[libpng16] Added configuration support for benign errors and changed the read
default. Also changed some warnings in the iCCP and sRGB handling
from to benign errors. Configuration now makes read benign
errors warnings and write benign errors to errors by default (thus
changing the behavior on read). The simplified API always forces
read benign errors to errors (regardless of the system default, unless
this is disabled in which case the simplified API can't be built.)
diff --git a/ANNOUNCE b/ANNOUNCE
index faa48cd..5c37932 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -310,6 +310,13 @@
this is necessary because the VS2010 output window otherwise simply loses
the error messages on error (they weren't flushed to the window before
the process exited, apparently!)
+ Added configuration support for benign errors and changed the read
+ default. Also changed some warnings in the iCCP and sRGB handling
+ from to benign errors. Configuration now makes read benign
+ errors warnings and write benign errors to errors by default (thus
+ changing the behavior on read). The simplified API always forces
+ read errors to benign errors (regardless of the system default, unless
+ this is disabled in which case the simplified API can't be built.)
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diff --git a/CHANGES b/CHANGES
index 40cebb7..5dec7bd 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4061,6 +4061,13 @@
this is necessary because the VS2010 output window otherwise simply loses
the error messages on error (they weren't flushed to the window before
the process exited, apparently!)
+ Added configuration support for benign errors and changed the read
+ default. Also changed some warnings in the iCCP and sRGB handling
+ from to benign errors. Configuration now makes read benign
+ errors warnings and write benign errors to errors by default (thus
+ changing the behavior on read). The simplified API always forces
+ read errors to benign errors (regardless of the system default, unless
+ this is disabled in which case the simplified API can't be built.)
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diff --git a/pngread.c b/pngread.c
index 36e02d5..4601f8e 100644
--- a/pngread.c
+++ b/pngread.c
@@ -50,12 +50,17 @@
{
png_ptr->mode = PNG_IS_READ_STRUCT;
- /* Adding in libpng-1.6.0; this can be used to detect a read structure if
+ /* Added in libpng-1.6.0; this can be used to detect a read structure if
* required (it will be zero in a write structure.)
*/
# ifdef PNG_SEQUENTIAL_READ_SUPPORTED
png_ptr->IDAT_read_size = PNG_IDAT_READ_SIZE;
# endif
+
+# ifdef PNG_BENIGN_READ_ERRORS_SUPPORTED
+ png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
+# endif
+
/* TODO: delay this, it can be done in png_init_io (if the app doesn't
* do it itself) avoiding setting the default function if it is not
* required.
@@ -1085,6 +1090,7 @@
/* Arguments to png_image_finish_read: */
/* Encoding of PNG data (used by the color-map code) */
+/* TODO: change these, dang, ANSI-C reserves the 'E' namespace. */
# define E_NOTSET 0 /* File encoding not yet known */
# define E_sRGB 1 /* 8-bit encoded to sRGB gamma */
# define E_LINEAR 2 /* 16-bit linear: not encoded, NOT pre-multiplied! */
@@ -1237,6 +1243,7 @@
png_structrp png_ptr = image->opaque->png_ptr;
png_inforp info_ptr = image->opaque->info_ptr;
+ png_set_benign_errors(png_ptr, 1/*warn*/);
png_read_info(png_ptr, info_ptr);
/* Do this the fast way; just read directly out of png_struct. */
diff --git a/pngrutil.c b/pngrutil.c
index 981a1bb..6d7eec4 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -1297,31 +1297,33 @@
png_debug(1, "in png_handle_sRGB");
+ if (png_ptr->mode & PNG_HAVE_iCCP)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "duplicate color profile");
+ return;
+ }
+
+ png_ptr->mode |= PNG_HAVE_iCCP; /* well, a colorspace */
+
if (!(png_ptr->mode & PNG_HAVE_IHDR))
- png_error(png_ptr, "Missing IHDR before sRGB");
+ png_error(png_ptr, "missing IHDR");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
- png_warning(png_ptr, "Invalid sRGB after IDAT");
png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid after IDAT");
return;
}
else if (png_ptr->mode & PNG_HAVE_PLTE)
/* Should be an error, but we can cope with it */
- png_warning(png_ptr, "Out of place sRGB chunk");
-
- if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB))
- {
- png_warning(png_ptr, "Duplicate sRGB chunk");
- png_crc_finish(png_ptr, length);
- return;
- }
+ png_chunk_benign_error(png_ptr, "out of place");
if (length != 1)
{
- png_warning(png_ptr, "Incorrect sRGB chunk length");
png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "incorrect length");
return;
}
@@ -1419,7 +1421,7 @@
#ifdef PNG_READ_iCCP_SUPPORTED
void /* PRIVATE */
png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
-/* Note: this does not properly handle chunks that are > 64K under DOS */
+/* Note: this does not properly handle profiles that are > 64K under DOS */
{
png_uint_32 keyword_length;
png_const_charp error_message = NULL;
@@ -1427,13 +1429,23 @@
png_debug(1, "in png_handle_iCCP");
+ /* Do this first to set the 'HAVE_iCCP' flag in all cases, even errors */
+ if (png_ptr->mode & PNG_HAVE_iCCP)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "duplicate color profile");
+ return;
+ }
+
+ png_ptr->mode |= PNG_HAVE_iCCP;
+
if (!(png_ptr->mode & PNG_HAVE_IHDR))
- png_error(png_ptr, "Missing IHDR before iCCP");
+ png_error(png_ptr, "missing IHDR");
else if (png_ptr->mode & PNG_HAVE_IDAT)
{
png_crc_finish(png_ptr, length);
- png_chunk_benign_error(png_ptr, "Invalid iCCP after IDAT");
+ png_chunk_benign_error(png_ptr, "invalid after IDAT");
return;
}
@@ -1443,19 +1455,22 @@
* *have* to do so, so it is misleading if libpng handles them.
*/
png_crc_finish(png_ptr, length);
- png_chunk_benign_error(png_ptr, "Out of place iCCP chunk");
+ png_chunk_benign_error(png_ptr, "out of place");
return;
}
- if ((png_ptr->mode & PNG_HAVE_iCCP) || (info_ptr != NULL &&
- (info_ptr->valid & (PNG_INFO_iCCP|PNG_INFO_sRGB))))
+ else if (length < 132) /* minimum ICC profile size */
{
png_crc_finish(png_ptr, length);
- png_chunk_benign_error(png_ptr, "Duplicate color profile");
+ png_chunk_benign_error(png_ptr, "too short");
return;
}
- png_ptr->mode |= PNG_HAVE_iCCP;
+ /* Now read the first 132 bytes. The largest LZ data requirement for 132
+ * bytes of input is infinite; by doing really foolish things with the SYNC
+ * options to deflate it is possible to extend 132 bytes without limit.
+ */
+ /**** WIP ****/
/* TODO: read the chunk in pieces, validating it as we go. */
buffer = png_read_buffer(png_ptr, length, 0/*!warn*/);
diff --git a/pngwrite.c b/pngwrite.c
index 7f213c9..8b3ed06 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -491,6 +491,15 @@
png_ptr->zlib_text_method = 8;
#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
+ /* This is a highly dubious configuration option; by default it is off, but
+ * it may be appropriate for private builds that are testing extensions not
+ * conformant to the current specification, or of applications that must not
+ * fail to write at all costs!
+ */
+# ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
+ png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
+# endif
+
if (png_ptr != NULL)
{
/* TODO: delay this, it can be done in png_init_io() (if the app doesn't
@@ -1982,6 +1991,11 @@
int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA) != 0;
int write_16bit = linear && !colormap && !display->convert_to_8bit;
+# ifdef PNG_BENIGN_ERRORS_SUPPORTED
+ /* Make sure we error out on any bad situation */
+ png_set_benign_errors(png_ptr, 0/*error*/);
+# endif
+
/* Default the 'row_stride' parameter if required. */
if (display->row_stride == 0)
display->row_stride = PNG_IMAGE_ROW_STRIDE(*image);
diff --git a/scripts/pnglibconf.dfa b/scripts/pnglibconf.dfa
index cc8e786..9714977 100644
--- a/scripts/pnglibconf.dfa
+++ b/scripts/pnglibconf.dfa
@@ -186,10 +186,36 @@
option WRITE_INT_FUNCTIONS disabled
option WRITE enables WRITE_INT_FUNCTIONS
-# Generic options - affect both read and write.
+# Error controls
+#
+# WARNINGS: normally on, if off no warnings are generated
+# ERROR_TEXT: normally on, if off errors happen but there is no message
+# ERROR_NUMBERS: unimplemented feature, therefore disabled
+# BENIGN_ERRORS: support for just issuing warnings for recoverable errors
+#
+# BENIGN_READ_ERRORS:
+# By default recoverable errors on read should just generate warnings,
+# generally safe but PNG files that don't conform to the specification will
+# be accepted if a meaningful result can be produced.
+#
+# BENIGN_WRITE_ERRORS:
+# By default recoverable errors on write should just generate warnings,
+# not generally safe because this allows the application to write invalid
+# PNG files. Applications should enable this themselves; it's useful
+# because it means that a failure to write an ancilliary chunk can often be
+# ignored.
option WARNINGS
+option ERROR_TEXT
+option ERROR_NUMBERS disabled
+
option BENIGN_ERRORS
+option BENIGN_WRITE_ERRORS requires BENIGN_ERRORS disabled
+option BENIGN_READ_ERRORS requires BENIGN_ERRORS
+
+
+# Generic options - affect both read and write.
+
option MNG_FEATURES
# Arithmetic options, the first is the big switch that chooses between internal
@@ -200,10 +226,6 @@
option FLOATING_POINT enables ok_math
option FIXED_POINT enables ok_math
-# Added at libpng version 1.4.0
-
-option ERROR_TEXT
-
# The following is always on (defined empty)
setting CALLOC_SUPPORTED default
@@ -230,10 +252,6 @@
option SETJMP
= NO_SETJMP SETJMP_NOT_SUPPORTED
-# For the moment this is disabled (no code support):
-
-option ERROR_NUMBERS disabled
-
# If this is disabled it is not possible for apps to get the
# values from the 'info' structure, this effectively removes
# quite a lot of the READ API.
@@ -622,6 +640,7 @@
# Simplified API options (added at libpng-1.6.0)
# Read:
option SIMPLIFIED_READ requires SEQUENTIAL_READ READ_TRANSFORMS SETJMP
+option SIMPLIFIED_READ requires BENIGN_ERRORS
option SIMPLIFIED_READ enables READ_EXPAND READ_16BIT READ_EXPAND_16
option SIMPLIFIED_READ enables READ_SCALE_16_TO_8 READ_RGB_TO_GRAY
option SIMPLIFIED_READ enables READ_ALPHA_MODE READ_BACKGROUND READ_STRIP_ALPHA
diff --git a/scripts/pnglibconf.h.prebuilt b/scripts/pnglibconf.h.prebuilt
index 07505ff..b7ac983 100644
--- a/scripts/pnglibconf.h.prebuilt
+++ b/scripts/pnglibconf.h.prebuilt
@@ -3,7 +3,7 @@
/* pnglibconf.h - library build configuration */
-/* Libpng 1.6.0beta18 - March 10, 2012 */
+/* Libpng 1.6.0beta18 - March 16, 2012 */
/* Copyright (c) 1998-2012 Glenn Randers-Pehrson */
@@ -40,6 +40,8 @@
#define PNG_16BIT_SUPPORTED
#define PNG_ALIGN_MEMORY_SUPPORTED
#define PNG_BENIGN_ERRORS_SUPPORTED
+#define PNG_BENIGN_READ_ERRORS_SUPPORTED
+/*#undef PNG_BENIGN_WRITE_ERRORS_SUPPORTED*/
#define PNG_bKGD_SUPPORTED
#define PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
#define PNG_CHECK_cHRM_SUPPORTED
@@ -120,6 +122,7 @@
#define PNG_READ_USER_CHUNKS_SUPPORTED
#define PNG_READ_USER_TRANSFORM_SUPPORTED
#define PNG_READ_zTXt_SUPPORTED
+/*#undef PNG_SAFE_LIMITS_SUPPORTED*/
#define PNG_SAVE_INT_32_SUPPORTED
#define PNG_sBIT_SUPPORTED
#define PNG_sCAL_SUPPORTED
