This release is primarily bug fixes, mostly spotted through improved fuzz testing.
One big change however is the SIMD rANS codecs are now performant on Intel CPUs with the DownFall mitigation microcode applied.
Changes
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Replaced the rANS codec SIMD gathers with simulated gathers via scalar memory fetches. This helps AMD Zen4, but importantly it also fixes a disastrous performance regression caused by Intel's DownFall microcode fix.
There is an impact on pre-DownFall speeds, but we should focus on patched CPUs as a priority.
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A small speed up to the rans_F_to_s3 function used by order-0 rans decode.
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Small speed up to SIMD rans32x16 order-1 encoder by reducing cache misses. Also sped up the rans4x8 order-1 encoder, particularly on AMD Zen4.
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Now supports building with "zig cc"
(Issue #109, reported by David Jackson)
Bug fixes
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Improve robustness of name tokeniser when given non 7-bit ASCII and on machines where "char" defaults to unsigned.
(Issue #105, reported by Shubham Chandak) -
Also fixed a 1 byte buffer read-overrun in name tokeniser.
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Fix name tokeniser encoder failure with some duplicated streams.
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Fixed rans_set_cpu to work multiple times, as well as reinstating the ability to change decode and encode side independently (accidentally lost in commit 958032c). No effect on usage, but it improves the test coverage.
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Added a round-trip fuzz tester to test the ability to encode. The old fuzz testing was decode streams only.
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Fixed bounds checking in rans_uncompress_O0_32x16_avx2, fixing buffer read overruns.
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Removed undefined behaviour in transpose_and_copy(), fixing zig cc builds.