Separate writer finalization from resource cleanup in close.c to
enable a future reader-only library target (aaruformatread).
close_write.c contains all write_* helpers and aaruf_finalize_write().
close.c retains aaruf_close() with cleanup only, dispatching writer
finalization via a function pointer set by aaruf_create()/aaruf_open().
Zero behavioral change — same tests pass, same error semantics.
The LZMA encoder was called with numThreads=8 at all 19 call sites,
but LZMA only supports 1 or 2 (and _7ZIP_ST forces it to 1 anyway).
Replace with LZMA_THREADS(ctx) macro that clamps ctx->num_threads
to [1, 2], making the code say what it means and honoring the
consumer's threading preference from the threads=N option.
Switch zstd encoder from simple API (ZSTD_compress) to advanced API
(ZSTD_CCtx + ZSTD_compress2) with configurable worker threads via
ZSTD_c_nbWorkers. Consumer controls threading through threads=N
option string parameter. Default is 1 (single-threaded, bit-identical
output to previous behavior).
- Enable ZSTD_MULTITHREAD compile definition and link pthreads
- Add num_threads field to options struct and context
- Parse threads=N in option string (clamped >= 1)
- Rewrite aaruf_zstd_encode_buffer() with num_threads parameter
- Update all call sites (write.c, close.c)
Replace string-keyed uthash lookups with HASH_FIND/HASH_ADD on native
uint64_t keys. This eliminates per-lookup malloc/snprintf/strlen/free
overhead from the block cache hot path (2 lookups per sector read).
Before: malloc(17) + snprintf hex + HASH_FIND_STR + free per lookup
After: HASH_FIND with 8-byte integer key, zero allocations
Also removes the unused string-key API (find_in_cache/add_to_cache)
and the uint64_to_string helper — all callers use uint64 keys.
Fix off-by-one in eviction: >= caused cache to hold max_items-1
entries instead of max_items. Changed to > so the configured
capacity is honored exactly.
Implements zstd as an alternative to LZMA for data block and
subchannel compression using the allocated compression IDs 4
(kCompressionZstd) and 5 (kCompressionZstdCst).
Adds zstd v1.5.7 as a bundled submodule with a static library
build including x86_64 assembly fast path for decompression.
Write path selects zstd or LZMA based on the zstd option.
Subchannel blocks use zstd+CST instead of LZMA+CST when enabled.
LZMA properties header is only written for LZMA-based compression
types, preventing format corruption in zstd-compressed images.
Activated via options string: "zstd=true;zstd_level=19".
Default remains LZMA for backwards compatibility.
Tested: SHA-256 verified lossless roundtrips across 9 disc systems
(Dreamcast, Saturn, Mega CD, PC Engine CD, Neo Geo CD, PS1, PS2 CD,
PS2 DVD) and PS1 SBI subchannel preservation with zstd+CST.
