WebSVN – Kolibri OS – Diff – /programs/develop/libraries/libpng/pngwutil.c

 /* pngwutil.c - utilities to write a PNG file
+ *
- * Last changed in libpng 1.5.0 [January 6, 2011]
+ * Last changed in libpng 1.6.2 [April 25, 2013]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2013 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
    buf[2] = (png_byte)((i >> 8) & 0xff);
    buf[3] = (png_byte)(i & 0xff);
+}
-#ifdef PNG_SAVE_INT_32_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.  Note that,
- * the following works correctly even if png_int_32 has more than 32 bits
- * (compare the more complex code required on read for sign extention.)
- */
-void PNGAPI
-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 PNGAPI
  * we should call png_set_sig_bytes() to tell libpng how many of the
  * bytes have already been written.
  */
 void PNGAPI
-png_write_sig(png_structp png_ptr)
+png_write_sig(png_structrp png_ptr)
 {
    png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
 #ifdef PNG_IO_STATE_SUPPORTED
    /* Inform the I/O callback that the signature is being written */
    if (png_ptr->sig_bytes < 3)
       png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
+}
-/* 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_const_bytep chunk_name,
-   png_const_bytep data, png_size_t length)
-{
-   if (png_ptr == NULL)
-      return;
-   png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length);
-   png_write_chunk_data(png_ptr, data, (png_size_t)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
+static void
-png_write_chunk_start(png_structp png_ptr, png_const_bytep chunk_name,
+png_write_chunk_header(png_structrp png_ptr, png_uint_32 chunk_name,
     png_uint_32 length)
+{
+   png_byte buf[8];
-   png_byte buf[8];
+#if defined(PNG_DEBUG) && (PNG_DEBUG > 0)
+   PNG_CSTRING_FROM_CHUNK(buf, chunk_name);
-   png_debug2(0, "Writing %s chunk, length = %lu", chunk_name,
+   png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length);
-      (unsigned long)length);
+#endif
 #endif
    /* Write the length and the chunk name */
    png_save_uint_32(buf, length);
-   png_memcpy(buf + 4, chunk_name, 4);
+   png_save_uint_32(buf + 4, chunk_name);
-   png_write_data(png_ptr, buf, (png_size_t)8);
+   png_write_data(png_ptr, buf, 8);
    /* Put the chunk name into png_ptr->chunk_name */
-   png_memcpy(png_ptr->chunk_name, chunk_name, 4);
+   png_ptr->chunk_name = chunk_name;
    /* Reset the crc and run it over the chunk name */
    png_reset_crc(png_ptr);
-   png_calculate_crc(png_ptr, chunk_name, 4);
+   png_calculate_crc(png_ptr, buf + 4, 4);
 #ifdef PNG_IO_STATE_SUPPORTED
    /* Inform the I/O callback that chunk data will (possibly) be written.
     * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls.
+    */
+   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA;
+#endif
+}
+void PNGAPI
+png_write_chunk_start(png_structrp png_ptr, png_const_bytep chunk_string,
-    */
+    png_uint_32 length)
    png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA;
-#endif
+   png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length);
 }
-/* Write the data of a PNG chunk started with png_write_chunk_start().
+/* Write the data of a PNG chunk started with png_write_chunk_header().
  * 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().
+ * given to png_write_chunk_header().
  */
 void PNGAPI
-png_write_chunk_data(png_structp png_ptr, png_const_bytep data,
+png_write_chunk_data(png_structrp png_ptr, png_const_bytep data,
       png_calculate_crc(png_ptr, data, length);
+   }
+}
-/* Finish a chunk started with png_write_chunk_start(). */
+/* Finish a chunk started with png_write_chunk_header(). */
 void PNGAPI
-png_write_chunk_end(png_structp png_ptr)
+png_write_chunk_end(png_structrp png_ptr)
+{
    png_byte buf[4];
    png_write_data(png_ptr, buf, (png_size_t)4);
+}
-#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)
+/* Write a PNG chunk all at once.  The type is an array of ASCII characters
-/* This pair of functions encapsulates the operation of (a) compressing a
+ * representing the chunk name.  The array must be at least 4 bytes in
- * text string, and (b) issuing it later as a series of chunk data writes.
+ * length, and does not need to be null terminated.  To be safe, pass the
- * The compression_state structure is shared context for these functions
+ * 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()
- * set up by the caller in order to make the whole mess thread-safe.
+ * functions instead.
+ */
+static void
+png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,
+   png_const_bytep data, png_size_t length)
+{
+   if (png_ptr == NULL)
+      return;
+   /* On 64 bit architectures 'length' may not fit in a png_uint_32. */
+   if (length > PNG_UINT_31_MAX)
+      png_error(png_ptr, "length exceeds PNG maxima");
+   png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
+   png_write_chunk_data(png_ptr, data, length);
+   png_write_chunk_end(png_ptr);
+}
- */
+/* This is the API that calls the internal function above. */
+void PNGAPI
 png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string,
-typedef struct
+   png_const_bytep data, png_size_t length)
-{
-   png_const_bytep input;   /* The uncompressed input data */
-   png_size_t input_len;    /* Its length */
-   int num_output_ptr;      /* Number of output pointers used */
-   int max_output_ptr;      /* Size of output_ptr */
+{
+   png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,
-   png_bytep *output_ptr;   /* Array of pointers to output */
+      length);
-} compression_state;
+}
+/* This is used below to find the size of an image to pass to png_deflate_claim,
-/* Compress given text into storage in the png_ptr structure */
+ * so it only needs to be accurate if the size is less than 16384 bytes (the
-static int /* PRIVATE */
+ * point at which a lower LZ window size can be used.)
-png_text_compress(png_structp png_ptr,
+ */
+static png_alloc_size_t
+png_image_size(png_structrp png_ptr)
-    png_const_charp text, png_size_t text_len, int compression,
+{
+   /* Only return sizes up to the maximum of a png_uint_32, do this by limiting
-    compression_state *comp)
+    * the width and height used to 15 bits.
+    */
-{
+   png_uint_32 h = png_ptr->height;
+   if (png_ptr->rowbytes < 32768 && h < 32768)
+   {
+      if (png_ptr->interlaced)
-   int ret;
+      {
+         /* Interlacing makes the image larger because of the replication of
+          * both the filter byte and the padding to a byte boundary.
-   comp->num_output_ptr = 0;
+          */
-   comp->max_output_ptr = 0;
+         png_uint_32 w = png_ptr->width;
-   comp->output_ptr = NULL;
-   comp->input = NULL;
+         unsigned int pd = png_ptr->pixel_depth;
-   comp->input_len = 0;
+         png_alloc_size_t cb_base;
+         int pass;
+         for (cb_base=0, pass=0; pass<=6; ++pass)
+         {
+            png_uint_32 pw = PNG_PASS_COLS(w, pass);
+            if (pw > 0)
+               cb_base += (PNG_ROWBYTES(pd, pw)+1) * PNG_PASS_ROWS(h, pass);
+         }
+         return cb_base;
+      }
-   /* We may just want to pass the text right through */
+      else
-   if (compression == PNG_TEXT_COMPRESSION_NONE)
+         return (png_ptr->rowbytes+1) * h;
+   }
+   else
+      return 0xffffffffU;
+}
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+   /* This is the code to hack the first two bytes of the deflate stream (the
+    * deflate header) to correct the windowBits value to match the actual data
+    * size.  Note that the second argument is the *uncompressed* size but the
+    * first argument is the *compressed* data (and it must be deflate
+    * compressed.)
+    */
+static void
+optimize_cmf(png_bytep data, png_alloc_size_t data_size)
+{
+   /* Optimize the CMF field in the zlib stream.  The resultant zlib stream is
-   {
+    * still compliant to the stream specification.
+    */
+   if (data_size <= 16384) /* else windowBits must be 15 */
+   {
+      unsigned int z_cmf = data[0];  /* zlib compression method and flags */
+      if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
+      {
+         unsigned int z_cinfo;
+         unsigned int half_z_window_size;
+         z_cinfo = z_cmf >> 4;
+         half_z_window_size = 1U << (z_cinfo + 7);
       comp->input = (png_const_bytep)text;
+         if (data_size <= half_z_window_size) /* else no change */
+         {
+            unsigned int tmp;
+            do
+            {
+               half_z_window_size >>= 1;
+               --z_cinfo;
+            }
+            while (z_cinfo > 0 && data_size <= half_z_window_size);
+            z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
+            data[0] = (png_byte)z_cmf;
+            tmp = data[1] & 0xe0;
+            tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
+            data[1] = (png_byte)tmp;
-      comp->input_len = text_len;
+         }
+      }
+   }
+}
+#else
+#  define optimize_cmf(dp,dl) ((void)0)
+#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */
+/* Initialize the compressor for the appropriate type of compression. */
-      return((int)text_len);
+static int
+png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
+   png_alloc_size_t data_size)
+{
+   if (png_ptr->zowner != 0)
+   {
+      char msg[64];
+      PNG_STRING_FROM_CHUNK(msg, owner);
+      msg[4] = ':';
-   }
+      msg[5] = ' ';
+      PNG_STRING_FROM_CHUNK(msg+6, png_ptr->zowner);
       /* So the message that results is " using zstream"; this is an
+       * internal error, but is very useful for debugging.  i18n requirements
+       * are minimal.
+       */
+      (void)png_safecat(msg, (sizeof msg), 10, " using zstream");
+#     if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+         png_warning(png_ptr, msg);
+         /* Attempt sane error recovery */
+         if (png_ptr->zowner == png_IDAT) /* don't steal from IDAT */
    if (compression >= PNG_TEXT_COMPRESSION_LAST)
-   {
+            png_ptr->zstream.msg = PNGZ_MSG_CAST("in use by IDAT");
-#ifdef PNG_CONSOLE_IO_SUPPORTED
+            return Z_STREAM_ERROR;
       char msg[50];
-      png_snprintf(msg, 50, "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 */
-   /* TODO: the following cast hides a potential overflow problem. */
-   png_ptr->zstream.avail_in = (uInt)text_len;
    /* NOTE: assume zlib doesn't overwrite the input */
+         png_ptr->zowner = 0;
-   png_ptr->zstream.next_in = (Bytef *)text;
+#     else
-   png_ptr->zstream.avail_out = png_ptr->zbuf_size;
+         png_error(png_ptr, msg);
+#     endif
+   }
-   png_ptr->zstream.next_out = png_ptr->zbuf;
+   {
       int level = png_ptr->zlib_level;
+      int method = png_ptr->zlib_method;
-   /* This is the same compression loop as in png_write_row() */
+      int windowBits = png_ptr->zlib_window_bits;
+      int memLevel = png_ptr->zlib_mem_level;
-   do
+      int strategy; /* set below */
-   {
+      int ret; /* zlib return code */
       /* Compress the data */
-      ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
+      if (owner == png_IDAT)
+      {
-      if (ret != Z_OK)
-      {
+         if (png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY)
-         /* Error */
+            strategy = png_ptr->zlib_strategy;
+         else if (png_ptr->do_filter != PNG_FILTER_NONE)
+            strategy = PNG_Z_DEFAULT_STRATEGY;
+         else
+            strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY;
+      }
+      else
+      {
-         if (png_ptr->zstream.msg != NULL)
+#        ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+            level = png_ptr->zlib_text_level;
+            method = png_ptr->zlib_text_method;
+            windowBits = png_ptr->zlib_text_window_bits;
+            memLevel = png_ptr->zlib_text_mem_level;
+            strategy = png_ptr->zlib_text_strategy;
+#        else
+            /* If customization is not supported the values all come from the
+             * IDAT values except for the strategy, which is fixed to the
+             * default.  (This is the pre-1.6.0 behavior too, although it was
+             * implemented in a very different way.)
+             */
+            strategy = Z_DEFAULT_STRATEGY;
+#        endif
+      }
+      /* Adjust 'windowBits' down if larger than 'data_size'; to stop this
+       * happening just pass 32768 as the data_size parameter.  Notice that zlib
-            png_error(png_ptr, png_ptr->zstream.msg);
+       * requires an extra 262 bytes in the window in addition to the data to be
+       * able to see the whole of the data, so if data_size+262 takes us to the
+       * next windowBits size we need to fix up the value later.  (Because even
+       * though deflate needs the extra window, inflate does not!)
+       */
       if (data_size <= 16384)
+      {
-         else
+         /* IMPLEMENTATION NOTE: this 'half_window_size' stuff is only here to
+          * work round a Microsoft Visual C misbehavior which, contrary to C-90,
+          * widens the result of the following shift to 64-bits if (and,
+          * apparently, only if) it is used in a test.
+          */
+         unsigned int half_window_size = 1U << (windowBits-1);
-            png_error(png_ptr, "zlib error");
-      }
+         while (data_size + 262 <= half_window_size)
+         {
+            half_window_size >>= 1;
-      /* Check to see if we need more room */
+            --windowBits;
-      if (!(png_ptr->zstream.avail_out))
+         }
+      }
-      {
+      /* Check against the previous initialized values, if any. */
-         /* Make sure the output array has room */
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) &&
+         (png_ptr->zlib_set_level != level ||
+         png_ptr->zlib_set_method != method ||
+         png_ptr->zlib_set_window_bits != windowBits ||
-         if (comp->num_output_ptr >= comp->max_output_ptr)
+         png_ptr->zlib_set_mem_level != memLevel ||
-         {
+         png_ptr->zlib_set_strategy != strategy))
+      {
+         if (deflateEnd(&png_ptr->zstream) != Z_OK)
-            int old_max;
+            png_warning(png_ptr, "deflateEnd failed (ignored)");
+         png_ptr->flags &= ~PNG_FLAG_ZSTREAM_INITIALIZED;
+      }
+      /* For safety clear out the input and output pointers (currently zlib
+       * doesn't use them on Init, but it might in the future).
-            old_max = comp->max_output_ptr;
+       */
+      png_ptr->zstream.next_in = NULL;
+      png_ptr->zstream.avail_in = 0;
+      png_ptr->zstream.next_out = NULL;
-            comp->max_output_ptr = comp->num_output_ptr + 4;
+      png_ptr->zstream.avail_out = 0;
+      /* Now initialize if required, setting the new parameters, otherwise just
+       * to a simple reset to the previous parameters.
+       */
+      if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)
+         ret = deflateReset(&png_ptr->zstream);
-            if (comp->output_ptr != NULL)
+      else
-            {
+      {
+         ret = deflateInit2(&png_ptr->zstream, level, method, windowBits,
-               png_bytepp old_ptr;
+            memLevel, strategy);
-               old_ptr = comp->output_ptr;
+         if (ret == Z_OK)
+            png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
+      }
-               comp->output_ptr = (png_bytepp)png_malloc(png_ptr,
+      /* The return code is from either deflateReset or deflateInit2; they have
-                   (png_alloc_size_t)
+       * pretty much the same set of error codes.
+       */
+      if (ret == Z_OK)
+         png_ptr->zowner = owner;
+      else
+         png_zstream_error(png_ptr, ret);
-                   (comp->max_output_ptr * png_sizeof(png_charpp)));
+      return ret;
+   }
+}
-               png_memcpy(comp->output_ptr, old_ptr, old_max
+/* Clean up (or trim) a linked list of compression buffers. */
+void /* PRIVATE */
+png_free_buffer_list(png_structrp png_ptr, png_compression_bufferp *listp)
+{
+   png_compression_bufferp list = *listp;
+   if (list != NULL)
+   {
+      *listp = NULL;
+      do
+      {
+         png_compression_bufferp next = list->next;
+         png_free(png_ptr, list);
+         list = next;
+      }
+      while (list != NULL);
+   }
+}
-                   * png_sizeof(png_charp));
+#ifdef PNG_WRITE_COMPRESSED_TEXT_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
-               png_free(png_ptr, old_ptr);
+ * set up by the caller to allow access to the relevant local variables.
-            }
+ *
+ * compression_buffer (new in 1.6.0) is just a linked list of zbuffer_size
-            else
+ * temporary buffers.  From 1.6.0 it is retained in png_struct so that it will
-               comp->output_ptr = (png_bytepp)png_malloc(png_ptr,
-                   (png_alloc_size_t)
+ * be correctly freed in the event of a write error (previous implementations
+ * just leaked memory.)
+ */
+typedef struct
+{
+   png_const_bytep      input;        /* The uncompressed input data */
+   png_alloc_size_t     input_len;    /* Its length */
+   png_uint_32          output_len;   /* Final compressed length */
+   png_byte             output[1024]; /* First block of output */
+} compression_state;
+static void
+png_text_compress_init(compression_state *comp, png_const_bytep input,
+   png_alloc_size_t input_len)
+{
+   comp->input = input;
+   comp->input_len = input_len;
+   comp->output_len = 0;
+}
+/* Compress the data in the compression state input */
+static int
+png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
+   compression_state *comp, png_uint_32 prefix_len)
+{
+   int ret;
+   /* To find the length of the output it is necessary to first compress the
+    * input, the result is buffered rather than using the two-pass algorithm
+    * that is used on the inflate side; deflate is assumed to be slower and a
+    * PNG writer is assumed to have more memory available than a PNG reader.
+    *
+    * IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an
-                   (comp->max_output_ptr * png_sizeof(png_charp)));
+    * upper limit on the output size, but it is always bigger than the input
+    * size so it is likely to be more efficient to use this linked-list
+    * approach.
+    */
+   ret = png_deflate_claim(png_ptr, chunk_name, comp->input_len);
+   if (ret != Z_OK)
+      return ret;
    /* Set up the compression buffers, we need a loop here to avoid overflowing a
-         /* Save the data */
+    * uInt.  Use ZLIB_IO_MAX to limit the input.  The output is always limited
-         comp->output_ptr[comp->num_output_ptr] =
+    * by the output buffer size, so there is no need to check that.  Since this
+    * is ANSI-C we know that an 'int', hence a uInt, is always at least 16 bits
+    * in size.
-             (png_bytep)png_malloc(png_ptr,
+    */
+   {
+      png_compression_bufferp *end = &png_ptr->zbuffer_list;
+      png_alloc_size_t input_len = comp->input_len; /* may be zero! */
+      png_uint_32 output_len;
              (png_alloc_size_t)png_ptr->zbuf_size);
+      /* zlib updates these for us: */
+      png_ptr->zstream.next_in = PNGZ_INPUT_CAST(comp->input);
+      png_ptr->zstream.avail_in = 0; /* Set below */
-         png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
+      png_ptr->zstream.next_out = comp->output;
+      png_ptr->zstream.avail_out = (sizeof comp->output);
-             png_ptr->zbuf_size);
+      output_len = png_ptr->zstream.avail_out;
+      do
+      {
+         uInt avail_in = ZLIB_IO_MAX;
+         if (avail_in > input_len)
+            avail_in = (uInt)input_len;
-         comp->num_output_ptr++;
+         input_len -= avail_in;
+         png_ptr->zstream.avail_in = avail_in;
-         /* and reset the buffer */
-         png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
-         png_ptr->zstream.next_out = png_ptr->zbuf;
-      }
+         if (png_ptr->zstream.avail_out == 0)
    /* Continue until we don't have any more to compress */
-   } while (png_ptr->zstream.avail_in);
+            png_compression_buffer *next;
+            /* Chunk data is limited to 2^31 bytes in length, so the prefix
+             * length must be counted here.
+             */
+            if (output_len + prefix_len > PNG_UINT_31_MAX)
+            {
-   /* Finish the compression */
+               ret = Z_MEM_ERROR;
-   do
+               break;
-   {
-      /* Tell zlib we are finished */
+            }
-      ret = deflate(&png_ptr->zstream, Z_FINISH);
+            /* Need a new (malloc'ed) buffer, but there may be one present
+             * already.
+             */
-      if (ret == Z_OK)
+            next = *end;
+            if (next == NULL)
+            {
+               next = png_voidcast(png_compression_bufferp, png_malloc_base
+                  (png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
+               if (next == NULL)
+               {
                   ret = Z_MEM_ERROR;
+                  break;
+               }
+               /* Link in this buffer (so that it will be freed later) */
+               next->next = NULL;
+               *end = next;
+            }
+            png_ptr->zstream.next_out = next->output;
+            png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
-         /* Check to see if we need more room */
+            output_len += png_ptr->zstream.avail_out;
-         if (!(png_ptr->zstream.avail_out))
+            /* Move 'end' to the next buffer pointer. */
+            end = &next->next;
-         {
+         }
-            /* Check to make sure our output array has room */
-            if (comp->num_output_ptr >= comp->max_output_ptr)
+         /* Compress the data */
-            {
+         ret = deflate(&png_ptr->zstream,
-               int old_max;
+            input_len > 0 ? Z_NO_FLUSH : Z_FINISH);
+         /* Claw back input data that was not consumed (because avail_in is
-               old_max = comp->max_output_ptr;
+          * reset above every time round the loop).
-               comp->max_output_ptr = comp->num_output_ptr + 4;
+          */
-               if (comp->output_ptr != NULL)
+         input_len += png_ptr->zstream.avail_in;
+         png_ptr->zstream.avail_in = 0; /* safety */
+      }
+      while (ret == Z_OK);
+      /* There may be some space left in the last output buffer, this needs to
+       * be subtracted from output_len.
+       */
-               {
+      output_len -= png_ptr->zstream.avail_out;
+      png_ptr->zstream.avail_out = 0; /* safety */
+      comp->output_len = output_len;
-                  png_bytepp old_ptr;
+      /* Now double check the output length, put in a custom message if it is
-                  old_ptr = comp->output_ptr;
+       * too long.  Otherwise ensure the z_stream::msg pointer is set to
        * something.
-                  /* This could be optimized to realloc() */
+       */
+      if (output_len + prefix_len >= PNG_UINT_31_MAX)
-                  comp->output_ptr = (png_bytepp)png_malloc(png_ptr,
+      {
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("compressed data too long");
+         ret = Z_MEM_ERROR;
                       (png_alloc_size_t)(comp->max_output_ptr *
-                      png_sizeof(png_charp)));
+      else
+         png_zstream_error(png_ptr, ret);
-                  png_memcpy(comp->output_ptr, old_ptr,
+      /* Reset zlib for another zTXt/iTXt or image data */
+      png_ptr->zowner = 0;
+      /* The only success case is Z_STREAM_END, input_len must be 0, if not this
+       * is an internal error.
+       */
+      if (ret == Z_STREAM_END && input_len == 0)
+      {
+         /* Fix up the deflate header, if required */
+         optimize_cmf(comp->output, comp->input_len);
-                      old_max * png_sizeof(png_charp));
+         /* But Z_OK is returned, not Z_STREAM_END; this allows the claim
+          * function above to return Z_STREAM_END on an error (though it never
+          * does in the current versions of zlib.)
+          */
+         return Z_OK;
+      }
+      else
+         return ret;
                   png_free(png_ptr, old_ptr);
-               }
+}
+/* Ship the compressed text out via chunk writes */
+static void
+png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp)
+{
+   png_uint_32 output_len = comp->output_len;
+   png_const_bytep output = comp->output;
+   png_uint_32 avail = (sizeof comp->output);
+   png_compression_buffer *next = png_ptr->zbuffer_list;
+   for (;;)
+   {
+      if (avail > output_len)
-               else
+         avail = output_len;
+      png_write_chunk_data(png_ptr, output, avail);
+      output_len -= avail;
-                  comp->output_ptr = (png_bytepp)png_malloc(png_ptr,
+      if (output_len == 0 || next == NULL)
-                      (png_alloc_size_t)(comp->max_output_ptr *
+         break;
-                      png_sizeof(png_charp)));
+      avail = png_ptr->zbuffer_size;
+      output = next->output;
       next = next->next;
-            /* Save the data */
+   }
-            comp->output_ptr[comp->num_output_ptr] =
                 (png_bytep)png_malloc(png_ptr,
-                (png_alloc_size_t)png_ptr->zbuf_size);
+   /* This is an internal error; 'next' must have been NULL! */
+   if (output_len > 0)
+      png_error(png_ptr, "error writing ancillary chunked compressed data");
+}
-            png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
+#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
                 png_ptr->zbuf_size);
+#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
-            comp->num_output_ptr++;
+ * length, forbids leading or trailing whitespace, multiple internal spaces,
+ * and the non-break space (0x80) from ISO 8859-1.  Returns keyword length.
+ *
-            /* and reset the buffer pointers */
+ * The 'new_key' buffer must be 80 characters in size (for the keyword plus a
-            png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+ * trailing '\0').  If this routine returns 0 then there was no keyword, or a
-            png_ptr->zstream.next_out = png_ptr->zbuf;
+ * valid one could not be generated, and the caller must png_error.
-         }
-      }
+ */
+static png_uint_32
-      else if (ret != Z_STREAM_END)
+png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
+{
+   png_const_charp orig_key = key;
    png_uint_32 key_len = 0;
-         /* We got an error */
+   int bad_character = 0;
-         if (png_ptr->zstream.msg != NULL)
+   int space = 1;
-            png_error(png_ptr, png_ptr->zstream.msg);
-         else
+   png_debug(1, "in png_check_keyword");
-            png_error(png_ptr, "zlib error");
-      }
+   if (key == NULL)
+   {
+      *new_key = 0;
-   } while (ret != Z_STREAM_END);
+      return 0;
+   }
+   while (*key && key_len < 79)
+   {
+      png_byte ch = (png_byte)(0xff & *key++);
+      if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/))
+         *new_key++ = ch, ++key_len, space = 0;
+      else if (!space)
    /* Text length is number of buffers plus last buffer */
-   text_len = png_ptr->zbuf_size * comp->num_output_ptr;
+         /* A space or an invalid character when one wasn't seen immediately
           * before; output just a space.
-   if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
+          */
-      text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;
+         *new_key++ = 32, ++key_len, space = 1;
-   return((int)text_len);
+         /* If the character was not a space then it is invalid. */
-}
+         if (ch != 32)
             bad_character = ch;
 /* 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;
       else if (!bad_character)
-   /* Handle the no-compression case */
+         bad_character = ch; /* just skip it, record the first error */
    if (comp->input)
    buf[11] = (png_byte)filter_type;
    buf[12] = (png_byte)interlace_type;
    /* Write the chunk */
-   png_write_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
+   png_write_complete_chunk(png_ptr, 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 ||
       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;
-   ret = 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);
-   if (ret != Z_OK)
-   {
-      if (ret == Z_VERSION_ERROR)
-         png_error(png_ptr,
-            "zlib failed to initialize compressor -- version error");
-      if (ret == Z_STREAM_ERROR)
-         png_error(png_ptr,
-             "zlib failed to initialize compressor -- stream error");
-      if (ret == Z_MEM_ERROR)
-         png_error(png_ptr,
-             "zlib failed to initialize compressor -- mem error");
-      png_error(png_ptr, "zlib failed to initialize compressor");
-   }
-   png_ptr->zstream.next_out = png_ptr->zbuf;
-   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
-   /* libpng is not interested in zstream.data_type, so set it
-    * to a predefined value, to avoid its evaluation inside zlib
-    */
-   png_ptr->zstream.data_type = Z_BINARY;
-   png_ptr->mode = PNG_HAVE_IHDR;
+   png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */
+}
 /* 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_const_colorp palette,
+png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
-    png_uint_32 num_pal)
     png_uint_32 num_pal)
    PNG_PLTE;
    png_uint_32 i;
    png_const_colorp pal_ptr;
    png_ptr->num_palette = (png_uint_16)num_pal;
    png_debug1(3, "num_palette = %d", png_ptr->num_palette);
-   png_write_chunk_start(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));
+   png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));
 #ifdef PNG_POINTER_INDEXING_SUPPORTED
    for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
    png_write_chunk_end(png_ptr);
    png_ptr->mode |= PNG_HAVE_PLTE;
+}
+/* This is similar to png_text_compress, above, except that it does not require
+ * all of the data at once and, instead of buffering the compressed result,
+ * writes it as IDAT chunks.  Unlike png_text_compress it *can* png_error out
+ * because it calls the write interface.  As a result it does its own error
+ * reporting and does not return an error code.  In the event of error it will
+ * just call png_error.  The input data length may exceed 32-bits.  The 'flush'
+ * parameter is exactly the same as that to deflate, with the following
-/* Write an IDAT chunk */
+ * meanings:
+ *
+ * Z_NO_FLUSH: normal incremental output of compressed data
+ * Z_SYNC_FLUSH: do a SYNC_FLUSH, used by png_write_flush
+ * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up
+ *
+ * The routine manages the acquire and release of the png_ptr->zstream by
+ * checking and (at the end) clearing png_ptr->zowner, it does some sanity
+ * checks on the 'mode' flags while doing this.
+ */
 void /* PRIVATE */
-png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
+png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
+   png_alloc_size_t input_len, int flush)
+{
-   PNG_IDAT;
-   png_debug(1, "in png_write_IDAT");
-   /* Optimize the CMF field in the zlib stream. */
-   /* This hack of the zlib stream is compliant to the stream specification. */
-   if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
+   if (png_ptr->zowner != png_IDAT)
-       png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+   {
+      /* First time.   Ensure we have a temporary buffer for compression and
+       * trim the buffer list if it has more than one entry to free memory.
+       * If 'WRITE_COMPRESSED_TEXT' is not set the list will never have been
-      unsigned int z_cmf = data[0];  /* zlib compression method and flags */
+       * created at this point, but the check here is quick and safe.
+       */
-      if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
+      if (png_ptr->zbuffer_list == NULL)
+      {
-         /* Avoid memory underflows and multiplication overflows.
+         png_ptr->zbuffer_list = png_voidcast(png_compression_bufferp,
+            png_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
+         png_ptr->zbuffer_list->next = NULL;
+      }
-          *
+      else
+         png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list->next);
-          * The conditions below are practically always satisfied;
+      /* It is a terminal error if we can't claim the zstream. */
+      if (png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)) != Z_OK)
+         png_error(png_ptr, png_ptr->zstream.msg);
+      /* The output state is maintained in png_ptr->zstream, so it must be
-          * however, they still must be checked.
+       * initialized here after the claim.
-          */
+       */
-         if (length >= 2 &&
+      png_ptr->zstream.next_out = png_ptr->zbuffer_list->output;
-             png_ptr->height < 16384 && png_ptr->width < 16384)
+      png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
+   }
+   /* Now loop reading and writing until all the input is consumed or an error
+    * terminates the operation.  The _out values are maintained across calls to
+    * this function, but the input must be reset each time.
+    */
+   png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
+   png_ptr->zstream.avail_in = 0; /* set below */
+   for (;;)
+   {
+      int ret;
+      /* INPUT: from the row data */
+      uInt avail = ZLIB_IO_MAX;
+      if (avail > input_len)
-            png_uint_32 uncompressed_idat_size = png_ptr->height *
+         avail = (uInt)input_len; /* safe because of the check */
-                ((png_ptr->width *
+      png_ptr->zstream.avail_in = avail;
+      input_len -= avail;
-                png_ptr->channels * png_ptr->bit_depth + 15) >> 3);
+      ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : flush);
-            unsigned int z_cinfo = z_cmf >> 4;
+      /* Include as-yet unconsumed input */
+      input_len += png_ptr->zstream.avail_in;
+      png_ptr->zstream.avail_in = 0;
+      /* OUTPUT: write complete IDAT chunks when avail_out drops to zero, note
-            unsigned int half_z_window_size = 1 << (z_cinfo + 7);
+       * that these two zstream fields are preserved across the calls, therefore
-            while (uncompressed_idat_size <= half_z_window_size &&
+       * there is no need to set these up on entry to the loop.
+       */
-                half_z_window_size >= 256)
+      if (png_ptr->zstream.avail_out == 0)
+      {
-               z_cinfo--;
+         png_bytep data = png_ptr->zbuffer_list->output;
-               half_z_window_size >>= 1;
+         uInt size = png_ptr->zbuffer_size;
-            }
+         /* Write an IDAT containing the data then reset the buffer.  The
+          * first IDAT may need deflate header optimization.
+          */
+#        ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+            if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
+               png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+               optimize_cmf(data, png_image_size(png_ptr));
+#        endif
+         png_write_complete_chunk(png_ptr, png_IDAT, data, size);
+         png_ptr->mode |= PNG_HAVE_IDAT;
+         png_ptr->zstream.next_out = data;
+         png_ptr->zstream.avail_out = size;
-            z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
+         /* For SYNC_FLUSH or FINISH it is essential to keep calling zlib with
+          * the same flush parameter until it has finished output, for NO_FLUSH
+          * it doesn't matter.
+          */
+         if (ret == Z_OK && flush != Z_NO_FLUSH)
+            continue;
+      }
+      /* The order of these checks doesn't matter much; it just effect which
+       * possible error might be detected if multiple things go wrong at once.
        */
+      if (ret == Z_OK) /* most likely return code! */
+      {
-            if (data[0] != z_cmf)
+         /* If all the input has been consumed then just return.  If Z_FINISH
+          * was used as the flush parameter something has gone wrong if we get
-            {
+          * here.
+          */
-               int tmp;
+         if (input_len == 0)
-               data[0] = (png_byte)z_cmf;
+         {
+            if (flush == Z_FINISH)
-               tmp = data[1] & 0xe0;
+               png_error(png_ptr, "Z_OK on Z_FINISH with output space");
                tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
-               data[1] = (png_byte)tmp;
+            return;
+         }
+      }
+      else if (ret == Z_STREAM_END && flush == Z_FINISH)
+      {
+         /* This is the end of the IDAT data; any pending output must be
+          * flushed.  For small PNG files we may still be at the beginning.
+          */
+         png_bytep data = png_ptr->zbuffer_list->output;
+         uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out;
+#        ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+            if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
+               png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+               optimize_cmf(data, png_image_size(png_ptr));
+#        endif
+         png_write_complete_chunk(png_ptr, png_IDAT, data, size);
+         png_ptr->zstream.avail_out = 0;
+         png_ptr->zstream.next_out = NULL;
+         png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT;
          png_ptr->zowner = 0; /* Release the stream */
          return;
+      }
-      }
+      else
+      {
+         /* This is an error condition. */
-      else
+         png_zstream_error(png_ptr, ret);
-         png_error(png_ptr,
-             "Invalid zlib compression method or flags in IDAT");
-   }
          png_error(png_ptr, png_ptr->zstream.msg);
    png_write_chunk(png_ptr, png_IDAT, data, length);
    png_ptr->mode |= PNG_HAVE_IDAT;
 }
-/* Write an IEND chunk */
-void /* PRIVATE */
-png_write_IEND(png_structp png_ptr)
+/* Write an IEND chunk */
-{
+void /* PRIVATE */
-   PNG_IEND;
+png_write_IEND(png_structrp png_ptr)
+{
    png_debug(1, "in png_write_IEND");
-   png_write_chunk(png_ptr, png_IEND, NULL, (png_size_t)0);
+   png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0);
    png_ptr->mode |= PNG_HAVE_IEND;
+}
 #ifdef PNG_WRITE_gAMA_SUPPORTED
-/* Write a gAMA chunk */
+#ifdef PNG_WRITE_gAMA_SUPPORTED
-void /* PRIVATE */
+/* Write a gAMA chunk */
-png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
+void /* PRIVATE */
-{
+png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma)
    PNG_gAMA;
    png_byte buf[4];
    png_debug(1, "in png_write_gAMA");
    /* file_gamma is saved in 1/100,000ths */
    png_save_uint_32(buf, (png_uint_32)file_gamma);
-   png_write_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);
    png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);
 #endif
 #endif
 #ifdef PNG_WRITE_sRGB_SUPPORTED
-/* Write a sRGB chunk */
+#ifdef PNG_WRITE_sRGB_SUPPORTED
-void /* PRIVATE */
+/* Write a sRGB chunk */
-png_write_sRGB(png_structp png_ptr, int srgb_intent)
+void /* PRIVATE */
 png_write_sRGB(png_structrp png_ptr, int srgb_intent)
    PNG_sRGB;
    png_byte buf[1];
    png_debug(1, "in png_write_sRGB");
    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_sRGB, buf, (png_size_t)1);
+   png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);
-}
 #endif
-#ifdef PNG_WRITE_iCCP_SUPPORTED
+#endif
-/* Write an iCCP chunk */
-void /* PRIVATE */
-png_write_iCCP(png_structp png_ptr, png_const_charp name, int compression_type,
-    png_const_charp profile, int profile_len)
-{
-   PNG_iCCP;
+#ifdef PNG_WRITE_iCCP_SUPPORTED
-   png_size_t name_len;
-   png_charp new_name;
-   compression_state comp;
-   int embedded_profile_len = 0;
 /* Write an iCCP chunk */
-   png_debug(1, "in png_write_iCCP");
+void /* PRIVATE */
-   comp.num_output_ptr = 0;
-   comp.max_output_ptr = 0;
-   comp.output_ptr = NULL;
-   comp.input = NULL;
-   comp.input_len = 0;
+png_write_iCCP(png_structrp png_ptr, png_const_charp name,
+    png_const_bytep profile)
-   if ((name_len = png_check_keyword(png_ptr, name, &new_name)) == 0)
-      return;
+{
-   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+   png_uint_32 name_len;
-      png_warning(png_ptr, "Unknown compression type in iCCP chunk");
+   png_uint_32 profile_len;
-   if (profile == NULL)
-      profile_len = 0;
+   png_byte new_name[81]; /* 1 byte for the compression byte */
-   if (profile_len > 3)
+   compression_state comp;
-      embedded_profile_len =
-          ((*( (png_const_bytep)profile    ))<<24) |
+   png_debug(1, "in png_write_iCCP");
           ((*( (png_const_bytep)profile + 1))<<16) |
-          ((*( (png_const_bytep)profile + 2))<< 8) |
+   /* These are all internal problems: the profile should have been checked
-          ((*( (png_const_bytep)profile + 3))    );
-   if (embedded_profile_len < 0)
+    * before when it was stored.
-   {
+    */
-      png_warning(png_ptr,
-          "Embedded profile length in iCCP chunk is negative");
-      png_free(png_ptr, new_name);
+   if (profile == NULL)
-      return;
+      png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */
-   }
-   if (profile_len < embedded_profile_len)
+   profile_len = png_get_uint_32(profile);
+   if (profile_len < 132)
+      png_error(png_ptr, "ICC profile too short");
-   {
+   if (profile_len & 0x03)
+      png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)");
-      png_warning(png_ptr,
-          "Embedded profile length too large in iCCP chunk");
+   {
-      png_free(png_ptr, new_name);
+      png_uint_32 embedded_profile_len = png_get_uint_32(profile);
-      return;
       if (profile_len != embedded_profile_len)
-   if (profile_len > embedded_profile_len)
+         png_error(png_ptr, "Profile length does not match profile");
+   }
       png_warning(png_ptr,
-          "Truncating profile to actual length in iCCP chunk");
+   name_len = png_check_keyword(png_ptr, name, new_name);
-      profile_len = embedded_profile_len;
-   }
+   if (name_len == 0)
+      png_error(png_ptr, "iCCP: invalid keyword");
    if (profile_len)
-      profile_len = png_text_compress(png_ptr, profile,
+   new_name[++name_len] = PNG_COMPRESSION_TYPE_BASE;
           (png_size_t)profile_len, PNG_COMPRESSION_TYPE_BASE, &comp);
    /* Make sure we include the NULL after the name and the compression type */
-   /* Make sure we include the NULL after the name and the compression type */
+   ++name_len;
    png_write_chunk_start(png_ptr, png_iCCP,
-       (png_uint_32)(name_len + profile_len + 2));
+   png_text_compress_init(&comp, profile, profile_len);
-   new_name[name_len + 1] = 0x00;
+   /* Allow for keyword terminator and compression byte */
+   if (png_text_compress(png_ptr, png_iCCP, &comp, name_len) != Z_OK)
+      png_error(png_ptr, png_ptr->zstream.msg);
-   png_write_chunk_data(png_ptr, (png_bytep)new_name,
+   png_write_chunk_header(png_ptr, png_iCCP, name_len + comp.output_len);
-       (png_size_t)(name_len + 2));
    png_write_chunk_data(png_ptr, new_name, name_len);
    if (profile_len)
-      png_write_compressed_data_out(png_ptr, &comp);
+   png_write_compressed_data_out(png_ptr, &comp);
          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);
+      png_write_chunk_data(png_ptr, entrybuf, entry_size);
+   }
 #else
    ep=spalette->entries;
    for (i = 0; i>spalette->nentries; i++)
+   {
          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, (png_size_t)entry_size);
+      png_write_chunk_data(png_ptr, entrybuf, entry_size);
+   }
 #endif
-   png_write_chunk_end(png_ptr);
-   png_free(png_ptr, new_name);
+   png_write_chunk_end(png_ptr);
+}
 #endif
 #ifdef PNG_WRITE_sBIT_SUPPORTED
 /* Write the sBIT chunk */
 void /* PRIVATE */
-png_write_sBIT(png_structp png_ptr, png_const_color_8p sbit, int color_type)
 png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
    PNG_sBIT;
    png_byte buf[4];
       buf[size++] = sbit->alpha;
+   }
-   png_write_chunk(png_ptr, png_sBIT, buf, size);
+   png_write_complete_chunk(png_ptr, png_sBIT, buf, size);
+}
 #endif
 #ifdef PNG_WRITE_cHRM_SUPPORTED
 /* Write the cHRM chunk */
-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,
+void /* PRIVATE */
-    png_fixed_point blue_y)
 png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy)
    PNG_cHRM;
    png_byte buf[32];
-   png_debug(1, "in png_write_cHRM");
-   /* Each value is saved in 1/100,000ths */
-#ifdef PNG_CHECK_cHRM_SUPPORTED
-   if (png_check_cHRM_fixed(png_ptr, white_x, white_y, red_x, red_y,
-       green_x, green_y, blue_x, blue_y))
+   png_debug(1, "in png_write_cHRM");
-#endif
-   {
+   /* Each value is saved in 1/100,000ths */
-      png_save_uint_32(buf, (png_uint_32)white_x);
+   png_save_int_32(buf,      xy->whitex);
-      png_save_uint_32(buf + 4, (png_uint_32)white_y);
+   png_save_int_32(buf +  4, xy->whitey);
-      png_save_uint_32(buf + 8, (png_uint_32)red_x);
+   png_save_int_32(buf +  8, xy->redx);
-      png_save_uint_32(buf + 12, (png_uint_32)red_y);
+   png_save_int_32(buf + 12, xy->redy);
       png_save_uint_32(buf + 16, (png_uint_32)green_x);
-      png_save_uint_32(buf + 20, (png_uint_32)green_y);
+   png_save_int_32(buf + 16, xy->greenx);
    png_save_int_32(buf + 20, xy->greeny);
       png_save_uint_32(buf + 24, (png_uint_32)blue_x);
-      png_save_uint_32(buf + 28, (png_uint_32)blue_y);
+   png_save_int_32(buf + 24, xy->bluex);
+   png_save_int_32(buf + 28, xy->bluey);
       png_write_chunk(png_ptr, png_cHRM, buf, (png_size_t)32);
    png_write_complete_chunk(png_ptr, png_cHRM, buf, 32);
-}
 #endif
 #endif
 #ifdef PNG_WRITE_tRNS_SUPPORTED
-/* Write the tRNS chunk */
+#ifdef PNG_WRITE_tRNS_SUPPORTED
-void /* PRIVATE */
+/* Write the tRNS chunk */
-png_write_tRNS(png_structp png_ptr, png_const_bytep trans_alpha,
+void /* PRIVATE */
+png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
     png_const_color_16p tran, int num_trans, int color_type)
+{
-   PNG_tRNS;
+   png_byte buf[6];
    png_byte buf[6];
+   png_debug(1, "in png_write_tRNS");
-   png_debug(1, "in png_write_tRNS");
+   if (color_type == PNG_COLOR_TYPE_PALETTE)
+   {
-   if (color_type == PNG_COLOR_TYPE_PALETTE)
+      if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
+      {
-      if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
+         png_app_warning(png_ptr,
              "Invalid number of transparent colors specified");
-         png_warning(png_ptr, "Invalid number of transparent colors specified");
+         return;
          return;
       /* Write the chunk out as it is */
-      /* Write the chunk out as it is */
+      png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha,
-      png_write_chunk(png_ptr, png_tRNS, trans_alpha, (png_size_t)num_trans);
+         (png_size_t)num_trans);
+   }
    else if (color_type == PNG_COLOR_TYPE_GRAY)
+   {
 #else
       if (buf[0] | buf[2] | buf[4])
 #endif
+      {
-         png_warning(png_ptr,
+         png_app_warning(png_ptr,
            "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
          return;
+      }
-      png_write_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
+      png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
+   }
    else
    {
-      png_warning(png_ptr, "Can't write tRNS with an alpha channel");
+      png_app_warning(png_ptr, "Can't write tRNS with an alpha channel");
+   }
+}
 #endif
 #ifdef PNG_WRITE_bKGD_SUPPORTED
 /* Write the background chunk */
 void /* PRIVATE */
-png_write_bKGD(png_structp png_ptr, png_const_color_16p back, int color_type)
 png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
    PNG_bKGD;
    png_byte buf[6];
          return;
+      }
       buf[0] = back->index;
-      png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
+      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
+   }
    else if (color_type & PNG_COLOR_MASK_COLOR)
+   {
          return;
+      }
-      png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
+      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
+   }
    else
          return;
+      }
       png_save_uint_16(buf, back->gray);
-      png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
+      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
+   }
+}
 #endif
 #ifdef PNG_WRITE_hIST_SUPPORTED
 /* Write the histogram */
 void /* PRIVATE */
-png_write_hIST(png_structp png_ptr, png_const_uint_16p hist, int num_hist)
 png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist)
    PNG_hIST;
    int i;
       png_warning(png_ptr, "Invalid number of histogram entries specified");
       return;
+   }
-   png_write_chunk_start(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
+   png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
    for (i = 0; i < num_hist; i++)
+   {
    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_const_charp key, png_charpp new_key)
-{
-   png_size_t key_len;
-   png_const_charp ikp;
-   png_charp kp, dp;
-   int kflag;
-   int kwarn=0;
-   png_debug(1, "in png_check_keyword");
-   *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'", key);
-   *new_key = (png_charp)png_malloc_warn(png_ptr, (png_uint_32)(key_len + 2));
-   if (*new_key == NULL)
-   {
-      png_warning(png_ptr, "Out of memory while procesing keyword");
-      return ((png_size_t)0);
-   }
-   /* Replace non-printing characters with a blank and print a warning */
-   for (ikp = key, dp = *new_key; *ikp != '\0'; ikp++, dp++)
-   {
-      if ((png_byte)*ikp < 0x20 ||
-         ((png_byte)*ikp > 0x7E && (png_byte)*ikp < 0xA1))
-      {
-#ifdef PNG_CONSOLE_IO_SUPPORTED
-         char msg[40];
-         png_snprintf(msg, 40,
-             "invalid keyword character 0x%02X", (png_byte)*ikp);
-         png_warning(png_ptr, msg);
-#else
-         png_warning(png_ptr, "invalid character in keyword");
-#endif
-         *dp = ' ';
-      }
-      else
-      {
-         *dp = *ikp;
-      }
-   }
-   *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'", 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);
-      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
 #ifdef PNG_WRITE_tEXt_SUPPORTED
 /* Write a tEXt chunk */
 void /* PRIVATE */
-png_write_tEXt(png_structp png_ptr, png_const_charp key, png_const_charp text,
+png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
     png_size_t text_len)
-{
-   PNG_tEXt;
+{
-   png_size_t key_len;
+   png_uint_32 key_len;
-   png_charp new_key;
+   png_byte new_key[80];
+   png_debug(1, "in png_write_tEXt");
-   png_debug(1, "in png_write_tEXt");
+   key_len = png_check_keyword(png_ptr, key, new_key);
-   if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)
+   if (key_len == 0)
-      return;
+      png_error(png_ptr, "tEXt: invalid keyword");
+   if (text == NULL || *text == '\0')
+      text_len = 0;
-   if (text == NULL || *text == '\0')
+   else
-      text_len = 0;
+      text_len = strlen(text);
-   else
+   if (text_len > PNG_UINT_31_MAX - (key_len+1))
-      text_len = png_strlen(text);
+      png_error(png_ptr, "tEXt: text too long");
    /* Make sure we include the 0 after the key */
-   png_write_chunk_start(png_ptr, png_tEXt,
+   png_write_chunk_header(png_ptr, png_tEXt,
-       (png_uint_32)(key_len + text_len + 1));
+       (png_uint_32)/*checked above*/(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
+    * We leave it to the application to meet PNG-1.0 requirements on the
-    * any non-Latin-1 characters except for NEWLINE.  ISO PNG will forbid them.
+    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of
-    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
-    */
+    * any non-Latin-1 characters except for NEWLINE.  ISO PNG will forbid them.
-   png_write_chunk_data(png_ptr, (png_bytep)new_key,
-       (png_size_t)(key_len + 1));
+    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
     */
-   if (text_len)
+   png_write_chunk_data(png_ptr, new_key, key_len + 1);
       png_write_chunk_data(png_ptr, (png_const_bytep)text,
-          (png_size_t)text_len);
+   if (text_len)
+      png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len);
    png_write_chunk_end(png_ptr);
-   png_free(png_ptr, new_key);
+   png_write_chunk_end(png_ptr);
-}
-#endif
+}
-#ifdef PNG_WRITE_zTXt_SUPPORTED
+#endif
 /* Write a compressed text chunk */
-void /* PRIVATE */
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+/* Write a compressed text chunk */
-png_write_zTXt(png_structp png_ptr, png_const_charp key, png_const_charp text,
-    png_size_t text_len, int compression)
-{
-   PNG_zTXt;
-   png_size_t key_len;
-   png_byte buf;
-   png_charp new_key;
+void /* PRIVATE */
-   compression_state comp;
+png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
+    png_size_t text_len, int compression)
    png_debug(1, "in png_write_zTXt");
    png_uint_32 key_len;
-   comp.num_output_ptr = 0;
+   png_byte new_key[81];
-   comp.max_output_ptr = 0;
-   comp.output_ptr = NULL;
+   compression_state comp;
-   comp.input = NULL;
-   comp.input_len = 0;
-   if ((key_len = png_check_keyword(png_ptr, key, &new_key)) == 0)
-   {
+   png_debug(1, "in png_write_zTXt");
-      png_free(png_ptr, new_key);
+   PNG_UNUSED(text_len) /* Always use strlen */
-      return;
-   }
+   if (compression == PNG_TEXT_COMPRESSION_NONE)
-   if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)
+   {
-   {
+      png_write_tEXt(png_ptr, key, text, 0);
-      png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);
+      return;
-      png_free(png_ptr, new_key);
+   }
-      return;
+   if (compression != PNG_TEXT_COMPRESSION_zTXt)
-   }
+      png_error(png_ptr, "zTXt: invalid compression type");
+   key_len = png_check_keyword(png_ptr, key, new_key);
-   text_len = png_strlen(text);
    if (key_len == 0)
-   /* Compute the compressed data; do it now for the length */
+      png_error(png_ptr, "zTXt: invalid keyword");
    text_len = png_text_compress(png_ptr, text, text_len, compression,
 #ifdef PNG_WRITE_iTXt_SUPPORTED
 /* Write an iTXt chunk */
 void /* PRIVATE */
-png_write_iTXt(png_structp png_ptr, int compression, png_const_charp key,
+png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key,
     png_const_charp lang, png_const_charp lang_key, png_const_charp text)
+{
-   PNG_iTXt;
-   png_size_t lang_len, key_len, lang_key_len, text_len;
+   png_uint_32 key_len, prefix_len;
-   png_charp new_lang;
+   png_size_t lang_len, lang_key_len;
-   png_charp new_key = NULL;
-   png_byte cbuf[2];
+   png_byte new_key[82];
    compression_state comp;
-   png_debug(1, "in png_write_iTXt");
+   png_debug(1, "in png_write_iTXt");
-   comp.num_output_ptr = 0;
-   comp.max_output_ptr = 0;
-   comp.output_ptr = NULL;
-   comp.input = NULL;
+   key_len = png_check_keyword(png_ptr, key, new_key);
+   if (key_len == 0)
-   if ((key_len = png_check_keyword(png_ptr, key, &new_key)) == 0)
+      png_error(png_ptr, "iTXt: invalid keyword");
-      return;
-   if ((lang_len = png_check_keyword(png_ptr, lang, &new_lang)) == 0)
-   {
-      png_warning(png_ptr, "Empty language field in iTXt chunk");
-      new_lang = NULL;
-      lang_len = 0;
-   }
-   if (lang_key == NULL)
-      lang_key_len = 0;
-   else
-      lang_key_len = png_strlen(lang_key);
-   if (text == NULL)
+   /* Set the compression flag */
-      text_len = 0;
-   else
+   switch (compression)
-      text_len = png_strlen(text);
+   {
+      case PNG_ITXT_COMPRESSION_NONE:
+      case PNG_TEXT_COMPRESSION_NONE:
+         compression = new_key[++key_len] = 0; /* no compression */
+         break;
-   /* Compute the compressed data; do it now for the length */
+      case PNG_TEXT_COMPRESSION_zTXt:
-   text_len = png_text_compress(png_ptr, text, text_len, compression - 2,
+      case PNG_ITXT_COMPRESSION_zTXt:
-       &comp);
+         compression = new_key[++key_len] = 1; /* compressed */
+         break;
-   /* 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_iTXt, (png_uint_32)(
+      default:
-/* comp byte, comp flag, terminators for key, lang and lang_key */
+         png_error(png_ptr, "iTXt: invalid compression");
+   }
+   new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
-        + key_len
+   ++key_len; /* for the keywod separator */
+   /* We leave it to the application to meet PNG-1.0 requirements on the
-        + lang_len
+    * 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, however,
+    * specifies that the text is UTF-8 and this really doesn't require any
-        + lang_key_len
+    * checking.
+    *
+    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
-        + text_len));
+    *
+    * TODO: validate the language tag correctly (see the spec.)
+    */
+   if (lang == NULL) lang = ""; /* empty language is valid */
+   lang_len = strlen(lang)+1;
+   if (lang_key == NULL) lang_key = ""; /* may be empty */
-   /* We leave it to the application to meet PNG-1.0 requirements on the
+   lang_key_len = strlen(lang_key)+1;
-    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of
+   if (text == NULL) text = ""; /* may be empty */
+   prefix_len = key_len;
+   if (lang_len > PNG_UINT_31_MAX-prefix_len)
+      prefix_len = PNG_UINT_31_MAX;
+   else
+      prefix_len = (png_uint_32)(prefix_len + lang_len);
-    * any non-Latin-1 characters except for NEWLINE.  ISO PNG will forbid them.
+   if (lang_key_len > PNG_UINT_31_MAX-prefix_len)
-    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
+      prefix_len = PNG_UINT_31_MAX;
-    */
+   else
-   png_write_chunk_data(png_ptr, (png_bytep)new_key, (png_size_t)(key_len + 1));
+      prefix_len = (png_uint_32)(prefix_len + lang_key_len);
+   png_text_compress_init(&comp, (png_const_bytep)text, strlen(text));
+   if (compression)
+   {
+      if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK)
+         png_error(png_ptr, png_ptr->zstream.msg);
-   /* Set the compression flag */
-   if (compression == PNG_ITXT_COMPRESSION_NONE ||
+   }
-       compression == PNG_TEXT_COMPRESSION_NONE)
-      cbuf[0] = 0;
+   else
+   {
+      if (comp.input_len > PNG_UINT_31_MAX-prefix_len)
-   else /* compression == PNG_ITXT_COMPRESSION_zTXt */
+         png_error(png_ptr, "iTXt: uncompressed text too long");
-      cbuf[0] = 1;
+      /* So the string will fit in a chunk: */
+      comp.output_len = (png_uint_32)/*SAFE*/comp.input_len;
-   /* Set the compression method */
    cbuf[1] = 0;
-   png_write_chunk_data(png_ptr, cbuf, (png_size_t)2);
+   png_write_chunk_header(png_ptr, png_iTXt, comp.output_len + prefix_len);
-   cbuf[0] = 0;
+   png_write_chunk_data(png_ptr, new_key, key_len);
-   png_write_chunk_data(png_ptr, (new_lang ? (png_const_bytep)new_lang : cbuf),
-       (png_size_t)(lang_len + 1));
+   png_write_chunk_data(png_ptr, (png_const_bytep)lang, lang_len);
-   png_write_chunk_data(png_ptr, (lang_key ? (png_const_bytep)lang_key : cbuf),
-       (png_size_t)(lang_key_len + 1));
+   png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len);
-   png_write_compressed_data_out(png_ptr, &comp);
+   if (compression)
    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_oFFs, buf, (png_size_t)9);
+   png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);
+}
 #endif
 #ifdef 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_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0,
     png_int_32 X1, int type, int nparams, png_const_charp units,
     png_charpp params)
 {
-   PNG_pCAL;
+   png_uint_32 purpose_len;
-   png_size_t purpose_len, units_len, total_len;
+   png_size_t units_len, total_len;
-   png_uint_32p params_len;
+   png_size_tp params_len;
    png_byte buf[10];
-   png_charp new_purpose;
+   png_byte new_purpose[80];
    int i;
    png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
+   if (type >= PNG_EQUATION_LAST)
+      png_error(png_ptr, "Unrecognized equation type for pCAL chunk");
+   purpose_len = png_check_keyword(png_ptr, purpose, new_purpose);
+   if (purpose_len == 0)
-   if (type >= PNG_EQUATION_LAST)
+      png_error(png_ptr, "pCAL: invalid keyword");
-      png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
    ++purpose_len; /* terminator */
    purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1;
    png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);
-   units_len = png_strlen(units) + (nparams == 0 ? 0 : 1);
+   units_len = strlen(units) + (nparams == 0 ? 0 : 1);
    png_debug1(3, "pCAL units length = %d", (int)units_len);
    total_len = purpose_len + units_len + 10;
-   params_len = (png_uint_32p)png_malloc(png_ptr,
+   params_len = (png_size_tp)png_malloc(png_ptr,
-       (png_alloc_size_t)(nparams * png_sizeof(png_uint_32)));
+       (png_alloc_size_t)(nparams * (sizeof (png_size_t))));
    /* 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);
+      params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
       png_debug2(3, "pCAL parameter %d length = %lu", i,
-          (unsigned long)params_len[i]);
-      total_len += (png_size_t)params_len[i];
+          (unsigned long)params_len[i]);
       total_len += params_len[i];
+   }
    png_debug1(3, "pCAL total length = %d", (int)total_len);
-   png_write_chunk_start(png_ptr, png_pCAL, (png_uint_32)total_len);
+   png_debug1(3, "pCAL total length = %d", (int)total_len);
-   png_write_chunk_data(png_ptr, (png_const_bytep)new_purpose,
+   png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len);
-       (png_size_t)purpose_len);
-   png_save_int_32(buf, X0);
-   png_save_int_32(buf + 4, X1);
+   png_write_chunk_data(png_ptr, new_purpose, purpose_len);
-   buf[8] = (png_byte)type;
+   png_save_int_32(buf, X0);
-   buf[9] = (png_byte)nparams;
+   png_save_int_32(buf + 4, X1);
-   png_write_chunk_data(png_ptr, buf, (png_size_t)10);
-   png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len);
+   buf[8] = (png_byte)type;
    buf[9] = (png_byte)nparams;
-   png_free(png_ptr, new_purpose);
+   png_write_chunk_data(png_ptr, buf, (png_size_t)10);
    png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len);
    for (i = 0; i < nparams; i++)
    for (i = 0; i < nparams; i++)
       png_write_chunk_data(png_ptr, (png_const_bytep)params[i],
-          (png_size_t)params_len[i]);
+      png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]);
    }
    png_free(png_ptr, params_len);
-   png_write_chunk_end(png_ptr);
    png_write_chunk_end(png_ptr);
 #endif
 #endif
-#ifdef PNG_WRITE_sCAL_SUPPORTED
-/* Write the sCAL chunk */
+#ifdef PNG_WRITE_sCAL_SUPPORTED
-void /* PRIVATE */
+/* Write the sCAL chunk */
-png_write_sCAL_s(png_structp png_ptr, int unit, png_const_charp width,
+void /* PRIVATE */
-    png_const_charp height)
+png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width,
     png_const_charp height)
    PNG_sCAL;
    png_byte buf[64];
    png_size_t wlen, hlen, total_len;
    png_debug(1, "in png_write_sCAL_s");
-   wlen = png_strlen(width);
+   wlen = strlen(width);
-   hlen = png_strlen(height);
+   hlen = strlen(height);
    total_len = wlen + hlen + 2;
    if (total_len > 64)
+   {
       png_warning(png_ptr, "Can't write sCAL (buffer too small)");
       return;
+   }
-   buf[0] = (png_byte)unit;
-   png_memcpy(buf + 1, width, wlen + 1);      /* Append the '\0' here */
+   buf[0] = (png_byte)unit;
-   png_memcpy(buf + wlen + 2, height, hlen);  /* Do NOT append the '\0' here */
+   memcpy(buf + 1, width, wlen + 1);      /* Append the '\0' here */
    memcpy(buf + wlen + 2, height, hlen);  /* Do NOT append the '\0' here */
    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_pHYs, buf, (png_size_t)9);
+   png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);
+}
 #endif
 #ifdef 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_const_timep mod_time)
 png_write_tIME(png_structrp png_ptr, png_const_timep mod_time)
    PNG_tIME;
    png_byte buf[7];
    buf[4] = mod_time->hour;
    buf[5] = mod_time->minute;
    buf[6] = mod_time->second;
-   png_write_chunk(png_ptr, png_tIME, buf, (png_size_t)7);
+   png_write_complete_chunk(png_ptr, 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)
+png_write_start_row(png_structrp png_ptr)
+{
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
    /* 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};
+   static PNG_CONST png_byte 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};
+   static PNG_CONST png_byte 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};
+   static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
    /* Offset to next interlace block in the y direction */
+   static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
-   /* Offset to next interlace block in the y direction */
+#endif
+   png_alloc_size_t buf_size;
-   int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+   int usr_pixel_depth;
-#endif
+   png_debug(1, "in png_write_start_row");
-   png_size_t buf_size;
    usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
-   png_debug(1, "in png_write_start_row");
+   buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1;
    /* 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_calloc(png_ptr,
+      png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size);
-          (png_alloc_size_t)buf_size);
       if (png_ptr->do_filter & PNG_FILTER_UP)
+      {
          png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
+   {
       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)
+png_write_finish_row(png_structrp png_ptr)
+{
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
    /* 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};
+   static PNG_CONST png_byte 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};
+   static PNG_CONST png_byte 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};
+   static PNG_CONST png_byte 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
+   /* Offset to next interlace block in the y direction */
    static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
       /* 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,
+            memset(png_ptr->prev_row, 0,
                 (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
                 png_ptr->usr_bit_depth, png_ptr->width)) + 1);
          return;
+      }
+   }
 #endif
-   /* If we get here, we've just written the last row, so we need
-      to flush the compressor */
-   do
-   {
+   /* If we get here, we've just written the last row, so we need
-      /* 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);
+      to flush the compressor */
-   png_ptr->zstream.data_type = Z_BINARY;
+   png_compress_IDAT(png_ptr, NULL, 0, Z_FINISH);
+}
+{
    /* 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};
+   static PNG_CONST png_byte 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};
+   static PNG_CONST png_byte  png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
    png_debug(1, "in png_do_write_interlace");
                sp = row + (png_size_t)i * pixel_bytes;
                /* Move the pixel */
                if (dp != sp)
-                  png_memcpy(dp, sp, pixel_bytes);
+                  memcpy(dp, sp, pixel_bytes);
                /* Next pixel */
                dp += pixel_bytes;
+            }
 /* 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.
  */
+static void png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
+   png_size_t row_bytes);
 #define PNG_MAXSUM (((png_uint_32)(-1)) >> 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_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
+{
    png_bytep best_row;
 #ifdef PNG_WRITE_FILTER_SUPPORTED
    png_bytep prev_row, row_buf;
    png_uint_32 mins, bpp;
    png_byte filter_to_do = png_ptr->do_filter;
    png_size_t row_bytes = row_info->rowbytes;
 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-   int num_p_filters = (int)png_ptr->num_prev_filters;
+   int num_p_filters = png_ptr->num_prev_filters;
 #endif
    png_debug(1, "in png_write_find_filter");
          best_row = png_ptr->paeth_row;
+      }
+   }
 #endif /* PNG_WRITE_FILTER_SUPPORTED */
    /* Do the actual writing of the filtered row data from the chosen filter. */
+   /* Do the actual writing of the filtered row data from the chosen filter. */
-   png_write_filtered_row(png_ptr, best_row);
+   png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
 #ifdef PNG_WRITE_FILTER_SUPPORTED
 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
    /* Save the type of filter we picked this time for future calculations */
+}
 /* Do the actual writing of a previously filtered row. */
-void /* PRIVATE */
+static void
+png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
-png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
+   png_size_t full_row_length/*includes filter byte*/)
-{
-   png_size_t avail;
+{
    png_debug(1, "in png_write_filtered_row");
-   png_debug1(2, "filter = %d", filtered_row[0]);
-   /* Set up the zlib input buffer */
-   png_ptr->zstream.next_in = filtered_row;
-   png_ptr->zstream.avail_in = 0;
-   avail = png_ptr->row_info.rowbytes + 1;
-   /* Repeat until we have compressed all the data */
-   do
-   {
-      int ret; /* Return of zlib */
-      /* Record the number of bytes available - zlib supports at least 65535
-       * bytes at one step, depending on the size of the zlib type 'uInt', the
-       * maximum size zlib can write at once is ZLIB_IO_MAX (from pngpriv.h).
-       * Use this because on 16 bit systems 'rowbytes' can be up to 65536 (i.e.
-       * one more than 16 bits) and, in this case 'rowbytes+1' can overflow a
-       * uInt.  ZLIB_IO_MAX can be safely reduced to cause zlib to be called
-       * with smaller chunks of data.
-       */
-      if (png_ptr->zstream.avail_in == 0)
-      {
-         if (avail > ZLIB_IO_MAX)
-         {
-            png_ptr->zstream.avail_in  = ZLIB_IO_MAX;
-            avail -= ZLIB_IO_MAX;
-         }
-         else
-         {
-            /* So this will fit in the available uInt space: */
-            png_ptr->zstream.avail_in = (uInt)avail;
-            avail = 0;
-         }
-      }
-      /* 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;
    png_debug1(2, "filter = %d", filtered_row[0]);
    /* Repeat until all data has been compressed */
-   } while (avail > 0 || png_ptr->zstream.avail_in > 0);
+   png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH);

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(root)/programs/develop/libraries/libpng/pngwutil.c – Rev 1897 → 3928