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Diffstat (limited to 'experimental/tqtinterface/qt4/src/3rdparty/libpng/Y2KINFO')
-rw-r--r-- | experimental/tqtinterface/qt4/src/3rdparty/libpng/Y2KINFO | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/experimental/tqtinterface/qt4/src/3rdparty/libpng/Y2KINFO b/experimental/tqtinterface/qt4/src/3rdparty/libpng/Y2KINFO new file mode 100644 index 000000000..f86ebd134 --- /dev/null +++ b/experimental/tqtinterface/qt4/src/3rdparty/libpng/Y2KINFO @@ -0,0 +1,55 @@ + Y2K compliance in libpng: + ========================= + + October 3, 2002 + + 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 1.2.5 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 tqcontains + no date-related code. + + + Glenn Randers-Pehrson + libpng maintainer + PNG Development Group |