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https://git.code.sf.net/p/libpng/code.git
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[libpng16] Recognize known sRGB ICC profiles while reading; prefer writing the
iCCP profile over writing the sRGB chunk, controlled by the
PNG_sRGB_PROFILE_CHECKS option.
This commit is contained in:
John Bowler
committed by
Glenn Randers-Pehrson
Glenn Randers-Pehrson
parent
23a30f8583
commit
921648a997
189
pngrutil.c
189
pngrutil.c
@@ -338,7 +338,7 @@ png_inflate_claim(png_structrp png_ptr, png_uint_32 owner, int window_bits)
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* are minimal.
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*/
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(void)png_safecat(msg, sizeof msg, 4, " using zstream");
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# if PNG_LIBPNG_BUILD_BASE_TYPE == PNG_LIBPNG_BUILD_STABLE
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# if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
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png_chunk_warning(png_ptr, msg);
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png_ptr->zowner = 0;
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# else
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@@ -1314,72 +1314,12 @@ png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
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#endif /* PNG_READ_sRGB_SUPPORTED */
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#ifdef PNG_READ_iCCP_SUPPORTED
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#ifdef PNG_WARN_IF_iCCP_IS_sRGB_SUPPORTED
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int /* PRIVATE */
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png_compare_ICC_profile_with_sRGB(png_structrp png_ptr, png_bytep profile,
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png_uint_32 length)
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{
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/* See if it's a known sRGB profile. If it is, return intent;
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* if not, return -1.
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*/
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int
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icheck;
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/* Known sRGB profiles:
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* 0: not a known sRGB profile
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* 1: HP-Microsoft sRGB v2 perceptual
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* 2: ICC sRGB v4 perceptual
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* 3: ICC sRGB v2 perceptual
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* no black-compensation
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*/
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typedef struct png_sRGB_check_struct
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{
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uLong crc;
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uLong adler;
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png_uint_32 check_len;
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int intent;
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} png_sRGB_check;
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png_sRGB_check check[3] =
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{
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{ 0xf29e526dUL, 0x0398f3fcUL, 3144UL, 0 },
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{ 0xbbef7812UL, 0x209c35d2UL, 60960UL, 0 },
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{ 0x427ebb21UL, 0x4909e5e1UL, 3052UL, 0 }
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};
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if (png_ptr == NULL)
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return -1;
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for (icheck = 2; icheck >= 0; icheck--)
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{
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if (length == check[icheck].check_len)
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{
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uLong profile_adler = adler32(1, profile, length);
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if (profile_adler == (uLong) check[icheck].adler)
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{
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uLong profile_crc = crc32(0, profile, length);
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if (profile_crc == (uLong) check[icheck].crc)
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return check[icheck].intent;
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else
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return -1;
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}
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}
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}
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return -1;
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}
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#endif
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void /* PRIVATE */
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png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
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/* Note: this does not properly handle profiles that are > 64K under DOS */
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{
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png_const_charp errmsg;
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png_const_charp errmsg = NULL; /* error message output, or no error */
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int finished = 0; /* crc checked */
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png_debug(1, "in png_handle_iCCP");
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@@ -1452,14 +1392,13 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
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if (png_inflate_claim(png_ptr, png_iCCP,
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png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN ? 15 : 0) == Z_OK)
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{
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int ret;
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Byte profile_header[132];
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Byte local_buffer[PNG_INFLATE_BUF_SIZE];
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png_alloc_size_t size = sizeof profile_header;
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png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2);
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png_ptr->zstream.avail_in = read_length;
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ret = png_inflate_read(png_ptr, local_buffer,
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(void)png_inflate_read(png_ptr, local_buffer,
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sizeof local_buffer, &length, profile_header, &size,
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0/*finish: don't, because the output is too small*/);
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@@ -1470,8 +1409,6 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
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const png_uint_32 profile_length =
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png_get_uint_32(profile_header);
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errmsg = NULL; /* flag to say error message output */
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if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
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keyword, profile_length))
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{
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@@ -1498,10 +1435,13 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
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size = 12 * tag_count;
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ret = png_inflate_read(png_ptr, local_buffer,
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(void)png_inflate_read(png_ptr, local_buffer,
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sizeof local_buffer, &length,
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profile + (sizeof profile_header), &size, 0);
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/* Still expect a a buffer error because we expect
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* there to be some tag data!
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*/
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if (size == 0)
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{
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if (png_icc_check_tag_table(png_ptr,
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@@ -1514,53 +1454,43 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
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size = profile_length - (sizeof profile_header)
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- 12 * tag_count;
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ret = png_inflate_read(png_ptr, local_buffer,
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(void)png_inflate_read(png_ptr, local_buffer,
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sizeof local_buffer, &length,
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profile + (sizeof profile_header) +
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12 * tag_count, &size, 1/*finish*/);
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if (size == 0)
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if (length > 0 && !(png_ptr->flags &
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PNG_FLAG_BENIGN_ERRORS_WARN))
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errmsg = "extra compressed data";
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/* But otherwise allow extra data: */
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else if (size == 0)
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{
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#ifdef PNG_WARN_IF_iCCP_IS_sRGB_SUPPORTED
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int
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intent;
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#endif
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int ok;
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if (ret != Z_STREAM_END)
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png_chunk_warning(png_ptr,
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png_ptr->zstream.msg);
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else if (length > 0)
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if (length > 0)
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{
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/* This can be handled completely, so
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* keep going.
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*/
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png_chunk_warning(png_ptr,
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"extra compressed data");
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}
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/* But, because we got the whole profile,
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* assume it is ok.
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png_crc_finish(png_ptr, length);
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finished = 1;
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/* Set the gAMA and cHRM information, this
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* checks for a known sRGB profile. The
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* result is 0 on error.
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*/
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png_ptr->zowner = 0;
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/* Yet the CRC should still be correct */
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if (png_crc_finish(png_ptr, length))
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return;
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#ifdef PNG_WARN_IF_iCCP_IS_sRGB_SUPPORTED
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/* See if it's a known sRGB profile. */
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intent =
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png_compare_ICC_profile_with_sRGB(
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png_ptr, profile, profile_length);
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if (intent >= 0)
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png_chunk_warning(png_ptr,
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"describes sRGB\n");
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#endif
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/* Set the gAMA and cHRM information */
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png_icc_set_gAMA_and_cHRM(png_ptr,
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ok = png_icc_set_gAMA_and_cHRM(png_ptr,
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&png_ptr->colorspace, keyword, profile,
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png_ptr->zstream.adler,
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0/*prefer explicit gAMA/cHRM*/);
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/* Steal the profile for info_ptr. */
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if (info_ptr != NULL)
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if (ok && info_ptr != NULL)
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{
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png_free_data(png_ptr, info_ptr,
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PNG_FREE_ICCP, 0);
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@@ -1568,33 +1498,50 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
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info_ptr->iccp_name = png_voidcast(char*,
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png_malloc_base(png_ptr,
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keyword_length+1));
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if (info_ptr->iccp_name == NULL)
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if (info_ptr->iccp_name != NULL)
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{
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memcpy(info_ptr->iccp_name, keyword,
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keyword_length+1);
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info_ptr->iccp_proflen =
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profile_length;
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info_ptr->iccp_profile = profile;
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png_ptr->read_buffer = NULL; /*steal*/
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info_ptr->free_me |= PNG_FREE_ICCP;
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info_ptr->valid |= PNG_INFO_iCCP;
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}
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else
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{
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png_ptr->colorspace.flags |=
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PNG_COLORSPACE_INVALID;
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png_colorspace_sync(png_ptr,
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info_ptr);
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png_chunk_benign_error(png_ptr,
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"out of memory");
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return;
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errmsg = "out of memory";
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}
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memcpy(info_ptr->iccp_name, keyword,
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keyword_length+1);
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info_ptr->iccp_proflen = profile_length;
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info_ptr->iccp_profile = profile;
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png_ptr->read_buffer = NULL; /*steal*/
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info_ptr->free_me |= PNG_FREE_ICCP;
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info_ptr->valid |= PNG_INFO_iCCP;
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png_colorspace_sync(png_ptr, info_ptr);
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}
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return;
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/* else the profile remains in the read
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* buffer which gets reused for subsequent
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* chunks.
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*/
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if (info_ptr != NULL)
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png_colorspace_sync(png_ptr, info_ptr);
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if (errmsg == NULL && ok)
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{
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png_ptr->zowner = 0;
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return;
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}
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/* else png_icc_set_gAMA_and_cHRM has
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* already output an error.
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*/
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}
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else
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else if (size > 0)
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errmsg = "truncated";
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else
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errmsg = png_ptr->zstream.msg;
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}
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/* else png_icc_check_tag_table output an error */
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@@ -1637,7 +1584,9 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
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errmsg = "too many profiles";
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/* Failure: the reason is in 'errmsg' */
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png_crc_finish(png_ptr, length);
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if (!finished)
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png_crc_finish(png_ptr, length);
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png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
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png_colorspace_sync(png_ptr, info_ptr);
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if (errmsg != NULL) /* else already output */
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