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-rw-r--r--libpng/pngwutil.c2669
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diff --git a/libpng/pngwutil.c b/libpng/pngwutil.c
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+++ b/libpng/pngwutil.c
@@ -0,0 +1,2669 @@
+
+/* pngwutil.c - utilities to write a PNG file
+ *
+ * libpng 1.2.1 - December 12, 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_WRITE_SUPPORTED
+
+/* Place a 32-bit number into a buffer in PNG byte order. We work
+ * with unsigned numbers for convenience, although one supported
+ * ancillary chunk uses signed (two's complement) numbers.
+ */
+void /* PRIVATE */
+png_save_uint_32(png_bytep buf, png_uint_32 i)
+{
+ buf[0] = (png_byte)((i >> 24) & 0xff);
+ buf[1] = (png_byte)((i >> 16) & 0xff);
+ buf[2] = (png_byte)((i >> 8) & 0xff);
+ buf[3] = (png_byte)(i & 0xff);
+}
+
+#if defined(PNG_WRITE_pCAL_SUPPORTED) || defined(PNG_WRITE_oFFs_SUPPORTED)
+/* The png_save_int_32 function assumes integers are stored in two's
+ * complement format. If this isn't the case, then this routine needs to
+ * be modified to write data in two's complement format.
+ */
+void /* PRIVATE */
+png_save_int_32(png_bytep buf, png_int_32 i)
+{
+ buf[0] = (png_byte)((i >> 24) & 0xff);
+ buf[1] = (png_byte)((i >> 16) & 0xff);
+ buf[2] = (png_byte)((i >> 8) & 0xff);
+ buf[3] = (png_byte)(i & 0xff);
+}
+#endif
+
+/* Place a 16-bit number into a buffer in PNG byte order.
+ * The parameter is declared unsigned int, not png_uint_16,
+ * just to avoid potential problems on pre-ANSI C compilers.
+ */
+void /* PRIVATE */
+png_save_uint_16(png_bytep buf, unsigned int i)
+{
+ buf[0] = (png_byte)((i >> 8) & 0xff);
+ buf[1] = (png_byte)(i & 0xff);
+}
+
+/* Write a PNG chunk all at once. The type is an array of ASCII characters
+ * representing the chunk name. The array must be at least 4 bytes in
+ * length, and does not need to be null terminated. To be safe, pass the
+ * pre-defined chunk names here, and if you need a new one, define it
+ * where the others are defined. The length is the length of the data.
+ * All the data must be present. If that is not possible, use the
+ * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
+ * functions instead.
+ */
+void PNGAPI
+png_write_chunk(png_structp png_ptr, png_bytep chunk_name,
+ png_bytep data, png_size_t length)
+{
+ png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length);
+ png_write_chunk_data(png_ptr, data, length);
+ png_write_chunk_end(png_ptr);
+}
+
+/* Write the start of a PNG chunk. The type is the chunk type.
+ * The total_length is the sum of the lengths of all the data you will be
+ * passing in png_write_chunk_data().
+ */
+void PNGAPI
+png_write_chunk_start(png_structp png_ptr, png_bytep chunk_name,
+ png_uint_32 length)
+{
+ png_byte buf[4];
+ png_debug2(0, "Writing %s chunk (%lu bytes)\n", chunk_name, length);
+
+ /* write the length */
+ png_save_uint_32(buf, length);
+ png_write_data(png_ptr, buf, (png_size_t)4);
+
+ /* write the chunk name */
+ png_write_data(png_ptr, chunk_name, (png_size_t)4);
+ /* reset the crc and run it over the chunk name */
+ png_reset_crc(png_ptr);
+ png_calculate_crc(png_ptr, chunk_name, (png_size_t)4);
+}
+
+/* Write the data of a PNG chunk started with png_write_chunk_start().
+ * Note that multiple calls to this function are allowed, and that the
+ * sum of the lengths from these calls *must* add up to the total_length
+ * given to png_write_chunk_start().
+ */
+void PNGAPI
+png_write_chunk_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+ /* write the data, and run the CRC over it */
+ if (data != NULL && length > 0)
+ {
+ png_calculate_crc(png_ptr, data, length);
+ png_write_data(png_ptr, data, length);
+ }
+}
+
+/* Finish a chunk started with png_write_chunk_start(). */
+void PNGAPI
+png_write_chunk_end(png_structp png_ptr)
+{
+ png_byte buf[4];
+
+ /* write the crc */
+ png_save_uint_32(buf, png_ptr->crc);
+
+ png_write_data(png_ptr, buf, (png_size_t)4);
+}
+
+/* Simple function to write the signature. If we have already written
+ * the magic bytes of the signature, or more likely, the PNG stream is
+ * being embedded into another stream and doesn't need its own signature,
+ * we should call png_set_sig_bytes() to tell libpng how many of the
+ * bytes have already been written.
+ */
+void /* PRIVATE */
+png_write_sig(png_structp png_ptr)
+{
+ png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
+ /* write the rest of the 8 byte signature */
+ png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
+ (png_size_t)8 - png_ptr->sig_bytes);
+ if(png_ptr->sig_bytes < 3)
+ png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
+}
+
+#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)
+/*
+ * This pair of functions encapsulates the operation of (a) compressing a
+ * text string, and (b) issuing it later as a series of chunk data writes.
+ * The compression_state structure is shared context for these functions
+ * set up by the caller in order to make the whole mess thread-safe.
+ */
+
+typedef struct
+{
+ char *input; /* the uncompressed input data */
+ int input_len; /* its length */
+ int num_output_ptr; /* number of output pointers used */
+ int max_output_ptr; /* size of output_ptr */
+ png_charpp output_ptr; /* array of pointers to output */
+} compression_state;
+
+/* compress given text into storage in the png_ptr structure */
+static int /* PRIVATE */
+png_text_compress(png_structp png_ptr,
+ png_charp text, png_size_t text_len, int compression,
+ compression_state *comp)
+{
+ int ret;
+
+ comp->num_output_ptr = comp->max_output_ptr = 0;
+ comp->output_ptr = NULL;
+ comp->input = NULL;
+
+ /* we may just want to pass the text right through */
+ if (compression == PNG_TEXT_COMPRESSION_NONE)
+ {
+ comp->input = text;
+ comp->input_len = text_len;
+ return((int)text_len);
+ }
+
+ if (compression >= PNG_TEXT_COMPRESSION_LAST)
+ {
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+ char msg[50];
+ sprintf(msg, "Unknown compression type %d", compression);
+ png_warning(png_ptr, msg);
+#else
+ png_warning(png_ptr, "Unknown compression type");
+#endif
+ }
+
+ /* We can't write the chunk until we find out how much data we have,
+ * which means we need to run the compressor first and save the
+ * output. This shouldn't be a problem, as the vast majority of
+ * comments should be reasonable, but we will set up an array of
+ * malloc'd pointers to be sure.
+ *
+ * If we knew the application was well behaved, we could simplify this
+ * greatly by assuming we can always malloc an output buffer large
+ * enough to hold the compressed text ((1001 * text_len / 1000) + 12)
+ * and malloc this directly. The only time this would be a bad idea is
+ * if we can't malloc more than 64K and we have 64K of random input
+ * data, or if the input string is incredibly large (although this
+ * wouldn't cause a failure, just a slowdown due to swapping).
+ */
+
+ /* set up the compression buffers */
+ png_ptr->zstream.avail_in = (uInt)text_len;
+ png_ptr->zstream.next_in = (Bytef *)text;
+ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+ png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;
+
+ /* this is the same compression loop as in png_write_row() */
+ do
+ {
+ /* compress the data */
+ ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
+ if (ret != Z_OK)
+ {
+ /* error */
+ if (png_ptr->zstream.msg != NULL)
+ png_error(png_ptr, png_ptr->zstream.msg);
+ else
+ png_error(png_ptr, "zlib error");
+ }
+ /* check to see if we need more room */
+ if (!png_ptr->zstream.avail_out && png_ptr->zstream.avail_in)
+ {
+ /* make sure the output array has room */
+ if (comp->num_output_ptr >= comp->max_output_ptr)
+ {
+ int old_max;
+
+ old_max = comp->max_output_ptr;
+ comp->max_output_ptr = comp->num_output_ptr + 4;
+ if (comp->output_ptr != NULL)
+ {
+ png_charpp old_ptr;
+
+ old_ptr = comp->output_ptr;
+ comp->output_ptr = (png_charpp)png_malloc(png_ptr,
+ (png_uint_32)(comp->max_output_ptr * sizeof (png_charpp)));
+ png_memcpy(comp->output_ptr, old_ptr, old_max
+ * sizeof (png_charp));
+ png_free(png_ptr, old_ptr);
+ }
+ else
+ comp->output_ptr = (png_charpp)png_malloc(png_ptr,
+ (png_uint_32)(comp->max_output_ptr * sizeof (png_charp)));
+ }
+
+ /* save the data */
+ comp->output_ptr[comp->num_output_ptr] = (png_charp)png_malloc(png_ptr,
+ (png_uint_32)png_ptr->zbuf_size);
+ png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
+ png_ptr->zbuf_size);
+ comp->num_output_ptr++;
+
+ /* and reset the buffer */
+ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+ png_ptr->zstream.next_out = png_ptr->zbuf;
+ }
+ /* continue until we don't have any more to compress */
+ } while (png_ptr->zstream.avail_in);
+
+ /* finish the compression */
+ do
+ {
+ /* tell zlib we are finished */
+ ret = deflate(&png_ptr->zstream, Z_FINISH);
+
+ if (ret == Z_OK)
+ {
+ /* check to see if we need more room */
+ if (!(png_ptr->zstream.avail_out))
+ {
+ /* check to make sure our output array has room */
+ if (comp->num_output_ptr >= comp->max_output_ptr)
+ {
+ int old_max;
+
+ old_max = comp->max_output_ptr;
+ comp->max_output_ptr = comp->num_output_ptr + 4;
+ if (comp->output_ptr != NULL)
+ {
+ png_charpp old_ptr;
+
+ old_ptr = comp->output_ptr;
+ /* This could be optimized to realloc() */
+ comp->output_ptr = (png_charpp)png_malloc(png_ptr,
+ (png_uint_32)(comp->max_output_ptr * sizeof (png_charpp)));
+ png_memcpy(comp->output_ptr, old_ptr,
+ old_max * sizeof (png_charp));
+ png_free(png_ptr, old_ptr);
+ }
+ else
+ comp->output_ptr = (png_charpp)png_malloc(png_ptr,
+ (png_uint_32)(comp->max_output_ptr * sizeof (png_charp)));
+ }
+
+ /* save off the data */
+ comp->output_ptr[comp->num_output_ptr] =
+ (png_charp)png_malloc(png_ptr, (png_uint_32)png_ptr->zbuf_size);
+ png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
+ png_ptr->zbuf_size);
+ comp->num_output_ptr++;
+
+ /* and reset the buffer pointers */
+ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+ png_ptr->zstream.next_out = png_ptr->zbuf;
+ }
+ }
+ else if (ret != Z_STREAM_END)
+ {
+ /* we got an error */
+ if (png_ptr->zstream.msg != NULL)
+ png_error(png_ptr, png_ptr->zstream.msg);
+ else
+ png_error(png_ptr, "zlib error");
+ }
+ } while (ret != Z_STREAM_END);
+
+ /* text length is number of buffers plus last buffer */
+ text_len = png_ptr->zbuf_size * comp->num_output_ptr;
+ if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
+ text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;
+
+ return((int)text_len);
+}
+
+/* ship the compressed text out via chunk writes */
+static void /* PRIVATE */
+png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
+{
+ int i;
+
+ /* handle the no-compression case */
+ if (comp->input)
+ {
+ png_write_chunk_data(png_ptr, (png_bytep)comp->input,
+ (png_size_t)comp->input_len);
+ return;
+ }
+
+ /* write saved output buffers, if any */
+ for (i = 0; i < comp->num_output_ptr; i++)
+ {
+ png_write_chunk_data(png_ptr,(png_bytep)comp->output_ptr[i],
+ png_ptr->zbuf_size);
+ png_free(png_ptr, comp->output_ptr[i]);
+ comp->output_ptr[i]=NULL;
+ }
+ if (comp->max_output_ptr != 0)
+ png_free(png_ptr, comp->output_ptr);
+ comp->output_ptr=NULL;
+ /* write anything left in zbuf */
+ if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size)
+ png_write_chunk_data(png_ptr, png_ptr->zbuf,
+ png_ptr->zbuf_size - png_ptr->zstream.avail_out);
+
+ /* reset zlib for another zTXt/iTXt or the image data */
+ deflateReset(&png_ptr->zstream);
+
+}
+#endif
+
+/* Write the IHDR chunk, and update the png_struct with the necessary
+ * information. Note that the rest of this code depends upon this
+ * information being correct.
+ */
+void /* PRIVATE */
+png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
+ int bit_depth, int color_type, int compression_type, int filter_type,
+ int interlace_type)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_IHDR;
+#endif
+ png_byte buf[13]; /* buffer to store the IHDR info */
+
+ png_debug(1, "in png_write_IHDR\n");
+ /* Check that we have valid input data from the application info */
+ switch (color_type)
+ {
+ case PNG_COLOR_TYPE_GRAY:
+ switch (bit_depth)
+ {
+ case 1:
+ case 2:
+ case 4:
+ case 8:
+ case 16: png_ptr->channels = 1; break;
+ default: png_error(png_ptr,"Invalid bit depth for grayscale image");
+ }
+ break;
+ case PNG_COLOR_TYPE_RGB:
+ if (bit_depth != 8 && bit_depth != 16)
+ png_error(png_ptr, "Invalid bit depth for RGB image");
+ png_ptr->channels = 3;
+ break;
+ case PNG_COLOR_TYPE_PALETTE:
+ switch (bit_depth)
+ {
+ case 1:
+ case 2:
+ case 4:
+ case 8: png_ptr->channels = 1; break;
+ default: png_error(png_ptr, "Invalid bit depth for paletted image");
+ }
+ break;
+ case PNG_COLOR_TYPE_GRAY_ALPHA:
+ if (bit_depth != 8 && bit_depth != 16)
+ png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
+ png_ptr->channels = 2;
+ break;
+ case PNG_COLOR_TYPE_RGB_ALPHA:
+ if (bit_depth != 8 && bit_depth != 16)
+ png_error(png_ptr, "Invalid bit depth for RGBA image");
+ png_ptr->channels = 4;
+ break;
+ default:
+ png_error(png_ptr, "Invalid image color type specified");
+ }
+
+ if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+ {
+ png_warning(png_ptr, "Invalid compression type specified");
+ compression_type = PNG_COMPRESSION_TYPE_BASE;
+ }
+
+ /* Write filter_method 64 (intrapixel differencing) only if
+ * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+ * 2. Libpng did not write a PNG signature (this filter_method is only
+ * used in PNG datastreams that are embedded in MNG datastreams) and
+ * 3. The application called png_permit_mng_features with a mask that
+ * included PNG_FLAG_MNG_FILTER_64 and
+ * 4. The filter_method is 64 and
+ * 5. The color_type is RGB or RGBA
+ */
+ if (
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+ !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+ ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
+ (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
+ (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
+#endif
+ filter_type != PNG_FILTER_TYPE_BASE)
+ {
+ png_warning(png_ptr, "Invalid filter type specified");
+ filter_type = PNG_FILTER_TYPE_BASE;
+ }
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ if (interlace_type != PNG_INTERLACE_NONE &&
+ interlace_type != PNG_INTERLACE_ADAM7)
+ {
+ png_warning(png_ptr, "Invalid interlace type specified");
+ interlace_type = PNG_INTERLACE_ADAM7;
+ }
+#else
+ interlace_type=PNG_INTERLACE_NONE;
+#endif
+
+ /* save off the relevent information */
+ png_ptr->bit_depth = (png_byte)bit_depth;
+ png_ptr->color_type = (png_byte)color_type;
+ png_ptr->interlaced = (png_byte)interlace_type;
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+ png_ptr->filter_type = (png_byte)filter_type;
+#endif
+ png_ptr->width = width;
+ png_ptr->height = height;
+
+ png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
+ png_ptr->rowbytes = ((width * (png_size_t)png_ptr->pixel_depth + 7) >> 3);
+ /* set the usr info, so any transformations can modify it */
+ png_ptr->usr_width = png_ptr->width;
+ png_ptr->usr_bit_depth = png_ptr->bit_depth;
+ png_ptr->usr_channels = png_ptr->channels;
+
+ /* pack the header information into the buffer */
+ png_save_uint_32(buf, width);
+ png_save_uint_32(buf + 4, height);
+ buf[8] = (png_byte)bit_depth;
+ buf[9] = (png_byte)color_type;
+ buf[10] = (png_byte)compression_type;
+ buf[11] = (png_byte)filter_type;
+ buf[12] = (png_byte)interlace_type;
+
+ /* write the chunk */
+ png_write_chunk(png_ptr, (png_bytep)png_IHDR, buf, (png_size_t)13);
+
+ /* initialize zlib with PNG info */
+ png_ptr->zstream.zalloc = png_zalloc;
+ png_ptr->zstream.zfree = png_zfree;
+ png_ptr->zstream.opaque = (voidpf)png_ptr;
+ if (!(png_ptr->do_filter))
+ {
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
+ png_ptr->bit_depth < 8)
+ png_ptr->do_filter = PNG_FILTER_NONE;
+ else
+ png_ptr->do_filter = PNG_ALL_FILTERS;
+ }
+ if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY))
+ {
+ if (png_ptr->do_filter != PNG_FILTER_NONE)
+ png_ptr->zlib_strategy = Z_FILTERED;
+ else
+ png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;
+ }
+ if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL))
+ png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;
+ if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL))
+ png_ptr->zlib_mem_level = 8;
+ if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS))
+ png_ptr->zlib_window_bits = 15;
+ if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))
+ png_ptr->zlib_method = 8;
+ deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
+ png_ptr->zlib_method, png_ptr->zlib_window_bits,
+ png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
+ png_ptr->zstream.next_out = png_ptr->zbuf;
+ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+
+ png_ptr->mode = PNG_HAVE_IHDR;
+}
+
+/* write the palette. We are careful not to trust png_color to be in the
+ * correct order for PNG, so people can redefine it to any convenient
+ * structure.
+ */
+void /* PRIVATE */
+png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_PLTE;
+#endif
+ png_uint_32 i;
+ png_colorp pal_ptr;
+ png_byte buf[3];
+
+ png_debug(1, "in png_write_PLTE\n");
+ if ((
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+ !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
+#endif
+ num_pal == 0) || num_pal > 256)
+ {
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ png_error(png_ptr, "Invalid number of colors in palette");
+ }
+ else
+ {
+ png_warning(png_ptr, "Invalid number of colors in palette");
+ return;
+ }
+ }
+
+ if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
+ {
+ png_warning(png_ptr,
+ "Ignoring request to write a PLTE chunk in grayscale PNG");
+ return;
+ }
+
+ png_ptr->num_palette = (png_uint_16)num_pal;
+ png_debug1(3, "num_palette = %d\n", png_ptr->num_palette);
+
+ png_write_chunk_start(png_ptr, (png_bytep)png_PLTE, num_pal * 3);
+#ifndef PNG_NO_POINTER_INDEXING
+ for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
+ {
+ buf[0] = pal_ptr->red;
+ buf[1] = pal_ptr->green;
+ buf[2] = pal_ptr->blue;
+ png_write_chunk_data(png_ptr, buf, (png_size_t)3);
+ }
+#else
+ /* This is a little slower but some buggy compilers need to do this instead */
+ pal_ptr=palette;
+ for (i = 0; i < num_pal; i++)
+ {
+ buf[0] = pal_ptr[i].red;
+ buf[1] = pal_ptr[i].green;
+ buf[2] = pal_ptr[i].blue;
+ png_write_chunk_data(png_ptr, buf, (png_size_t)3);
+ }
+#endif
+ png_write_chunk_end(png_ptr);
+ png_ptr->mode |= PNG_HAVE_PLTE;
+}
+
+/* write an IDAT chunk */
+void /* PRIVATE */
+png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_IDAT;
+#endif
+ png_debug(1, "in png_write_IDAT\n");
+ png_write_chunk(png_ptr, (png_bytep)png_IDAT, data, length);
+ png_ptr->mode |= PNG_HAVE_IDAT;
+}
+
+/* write an IEND chunk */
+void /* PRIVATE */
+png_write_IEND(png_structp png_ptr)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_IEND;
+#endif
+ png_debug(1, "in png_write_IEND\n");
+ png_write_chunk(png_ptr, (png_bytep)png_IEND, png_bytep_NULL,
+ (png_size_t)0);
+ png_ptr->mode |= PNG_HAVE_IEND;
+}
+
+#if defined(PNG_WRITE_gAMA_SUPPORTED)
+/* write a gAMA chunk */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+void /* PRIVATE */
+png_write_gAMA(png_structp png_ptr, double file_gamma)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_gAMA;
+#endif
+ png_uint_32 igamma;
+ png_byte buf[4];
+
+ png_debug(1, "in png_write_gAMA\n");
+ /* file_gamma is saved in 1/100,000ths */
+ igamma = (png_uint_32)(file_gamma * 100000.0 + 0.5);
+ png_save_uint_32(buf, igamma);
+ png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
+}
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+void /* PRIVATE */
+png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_gAMA;
+#endif
+ png_byte buf[4];
+
+ png_debug(1, "in png_write_gAMA\n");
+ /* file_gamma is saved in 1/100,000ths */
+ png_save_uint_32(buf, (png_uint_32)file_gamma);
+ png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
+}
+#endif
+#endif
+
+#if defined(PNG_WRITE_sRGB_SUPPORTED)
+/* write a sRGB chunk */
+void /* PRIVATE */
+png_write_sRGB(png_structp png_ptr, int srgb_intent)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_sRGB;
+#endif
+ png_byte buf[1];
+
+ png_debug(1, "in png_write_sRGB\n");
+ if(srgb_intent >= PNG_sRGB_INTENT_LAST)
+ png_warning(png_ptr,
+ "Invalid sRGB rendering intent specified");
+ buf[0]=(png_byte)srgb_intent;
+ png_write_chunk(png_ptr, (png_bytep)png_sRGB, buf, (png_size_t)1);
+}
+#endif
+
+#if defined(PNG_WRITE_iCCP_SUPPORTED)
+/* write an iCCP chunk */
+void /* PRIVATE */
+png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,
+ png_charp profile, int profile_len)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_iCCP;
+#endif
+ png_size_t name_len;
+ png_charp new_name;
+ compression_state comp;
+
+ png_debug(1, "in png_write_iCCP\n");
+ if (name == NULL || (name_len = png_check_keyword(png_ptr, name,
+ &new_name)) == 0)
+ {
+ png_warning(png_ptr, "Empty keyword in iCCP chunk");
+ return;
+ }
+
+ if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+ png_warning(png_ptr, "Unknown compression type in iCCP chunk");
+
+ if (profile == NULL)
+ profile_len = 0;
+
+ if (profile_len)
+ profile_len = png_text_compress(png_ptr, profile, (png_size_t)profile_len,
+ PNG_COMPRESSION_TYPE_BASE, &comp);
+
+ /* make sure we include the NULL after the name and the compression type */
+ png_write_chunk_start(png_ptr, (png_bytep)png_iCCP,
+ (png_uint_32)name_len+profile_len+2);
+ new_name[name_len+1]=0x00;
+ png_write_chunk_data(png_ptr, (png_bytep)new_name, name_len + 2);
+
+ if (profile_len)
+ png_write_compressed_data_out(png_ptr, &comp);
+
+ png_write_chunk_end(png_ptr);
+ png_free(png_ptr, new_name);
+}
+#endif
+
+#if defined(PNG_WRITE_sPLT_SUPPORTED)
+/* write a sPLT chunk */
+void /* PRIVATE */
+png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_sPLT;
+#endif
+ png_size_t name_len;
+ png_charp new_name;
+ png_byte entrybuf[10];
+ int entry_size = (spalette->depth == 8 ? 6 : 10);
+ int palette_size = entry_size * spalette->nentries;
+ png_sPLT_entryp ep;
+#ifdef PNG_NO_POINTER_INDEXING
+ int i;
+#endif
+
+ png_debug(1, "in png_write_sPLT\n");
+ if (spalette->name == NULL || (name_len = png_check_keyword(png_ptr,
+ spalette->name, &new_name))==0)
+ {
+ png_warning(png_ptr, "Empty keyword in sPLT chunk");
+ return;
+ }
+
+ /* make sure we include the NULL after the name */
+ png_write_chunk_start(png_ptr, (png_bytep)png_sPLT,
+ (png_uint_32)(name_len + 2 + palette_size));
+ png_write_chunk_data(png_ptr, (png_bytep)new_name, name_len + 1);
+ png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, 1);
+
+ /* loop through each palette entry, writing appropriately */
+#ifndef PNG_NO_POINTER_INDEXING
+ for (ep = spalette->entries; ep<spalette->entries+spalette->nentries; ep++)
+ {
+ if (spalette->depth == 8)
+ {
+ entrybuf[0] = (png_byte)ep->red;
+ entrybuf[1] = (png_byte)ep->green;
+ entrybuf[2] = (png_byte)ep->blue;
+ entrybuf[3] = (png_byte)ep->alpha;
+ png_save_uint_16(entrybuf + 4, ep->frequency);
+ }
+ else
+ {
+ png_save_uint_16(entrybuf + 0, ep->red);
+ png_save_uint_16(entrybuf + 2, ep->green);
+ png_save_uint_16(entrybuf + 4, ep->blue);
+ png_save_uint_16(entrybuf + 6, ep->alpha);
+ png_save_uint_16(entrybuf + 8, ep->frequency);
+ }
+ png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
+ }
+#else
+ ep=spalette->entries;
+ for (i=0; i>spalette->nentries; i++)
+ {
+ if (spalette->depth == 8)
+ {
+ entrybuf[0] = (png_byte)ep[i].red;
+ entrybuf[1] = (png_byte)ep[i].green;
+ entrybuf[2] = (png_byte)ep[i].blue;
+ entrybuf[3] = (png_byte)ep[i].alpha;
+ png_save_uint_16(entrybuf + 4, ep[i].frequency);
+ }
+ else
+ {
+ png_save_uint_16(entrybuf + 0, ep[i].red);
+ png_save_uint_16(entrybuf + 2, ep[i].green);
+ png_save_uint_16(entrybuf + 4, ep[i].blue);
+ png_save_uint_16(entrybuf + 6, ep[i].alpha);
+ png_save_uint_16(entrybuf + 8, ep[i].frequency);
+ }
+ png_write_chunk_data(png_ptr, entrybuf, entry_size);
+ }
+#endif
+
+ png_write_chunk_end(png_ptr);
+ png_free(png_ptr, new_name);
+}
+#endif
+
+#if defined(PNG_WRITE_sBIT_SUPPORTED)
+/* write the sBIT chunk */
+void /* PRIVATE */
+png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_sBIT;
+#endif
+ png_byte buf[4];
+ png_size_t size;
+
+ png_debug(1, "in png_write_sBIT\n");
+ /* make sure we don't depend upon the order of PNG_COLOR_8 */
+ if (color_type & PNG_COLOR_MASK_COLOR)
+ {
+ png_byte maxbits;
+
+ maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
+ png_ptr->usr_bit_depth);
+ if (sbit->red == 0 || sbit->red > maxbits ||
+ sbit->green == 0 || sbit->green > maxbits ||
+ sbit->blue == 0 || sbit->blue > maxbits)
+ {
+ png_warning(png_ptr, "Invalid sBIT depth specified");
+ return;
+ }
+ buf[0] = sbit->red;
+ buf[1] = sbit->green;
+ buf[2] = sbit->blue;
+ size = 3;
+ }
+ else
+ {
+ if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
+ {
+ png_warning(png_ptr, "Invalid sBIT depth specified");
+ return;
+ }
+ buf[0] = sbit->gray;
+ size = 1;
+ }
+
+ if (color_type & PNG_COLOR_MASK_ALPHA)
+ {
+ if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
+ {
+ png_warning(png_ptr, "Invalid sBIT depth specified");
+ return;
+ }
+ buf[size++] = sbit->alpha;
+ }
+
+ png_write_chunk(png_ptr, (png_bytep)png_sBIT, buf, size);
+}
+#endif
+
+#if defined(PNG_WRITE_cHRM_SUPPORTED)
+/* write the cHRM chunk */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+void /* PRIVATE */
+png_write_cHRM(png_structp png_ptr, double white_x, double white_y,
+ double red_x, double red_y, double green_x, double green_y,
+ double blue_x, double blue_y)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_cHRM;
+#endif
+ png_byte buf[32];
+ png_uint_32 itemp;
+
+ png_debug(1, "in png_write_cHRM\n");
+ /* each value is saved in 1/100,000ths */
+ if (white_x < 0 || white_x > 0.8 || white_y < 0 || white_y > 0.8 ||
+ white_x + white_y > 1.0)
+ {
+ png_warning(png_ptr, "Invalid cHRM white point specified");
+#if !defined(PNG_NO_CONSOLE_IO)
+ fprintf(stderr,"white_x=%f, white_y=%f\n",white_x, white_y);
+#endif
+ return;
+ }
+ itemp = (png_uint_32)(white_x * 100000.0 + 0.5);
+ png_save_uint_32(buf, itemp);
+ itemp = (png_uint_32)(white_y * 100000.0 + 0.5);
+ png_save_uint_32(buf + 4, itemp);
+
+ if (red_x < 0 || red_x > 0.8 || red_y < 0 || red_y > 0.8 ||
+ red_x + red_y > 1.0)
+ {
+ png_warning(png_ptr, "Invalid cHRM red point specified");
+ return;
+ }
+ itemp = (png_uint_32)(red_x * 100000.0 + 0.5);
+ png_save_uint_32(buf + 8, itemp);
+ itemp = (png_uint_32)(red_y * 100000.0 + 0.5);
+ png_save_uint_32(buf + 12, itemp);
+
+ if (green_x < 0 || green_x > 0.8 || green_y < 0 || green_y > 0.8 ||
+ green_x + green_y > 1.0)
+ {
+ png_warning(png_ptr, "Invalid cHRM green point specified");
+ return;
+ }
+ itemp = (png_uint_32)(green_x * 100000.0 + 0.5);
+ png_save_uint_32(buf + 16, itemp);
+ itemp = (png_uint_32)(green_y * 100000.0 + 0.5);
+ png_save_uint_32(buf + 20, itemp);
+
+ if (blue_x < 0 || blue_x > 0.8 || blue_y < 0 || blue_y > 0.8 ||
+ blue_x + blue_y > 1.0)
+ {
+ png_warning(png_ptr, "Invalid cHRM blue point specified");
+ return;
+ }
+ itemp = (png_uint_32)(blue_x * 100000.0 + 0.5);
+ png_save_uint_32(buf + 24, itemp);
+ itemp = (png_uint_32)(blue_y * 100000.0 + 0.5);
+ png_save_uint_32(buf + 28, itemp);
+
+ png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
+}
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+void /* PRIVATE */
+png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,
+ png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y,
+ png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x,
+ png_fixed_point blue_y)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_cHRM;
+#endif
+ png_byte buf[32];
+
+ png_debug(1, "in png_write_cHRM\n");
+ /* each value is saved in 1/100,000ths */
+ if (white_x > 80000L || white_y > 80000L || white_x + white_y > 100000L)
+ {
+ png_warning(png_ptr, "Invalid fixed cHRM white point specified");
+#if !defined(PNG_NO_CONSOLE_IO)
+ fprintf(stderr,"white_x=%ld, white_y=%ld\n",white_x, white_y);
+#endif
+ return;
+ }
+ png_save_uint_32(buf, (png_uint_32)white_x);
+ png_save_uint_32(buf + 4, (png_uint_32)white_y);
+
+ if (red_x > 80000L || red_y > 80000L || red_x + red_y > 100000L)
+ {
+ png_warning(png_ptr, "Invalid cHRM fixed red point specified");
+ return;
+ }
+ png_save_uint_32(buf + 8, (png_uint_32)red_x);
+ png_save_uint_32(buf + 12, (png_uint_32)red_y);
+
+ if (green_x > 80000L || green_y > 80000L || green_x + green_y > 100000L)
+ {
+ png_warning(png_ptr, "Invalid fixed cHRM green point specified");
+ return;
+ }
+ png_save_uint_32(buf + 16, (png_uint_32)green_x);
+ png_save_uint_32(buf + 20, (png_uint_32)green_y);
+
+ if (blue_x > 80000L || blue_y > 80000L || blue_x + blue_y > 100000L)
+ {
+ png_warning(png_ptr, "Invalid fixed cHRM blue point specified");
+ return;
+ }
+ png_save_uint_32(buf + 24, (png_uint_32)blue_x);
+ png_save_uint_32(buf + 28, (png_uint_32)blue_y);
+
+ png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
+}
+#endif
+#endif
+
+#if defined(PNG_WRITE_tRNS_SUPPORTED)
+/* write the tRNS chunk */
+void /* PRIVATE */
+png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
+ int num_trans, int color_type)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_tRNS;
+#endif
+ png_byte buf[6];
+
+ png_debug(1, "in png_write_tRNS\n");
+ if (color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
+ {
+ png_warning(png_ptr,"Invalid number of transparent colors specified");
+ return;
+ }
+ /* write the chunk out as it is */
+ png_write_chunk(png_ptr, (png_bytep)png_tRNS, trans, (png_size_t)num_trans);
+ }
+ else if (color_type == PNG_COLOR_TYPE_GRAY)
+ {
+ /* one 16 bit value */
+ if(tran->gray >= (1 << png_ptr->bit_depth))
+ {
+ png_warning(png_ptr,
+ "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
+ return;
+ }
+ png_save_uint_16(buf, tran->gray);
+ png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)2);
+ }
+ else if (color_type == PNG_COLOR_TYPE_RGB)
+ {
+ /* three 16 bit values */
+ png_save_uint_16(buf, tran->red);
+ png_save_uint_16(buf + 2, tran->green);
+ png_save_uint_16(buf + 4, tran->blue);
+ if(png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
+ {
+ png_warning(png_ptr,
+ "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
+ return;
+ }
+ png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)6);
+ }
+ else
+ {
+ png_warning(png_ptr, "Can't write tRNS with an alpha channel");
+ }
+}
+#endif
+
+#if defined(PNG_WRITE_bKGD_SUPPORTED)
+/* write the background chunk */
+void /* PRIVATE */
+png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_bKGD;
+#endif
+ png_byte buf[6];
+
+ png_debug(1, "in png_write_bKGD\n");
+ if (color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ if (
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+ (png_ptr->num_palette ||
+ (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
+#endif
+ back->index > png_ptr->num_palette)
+ {
+ png_warning(png_ptr, "Invalid background palette index");
+ return;
+ }
+ buf[0] = back->index;
+ png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)1);
+ }
+ else if (color_type & PNG_COLOR_MASK_COLOR)
+ {
+ png_save_uint_16(buf, back->red);
+ png_save_uint_16(buf + 2, back->green);
+ png_save_uint_16(buf + 4, back->blue);
+ if(png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
+ {
+ png_warning(png_ptr,
+ "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
+ return;
+ }
+ png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)6);
+ }
+ else
+ {
+ if(back->gray >= (1 << png_ptr->bit_depth))
+ {
+ png_warning(png_ptr,
+ "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
+ return;
+ }
+ png_save_uint_16(buf, back->gray);
+ png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)2);
+ }
+}
+#endif
+
+#if defined(PNG_WRITE_hIST_SUPPORTED)
+/* write the histogram */
+void /* PRIVATE */
+png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_hIST;
+#endif
+ int i;
+ png_byte buf[3];
+
+ png_debug(1, "in png_write_hIST\n");
+ if (num_hist > (int)png_ptr->num_palette)
+ {
+ png_debug2(3, "num_hist = %d, num_palette = %d\n", num_hist,
+ png_ptr->num_palette);
+ png_warning(png_ptr, "Invalid number of histogram entries specified");
+ return;
+ }
+
+ png_write_chunk_start(png_ptr, (png_bytep)png_hIST, (png_uint_32)(num_hist * 2));
+ for (i = 0; i < num_hist; i++)
+ {
+ png_save_uint_16(buf, hist[i]);
+ png_write_chunk_data(png_ptr, buf, (png_size_t)2);
+ }
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
+#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
+ defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
+/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
+ * and if invalid, correct the keyword rather than discarding the entire
+ * chunk. The PNG 1.0 specification requires keywords 1-79 characters in
+ * length, forbids leading or trailing whitespace, multiple internal spaces,
+ * and the non-break space (0x80) from ISO 8859-1. Returns keyword length.
+ *
+ * The new_key is allocated to hold the corrected keyword and must be freed
+ * by the calling routine. This avoids problems with trying to write to
+ * static keywords without having to have duplicate copies of the strings.
+ */
+png_size_t /* PRIVATE */
+png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
+{
+ png_size_t key_len;
+ png_charp kp, dp;
+ int kflag;
+ int kwarn=0;
+
+ png_debug(1, "in png_check_keyword\n");
+ *new_key = NULL;
+
+ if (key == NULL || (key_len = png_strlen(key)) == 0)
+ {
+ png_warning(png_ptr, "zero length keyword");
+ return ((png_size_t)0);
+ }
+
+ png_debug1(2, "Keyword to be checked is '%s'\n", key);
+
+ *new_key = (png_charp)png_malloc(png_ptr, (png_uint_32)(key_len + 2));
+
+ /* Replace non-printing characters with a blank and print a warning */
+ for (kp = key, dp = *new_key; *kp != '\0'; kp++, dp++)
+ {
+ if (*kp < 0x20 || (*kp > 0x7E && (png_byte)*kp < 0xA1))
+ {
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+ char msg[40];
+
+ sprintf(msg, "invalid keyword character 0x%02X", *kp);
+ png_warning(png_ptr, msg);
+#else
+ png_warning(png_ptr, "invalid character in keyword");
+#endif
+ *dp = ' ';
+ }
+ else
+ {
+ *dp = *kp;
+ }
+ }
+ *dp = '\0';
+
+ /* Remove any trailing white space. */
+ kp = *new_key + key_len - 1;
+ if (*kp == ' ')
+ {
+ png_warning(png_ptr, "trailing spaces removed from keyword");
+
+ while (*kp == ' ')
+ {
+ *(kp--) = '\0';
+ key_len--;
+ }
+ }
+
+ /* Remove any leading white space. */
+ kp = *new_key;
+ if (*kp == ' ')
+ {
+ png_warning(png_ptr, "leading spaces removed from keyword");
+
+ while (*kp == ' ')
+ {
+ kp++;
+ key_len--;
+ }
+ }
+
+ png_debug1(2, "Checking for multiple internal spaces in '%s'\n", kp);
+
+ /* Remove multiple internal spaces. */
+ for (kflag = 0, dp = *new_key; *kp != '\0'; kp++)
+ {
+ if (*kp == ' ' && kflag == 0)
+ {
+ *(dp++) = *kp;
+ kflag = 1;
+ }
+ else if (*kp == ' ')
+ {
+ key_len--;
+ kwarn=1;
+ }
+ else
+ {
+ *(dp++) = *kp;
+ kflag = 0;
+ }
+ }
+ *dp = '\0';
+ if(kwarn)
+ png_warning(png_ptr, "extra interior spaces removed from keyword");
+
+ if (key_len == 0)
+ {
+ png_free(png_ptr, *new_key);
+ *new_key=NULL;
+ png_warning(png_ptr, "Zero length keyword");
+ }
+
+ if (key_len > 79)
+ {
+ png_warning(png_ptr, "keyword length must be 1 - 79 characters");
+ new_key[79] = '\0';
+ key_len = 79;
+ }
+
+ return (key_len);
+}
+#endif
+
+#if defined(PNG_WRITE_tEXt_SUPPORTED)
+/* write a tEXt chunk */
+void /* PRIVATE */
+png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
+ png_size_t text_len)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_tEXt;
+#endif
+ png_size_t key_len;
+ png_charp new_key;
+
+ png_debug(1, "in png_write_tEXt\n");
+ if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
+ {
+ png_warning(png_ptr, "Empty keyword in tEXt chunk");
+ return;
+ }
+
+ if (text == NULL || *text == '\0')
+ text_len = 0;
+ else
+ text_len = png_strlen(text);
+
+ /* make sure we include the 0 after the key */
+ png_write_chunk_start(png_ptr, (png_bytep)png_tEXt, (png_uint_32)key_len+text_len+1);
+ /*
+ * We leave it to the application to meet PNG-1.0 requirements on the
+ * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
+ * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
+ * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
+ */
+ png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1);
+ if (text_len)
+ png_write_chunk_data(png_ptr, (png_bytep)text, text_len);
+
+ png_write_chunk_end(png_ptr);
+ png_free(png_ptr, new_key);
+}
+#endif
+
+#if defined(PNG_WRITE_zTXt_SUPPORTED)
+/* write a compressed text chunk */
+void /* PRIVATE */
+png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
+ png_size_t text_len, int compression)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_zTXt;
+#endif
+ png_size_t key_len;
+ char buf[1];
+ png_charp new_key;
+ compression_state comp;
+
+ png_debug(1, "in png_write_zTXt\n");
+
+ if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
+ {
+ png_warning(png_ptr, "Empty keyword in zTXt chunk");
+ return;
+ }
+
+ if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)
+ {
+ png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);
+ png_free(png_ptr, new_key);
+ return;
+ }
+
+ text_len = png_strlen(text);
+
+ png_free(png_ptr, new_key);
+
+ /* compute the compressed data; do it now for the length */
+ text_len = png_text_compress(png_ptr, text, text_len, compression,
+ &comp);
+
+ /* write start of chunk */
+ png_write_chunk_start(png_ptr, (png_bytep)png_zTXt, (png_uint_32)
+ (key_len+text_len+2));
+ /* write key */
+ png_write_chunk_data(png_ptr, (png_bytep)key, key_len + 1);
+ buf[0] = (png_byte)compression;
+ /* write compression */
+ png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1);
+ /* write the compressed data */
+ png_write_compressed_data_out(png_ptr, &comp);
+
+ /* close the chunk */
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
+#if defined(PNG_WRITE_iTXt_SUPPORTED)
+/* write an iTXt chunk */
+void /* PRIVATE */
+png_write_iTXt(png_structp png_ptr, int compression, png_charp key,
+ png_charp lang, png_charp lang_key, png_charp text)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_iTXt;
+#endif
+ png_size_t lang_len, key_len, lang_key_len, text_len;
+ png_charp new_lang, new_key;
+ png_byte cbuf[2];
+ compression_state comp;
+
+ png_debug(1, "in png_write_iTXt\n");
+
+ if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
+ {
+ png_warning(png_ptr, "Empty keyword in iTXt chunk");
+ return;
+ }
+ if (lang == NULL || (lang_len = png_check_keyword(png_ptr, lang,
+ &new_lang))==0)
+ {
+ png_warning(png_ptr, "Empty language field in iTXt chunk");
+ return;
+ }
+ lang_key_len = png_strlen(lang_key);
+ text_len = png_strlen(text);
+
+ if (text == NULL || *text == '\0')
+ text_len = 0;
+
+ /* compute the compressed data; do it now for the length */
+ text_len = png_text_compress(png_ptr, text, text_len, compression-2,
+ &comp);
+
+ /* make sure we include the compression flag, the compression byte,
+ * and the NULs after the key, lang, and lang_key parts */
+
+ png_write_chunk_start(png_ptr, (png_bytep)png_iTXt,
+ (png_uint_32)(
+ 5 /* comp byte, comp flag, terminators for key, lang and lang_key */
+ + key_len
+ + lang_len
+ + lang_key_len
+ + text_len));
+
+ /*
+ * We leave it to the application to meet PNG-1.0 requirements on the
+ * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
+ * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
+ * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
+ */
+ png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1);
+
+ /* set the compression flag */
+ if (compression == PNG_ITXT_COMPRESSION_NONE || \
+ compression == PNG_TEXT_COMPRESSION_NONE)
+ cbuf[0] = 0;
+ else /* compression == PNG_ITXT_COMPRESSION_zTXt */
+ cbuf[0] = 1;
+ /* set the compression method */
+ cbuf[1] = 0;
+ png_write_chunk_data(png_ptr, cbuf, 2);
+
+ png_write_chunk_data(png_ptr, (png_bytep)new_lang, lang_len + 1);
+ png_write_chunk_data(png_ptr, (png_bytep)lang_key, lang_key_len+1);
+ png_write_chunk_data(png_ptr, '\0', 1);
+
+ png_write_compressed_data_out(png_ptr, &comp);
+
+ png_write_chunk_end(png_ptr);
+ png_free(png_ptr, new_key);
+ png_free(png_ptr, new_lang);
+}
+#endif
+
+#if defined(PNG_WRITE_oFFs_SUPPORTED)
+/* write the oFFs chunk */
+void /* PRIVATE */
+png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
+ int unit_type)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_oFFs;
+#endif
+ png_byte buf[9];
+
+ png_debug(1, "in png_write_oFFs\n");
+ if (unit_type >= PNG_OFFSET_LAST)
+ png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
+
+ png_save_int_32(buf, x_offset);
+ png_save_int_32(buf + 4, y_offset);
+ buf[8] = (png_byte)unit_type;
+
+ png_write_chunk(png_ptr, (png_bytep)png_oFFs, buf, (png_size_t)9);
+}
+#endif
+
+#if defined(PNG_WRITE_pCAL_SUPPORTED)
+/* write the pCAL chunk (described in the PNG extensions document) */
+void /* PRIVATE */
+png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
+ png_int_32 X1, int type, int nparams, png_charp units, png_charpp params)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_pCAL;
+#endif
+ png_size_t purpose_len, units_len, total_len;
+ png_uint_32p params_len;
+ png_byte buf[10];
+ png_charp new_purpose;
+ int i;
+
+ png_debug1(1, "in png_write_pCAL (%d parameters)\n", nparams);
+ if (type >= PNG_EQUATION_LAST)
+ png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
+
+ purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1;
+ png_debug1(3, "pCAL purpose length = %d\n", (int)purpose_len);
+ units_len = png_strlen(units) + (nparams == 0 ? 0 : 1);
+ png_debug1(3, "pCAL units length = %d\n", (int)units_len);
+ total_len = purpose_len + units_len + 10;
+
+ params_len = (png_uint_32p)png_malloc(png_ptr, (png_uint_32)(nparams
+ *sizeof(png_uint_32)));
+
+ /* Find the length of each parameter, making sure we don't count the
+ null terminator for the last parameter. */
+ for (i = 0; i < nparams; i++)
+ {
+ params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
+ png_debug2(3, "pCAL parameter %d length = %lu\n", i, params_len[i]);
+ total_len += (png_size_t)params_len[i];
+ }
+
+ png_debug1(3, "pCAL total length = %d\n", (int)total_len);
+ png_write_chunk_start(png_ptr, (png_bytep)png_pCAL, (png_uint_32)total_len);
+ png_write_chunk_data(png_ptr, (png_bytep)new_purpose, purpose_len);
+ png_save_int_32(buf, X0);
+ png_save_int_32(buf + 4, X1);
+ buf[8] = (png_byte)type;
+ buf[9] = (png_byte)nparams;
+ png_write_chunk_data(png_ptr, buf, (png_size_t)10);
+ png_write_chunk_data(png_ptr, (png_bytep)units, (png_size_t)units_len);
+
+ png_free(png_ptr, new_purpose);
+
+ for (i = 0; i < nparams; i++)
+ {
+ png_write_chunk_data(png_ptr, (png_bytep)params[i],
+ (png_size_t)params_len[i]);
+ }
+
+ png_free(png_ptr, params_len);
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
+#if defined(PNG_WRITE_sCAL_SUPPORTED)
+/* write the sCAL chunk */
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
+void /* PRIVATE */
+png_write_sCAL(png_structp png_ptr, int unit, double width,double height)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_sCAL;
+#endif
+ png_size_t total_len;
+ char wbuf[32], hbuf[32];
+
+ png_debug(1, "in png_write_sCAL\n");
+
+#if defined(_WIN32_WCE)
+/* sprintf() function is not supported on WindowsCE */
+ {
+ wchar_t wc_buf[32];
+ swprintf(wc_buf, TEXT("%12.12e"), width);
+ WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, wbuf, 32, NULL, NULL);
+ swprintf(wc_buf, TEXT("%12.12e"), height);
+ WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, hbuf, 32, NULL, NULL);
+ }
+#else
+ sprintf(wbuf, "%12.12e", width);
+ sprintf(hbuf, "%12.12e", height);
+#endif
+ total_len = 1 + png_strlen(wbuf)+1 + png_strlen(hbuf);
+
+ png_debug1(3, "sCAL total length = %d\n", (int)total_len);
+ png_write_chunk_start(png_ptr, (png_bytep)png_sCAL, (png_uint_32)total_len);
+ png_write_chunk_data(png_ptr, (png_bytep)&unit, 1);
+ png_write_chunk_data(png_ptr, (png_bytep)wbuf, png_strlen(wbuf)+1);
+ png_write_chunk_data(png_ptr, (png_bytep)hbuf, png_strlen(hbuf));
+
+ png_write_chunk_end(png_ptr);
+}
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+void /* PRIVATE */
+png_write_sCAL_s(png_structp png_ptr, int unit, png_charp width,
+ png_charp height)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_sCAL;
+#endif
+ png_size_t total_len;
+ char wbuf[32], hbuf[32];
+
+ png_debug(1, "in png_write_sCAL_s\n");
+
+ png_strcpy(wbuf,(const char *)width);
+ png_strcpy(hbuf,(const char *)height);
+ total_len = 1 + png_strlen(wbuf)+1 + png_strlen(hbuf);
+
+ png_debug1(3, "sCAL total length = %d\n", total_len);
+ png_write_chunk_start(png_ptr, (png_bytep)png_sCAL, (png_uint_32)total_len);
+ png_write_chunk_data(png_ptr, (png_bytep)&unit, 1);
+ png_write_chunk_data(png_ptr, (png_bytep)wbuf, png_strlen(wbuf)+1);
+ png_write_chunk_data(png_ptr, (png_bytep)hbuf, png_strlen(hbuf));
+
+ png_write_chunk_end(png_ptr);
+}
+#endif
+#endif
+#endif
+
+#if defined(PNG_WRITE_pHYs_SUPPORTED)
+/* write the pHYs chunk */
+void /* PRIVATE */
+png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
+ png_uint_32 y_pixels_per_unit,
+ int unit_type)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_pHYs;
+#endif
+ png_byte buf[9];
+
+ png_debug(1, "in png_write_pHYs\n");
+ if (unit_type >= PNG_RESOLUTION_LAST)
+ png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
+
+ png_save_uint_32(buf, x_pixels_per_unit);
+ png_save_uint_32(buf + 4, y_pixels_per_unit);
+ buf[8] = (png_byte)unit_type;
+
+ png_write_chunk(png_ptr, (png_bytep)png_pHYs, buf, (png_size_t)9);
+}
+#endif
+
+#if defined(PNG_WRITE_tIME_SUPPORTED)
+/* Write the tIME chunk. Use either png_convert_from_struct_tm()
+ * or png_convert_from_time_t(), or fill in the structure yourself.
+ */
+void /* PRIVATE */
+png_write_tIME(png_structp png_ptr, png_timep mod_time)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ PNG_tIME;
+#endif
+ png_byte buf[7];
+
+ png_debug(1, "in png_write_tIME\n");
+ if (mod_time->month > 12 || mod_time->month < 1 ||
+ mod_time->day > 31 || mod_time->day < 1 ||
+ mod_time->hour > 23 || mod_time->second > 60)
+ {
+ png_warning(png_ptr, "Invalid time specified for tIME chunk");
+ return;
+ }
+
+ png_save_uint_16(buf, mod_time->year);
+ buf[2] = mod_time->month;
+ buf[3] = mod_time->day;
+ buf[4] = mod_time->hour;
+ buf[5] = mod_time->minute;
+ buf[6] = mod_time->second;
+
+ png_write_chunk(png_ptr, (png_bytep)png_tIME, buf, (png_size_t)7);
+}
+#endif
+
+/* initializes the row writing capability of libpng */
+void /* PRIVATE */
+png_write_start_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 */
+ int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+ /* offset to next interlace block */
+ int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+ /* start of interlace block in the y direction */
+ int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+ /* offset to next interlace block in the y direction */
+ int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+ png_size_t buf_size;
+
+ png_debug(1, "in png_write_start_row\n");
+ buf_size = (png_size_t)(((png_ptr->width * png_ptr->usr_channels *
+ png_ptr->usr_bit_depth + 7) >> 3) + 1);
+
+ /* set up row buffer */
+ png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size);
+ png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
+
+ /* set up filtering buffer, if using this filter */
+ if (png_ptr->do_filter & PNG_FILTER_SUB)
+ {
+ png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
+ (png_ptr->rowbytes + 1));
+ png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
+ }
+
+ /* We only need to keep the previous row if we are using one of these. */
+ if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
+ {
+ /* set up previous row buffer */
+ png_ptr->prev_row = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size);
+ png_memset(png_ptr->prev_row, 0, buf_size);
+
+ if (png_ptr->do_filter & PNG_FILTER_UP)
+ {
+ png_ptr->up_row = (png_bytep )png_malloc(png_ptr,
+ (png_ptr->rowbytes + 1));
+ png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
+ }
+
+ if (png_ptr->do_filter & PNG_FILTER_AVG)
+ {
+ png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
+ (png_ptr->rowbytes + 1));
+ png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
+ }
+
+ if (png_ptr->do_filter & PNG_FILTER_PAETH)
+ {
+ png_ptr->paeth_row = (png_bytep )png_malloc(png_ptr,
+ (png_ptr->rowbytes + 1));
+ png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
+ }
+ }
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ /* if interlaced, we need to set up width and height of pass */
+ 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];
+ png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
+ png_pass_start[0]) / png_pass_inc[0];
+ }
+ else
+ {
+ png_ptr->num_rows = png_ptr->height;
+ png_ptr->usr_width = png_ptr->width;
+ }
+ }
+ else
+#endif
+ {
+ png_ptr->num_rows = png_ptr->height;
+ png_ptr->usr_width = png_ptr->width;
+ }
+ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+ png_ptr->zstream.next_out = png_ptr->zbuf;
+}
+
+/* Internal use only. Called when finished processing a row of data. */
+void /* PRIVATE */
+png_write_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 */
+ int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+ /* offset to next interlace block */
+ int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+ /* start of interlace block in the y direction */
+ int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+ /* offset to next interlace block in the y direction */
+ int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+ int ret;
+
+ png_debug(1, "in png_write_finish_row\n");
+ /* next row */
+ png_ptr->row_number++;
+
+ /* see if we are done */
+ if (png_ptr->row_number < png_ptr->num_rows)
+ return;
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ /* if interlaced, go to next pass */
+ if (png_ptr->interlaced)
+ {
+ png_ptr->row_number = 0;
+ if (png_ptr->transformations & PNG_INTERLACE)
+ {
+ png_ptr->pass++;
+ }
+ else
+ {
+ /* loop until we find a non-zero width or height pass */
+ do
+ {
+ png_ptr->pass++;
+ if (png_ptr->pass >= 7)
+ break;
+ png_ptr->usr_width = (png_ptr->width +
+ png_pass_inc[png_ptr->pass] - 1 -
+ png_pass_start[png_ptr->pass]) /
+ png_pass_inc[png_ptr->pass];
+ 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->transformations & PNG_INTERLACE)
+ break;
+ } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
+
+ }
+
+ /* reset the row above the image for the next pass */
+ if (png_ptr->pass < 7)
+ {
+ if (png_ptr->prev_row != NULL)
+ png_memset(png_ptr->prev_row, 0,
+ (png_size_t) (((png_uint_32)png_ptr->usr_channels *
+ (png_uint_32)png_ptr->usr_bit_depth *
+ png_ptr->width + 7) >> 3) + 1);
+ return;
+ }
+ }
+#endif
+
+ /* if we get here, we've just written the last row, so we need
+ to flush the compressor */
+ do
+ {
+ /* tell the compressor we are done */
+ ret = deflate(&png_ptr->zstream, Z_FINISH);
+ /* check for an error */
+ if (ret == Z_OK)
+ {
+ /* check to see if we need more room */
+ if (!(png_ptr->zstream.avail_out))
+ {
+ png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
+ png_ptr->zstream.next_out = png_ptr->zbuf;
+ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+ }
+ }
+ else if (ret != Z_STREAM_END)
+ {
+ if (png_ptr->zstream.msg != NULL)
+ png_error(png_ptr, png_ptr->zstream.msg);
+ else
+ png_error(png_ptr, "zlib error");
+ }
+ } while (ret != Z_STREAM_END);
+
+ /* write any extra space */
+ if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
+ {
+ png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -
+ png_ptr->zstream.avail_out);
+ }
+
+ deflateReset(&png_ptr->zstream);
+}
+
+#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
+/* Pick out the correct pixels for the interlace pass.
+ * The basic idea here is to go through the row with a source
+ * pointer and a destination pointer (sp and dp), and copy the
+ * correct pixels for the pass. As the row gets compacted,
+ * sp will always be >= dp, so we should never overwrite anything.
+ * See the default: case for the easiest code to understand.
+ */
+void /* PRIVATE */
+png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+ /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+ /* start of interlace block */
+ int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+ /* offset to next interlace block */
+ int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+#endif
+
+ png_debug(1, "in png_do_write_interlace\n");
+ /* we don't have to do anything on the last pass (6) */
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+ if (row != NULL && row_info != NULL && pass < 6)
+#else
+ if (pass < 6)
+#endif
+ {
+ /* each pixel depth is handled separately */
+ switch (row_info->pixel_depth)
+ {
+ case 1:
+ {
+ png_bytep sp;
+ png_bytep dp;
+ int shift;
+ int d;
+ int value;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ dp = row;
+ d = 0;
+ shift = 7;
+ for (i = png_pass_start[pass]; i < row_width;
+ i += png_pass_inc[pass])
+ {
+ sp = row + (png_size_t)(i >> 3);
+ value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
+ d |= (value << shift);
+
+ if (shift == 0)
+ {
+ shift = 7;
+ *dp++ = (png_byte)d;
+ d = 0;
+ }
+ else
+ shift--;
+
+ }
+ if (shift != 7)
+ *dp = (png_byte)d;
+ break;
+ }
+ case 2:
+ {
+ png_bytep sp;
+ png_bytep dp;
+ int shift;
+ int d;
+ int value;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ dp = row;
+ shift = 6;
+ d = 0;
+ for (i = png_pass_start[pass]; i < row_width;
+ i += png_pass_inc[pass])
+ {
+ sp = row + (png_size_t)(i >> 2);
+ value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
+ d |= (value << shift);
+
+ if (shift == 0)
+ {
+ shift = 6;
+ *dp++ = (png_byte)d;
+ d = 0;
+ }
+ else
+ shift -= 2;
+ }
+ if (shift != 6)
+ *dp = (png_byte)d;
+ break;
+ }
+ case 4:
+ {
+ png_bytep sp;
+ png_bytep dp;
+ int shift;
+ int d;
+ int value;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ dp = row;
+ shift = 4;
+ d = 0;
+ for (i = png_pass_start[pass]; i < row_width;
+ i += png_pass_inc[pass])
+ {
+ sp = row + (png_size_t)(i >> 1);
+ value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
+ d |= (value << shift);
+
+ if (shift == 0)
+ {
+ shift = 4;
+ *dp++ = (png_byte)d;
+ d = 0;
+ }
+ else
+ shift -= 4;
+ }
+ if (shift != 4)
+ *dp = (png_byte)d;
+ break;
+ }
+ default:
+ {
+ png_bytep sp;
+ png_bytep dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+ png_size_t pixel_bytes;
+
+ /* start at the beginning */
+ dp = row;
+ /* find out how many bytes each pixel takes up */
+ pixel_bytes = (row_info->pixel_depth >> 3);
+ /* loop through the row, only looking at the pixels that
+ matter */
+ for (i = png_pass_start[pass]; i < row_width;
+ i += png_pass_inc[pass])
+ {
+ /* find out where the original pixel is */
+ sp = row + (png_size_t)i * pixel_bytes;
+ /* move the pixel */
+ if (dp != sp)
+ png_memcpy(dp, sp, pixel_bytes);
+ /* next pixel */
+ dp += pixel_bytes;
+ }
+ break;
+ }
+ }
+ /* set new row width */
+ row_info->width = (row_info->width +
+ png_pass_inc[pass] - 1 -
+ png_pass_start[pass]) /
+ png_pass_inc[pass];
+ row_info->rowbytes = ((row_info->width *
+ row_info->pixel_depth + 7) >> 3);
+ }
+}
+#endif
+
+/* This filters the row, chooses which filter to use, if it has not already
+ * been specified by the application, and then writes the row out with the
+ * chosen filter.
+ */
+#define PNG_MAXSUM (~((png_uint_32)0) >> 1)
+#define PNG_HISHIFT 10
+#define PNG_LOMASK ((png_uint_32)0xffffL)
+#define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
+void /* PRIVATE */
+png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
+{
+ png_bytep prev_row, best_row, row_buf;
+ png_uint_32 mins, bpp;
+ png_byte filter_to_do = png_ptr->do_filter;
+ png_uint_32 row_bytes = row_info->rowbytes;
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+ int num_p_filters = (int)png_ptr->num_prev_filters;
+#endif
+
+ png_debug(1, "in png_write_find_filter\n");
+ /* find out how many bytes offset each pixel is */
+ bpp = (row_info->pixel_depth + 7) / 8;
+
+ prev_row = png_ptr->prev_row;
+ best_row = row_buf = png_ptr->row_buf;
+ mins = PNG_MAXSUM;
+
+ /* The prediction method we use is to find which method provides the
+ * smallest value when summing the absolute values of the distances
+ * from zero, using anything >= 128 as negative numbers. This is known
+ * as the "minimum sum of absolute differences" heuristic. Other
+ * heuristics are the "weighted minimum sum of absolute differences"
+ * (experimental and can in theory improve compression), and the "zlib
+ * predictive" method (not implemented yet), which does test compressions
+ * of lines using different filter methods, and then chooses the
+ * (series of) filter(s) that give minimum compressed data size (VERY
+ * computationally expensive).
+ *
+ * GRR 980525: consider also
+ * (1) minimum sum of absolute differences from running average (i.e.,
+ * keep running sum of non-absolute differences & count of bytes)
+ * [track dispersion, too? restart average if dispersion too large?]
+ * (1b) minimum sum of absolute differences from sliding average, probably
+ * with window size <= deflate window (usually 32K)
+ * (2) minimum sum of squared differences from zero or running average
+ * (i.e., ~ root-mean-square approach)
+ */
+
+
+ /* We don't need to test the 'no filter' case if this is the only filter
+ * that has been chosen, as it doesn't actually do anything to the data.
+ */
+ if ((filter_to_do & PNG_FILTER_NONE) &&
+ filter_to_do != PNG_FILTER_NONE)
+ {
+ png_bytep rp;
+ png_uint_32 sum = 0;
+ png_uint_32 i;
+ int v;
+
+ for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
+ {
+ v = *rp;
+ sum += (v < 128) ? v : 256 - v;
+ }
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ png_uint_32 sumhi, sumlo;
+ int j;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
+
+ /* Reduce the sum if we match any of the previous rows */
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
+ {
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ /* Factor in the cost of this filter (this is here for completeness,
+ * but it makes no sense to have a "cost" for the NONE filter, as
+ * it has the minimum possible computational cost - none).
+ */
+ sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
+ PNG_COST_SHIFT;
+ sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+ mins = sum;
+ }
+
+ /* sub filter */
+ if (filter_to_do == PNG_FILTER_SUB)
+ /* it's the only filter so no testing is needed */
+ {
+ png_bytep rp, lp, dp;
+ png_uint_32 i;
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
+ i++, rp++, dp++)
+ {
+ *dp = *rp;
+ }
+ for (lp = row_buf + 1; i < row_bytes;
+ i++, rp++, lp++, dp++)
+ {
+ *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+ }
+ best_row = png_ptr->sub_row;
+ }
+
+ else if (filter_to_do & PNG_FILTER_SUB)
+ {
+ png_bytep rp, dp, lp;
+ png_uint_32 sum = 0, lmins = mins;
+ png_uint_32 i;
+ int v;
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+ /* We temporarily increase the "minimum sum" by the factor we
+ * would reduce the sum of this filter, so that we can do the
+ * early exit comparison without scaling the sum each time.
+ */
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 lmhi, lmlo;
+ lmlo = lmins & PNG_LOMASK;
+ lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
+ {
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+ PNG_COST_SHIFT;
+ lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+ PNG_COST_SHIFT;
+
+ if (lmhi > PNG_HIMASK)
+ lmins = PNG_MAXSUM;
+ else
+ lmins = (lmhi << PNG_HISHIFT) + lmlo;
+ }
+#endif
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
+ i++, rp++, dp++)
+ {
+ v = *dp = *rp;
+
+ sum += (v < 128) ? v : 256 - v;
+ }
+ for (lp = row_buf + 1; i < row_info->rowbytes;
+ i++, rp++, lp++, dp++)
+ {
+ v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+
+ sum += (v < 128) ? v : 256 - v;
+
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
+ }
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 sumhi, sumlo;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
+ {
+ sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+ PNG_COST_SHIFT;
+ sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+
+ if (sum < mins)
+ {
+ mins = sum;
+ best_row = png_ptr->sub_row;
+ }
+ }
+
+ /* up filter */
+ if (filter_to_do == PNG_FILTER_UP)
+ {
+ png_bytep rp, dp, pp;
+ png_uint_32 i;
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
+ pp = prev_row + 1; i < row_bytes;
+ i++, rp++, pp++, dp++)
+ {
+ *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+ }
+ best_row = png_ptr->up_row;
+ }
+
+ else if (filter_to_do & PNG_FILTER_UP)
+ {
+ png_bytep rp, dp, pp;
+ png_uint_32 sum = 0, lmins = mins;
+ png_uint_32 i;
+ int v;
+
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 lmhi, lmlo;
+ lmlo = lmins & PNG_LOMASK;
+ lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
+ {
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
+ PNG_COST_SHIFT;
+ lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
+ PNG_COST_SHIFT;
+
+ if (lmhi > PNG_HIMASK)
+ lmins = PNG_MAXSUM;
+ else
+ lmins = (lmhi << PNG_HISHIFT) + lmlo;
+ }
+#endif
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
+ pp = prev_row + 1; i < row_bytes; i++)
+ {
+ v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+
+ sum += (v < 128) ? v : 256 - v;
+
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
+ }
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 sumhi, sumlo;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
+ {
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
+ PNG_COST_SHIFT;
+ sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+
+ if (sum < mins)
+ {
+ mins = sum;
+ best_row = png_ptr->up_row;
+ }
+ }
+
+ /* avg filter */
+ if (filter_to_do == PNG_FILTER_AVG)
+ {
+ png_bytep rp, dp, pp, lp;
+ png_uint_32 i;
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
+ }
+ for (lp = row_buf + 1; i < row_bytes; i++)
+ {
+ *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
+ & 0xff);
+ }
+ best_row = png_ptr->avg_row;
+ }
+
+ else if (filter_to_do & PNG_FILTER_AVG)
+ {
+ png_bytep rp, dp, pp, lp;
+ png_uint_32 sum = 0, lmins = mins;
+ png_uint_32 i;
+ int v;
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 lmhi, lmlo;
+ lmlo = lmins & PNG_LOMASK;
+ lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
+ {
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
+ PNG_COST_SHIFT;
+ lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
+ PNG_COST_SHIFT;
+
+ if (lmhi > PNG_HIMASK)
+ lmins = PNG_MAXSUM;
+ else
+ lmins = (lmhi << PNG_HISHIFT) + lmlo;
+ }
+#endif
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
+
+ sum += (v < 128) ? v : 256 - v;
+ }
+ for (lp = row_buf + 1; i < row_bytes; i++)
+ {
+ v = *dp++ =
+ (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
+
+ sum += (v < 128) ? v : 256 - v;
+
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
+ }
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 sumhi, sumlo;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
+ {
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
+ PNG_COST_SHIFT;
+ sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+
+ if (sum < mins)
+ {
+ mins = sum;
+ best_row = png_ptr->avg_row;
+ }
+ }
+
+ /* Paeth filter */
+ if (filter_to_do == PNG_FILTER_PAETH)
+ {
+ png_bytep rp, dp, pp, cp, lp;
+ png_uint_32 i;
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+ }
+
+ for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
+ {
+ int a, b, c, pa, pb, pc, p;
+
+ b = *pp++;
+ c = *cp++;
+ a = *lp++;
+
+ 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
+
+ p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+
+ *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
+ }
+ best_row = png_ptr->paeth_row;
+ }
+
+ else if (filter_to_do & PNG_FILTER_PAETH)
+ {
+ png_bytep rp, dp, pp, cp, lp;
+ png_uint_32 sum = 0, lmins = mins;
+ png_uint_32 i;
+ int v;
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 lmhi, lmlo;
+ lmlo = lmins & PNG_LOMASK;
+ lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
+ {
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+ PNG_COST_SHIFT;
+ lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+ PNG_COST_SHIFT;
+
+ if (lmhi > PNG_HIMASK)
+ lmins = PNG_MAXSUM;
+ else
+ lmins = (lmhi << PNG_HISHIFT) + lmlo;
+ }
+#endif
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+
+ sum += (v < 128) ? v : 256 - v;
+ }
+
+ for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
+ {
+ int a, b, c, pa, pb, pc, p;
+
+ b = *pp++;
+ c = *cp++;
+ a = *lp++;
+
+#ifndef PNG_SLOW_PAETH
+ 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
+ p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+#else /* PNG_SLOW_PAETH */
+ p = a + b - c;
+ pa = abs(p - a);
+ pb = abs(p - b);
+ pc = abs(p - c);
+ if (pa <= pb && pa <= pc)
+ p = a;
+ else if (pb <= pc)
+ p = b;
+ else
+ p = c;
+#endif /* PNG_SLOW_PAETH */
+
+ v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
+
+ sum += (v < 128) ? v : 256 - v;
+
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
+ }
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 sumhi, sumlo;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
+ {
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+ PNG_COST_SHIFT;
+ sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+
+ if (sum < mins)
+ {
+ best_row = png_ptr->paeth_row;
+ }
+ }
+
+ /* Do the actual writing of the filtered row data from the chosen filter. */
+
+ png_write_filtered_row(png_ptr, best_row);
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+ /* Save the type of filter we picked this time for future calculations */
+ if (png_ptr->num_prev_filters > 0)
+ {
+ int j;
+ for (j = 1; j < num_p_filters; j++)
+ {
+ png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
+ }
+ png_ptr->prev_filters[j] = best_row[0];
+ }
+#endif
+}
+
+
+/* Do the actual writing of a previously filtered row. */
+void /* PRIVATE */
+png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
+{
+ png_debug(1, "in png_write_filtered_row\n");
+ png_debug1(2, "filter = %d\n", filtered_row[0]);
+ /* set up the zlib input buffer */
+
+ png_ptr->zstream.next_in = filtered_row;
+ png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1;
+ /* repeat until we have compressed all the data */
+ do
+ {
+ int ret; /* return of zlib */
+
+ /* compress the data */
+ ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
+ /* check for compression errors */
+ if (ret != Z_OK)
+ {
+ if (png_ptr->zstream.msg != NULL)
+ png_error(png_ptr, png_ptr->zstream.msg);
+ else
+ png_error(png_ptr, "zlib error");
+ }
+
+ /* see if it is time to write another IDAT */
+ if (!(png_ptr->zstream.avail_out))
+ {
+ /* write the IDAT and reset the zlib output buffer */
+ png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
+ png_ptr->zstream.next_out = png_ptr->zbuf;
+ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+ }
+ /* repeat until all data has been compressed */
+ } while (png_ptr->zstream.avail_in);
+
+ /* swap the current and previous rows */
+ if (png_ptr->prev_row != NULL)
+ {
+ png_bytep tptr;
+
+ tptr = png_ptr->prev_row;
+ png_ptr->prev_row = png_ptr->row_buf;
+ png_ptr->row_buf = tptr;
+ }
+
+ /* finish row - updates counters and flushes zlib if last row */
+ png_write_finish_row(png_ptr);
+
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+ png_ptr->flush_rows++;
+
+ if (png_ptr->flush_dist > 0 &&
+ png_ptr->flush_rows >= png_ptr->flush_dist)
+ {
+ png_write_flush(png_ptr);
+ }
+#endif
+}
+#endif /* PNG_WRITE_SUPPORTED */
generated by cgit v0.12 at 2024-11-18 17:30:04 (GMT)