_row\n");
+png_ptr->row_number++;
+if (png_ptr->row_number < png_ptr->num_rows)
+return;
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+if (png_ptr->interlaced)
+{
+png_ptr->row_number = 0;
+png_memset_check(png_ptr, png_ptr->prev_row, 0,
+png_ptr->rowbytes + 1);
+do
+{
+png_ptr->pass++;
+if (png_ptr->pass >= 7)
+break;
+png_ptr->iwidth = (png_ptr->width +
+png_pass_inc[png_ptr->pass] - 1 -
+png_pass_start[png_ptr->pass]) /
+png_pass_inc[png_ptr->pass];
+png_ptr->irowbytes = PNG_ROWBYTES(png_ptr->pixel_depth,
+png_ptr->iwidth) + 1;
+if (!(png_ptr->transformations & PNG_INTERLACE))
+{
+png_ptr->num_rows = (png_ptr->height +
+png_pass_yinc[png_ptr->pass] - 1 -
+png_pass_ystart[png_ptr->pass]) /
+png_pass_yinc[png_ptr->pass];
+if (!(png_ptr->num_rows))
+continue;
+}
+else  /* if (png_ptr->transformations & PNG_INTERLACE) */
+break;
+} while (png_ptr->iwidth == 0);
+if (png_ptr->pass < 7)
+return;
+}
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
+if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+PNG_CONST PNG_IDAT;
+#endif
+char extra;
+int ret;
+png_ptr->zstream.next_out = (Byte *)&extra;
+png_ptr->zstream.avail_out = (uInt)1;
+for(;;)
+{
+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_31(png_ptr, 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_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_warning(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");
+if (!(png_ptr->zstream.avail_out))
+{
+png_warning(png_ptr, "Extra compressed data.");
+png_ptr->mode |= PNG_AFTER_IDAT;
+png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
+break;
+}
+}
+png_ptr->zstream.avail_out = 0;
+}
+if (png_ptr->idat_size || png_ptr->zstream.avail_in)
+png_warning(png_ptr, "Extra compression data");
+inflateReset(&png_ptr->zstream);
+png_ptr->mode |= PNG_AFTER_IDAT;
+}
+void /* PRIVATE */
+png_read_start_row(png_structp png_ptr)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+/* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+/* start of interlace block */
+PNG_CONST int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+/* offset to next interlace block */
+PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+/* start of interlace block in the y direction */
+PNG_CONST int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+/* offset to next interlace block in the y direction */
+PNG_CONST int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+#endif
+int max_pixel_depth;
+png_uint_32 row_bytes;
+png_debug(1, "in png_read_start_row\n");
+png_ptr->zstream.avail_in = 0;
+png_init_read_transformations(png_ptr);
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+if (png_ptr->interlaced)
+{
+if (!(png_ptr->transformations & PNG_INTERLACE))
+png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
+png_pass_ystart[0]) / png_pass_yinc[0];
+else
+png_ptr->num_rows = png_ptr->height;
+png_ptr->iwidth = (png_ptr->width +
+png_pass_inc[png_ptr->pass] - 1 -
+png_pass_start[png_ptr->pass]) /
+png_pass_inc[png_ptr->pass];
+row_bytes = PNG_ROWBYTES(png_ptr->pixel_depth,png_ptr->iwidth) + 1;
+png_ptr->irowbytes = (png_size_t)row_bytes;
+if((png_uint_32)png_ptr->irowbytes != row_bytes)
+png_error(png_ptr, "Rowbytes overflow in png_read_start_row");
+}
+else
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
+{
+png_ptr->num_rows = png_ptr->height;
+png_ptr->iwidth = png_ptr->width;
+png_ptr->irowbytes = png_ptr->rowbytes + 1;
+}
+max_pixel_depth = png_ptr->pixel_depth;
+#if defined(PNG_READ_PACK_SUPPORTED)
+if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8)
+max_pixel_depth = 8;
+#endif
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+if (png_ptr->transformations & PNG_EXPAND)
+{
+if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+{
+if (png_ptr->num_trans)
+max_pixel_depth = 32;
+else
+max_pixel_depth = 24;
+}
+else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+{
+if (max_pixel_depth < 8)
+max_pixel_depth = 8;
+if (png_ptr->num_trans)
+max_pixel_depth *= 2;
+}
+else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+{
+if (png_ptr->num_trans)
+{
+max_pixel_depth *= 4;
+max_pixel_depth /= 3;
+}
+}
+}
+#endif
+#if defined(PNG_READ_FILLER_SUPPORTED)
+if (png_ptr->transformations & (PNG_FILLER))
+{
+if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+max_pixel_depth = 32;
+else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+{
+if (max_pixel_depth <= 8)
+max_pixel_depth = 16;
+else
+max_pixel_depth = 32;
+}
+else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+{
+if (max_pixel_depth <= 32)
+max_pixel_depth = 32;
+else
+max_pixel_depth = 64;
+}
+}
+#endif
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+if (png_ptr->transformations & PNG_GRAY_TO_RGB)
+{
+if (
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+(png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND)) ||
+#endif
+#if defined(PNG_READ_FILLER_SUPPORTED)
+(png_ptr->transformations & (PNG_FILLER)) ||
+#endif
+png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+{
+if (max_pixel_depth <= 16)
+max_pixel_depth = 32;
+else
+max_pixel_depth = 64;
+}
+else
+{
+if (max_pixel_depth <= 8)
+{
+if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+max_pixel_depth = 32;
+else
+max_pixel_depth = 24;
+}
+else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+max_pixel_depth = 64;
+else
+max_pixel_depth = 48;
+}
+}
+#endif
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
+defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
+if(png_ptr->transformations & PNG_USER_TRANSFORM)
+{
+int user_pixel_depth=png_ptr->user_transform_depth*
+png_ptr->user_transform_channels;
+if(user_pixel_depth > max_pixel_depth)
+max_pixel_depth=user_pixel_depth;
+}
+#endif
+/* align the width on the next larger 8 pixels.  Mainly used
+for interlacing */
+row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
+/* calculate the maximum bytes needed, adding a byte and a pixel
+for safety's sake */
+row_bytes = PNG_ROWBYTES(max_pixel_depth,row_bytes) +
+1 + ((max_pixel_depth + 7) >> 3);
+#ifdef PNG_MAX_MALLOC_64K
+if (row_bytes > (png_uint_32)65536L)
+png_error(png_ptr, "This image requires a row greater than 64KB");
+#endif
+if(row_bytes + 64 > png_ptr->old_big_row_buf_size)
+{
+png_free(png_ptr,png_ptr->big_row_buf);
+png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes+64);
+png_ptr->row_buf = png_ptr->big_row_buf+32;
+png_ptr->old_big_row_buf_size = row_bytes+64;
+}
+#ifdef PNG_MAX_MALLOC_64K
+if ((png_uint_32)png_ptr->rowbytes + 1 > (png_uint_32)65536L)
+png_error(png_ptr, "This image requires a row greater than 64KB");
+#endif
+if ((png_uint_32)png_ptr->rowbytes > (png_uint_32)(PNG_SIZE_MAX - 1))
+png_error(png_ptr, "Row has too many bytes to allocate in memory.");
+if(png_ptr->rowbytes+1 > png_ptr->old_prev_row_size)
+{
+png_free(png_ptr,png_ptr->prev_row);
+png_ptr->prev_row = (png_bytep)png_malloc(png_ptr, (png_uint_32)(
+png_ptr->rowbytes + 1));
+png_ptr->old_prev_row_size = png_ptr->rowbytes+1;
+}
+png_memset_check(png_ptr, png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+png_debug1(3, "width = %lu,\n", png_ptr->width);
+png_debug1(3, "height = %lu,\n", png_ptr->height);
+png_debug1(3, "iwidth = %lu,\n", png_ptr->iwidth);
+png_debug1(3, "num_rows = %lu\n", png_ptr->num_rows);
+png_debug1(3, "rowbytes = %lu,\n", png_ptr->rowbytes);
+png_debug1(3, "irowbytes = %lu,\n", png_ptr->irowbytes);
+png_ptr->flags |= PNG_FLAG_ROW_INIT;
+}
+#endif /* PNG_READ_SUPPORTED */

Mercurial > fife-parpg

comparison ext/libpng-1.2.29/pngrutil.c @ 0:4a0efb7baf70