to conditions where types that are 32 bits in the GCC 32-bit
world (uLong and png_size_t) become 64 bits in the 64-bit
world. This produces potential truncation errors which the
compiler correctly flags.
wrong (high by one) 25% of the time. Dividing by 257 with rounding is
wrong in 128 out of 65536 cases. Getting the right answer all the time
without division is easy.
This was because the attempt to reset the zlib stream in png_write_IDAT
happened after the first IDAT chunk had been deflated - much too late.
In this change internal functions are added to claim/release the z_stream
and, hopefully, make the code more robust. Also deflateEnd checking is
added - previously libpng would ignore an error at the end of the stream.
This change adds internal APIs to allow png_warning messages to have parameters
without requiring the host OS to implelment snprintf. As a side effect the
dependency of the RFC1132 code on stdio is removed and PNG_NO_WARNINGS does
actually work now.
Certain optional gcc warning flags resulted in warnings in libpng code.
With these changes only -Wconversion and -Wcast-qual cannot be turned on.
Changes are trivial rearrangements of code. -Wconversion is not possible
for pngrutil.c (because of the widespread use of += et al on variables
smaller than (int) or (unsigned int)) and -Wcast-qual is not possible
with pngwio.c and pngwutil.c because the 'write' callback and zlib
compression both fail to declare their input buffers with 'const'.
Moved reading of file signature into png_read_sig (Cosmin)
Fixed atomicity of chunk header serialization (Cosmin)
Added test for io_state in pngtest.c (Cosmin)
Added "#!/bin/sh" at the top of contrib/pngminim/*/gather.sh scripts.
literal pointers declare them (John Bowler).
Many APIs did not change their arguments but were not declared using
PNG_CONST. This change corrects this. In a few cases APIs that return
constant string literal pointers have also been changed to declare this.
Unlike the argument change this may require app changes; however the
results could never be written to (the app would crash on some platforms
where strings are not writable), so this seems advisable.
