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API reduction, PNG compression level

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PNG compression level setting API: this allows the various compression settings
controlling deflate, fitlering, and so on to be set via a single setting with
six values.  This is currently documented in png.h ("Write compression
settings").

Internally the compression settings have been tuned both for the overall setting
and for any specific settings made by the original APIs.

APIs to control iCCP chunk compression separately have been added.

contrib/examples/pngcp.c has been modified to accomodate the new compression
setting and to include options for separate control of iCCP chunk compression.

The new ABI, png_setting, has been modified to accomodate a wider range of
settings and most of the old compression control ABIs have been replaced by
function-like macros with the same API which call png_setting.  This is an API
check in 1.7.0 for png_setting (alone).  png_setting now handles all of
png_set_option.  This eliminates 19 ABIs at the cost of adding 1 (png_setting).

CRC and benign error checking has been updated internally to use bit-fields and
the CRC calculation skip when the CRC is not used has been improved slightly to
avoid the initialization of the CRC.  A new png_setting based API allows more
detailed control of benign error/warning messages (this may change, the internal
error handling seems too complex.)  The ERROR_NUMBERS support has been removed
with the intent of implementing proper i18n.

The memcpy-size-0 issue in png_push_fill_buffer has been fixed, with an
appropriate debug() assert if a fill for 0 bytes occurs.

Most PNG_FLAG_ values for png_struct::flags have been eliminated (as a result of
the benign error handling changes).  Only one remains.

Signed-off-by: John Bowler <jbowler@acm.org>
This commit is contained in:
John Bowler
2016-06-07 06:48:52 -07:00
parent 120f80369b
commit 01ff090760
18 changed files with 1623 additions and 1086 deletions
Download Patch File Download Diff File Expand all files Collapse all files

219
png.c
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@@ -100,10 +100,26 @@ png_zfree(voidpf png_ptr, voidpf ptr)
* in case CRC is > 32 bits to leave the top bits 0.
*/
void /* PRIVATE */
png_reset_crc(png_structrp png_ptr)
png_reset_crc(png_structrp png_ptr, png_const_bytep chunk_tag)
{
/* The cast is safe because the crc is a 32 bit value. */
png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0);
# ifdef PNG_READ_SUPPORTED
if (png_ptr->read_struct)
{
/* Set png_struct::current_crc appropriately. */
if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))
png_ptr->current_crc = png_ptr->ancillary_crc;
else /* critical */
png_ptr->current_crc = png_ptr->critical_crc;
}
else
png_ptr->current_crc = crc_error_quit; /* for write */
/* Now do not calculate the CRC if it isn't required: */
if (png_ptr->current_crc != crc_quiet_use)
# endif /* READ */
png_ptr->crc = 0xFFFFFFFFU & crc32(0, chunk_tag, 4);
}
/* Calculate the CRC over a section of data. We can only pass as
@@ -114,27 +130,15 @@ png_reset_crc(png_structrp png_ptr)
void /* PRIVATE */
png_calculate_crc(png_structrp png_ptr, png_const_voidp ptr, png_size_t length)
{
int need_crc = 1;
if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
{
if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
(PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
need_crc = 0;
}
else /* critical */
{
if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
need_crc = 0;
}
/* 'uLong' is defined in zlib.h as unsigned long; this means that on some
* systems it is a 64 bit value. crc32, however, returns 32 bits so the
* following cast is safe. 'uInt' may be no more than 16 bits, so it is
* necessary to perform a loop here.
*/
if (need_crc != 0 && length > 0)
# ifdef PNG_READ_SUPPORTED
if (png_ptr->current_crc != crc_quiet_use)
# endif /* READ */
if (length > 0)
{
uLong crc = png_ptr->crc; /* Should never issue a warning */
const Bytef* rptr = png_voidcast(const Bytef*,ptr);
@@ -213,11 +217,6 @@ png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver)
png_warning(png_ptr, m);
#endif
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
png_ptr->flags = 0;
#endif
return 0;
}
@@ -2192,13 +2191,12 @@ png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
#endif
unsigned int i;
#ifdef PNG_SET_OPTION_SUPPORTED
/* First see if PNG_SKIP_sRGB_CHECK_PROFILE has been set to "on" */
if (((png_ptr->options >> PNG_SKIP_sRGB_CHECK_PROFILE) & 3) ==
PNG_OPTION_ON)
return 0;
#endif
# ifdef PNG_SET_OPTION_SUPPORTED
# ifdef PNG_SKIP_sRGB_CHECK_PROFILE
/* First see if PNG_SKIP_sRGB_CHECK_PROFILE has been set to "on" */
if (!png_ptr->skip_sRGB_profile_check)
# endif /* SKIP_sRGB_CHECK_PROFILE */
# endif /* SET_OPTION */
for (i=0; i < (sizeof png_sRGB_checks) / (sizeof png_sRGB_checks[0]); ++i)
{
if (png_get_uint_32(profile+84) == png_sRGB_checks[i].md5[0] &&
@@ -3355,67 +3353,128 @@ png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
}
#endif /* GAMMA || INCH_CONVERSIONS */
/* HARDWARE OPTION SUPPORT */
#ifdef PNG_SET_OPTION_SUPPORTED
int PNGAPI
png_set_option(png_structrp png_ptr, int option, int onoff)
{
if (png_ptr != NULL && option >= 0 && option < PNG_OPTION_NEXT &&
(option & 1) == 0)
{
unsigned int mask = 3U << option;
unsigned int setting = (2U + (onoff != 0)) << option;
unsigned int current = png_ptr->options;
png_ptr->options = (current & ~mask) | setting;
return (current & mask) >> option;
}
return PNG_OPTION_INVALID;
}
#endif /* SET_OPTION */
/* SOFTWARE SETTING SUPPORT */
#ifdef PNG_SETTING_SUPPORTED
png_int_32 PNGAPI
png_setting(png_structrp png_ptr, int setting, png_int_32 value)
png_setting(png_structrp png_ptr, png_uint_32 setting, png_uint_32 parameter,
png_int_32 value)
{
switch (setting)
png_int_32 result;
if (png_ptr != NULL)
{
# ifdef PNG_READ_GAMMA_SUPPORTED
case PNG_GAMMA_MINIMUM:
if (value < 0 || value > 0xFFFF)
value = PNG_GAMMA_THRESHOLD_FIXED;
int handle_error = (setting & PNG_SF_ERROR) != 0U;
setting &= ~PNG_SF_ERROR; /* because it is handled below. */
switch (setting & (PNG_SF_READ|PNG_SF_WRITE))
{
# ifdef PNG_READ_SUPPORTED
case PNG_SF_READ:
if (png_ptr->read_struct)
result = png_read_setting(png_ptr, setting, parameter, value);
else
result = PNG_EINVAL; /* read setting on write struct */
break;
# endif /* READ */
# ifdef PNG_WRITE_SUPPORTED
case PNG_SF_WRITE:
if (!png_ptr->read_struct)
result = png_write_setting(png_ptr, setting, parameter,
value);
else
result = PNG_EINVAL; /* write setting on read struct */
break;
# endif /* WRITE */
default:
/* Handle everything else here. This includes the error of not
* having either read or write set; that error will cause a
* PNG_ENOSYS return code.
*/
switch (setting)
{
png_int_32 old = png_ptr->gamma_threshold;
png_ptr->gamma_threshold = PNG_UINT_16(value);
return old;
# ifdef PNG_SET_OPTION_SUPPORTED
case PNG_SRW_OPTION:
if (parameter >= PNG_OPTION_NEXT)
return PNG_OPTION_INVALID;
if (parameter == PNG_SKIP_sRGB_CHECK_PROFILE)
{
if (png_ptr->skip_sRGB_profile_check)
{
if (!value)
png_ptr->skip_sRGB_profile_check = 0U;
result = PNG_OPTION_ON;
}
else
{
if (value)
png_ptr->skip_sRGB_profile_check = 1U;
result = PNG_OPTION_OFF;
}
break;
}
# ifdef PNG_READ_SUPPORTED
if (png_ptr->read_struct)
{
result = png_read_setting(png_ptr, setting,
parameter, value);
break;
}
# endif /* READ */
/* No write options at present */
result = PNG_OPTION_UNSET; /* i.e. ignore it */
# endif /* SET_OPTION */
default:
/* Any other option; handle in the appropriate setting: */
# ifdef PNG_READ_SUPPORTED
if (png_ptr->read_struct)
{
result = png_read_setting(png_ptr, setting,
parameter, value);
break;
}
# endif /* READ */
# ifdef PNG_WRITE_SUPPORTED
if (!png_ptr->read_struct)
{
result = png_write_setting(png_ptr, setting,
parameter, value);
break;
}
# endif /* WRITE */
NOT_REACHED;
result= PNG_ENOSYS;
break;
}
break;
} /* switch */
#if 0 /*NYI*/
case PNG_GAMMA_ACCURACY:
if (value < 0 || value > 1600)
value = PNG_DEFAULT_GAMMA_ACCURACY;
{
png_int_32 old = png_ptr->gamma_accuracy;
png_ptr->gamma_accuracy = value;
return old;
}
break;
#endif /*NYI*/
# endif /* READ_GAMMA */
default:
break;
/* Handle error returns here.
* TODO: this is crude, should use a formatted warning style message and
* output result/setting/parameter/value.
*/
if (handle_error && PNG_FAILED(result))
png_error(png_ptr, "png_setting");
}
PNG_UNUSED(png_ptr)
else /* png_ptr is NULL */
result = PNG_EINVAL;
return result;
PNG_UNUSED(parameter)
PNG_UNUSED(value)
return PNG_UNSUPPORTED_SETTING;
}
#endif /* SETTING */
/* sRGB support */
#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\