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Add archive creation with SuperMaster compression

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CLI: uc2 -w [-L level] archive.uc2 files...
Creates UC2 archives with long filename tags and the built-in 49KB
SuperMaster dictionary for improved compression via LZ77 prefix matching.

Library: uc2_compress_ex() accepts master data to pre-fill the sliding
window and hash chains. uc2_get_supermaster() decompresses the embedded
super.bin. uc2_compress() unchanged (backward compatible, NoMaster).

Tests: 5 SuperMaster roundtrip tests, CLI create/extract CTest script.
This commit is contained in:
Eremey Valetov
2026-03-12 02:04:13 -04:00
parent 7691dcc4fa
commit a30c8cf694
10 changed files with 511 additions and 13 deletions
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lib/src/compress.c
+29 -1
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@@ -813,8 +813,9 @@ static int count_write(void *ctx, const void *ptr, unsigned len)
return cw->write(cw->ctx, ptr, len);
}
int uc2_compress(
int uc2_compress_ex(
int level,
const void *master, unsigned master_size,
int (*read)(void *context, void *buf, unsigned len),
void *read_ctx,
int (*write)(void *context, const void *ptr, unsigned len),
@@ -852,6 +853,19 @@ int uc2_compress(
unsigned remaining = size;
u16 load_pos = 0;
/* Pre-fill circular buffer with master data (LZ77 dictionary prefix) */
if (master && master_size > 0) {
unsigned ms = master_size;
if (ms > UC2_BUF_SIZE - UC2_MIN_MATCH)
ms = UC2_BUF_SIZE - UC2_MIN_MATCH;
memcpy(c->data, master, ms);
for (unsigned i = 0; i + 2 < ms; i++)
hash_enter(c, (u16)i);
load_pos = (u16)ms;
c->pos = load_pos;
c->end = load_pos;
}
/* Pre-count EOB distance symbol frequency so the tree includes it */
c->bd_freq[NumByteSym + dist_to_sym(UC2_EOB_MARK)]++;
c->l_freq[0]++; /* length = 3 for EOB marker */
@@ -945,3 +959,17 @@ int uc2_compress(
free(ctx);
return 0;
}
int uc2_compress(
int level,
int (*read)(void *context, void *buf, unsigned len),
void *read_ctx,
int (*write)(void *context, const void *ptr, unsigned len),
void *write_ctx,
unsigned size,
unsigned short *checksum_out,
unsigned *compressed_size_out)
{
return uc2_compress_ex(level, NULL, 0, read, read_ctx, write, write_ctx,
size, checksum_out, compressed_size_out);
}