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| author | Vadim Dashevskiy <watcherhd@gmail.com> | 2012-10-12 10:49:29 +0000 |
|---|---|---|
| committer | Vadim Dashevskiy <watcherhd@gmail.com> | 2012-10-12 10:49:29 +0000 |
| commit | 557f2816f5cd30705dec989c97a8a67c026d36d1 (patch) | |
| tree | 4900789ab5d52219bf065744a61f9ea5863b3428 /plugins/FreeImage/src/LibPNG/Y2KINFO | |
| parent | 69fe21d6e2262d6fb2b14278b7a20364468cbdcf (diff) | |
FreeImage: folders restructurization
git-svn-id: http://svn.miranda-ng.org/main/trunk@1884 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c
Diffstat (limited to 'plugins/FreeImage/src/LibPNG/Y2KINFO')
| -rw-r--r-- | plugins/FreeImage/src/LibPNG/Y2KINFO | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/plugins/FreeImage/src/LibPNG/Y2KINFO b/plugins/FreeImage/src/LibPNG/Y2KINFO new file mode 100644 index 0000000000..7776d83732 --- /dev/null +++ b/plugins/FreeImage/src/LibPNG/Y2KINFO @@ -0,0 +1,55 @@ + Y2K compliance in libpng:
+ =========================
+
+ February 25, 2010
+
+ Since the PNG Development group is an ad-hoc body, we can't make
+ an official declaration.
+
+ This is your unofficial assurance that libpng from version 0.71 and
+ upward through 1.2.43 are Y2K compliant. It is my belief that earlier
+ versions were also Y2K compliant.
+
+ Libpng only has three year fields. One is a 2-byte unsigned integer
+ that will hold years up to 65535. The other two hold the date in text
+ format, and will hold years up to 9999.
+
+ The integer is
+ "png_uint_16 year" in png_time_struct.
+
+ The strings are
+ "png_charp time_buffer" in png_struct and
+ "near_time_buffer", which is a local character string in png.c.
+
+ There are seven time-related functions:
+
+ png_convert_to_rfc_1123() in png.c
+ (formerly png_convert_to_rfc_1152() in error)
+ png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
+ png_convert_from_time_t() in pngwrite.c
+ png_get_tIME() in pngget.c
+ png_handle_tIME() in pngrutil.c, called in pngread.c
+ png_set_tIME() in pngset.c
+ png_write_tIME() in pngwutil.c, called in pngwrite.c
+
+ All appear to handle dates properly in a Y2K environment. The
+ png_convert_from_time_t() function calls gmtime() to convert from system
+ clock time, which returns (year - 1900), which we properly convert to
+ the full 4-digit year. There is a possibility that applications using
+ libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
+ function, or that they are incorrectly passing only a 2-digit year
+ instead of "year - 1900" into the png_convert_from_struct_tm() function,
+ but this is not under our control. The libpng documentation has always
+ stated that it works with 4-digit years, and the APIs have been
+ documented as such.
+
+ The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
+ integer to hold the year, and can hold years as large as 65535.
+
+ zlib, upon which libpng depends, is also Y2K compliant. It contains
+ no date-related code.
+
+
+ Glenn Randers-Pehrson
+ libpng maintainer
+ PNG Development Group
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