Lua FastLZ binding

lfastlz.c

#define LUA_LIB
#include <lua.h>
#include <lauxlib.h>

#include "fastlz.h"
#include "fastlz.c"

#include <stdlib.h>

static int Lcompress(lua_State *L) {
    size_t len;
    const char *s = luaL_checklstring(L, 1, &len);
    int r, level = luaL_optinteger(L, 2, 0);
    char init_out[LUAL_BUFFERSIZE], *out = init_out;
    if (level != 0 && (level < 1 || level > 2))
        luaL_error(L, "level range error (0-2): %d", level);
    if ((size_t)(len*1.05+4) > LUAL_BUFFERSIZE)
        out = lua_newuserdata(L, (size_t)(len*1.05 + 4));
    out[0] = (len >> 24) & 0xFF;
    out[1] = (len >> 16) & 0xFF;
    out[2] = (len >>  8) & 0xFF;
    out[3] = (len >>  0) & 0xFF;
    r = level ?
        fastlz_compress_level(level, s, len, out+4) :
        fastlz_compress(s, len, out+4);
    lua_pushlstring(L, out, r+4);
    return 1;
}

static int Ldecompress(lua_State *L) {
    size_t len, size;
    const char *s = luaL_checklstring(L, 1, &len);
    char init_out[LUAL_BUFFERSIZE], *out = init_out;
    int r;
    if (len < 4) return luaL_error(L, "decompress error");
    size = ((s[0] & 0xFF) << 24) |
           ((s[1] & 0xFF) << 16) |
           ((s[2] & 0xFF) <<  8) |
           ((s[3] & 0xFF) <<  0);
    if (size > LUAL_BUFFERSIZE)
        out = lua_newuserdata(L, size);
    r = fastlz_decompress(s+4, len-4, out, size);
    if (r == 0) return luaL_error(L, "decompress error");
    lua_pushlstring(L, out, r);
    return 1;
}

LUALIB_API int luaopen_fastlz(lua_State *L) {
    luaL_Reg libs[] = {
#define ENTRY(name) { #name, L##name }
        ENTRY(compress),
        ENTRY(decompress),
#undef  ENTRY
        { NULL, NULL }
    };
    luaL_newlib(L, libs);
    return 1;
}

/* unixcc: flags+='-shared -fpic -undefined dynamic_lookup'
 * unixcc: output='fastlz.so'
 */