Commit Graph

3 Commits

Author SHA1 Message Date
Timothy B. Terriberry
c4d7e5e67e Eliminate more warnings.
This eliminates a large set of warnings exposed by the Mozilla build
 system (Use of C++ comments in ISO C90 source, commas at the end of
 enum lists, a couple incomplete initializers, and signed/unsigned
 comparisons).
It also eliminates many (but not all) of the warnings expose by newer
 GCC versions and _FORTIFY_SOURCE (e.g., calling fread and fwrite
 without checking the return values).
There are a few spurious warnings left on my system:

../vp8/encoder/encodemb.c:274:9: warning: 'sz' may be used
 uninitialized in this function
gcc seems to be unable to figure out that the value shortcut doesn't
 change between the two if blocks that test it here.

../vp8/encoder/onyx_if.c:5314:5: warning: comparison of unsigned
 expression >= 0 is always true
../vp8/encoder/onyx_if.c:5319:5: warning: comparison of unsigned
 expression >= 0 is always true
This is true, so far as it goes, but it's comparing against an enum, and the C
 standard does not mandate that enums be unsigned, so the checks can't be
 removed.

Change-Id: Iaf689ae3e3d0ddc5ade00faa474debe73b8d3395
2010-10-27 18:08:04 -07:00
Timothy B. Terriberry
c17b62e1bd Change bitreader to use a larger window.
Change bitreading functions to use a larger window which is refilled less
 often.

This makes it cheap enough to do bounds checking each time the window is
 refilled, which avoids the need to copy the input into a large circular
 buffer.
This uses less memory and speeds up the total decode time by 1.6% on an ARM11,
 2.8% on a Cortex A8, and 2.2% on x86-32, but less than 1% on x86-64.

Inlining vp8dx_bool_decoder_fill() has a big penalty on x86-32, as does moving
 the refill loop to the front of vp8dx_decode_bool().
However, having the refill loop between computation of the split values and
 the branch in vp8_decode_mb_tokens() is a big win on ARM (presumably due to
 memory latency and code size: refilling after normalization duplicates the
 code in the DECODE_AND_BRANCH_IF_ZERO and DECODE_AND_LOOP_IF_ZERO cases.
Unfortunately, refilling at the end of vp8dx_bool_decoder_fill() and at the
 beginning of each decode step in vp8_decode_mb_tokens() means the latter
 requires an extra refill at the end.
Platform-specific versions could avoid the problem, but would require most of
 detokenize.c to be duplicated.

Change-Id: I16c782a63376f2a15b78f8086d899b987204c1c7
2010-06-15 19:55:14 -07:00
John Koleszar
0ea50ce9cb Initial WebM release 2010-05-18 11:58:33 -04:00