[StevenLi-phoenix]

Fixes #1750

Problem

NEXTARG() in apps/avifenc.c and apps/avifdec.c treated every argument that starts with - as the next option. So avifenc --jobs -10 in.png out.avif failed with --jobs requires an argument. (with no trailing newline), and no option ever got to check a negative value.

Fix

NEXTARG() now passes the next argument to the current option when the - is followed by a digit, as in -10. Option names (-o, --jobs), a bare - and a missing argument still give <option> requires an argument., which now ends with \n. A side effect: an option can now take a file name such as -1.avif (-o -1.avif).

Some options turned a negative value into a large unsigned value. They now reject it:

• --jobs (avifenc and avifdec) and avifdec --index. --index -1 would otherwise mean all frames. --jobs 0 is still clamped to 1.
• The avifenc options parsed by parseU32List(): --depth, --scaling-mode, --grid, --cicp, --pasp, --crop and --clli. Without this, --cicp -1/-1/-1 wrote color primaries 65535 and --pasp -1,1 wrote an hSpacing of 4294967295. --clap still takes negative values, because its horizontal and vertical offsets are signed (ISO/IEC 14496-12:2022, 12.1.4.1). It calls parseIntList() with allowNegative, and avifCropRectFromCleanApertureBox() still rejects a negative width, height or denominator.
• avifenc --irot and --imir. The value is range-checked as an int before the cast to uint8_t, so --irot -253 is not read as 3.
• avifdec --size-limit and --dimension-limit, which now reject a leading -. strtoul("-1") returns ULONG_MAX, which equals UINT32_MAX where unsigned long is 32 bits (Windows), so -1 would have been accepted there as the largest limit.

Two kinds of command lines that work on main now fail. Both wrote wrapped values:

• a negative value that is not the first one in a parseU32List() option, for example --cicp 1/-1/1 (transfer characteristics 65535) or --pasp 1,-1;
• --irot 256 to 259 and --imir 256 or 257, which were read modulo 256 (--irot 259 as 3).

Not changed:

• Options that clamp out-of-range values (-q, --speed, --min/--max, --tilerowslog2, avifdec -q/--png-compress, ...) clamp negative values too. avifenc -k -3 behaves like -k 0, which means no maximum keyframe interval.
• Values outside the int range still overflow in atoi(), as on main, for positive and negative input alike.
• tests/avifyuv.c keeps its own copy of the old NEXTARG(), for its -m option, because it is a test tool.

For the maintainer: a negative --jobs could be clamped to 1 instead, as 0 is and as avifgainmaputil's JobsConverter does. I made it an error because the issue asks for a meaningful error message. I can switch it.

Testing

New assertions in tests/test_cmd.sh:

• These must fail with their ERROR: message: avifenc --jobs -10, --cicp -1/-1/-1, --pasp -1,1, --irot -253 and --imir -255; avifdec --jobs -10, --index -1 and --size-limit -1.
• --jobs -o and --jobs -i must still report --jobs requires an argument.
• --clap 100,1,100,1,-10,1,-20,1 must still encode, and avifdec --info must show hOff: -10/1, vOff: -20/1.

Build (macOS arm64, Apple clang, system aom 3.15.2 and dav1d 1.5.4):

cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Debug -DAVIF_CODEC_AOM=SYSTEM -DAVIF_CODEC_DAV1D=SYSTEM \
  -DAVIF_LIBYUV=OFF -DAVIF_BUILD_APPS=ON -DAVIF_BUILD_TESTS=ON -DAVIF_GTEST=LOCAL -DAVIF_ENABLE_WERROR=ON
ninja -C build

• With main's avifenc and avifdec, the new test_cmd.sh fails at grep 'ERROR: Invalid number of jobs: -10', because avifenc prints --jobs requires an argument.
• With only the NEXTARG(), --jobs and --index changes, it fails because avifenc --cicp -1/-1/-1 exits 0.
• With this change, ctest --test-dir build -R '^test_cmd' passes 11 of 11 tests, and the full ctest --test-dir build -j 8 passes 62 of 62. test_cmd_stdin is not built in this configuration because AVIF_ENABLE_JPEG_GAIN_MAP_CONVERSION is off.
• clang-format 19.1.7 (-style=file --dry-run --Werror) reports nothing for apps/avifenc.c and apps/avifdec.c.

I did not test on Windows or Linux. On macOS, unsigned long is 64 bits, so --size-limit -1 also fails without the new leading-- check.