minilz4.c

// This code is part of lua2exe
// Very simple LZ4 for lua
#include<lua/lua.h>
#include<lua/lualib.h>
#include<lua/lauxlib.h>
#include<stdlib.h>
#include<stdio.h>
#include<stdint.h>
#include<lz4.h>

 #ifdef __WIN32
#define LIBEXPORT __declspec(dllexport)
#else
#define LIBEXPORT
#endif

static int lz4c (lua_State* L) {
static char* out=NULL; static size_t outlen=0;
size_t inlen=0;
const char* in = luaL_checklstring(L, 1, &inlen);
int level = luaL_optinteger(L, 2, 1);
if (!out || outlen<inlen+10) out = realloc(out, outlen = inlen+10);
if (!out) return luaL_error(L, "memory allocation fail");
int relen = LZ4_compress_fast(in, out, inlen, outlen, level);
if (relen<0) return luaL_error(L, "Compression error %d", relen);
lua_pushlstring(L, out, relen);
return 1;
}

static int lz4d (lua_State* L) {
static char* out=NULL; static size_t outlen=0;
size_t inlen=0;
const char* in = luaL_checklstring(L, 1, &inlen);
size_t neededlen = luaL_optinteger(L, 2, inlen*10+10);
if (!out || outlen<neededlen) out = realloc(out, outlen=neededlen);
if (!out) return luaL_error(L, "memory allocation fail");
int relen = LZ4_decompress_safe(in, out, inlen, outlen);
if (relen<0) luaL_error(L, "decompression error %d", relen);
lua_pushlstring(L, out, relen);
return 1;
}

static const luaL_Reg lz4f[] = {
{ "compress", lz4c },
{ "decompress", lz4d },
{ NULL, NULL }
};

int LIBEXPORT luaopen_minilz4 (lua_State* L) {
luaL_newlib(L, lz4f);
return 1;
}