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forked from brimworks/lua-zlib
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lua_zlib.c
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lua_zlib.c
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#include <ctype.h>
#include <lauxlib.h>
#include <lua.h>
#include <stdlib.h>
#include <string.h>
#include <zlib.h>
/*
* ** compatibility with Lua 5.2
* */
#if (LUA_VERSION_NUM == 502)
#undef luaL_register
#define luaL_register(L,n,f) \
{ if ((n) == NULL) luaL_setfuncs(L,f,0); else luaL_newlib(L,f); }
#endif
static int lz_deflate(lua_State *L);
static int lz_deflate_delete(lua_State *L);
static int lz_inflate_delete(lua_State *L);
static int lz_inflate(lua_State *L);
static int lz_version(lua_State *L) {
const char* version = zlibVersion();
int count = strlen(version) + 1;
char* cur = (char*)memcpy(lua_newuserdata(L, count),
version, count);
count = 0;
while ( *cur ) {
char* begin = cur;
/* Find all digits: */
while ( isdigit(*cur) ) cur++;
if ( begin != cur ) {
int is_end = *cur == '\0';
*cur = '\0';
lua_pushnumber(L, atoi(begin));
count++;
if ( is_end ) break;
cur++;
}
while ( *cur && ! isdigit(*cur) ) cur++;
}
return count;
}
static int lz_assert(lua_State *L, int result, const z_stream* stream, const char* file, int line) {
/* Both of these are "normal" return codes: */
if ( result == Z_OK || result == Z_STREAM_END ) return result;
switch ( result ) {
case Z_NEED_DICT:
lua_pushfstring(L, "RequiresDictionary: input stream requires a dictionary to be deflated (%s) at %s line %d",
stream->msg, file, line);
break;
case Z_STREAM_ERROR:
lua_pushfstring(L, "InternalError: inconsistent internal zlib stream (%s) at %s line %d",
stream->msg, file, line);
break;
case Z_DATA_ERROR:
lua_pushfstring(L, "InvalidInput: input string does not conform to zlib format or checksum failed at %s line %d",
file, line);
break;
case Z_MEM_ERROR:
lua_pushfstring(L, "OutOfMemory: not enough memory (%s) at %s line %d",
stream->msg, file, line);
break;
case Z_BUF_ERROR:
lua_pushfstring(L, "InternalError: no progress possible (%s) at %s line %d",
stream->msg, file, line);
break;
case Z_VERSION_ERROR:
lua_pushfstring(L, "IncompatibleLibrary: built with version %s, but dynamically linked with version %s (%s) at %s line %d",
ZLIB_VERSION, zlibVersion(), stream->msg, file, line);
break;
default:
lua_pushfstring(L, "ZLibError: unknown code %d (%s) at %s line %d",
result, stream->msg, file, line);
}
lua_error(L);
return result;
}
/**
* @upvalue z_stream - Memory for the z_stream.
* @upvalue remainder - Any remainder from the last deflate call.
*
* @param string - "print" to deflate stream.
* @param int - flush output buffer? Z_SYNC_FLUSH, Z_FULL_FLUSH, or Z_FINISH.
*
* if no params, terminates the stream (as if we got empty string and Z_FINISH).
*/
static int lz_filter_impl(lua_State *L, int (*filter)(z_streamp, int), int (*end)(z_streamp), char* name) {
int flush = Z_NO_FLUSH, result;
z_stream* stream;
luaL_Buffer buff;
size_t avail_in;
if ( filter == deflate ) {
const char *const opts[] = { "none", "sync", "full", "finish", NULL };
flush = luaL_checkoption(L, 2, opts[0], opts);
if ( flush ) flush++;
/* Z_NO_FLUSH(0) Z_SYNC_FLUSH(2), Z_FULL_FLUSH(3), Z_FINISH (4) */
/* No arguments or nil, we are terminating the stream: */
if ( lua_gettop(L) == 0 || lua_isnil(L, 1) ) {
flush = Z_FINISH;
}
}
stream = (z_stream*)lua_touserdata(L, lua_upvalueindex(1));
if ( stream == NULL ) {
if ( lua_gettop(L) >= 1 && lua_isstring(L, 1) ) {
lua_pushfstring(L, "IllegalState: calling %s function when stream was previously closed", name);
lua_error(L);
}
lua_pushstring(L, "");
lua_pushboolean(L, 1);
return 2; /* Ignore duplicate calls to "close". */
}
luaL_buffinit(L, &buff);
if ( lua_gettop(L) > 1 ) lua_pushvalue(L, 1);
if ( lua_isstring(L, lua_upvalueindex(2)) ) {
lua_pushvalue(L, lua_upvalueindex(2));
if ( lua_gettop(L) > 1 && lua_isstring(L, -2) ) {
lua_concat(L, 2);
}
}
/* Do the actual deflate'ing: */
stream->next_in = lua_gettop(L) > 0 ?
(unsigned char*)lua_tolstring(L, -1, &avail_in) :
NULL;
stream->avail_in = avail_in;
if ( ! stream->avail_in && ! flush ) {
/* Passed empty string, make it a noop instead of erroring out. */
lua_pushstring(L, "");
lua_pushboolean(L, 0);
lua_pushinteger(L, stream->total_in);
lua_pushinteger(L, stream->total_out);
return 4;
}
do {
stream->next_out = (unsigned char*)luaL_prepbuffer(&buff);
stream->avail_out = LUAL_BUFFERSIZE;
result = filter(stream, flush);
if ( Z_BUF_ERROR != result ) {
/* Ignore Z_BUF_ERROR since that just indicates that we
* need a larger buffer in order to proceed. Thanks to
* Tobias Markmann for finding this bug!
*/
lz_assert(L, result, stream, __FILE__, __LINE__);
}
luaL_addsize(&buff, LUAL_BUFFERSIZE - stream->avail_out);
} while ( stream->avail_out == 0 );
/* Need to do this before we alter the stack: */
luaL_pushresult(&buff);
/* Save remainder in lua_upvalueindex(2): */
if ( NULL != stream->next_in ) {
lua_pushlstring(L, (char*)stream->next_in, stream->avail_in);
lua_replace(L, lua_upvalueindex(2));
}
/* "close" the stream/remove finalizer: */
if ( result == Z_STREAM_END ) {
/* Clear-out the metatable so end is not called twice: */
lua_pushnil(L);
lua_setmetatable(L, lua_upvalueindex(1));
/* nil the upvalue: */
lua_pushnil(L);
lua_replace(L, lua_upvalueindex(1));
/* Close the stream: */
lz_assert(L, end(stream), stream, __FILE__, __LINE__);
lua_pushboolean(L, 1);
} else {
lua_pushboolean(L, 0);
}
lua_pushinteger(L, stream->total_in);
lua_pushinteger(L, stream->total_out);
return 4;
}
static void lz_create_deflate_mt(lua_State *L) {
luaL_newmetatable(L, "lz.deflate.meta"); /* {} */
lua_pushcfunction(L, lz_deflate_delete);
lua_setfield(L, -2, "__gc");
lua_pop(L, 1); /* <empty> */
}
static int lz_deflate_new(lua_State *L) {
int level = luaL_optint(L, 1, Z_DEFAULT_COMPRESSION);
/* Allocate the stream: */
z_stream* stream = (z_stream*)lua_newuserdata(L, sizeof(z_stream));
stream->zalloc = Z_NULL;
stream->zfree = Z_NULL;
lz_assert(L, deflateInit(stream, level), stream, __FILE__, __LINE__);
/* Don't allow destructor to execute unless deflateInit was successful: */
luaL_getmetatable(L, "lz.deflate.meta");
lua_setmetatable(L, -2);
lua_pushnil(L);
lua_pushcclosure(L, lz_deflate, 2);
return 1;
}
static int lz_deflate(lua_State *L) {
return lz_filter_impl(L, deflate, deflateEnd, "deflate");
}
static int lz_deflate_delete(lua_State *L) {
z_stream* stream = (z_stream*)lua_touserdata(L, 1);
/* Ignore errors. */
deflateEnd(stream);
return 0;
}
static void lz_create_inflate_mt(lua_State *L) {
luaL_newmetatable(L, "lz.inflate.meta"); /* {} */
lua_pushcfunction(L, lz_inflate_delete);
lua_setfield(L, -2, "__gc");
lua_pop(L, 1); /* <empty> */
}
static int lz_inflate_new(lua_State *L) {
/* Allocate the stream */
z_stream* stream = (z_stream*)lua_newuserdata(L, sizeof(z_stream));
/* By default, we will do gzip header detection w/ max window size */
int window_size = lua_isnumber(L, 1) ? lua_tointeger(L, 1) : MAX_WBITS + 32;
stream->zalloc = Z_NULL;
stream->zfree = Z_NULL;
stream->next_in = Z_NULL;
stream->avail_in = 0;
lz_assert(L, inflateInit2(stream, window_size), stream, __FILE__, __LINE__);
/* Don't allow destructor to execute unless deflateInit was successful: */
luaL_getmetatable(L, "lz.inflate.meta");
lua_setmetatable(L, -2);
lua_pushnil(L);
lua_pushcclosure(L, lz_inflate, 2);
return 1;
}
static int lz_inflate(lua_State *L) {
return lz_filter_impl(L, inflate, inflateEnd, "inflate");
}
static int lz_inflate_delete(lua_State *L) {
z_stream* stream = (z_stream*)lua_touserdata(L, 1);
/* Ignore errors: */
inflateEnd(stream);
return 0;
}
static const luaL_Reg zlib_functions[] = {
{ "deflate", lz_deflate_new },
{ "inflate", lz_inflate_new },
{ "version", lz_version },
{ NULL, NULL }
};
#define SETLITERAL(n,v) (lua_pushliteral(L, n), lua_pushliteral(L, v), lua_settable(L, -3))
#define SETINT(n,v) (lua_pushliteral(L, n), lua_pushinteger(L, v), lua_settable(L, -3))
LUALIB_API int luaopen_zlib(lua_State * const L) {
lz_create_deflate_mt(L);
lz_create_inflate_mt(L);
luaL_register(L, "zlib", zlib_functions);
SETINT("BEST_SPEED", Z_BEST_SPEED);
SETINT("BEST_COMPRESSION", Z_BEST_COMPRESSION);
SETLITERAL("_COPYRIGHT", "Copyright (c) 2009-2010 Brian Maher");
SETLITERAL("_DESCRIPTION", "Yet another binding to the zlib library");
SETLITERAL("_VERSION", "lua-zlib $Id$ $Format:%d$");
/* Expose this to lua so we can do a test: */
SETINT("_TEST_BUFSIZ", LUAL_BUFFERSIZE);
return 1;
}