[libpng16] Start-up code size improvements, error handler flexibility.
These changes alter how the tricky allocation of the initial png_struct and
png_info structures are handled. png_info is now handled in pretty much the
same way as everything else, except that the allocations handle NULL return
silently. png_struct is changed in a similar way on allocation and on
deallocation a 'safety' error handler is put in place (which should never
be required). The error handler itself is changed to permit mismatches
in the application and libpng error buffer size; however, this means a
silent change to the API to return the jmp_buf if the size doesn't match
the size from the libpng compilation; libpng now allocates the memory and
this may fail. Overall these changes result in slight code size
reductions; however, this is a reduction in code that is always executed
so is particularly valuable. Overall on a 64-bit system the libpng DLL
decreases in code size by 1733 bytes. pngerror.o increases in size by
about 465 bytes because of the new functionality.
diff --git a/CHANGES b/CHANGES
index c5295e2..c4a6b9d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3811,6 +3811,21 @@
in libpng 1.5.7.
Version 1.6.0beta03 [December 21, 2011]
+ Start-up code size improvements, error handler flexibility. These changes
+ alter how the tricky allocation of the initial png_struct and png_info
+ structures are handled. png_info is now handled in pretty much the same
+ way as everything else, except that the allocations handle NULL return
+ silently. png_struct is changed in a similar way on allocation and on
+ deallocation a 'safety' error handler is put in place (which should never
+ be required). The error handler itself is changed to permit mismatches
+ in the application and libpng error buffer size; however, this means a
+ silent change to the API to return the jmp_buf if the size doesn't match
+ the size from the libpng compilation; libpng now allocates the memory and
+ this may fail. Overall these changes result in slight code size
+ reductions; however, this is a reduction in code that is always executed
+ so is particularly valuable. Overall on a 64-bit system the libpng DLL
+ decreases in code size by 1733 bytes. pngerror.o increases in size by
+ about 465 bytes because of the new functionality.
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