www.pudn.com > transparentdib.zip > pngpread.c
/* pngpread.c - read a png file in push mode
*
* libpng 1.0.12 - June 8, 2001
* For conditions of distribution and use, see copyright notice in png.h
* Copyright (c) 1998-2001 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)
{
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)
{
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_IHDR;
PNG_IDAT;
PNG_IEND;
PNG_PLTE;
#if defined(PNG_READ_bKGD_SUPPORTED)
PNG_bKGD;
#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
PNG_cHRM;
#endif
#if defined(PNG_READ_gAMA_SUPPORTED)
PNG_gAMA;
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
PNG_hIST;
#endif
#if defined(PNG_READ_iCCP_SUPPORTED)
PNG_iCCP;
#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
PNG_iTXt;
#endif
#if defined(PNG_READ_oFFs_SUPPORTED)
PNG_oFFs;
#endif
#if defined(PNG_READ_pCAL_SUPPORTED)
PNG_pCAL;
#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
PNG_pHYs;
#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
PNG_sBIT;
#endif
#if defined(PNG_READ_sCAL_SUPPORTED)
PNG_sCAL;
#endif
#if defined(PNG_READ_sRGB_SUPPORTED)
PNG_sRGB;
#endif
#if defined(PNG_READ_sPLT_SUPPORTED)
PNG_sPLT;
#endif
#if defined(PNG_READ_tEXt_SUPPORTED)
PNG_tEXt;
#endif
#if defined(PNG_READ_tIME_SUPPORTED)
PNG_tIME;
#endif
#if defined(PNG_READ_tRNS_SUPPORTED)
PNG_tRNS;
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
PNG_zTXt;
#endif
#endif /* PNG_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_32(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_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_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_bytep)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_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;
}
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);
}
#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))
{
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))
{
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))
{
png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
else
{
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 /* PRIVATE */
png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
{
png_bytep ptr;
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;
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_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_32(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_bytep)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);
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);
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;
}
}
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))
{
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_ptr->row_info.width *
(png_uint_32)png_ptr->row_info.pixel_depth + 7) >> 3);
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_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, 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, NULL);
png_read_push_finish_row(png_ptr);
}
}
if (png_ptr->pass == 6 && png_ptr->height <= 4)
{
png_push_have_row(png_ptr, 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, 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, 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, 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, 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, NULL);
png_read_push_finish_row(png_ptr);
}
if (png_ptr->pass == 6) /* pass 5 might be empty */
{
png_push_have_row(png_ptr, 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, 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, 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 */
const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
/* offset to next interlace block */
const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
/* start of interlace block in the y direction */
const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
/* offset to next interlace block in the y direction */
const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
/* Width of interlace block. This is not currently used - if you need
* it, uncomment it here and in png.h
const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
*/
/* Height of interlace block. This is not currently used - if you need
* it, uncomment it here and in png.h
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
{
png_ptr->pass++;
if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
(png_ptr->pass == 3 && png_ptr->width < 3) ||
(png_ptr->pass == 5 && png_ptr->width < 2))
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_ptr->iwidth *
png_ptr->pixel_depth + 7) >> 3) + 1;
if (png_ptr->transformations & PNG_INTERLACE)
break;
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];
} 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");
/* to quiet some compiler warnings */
if(info_ptr == NULL) return;
}
#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;
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;
png_ptr->current_text = 0;
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)sizeof(png_text));
text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
text_ptr->key = key;
#ifdef PNG_iTXt_SUPPORTED
text_ptr->lang = (char *)NULL;
text_ptr->lang_key = (char *)NULL;
#endif
text_ptr->text = text;
png_set_text(png_ptr, info_ptr, text_ptr, 1);
png_free(png_ptr, key);
png_free(png_ptr, text_ptr);
}
}
#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");
/* to quiet some compiler warnings */
if(info_ptr == NULL) return;
}
#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;
png_ptr->current_text = 0;
for (text = key; *text; text++)
/* empty loop */ ;
/* zTXt can't have zero text */
if (text == key + png_ptr->current_text_size)
{
png_free(png_ptr, key);
return;
}
text++;
if (*text != PNG_TEXT_COMPRESSION_zTXt) /* check compression byte */
{
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_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_free(png_ptr, key);
png_free(png_ptr, text);
return;
}
png_free(png_ptr, key);
key = text;
text += key_size;
text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
text_ptr->key = key;
#ifdef PNG_iTXt_SUPPORTED
text_ptr->lang = (char *)NULL;
text_ptr->lang_key = (char *)NULL;
#endif
text_ptr->text = text;
png_set_text(png_ptr, info_ptr, text_ptr, 1);
png_free(png_ptr, key);
png_free(png_ptr, text_ptr);
}
}
#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");
/* to quiet some compiler warnings */
if(info_ptr == NULL) return;
}
#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;
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;
png_ptr->current_text = 0;
for (lang = key; *lang; lang++)
/* empty loop */ ;
if (lang != key + png_ptr->current_text_size)
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 */
for (text = lang_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)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);
png_set_text(png_ptr, info_ptr, text_ptr, 1);
png_free(png_ptr, text_ptr);
}
}
#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) !=
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");
/* to quiet compiler warnings about unused info_ptr */
if (info_ptr == NULL)
return;
}
#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
{
png_unknown_chunk chunk;
#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_strcpy((png_charp)chunk.name, (png_charp)png_ptr->chunk_name);
chunk.data = (png_bytep)png_malloc(png_ptr, length);
png_crc_read(png_ptr, chunk.data, length);
chunk.size = length;
#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
if(png_ptr->read_user_chunk_fn != NULL)
{
/* callback to user unknown chunk handler */
if ((*(png_ptr->read_user_chunk_fn)) (png_ptr, &chunk) <= 0)
{
if (!(png_ptr->chunk_name[0] & 0x20))
if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
HANDLE_CHUNK_ALWAYS)
png_chunk_error(png_ptr, "unknown critical chunk");
}
png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
}
else
#endif
png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
png_free(png_ptr, chunk.data);
}
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
const int FARDATA png_pass_dsp_mask[7] =
{0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
#endif
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)
{
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)
{
return png_ptr->io_ptr;
}
#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */