mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-07-16 07:39:56 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Add raw parameter to redbean lua compress

Browse source
This commit is contained in:
Justine Tunney 2022-05-17 10:41:23 -07:00
parent f37524ef4f
commit 3d99ebb68c
4 changed files with 92 additions and 50 deletions
Download patch file Download diff file Expand all files Collapse all files

32
tool/net/help.txt
View file

@ -1308,7 +1308,7 @@ FUNCTIONS
the density of information. Cryptographic random should be in
the ballpark of 7.9 whereas plaintext will be more like 4.5.
Compress(uncompdata:str[, level:int]) → compdata:str
Compress(uncompdata:str[, level:int[, raw:bool]]) → compdata:str
Compresses data using DEFLATE algorithm. The compression
format here is defined to be quick and handy for things like
@ -1319,18 +1319,27 @@ FUNCTIONS
>: Uncompress(Compress('hello'))
"hello"
`level` is the compression level, which defaults to 7. The max
is 10. Lower numbers go faster. Higher numbers go slower, but
have better compression ratios.
[implementation details]
The binary wire format is defined as follows:
1. uleb64 uncompressed byte size (1 to 10 bytes)
2. uint32_t crc32 (4 bytes; zlib polynomial)
3. data (created by zlib compress function)
Uncompress(compdata:str) → uncompdata:str
`level` is the compression level, which defaults to 7. The max
is 10. Lower numbers go faster. Higher numbers go slower, but
have better compression ratios.
`raw` may be set to true if you only want `data` (3) to be
returned. In this case, it's assumed the caller will take
responsibility for storing the length (and optionall crc)
separately. See the redbean Crc32() API.
>: a = 'hello'
>: b = Compress(a, 9, true)
>: Uncompress(b, #a)
"hello"
Uncompress(compdata:str[, uncomplen:int]) → uncompdata:str
Uncompresses data using DEFLATE algorithm. This applies the
inverse transform of the Compress() function. See its docs for
@ -1341,6 +1350,15 @@ FUNCTIONS
of validity iron-clad. It's implemented using Intel CLMUL so
it has ludicrous speed performance as well.
If you used the `raw` parameter when calling Compress() i.e.
`compdata` doesn't have the redbean header described above,
then the `uncomplen` parameter may be supplied. IN that case
your data is handed over directly to zlib `uncompress()`. In
this case an exception will be raised if the value couldn't be
decoded, or if the resulting length differed from the supplied
length. It's recommended that Crc32() check still be performed
manually after using this method.
Benchmark(func[, count[, maxattempts]])
└─→ nanos:real, ticks:int, overhead-ticks:int, tries:int

60
tool/net/lfuncs.c
View file

@ -683,6 +683,7 @@ int LuaBenchmark(lua_State *L) {
}
int LuaCompress(lua_State *L) {
bool raw;
size_t n, m;
char *q, *e;
uint32_t crc;
@ -691,14 +692,23 @@ int LuaCompress(lua_State *L) {
p = luaL_checklstring(L, 1, &n);
level = luaL_optinteger(L, 2, Z_DEFAULT_COMPRESSION);
m = compressBound(n);
CHECK_NOTNULL((q = LuaAlloc(L, 10 + 4 + m)));
crc = crc32_z(0, p, n);
e = uleb64(q, n);
e = WRITE32LE(e, crc);
hdrlen = e - q;
CHECK_EQ(Z_OK, compress2((unsigned char *)(q + hdrlen), &m,
(unsigned char *)p, n, level));
lua_pushlstring(L, q, hdrlen + m);
if (lua_toboolean(L, 3)) {
// raw mode
CHECK_NOTNULL((q = LuaAlloc(L, m)));
CHECK_EQ(Z_OK,
compress2((unsigned char *)q, &m, (unsigned char *)p, n, level));
lua_pushlstring(L, q, m);
} else {
// easy mode
CHECK_NOTNULL((q = LuaAlloc(L, 10 + 4 + m)));
crc = crc32_z(0, p, n);
e = uleb64(q, n);
e = WRITE32LE(e, crc);
hdrlen = e - q;
CHECK_EQ(Z_OK, compress2((unsigned char *)(q + hdrlen), &m,
(unsigned char *)p, n, level));
lua_pushlstring(L, q, hdrlen + m);
}
free(q);
return 1;
}
@ -710,18 +720,28 @@ int LuaUncompress(lua_State *L) {
const char *p;
size_t n, m, len;
p = luaL_checklstring(L, 1, &n);
if ((rc = unuleb64(p, n, &m)) == -1 || n < rc + 4) {
luaL_error(L, "compressed value too short to be valid");
unreachable;
}
len = m;
crc = READ32LE(p + rc);
CHECK_NOTNULL((q = LuaAlloc(L, m)));
if (uncompress((void *)q, &m, (unsigned char *)p + rc + 4, n) != Z_OK ||
m != len || crc32_z(0, q, m) != crc) {
free(q);
luaL_error(L, "compressed value is corrupted");
unreachable;
if (lua_isnoneornil(L, 2)) {
if ((rc = unuleb64(p, n, &m)) == -1 || n < rc + 4) {
luaL_error(L, "compressed value too short to be valid");
unreachable;
}
len = m;
crc = READ32LE(p + rc);
CHECK_NOTNULL((q = LuaAlloc(L, m)));
if (uncompress((void *)q, &m, (unsigned char *)p + rc + 4, n) != Z_OK ||
m != len || crc32_z(0, q, m) != crc) {
free(q);
luaL_error(L, "compressed value is corrupted");
unreachable;
}
} else {
len = m = luaL_checkinteger(L, 2);
CHECK_NOTNULL((q = LuaAlloc(L, m)));
if (uncompress((void *)q, &m, (void *)p, n) != Z_OK || m != len) {
free(q);
luaL_error(L, "compressed value is corrupted");
unreachable;
}
}
lua_pushlstring(L, q, m);
free(q);