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lua/lauxlib.c

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/*
** $Id: lauxlib.c,v 1.197 2010/01/21 16:49:21 roberto Exp roberto $
** Auxiliary functions for building Lua libraries
** See Copyright Notice in lua.h
*/
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* This file uses only the official API of Lua.
** Any function declared here could be written as an application function.
*/
#define lauxlib_c
#define LUA_LIB
#include "lua.h"
#include "lauxlib.h"
/* convert a stack index to positive */
#define abs_index(L, i) ((i) > 0 || (i) <= LUA_REGISTRYINDEX ? (i) : \
lua_gettop(L) + (i) + 1)
/*
** {======================================================
** Traceback
** =======================================================
*/
#define LEVELS1 12 /* size of the first part of the stack */
#define LEVELS2 10 /* size of the second part of the stack */
/*
** search for 'objidx' in table at index -1.
** return 1 + string at top if find a good name.
*/
static int findfield (lua_State *L, int objidx, int level) {
int found = 0;
if (level == 0 || !lua_istable(L, -1))
return 0; /* not found */
lua_pushnil(L); /* start 'next' loop */
while (!found && lua_next(L, -2)) { /* for each pair in table */
if (lua_type(L, -2) == LUA_TSTRING) { /* ignore non-string keys */
if (lua_rawequal(L, objidx, -1)) { /* found object? */
lua_pop(L, 1); /* remove value (but keep name) */
return 1;
}
else if (findfield(L, objidx, level - 1)) { /* try recursively */
lua_remove(L, -2); /* remove table (but keep name) */
lua_pushliteral(L, ".");
lua_insert(L, -2); /* place '.' between the two names */
lua_concat(L, 3);
return 1;
}
}
lua_pop(L, 1); /* remove value */
}
return 0; /* not found */
}
static int pushglobalfuncname (lua_State *L, lua_Debug *ar) {
int top = lua_gettop(L);
lua_getinfo(L, "f", ar); /* push function */
lua_pushglobaltable(L);
if (findfield(L, top + 1, 2)) {
lua_copy(L, -1, top + 1); /* move name to proper place */
lua_pop(L, 2); /* remove pushed values */
return 1;
}
else {
lua_settop(L, top); /* remove function and global table */
return 0;
}
}
static void pushfuncname (lua_State *L, lua_Debug *ar) {
if (*ar->namewhat != '\0') /* is there a name? */
lua_pushfstring(L, "function " LUA_QS, ar->name);
else if (*ar->what == 'm') /* main? */
lua_pushfstring(L, "main chunk");
else if (*ar->what == 'C' || *ar->what == 't') {
if (pushglobalfuncname(L, ar)) {
lua_pushfstring(L, "function " LUA_QS, lua_tostring(L, -1));
lua_remove(L, -2); /* remove name */
}
else
lua_pushliteral(L, "?");
}
else
lua_pushfstring(L, "function <%s:%d>", ar->short_src, ar->linedefined);
}
static int countlevels (lua_State *L) {
lua_Debug ar;
int li = 1, le = 1;
/* find an upper bound */
while (lua_getstack(L, le, &ar)) { li = le; le *= 2; }
/* do a binary search */
while (li < le) {
int m = (li + le)/2;
if (lua_getstack(L, m, &ar)) li = m + 1;
else le = m;
}
return le - 1;
}
LUALIB_API void luaL_traceback (lua_State *L, lua_State *L1,
const char *msg, int level) {
lua_Debug ar;
int top = lua_gettop(L);
int numlevels = countlevels(L1);
int mark = (numlevels > LEVELS1 + LEVELS2) ? LEVELS1 : 0;
if (msg) lua_pushfstring(L, "%s\n", msg);
lua_pushliteral(L, "stack traceback:");
while (lua_getstack(L1, level++, &ar)) {
if (level == mark) { /* too many levels? */
lua_pushliteral(L, "\n\t..."); /* add a '...' */
level = numlevels - LEVELS2; /* and skip to last ones */
}
else {
lua_getinfo(L1, "Slnt", &ar);
lua_pushfstring(L, "\n\t%s:", ar.short_src);
if (ar.currentline > 0)
lua_pushfstring(L, "%d:", ar.currentline);
lua_pushliteral(L, " in ");
pushfuncname(L, &ar);
if (ar.istailcall)
lua_pushliteral(L, "\n\t(...tail calls...)");
lua_concat(L, lua_gettop(L) - top);
}
}
lua_concat(L, lua_gettop(L) - top);
}
/* }====================================================== */
/*
** {======================================================
** Error-report functions
** =======================================================
*/
LUALIB_API int luaL_argerror (lua_State *L, int narg, const char *extramsg) {
lua_Debug ar;
if (!lua_getstack(L, 0, &ar)) /* no stack frame? */
return luaL_error(L, "bad argument #%d (%s)", narg, extramsg);
lua_getinfo(L, "n", &ar);
if (strcmp(ar.namewhat, "method") == 0) {
narg--; /* do not count `self' */
if (narg == 0) /* error is in the self argument itself? */
return luaL_error(L, "calling " LUA_QS " on bad self", ar.name);
}
if (ar.name == NULL)
ar.name = (pushglobalfuncname(L, &ar)) ? lua_tostring(L, -1) : "?";
return luaL_error(L, "bad argument #%d to " LUA_QS " (%s)",
narg, ar.name, extramsg);
}
LUALIB_API int luaL_typeerror (lua_State *L, int narg, const char *tname) {
const char *msg = lua_pushfstring(L, "%s expected, got %s",
tname, luaL_typename(L, narg));
return luaL_argerror(L, narg, msg);
}
static void tag_error (lua_State *L, int narg, int tag) {
luaL_typeerror(L, narg, lua_typename(L, tag));
}
LUALIB_API void luaL_where (lua_State *L, int level) {
lua_Debug ar;
if (lua_getstack(L, level, &ar)) { /* check function at level */
lua_getinfo(L, "Sl", &ar); /* get info about it */
if (ar.currentline > 0) { /* is there info? */
lua_pushfstring(L, "%s:%d: ", ar.short_src, ar.currentline);
return;
}
}
lua_pushliteral(L, ""); /* else, no information available... */
}
LUALIB_API int luaL_error (lua_State *L, const char *fmt, ...) {
va_list argp;
va_start(argp, fmt);
luaL_where(L, 1);
lua_pushvfstring(L, fmt, argp);
va_end(argp);
lua_concat(L, 2);
return lua_error(L);
}
/* }====================================================== */
/*
** {======================================================
** Userdata's metatable manipulation
** =======================================================
*/
LUALIB_API int luaL_newmetatable (lua_State *L, const char *tname) {
lua_getfield(L, LUA_REGISTRYINDEX, tname); /* get registry.name */
if (!lua_isnil(L, -1)) /* name already in use? */
return 0; /* leave previous value on top, but return 0 */
lua_pop(L, 1);
lua_newtable(L); /* create metatable */
lua_pushvalue(L, -1);
lua_setfield(L, LUA_REGISTRYINDEX, tname); /* registry.name = metatable */
return 1;
}
LUALIB_API void *luaL_testudata (lua_State *L, int ud, const char *tname) {
void *p = lua_touserdata(L, ud);
if (p != NULL) { /* value is a userdata? */
if (lua_getmetatable(L, ud)) { /* does it have a metatable? */
lua_getfield(L, LUA_REGISTRYINDEX, tname); /* get correct metatable */
if (!lua_rawequal(L, -1, -2)) /* not the same? */
p = NULL; /* value is a userdata with wrong metatable */
lua_pop(L, 2); /* remove both metatables */
return p;
}
}
return NULL; /* value is not a userdata with a metatable */
}
LUALIB_API void *luaL_checkudata (lua_State *L, int ud, const char *tname) {
void *p = luaL_testudata(L, ud, tname);
if (p == NULL) luaL_typeerror(L, ud, tname);
return p;
}
/* }====================================================== */
/*
** {======================================================
** Argument check functions
** =======================================================
*/
LUALIB_API int luaL_checkoption (lua_State *L, int narg, const char *def,
const char *const lst[]) {
const char *name = (def) ? luaL_optstring(L, narg, def) :
luaL_checkstring(L, narg);
int i;
for (i=0; lst[i]; i++)
if (strcmp(lst[i], name) == 0)
return i;
return luaL_argerror(L, narg,
lua_pushfstring(L, "invalid option " LUA_QS, name));
}
LUALIB_API void luaL_checkstack (lua_State *L, int space, const char *msg) {
if (!lua_checkstack(L, space)) {
if (msg)
luaL_error(L, "stack overflow (%s)", msg);
else
luaL_error(L, "stack overflow");
}
}
LUALIB_API void luaL_checktype (lua_State *L, int narg, int t) {
if (lua_type(L, narg) != t)
tag_error(L, narg, t);
}
LUALIB_API void luaL_checkany (lua_State *L, int narg) {
if (lua_type(L, narg) == LUA_TNONE)
luaL_argerror(L, narg, "value expected");
}
LUALIB_API const char *luaL_checklstring (lua_State *L, int narg, size_t *len) {
const char *s = lua_tolstring(L, narg, len);
if (!s) tag_error(L, narg, LUA_TSTRING);
return s;
}
LUALIB_API const char *luaL_optlstring (lua_State *L, int narg,
const char *def, size_t *len) {
if (lua_isnoneornil(L, narg)) {
if (len)
*len = (def ? strlen(def) : 0);
return def;
}
else return luaL_checklstring(L, narg, len);
}
LUALIB_API lua_Number luaL_checknumber (lua_State *L, int narg) {
lua_Number d = lua_tonumber(L, narg);
if (d == 0 && !lua_isnumber(L, narg)) /* avoid extra test when d is not 0 */
tag_error(L, narg, LUA_TNUMBER);
return d;
}
LUALIB_API lua_Number luaL_optnumber (lua_State *L, int narg, lua_Number def) {
return luaL_opt(L, luaL_checknumber, narg, def);
}
LUALIB_API lua_Integer luaL_checkinteger (lua_State *L, int narg) {
lua_Integer d = lua_tointeger(L, narg);
if (d == 0 && !lua_isnumber(L, narg)) /* avoid extra test when d is not 0 */
tag_error(L, narg, LUA_TNUMBER);
return d;
}
LUALIB_API lua_Integer luaL_optinteger (lua_State *L, int narg,
lua_Integer def) {
return luaL_opt(L, luaL_checkinteger, narg, def);
}
/* }====================================================== */
/*
** {======================================================
** Generic Buffer manipulation
** =======================================================
*/
#define bufflen(B) ((B)->p - (B)->buffer)
#define bufffree(B) ((size_t)(LUAL_BUFFERSIZE - bufflen(B)))
#define LIMIT (LUA_MINSTACK/2)
static int emptybuffer (luaL_Buffer *B) {
size_t l = bufflen(B);
if (l == 0) return 0; /* put nothing on stack */
else {
lua_pushlstring(B->L, B->buffer, l);
B->p = B->buffer;
B->lvl++;
return 1;
}
}
static void adjuststack (luaL_Buffer *B) {
if (B->lvl > 1) {
lua_State *L = B->L;
int toget = 1; /* number of levels to concat */
size_t toplen = lua_rawlen(L, -1);
do {
size_t l = lua_rawlen(L, -(toget+1));
if (B->lvl - toget + 1 >= LIMIT || toplen > l) {
toplen += l;
toget++;
}
else break;
} while (toget < B->lvl);
lua_concat(L, toget);
B->lvl = B->lvl - toget + 1;
}
}
LUALIB_API char *luaL_prepbuffer (luaL_Buffer *B) {
if (emptybuffer(B))
adjuststack(B);
return B->buffer;
}
LUALIB_API void luaL_addlstring (luaL_Buffer *B, const char *s, size_t l) {
while (l--)
luaL_addchar(B, *s++);
}
LUALIB_API void luaL_addstring (luaL_Buffer *B, const char *s) {
luaL_addlstring(B, s, strlen(s));
}
LUALIB_API void luaL_pushresult (luaL_Buffer *B) {
emptybuffer(B);
lua_concat(B->L, B->lvl);
B->lvl = 1;
}
LUALIB_API void luaL_addvalue (luaL_Buffer *B) {
lua_State *L = B->L;
size_t vl;
const char *s = lua_tolstring(L, -1, &vl);
if (vl <= bufffree(B)) { /* fit into buffer? */
memcpy(B->p, s, vl); /* put it there */
B->p += vl;
lua_pop(L, 1); /* remove from stack */
}
else {
if (emptybuffer(B))
lua_insert(L, -2); /* put buffer before new value */
B->lvl++; /* add new value into B stack */
adjuststack(B);
}
}
LUALIB_API void luaL_buffinit (lua_State *L, luaL_Buffer *B) {
luaL_checkstack(L, LIMIT + LUA_MINSTACK, "no space for new buffer");
B->L = L;
B->p = B->buffer;
B->lvl = 0;
}
/* }====================================================== */
/*
** {======================================================
** Reference system
** =======================================================
*/
/* number of prereserved references (for internal use) */
#define FREELIST_REF (LUA_RIDX_LAST + 1) /* free list of references */
LUALIB_API int luaL_ref (lua_State *L, int t) {
int ref;
t = abs_index(L, t);
if (lua_isnil(L, -1)) {
lua_pop(L, 1); /* remove from stack */
return LUA_REFNIL; /* `nil' has a unique fixed reference */
}
lua_rawgeti(L, t, FREELIST_REF); /* get first free element */
ref = (int)lua_tointeger(L, -1); /* ref = t[FREELIST_REF] */
lua_pop(L, 1); /* remove it from stack */
if (ref != 0) { /* any free element? */
lua_rawgeti(L, t, ref); /* remove it from list */
lua_rawseti(L, t, FREELIST_REF); /* (t[FREELIST_REF] = t[ref]) */
}
else { /* no free elements */
ref = (int)lua_rawlen(L, t) + 1; /* get a new reference */
if (ref == FREELIST_REF) { /* FREELIST_REF not initialized? */
lua_pushinteger(L, 0);
lua_rawseti(L, t, FREELIST_REF);
ref = FREELIST_REF + 1;
}
}
lua_rawseti(L, t, ref);
return ref;
}
LUALIB_API void luaL_unref (lua_State *L, int t, int ref) {
if (ref >= 0) {
t = abs_index(L, t);
lua_rawgeti(L, t, FREELIST_REF);
lua_rawseti(L, t, ref); /* t[ref] = t[FREELIST_REF] */
lua_pushinteger(L, ref);
lua_rawseti(L, t, FREELIST_REF); /* t[FREELIST_REF] = ref */
}
}
/* }====================================================== */
/*
** {======================================================
** Load functions
** =======================================================
*/
typedef struct LoadF {
FILE *f;
char buff[LUAL_BUFFERSIZE];
} LoadF;
static const char *getF (lua_State *L, void *ud, size_t *size) {
LoadF *lf = (LoadF *)ud;
(void)L;
/* 'fread' can return > 0 *and* set the EOF flag. If next call to
'getF' calls 'fread', terminal may still wait for user input.
The next check avoids this problem. */
if (feof(lf->f)) return NULL;
*size = fread(lf->buff, 1, sizeof(lf->buff), lf->f);
return (*size > 0) ? lf->buff : NULL;
}
static int errfile (lua_State *L, const char *what, int fnameindex) {
const char *serr = strerror(errno);
const char *filename = lua_tostring(L, fnameindex) + 1;
lua_pushfstring(L, "cannot %s %s: %s", what, filename, serr);
lua_remove(L, fnameindex);
return LUA_ERRFILE;
}
LUALIB_API int luaL_loadfile (lua_State *L, const char *filename) {
LoadF lf;
int status, readstatus;
int c;
int fnameindex = lua_gettop(L) + 1; /* index of filename on the stack */
if (filename == NULL) {
lua_pushliteral(L, "=stdin");
lf.f = stdin;
}
else {
lua_pushfstring(L, "@%s", filename);
lf.f = fopen(filename, "r");
if (lf.f == NULL) return errfile(L, "open", fnameindex);
}
c = getc(lf.f);
if (c == '#') { /* Unix exec. file? */
while ((c = getc(lf.f)) != EOF && c != '\n') ; /* skip first line */
}
else if (c == LUA_SIGNATURE[0] && filename) { /* binary file? */
lf.f = freopen(filename, "rb", lf.f); /* reopen in binary mode */
if (lf.f == NULL) return errfile(L, "reopen", fnameindex);
}
ungetc(c, lf.f);
status = lua_load(L, getF, &lf, lua_tostring(L, -1));
readstatus = ferror(lf.f);
if (filename) fclose(lf.f); /* close file (even in case of errors) */
if (readstatus) {
lua_settop(L, fnameindex); /* ignore results from `lua_load' */
return errfile(L, "read", fnameindex);
}
lua_remove(L, fnameindex);
return status;
}
typedef struct LoadS {
const char *s;
size_t size;
} LoadS;
static const char *getS (lua_State *L, void *ud, size_t *size) {
LoadS *ls = (LoadS *)ud;
(void)L;
if (ls->size == 0) return NULL;
*size = ls->size;
ls->size = 0;
return ls->s;
}
LUALIB_API int luaL_loadbuffer (lua_State *L, const char *buff, size_t size,
const char *name) {
LoadS ls;
ls.s = buff;
ls.size = size;
return lua_load(L, getS, &ls, name);
}
LUALIB_API int luaL_loadstring (lua_State *L, const char *s) {
return luaL_loadbuffer(L, s, strlen(s), s);
}
/* }====================================================== */
LUALIB_API int luaL_getmetafield (lua_State *L, int obj, const char *event) {
if (!lua_getmetatable(L, obj)) /* no metatable? */
return 0;
lua_pushstring(L, event);
lua_rawget(L, -2);
if (lua_isnil(L, -1)) {
lua_pop(L, 2); /* remove metatable and metafield */
return 0;
}
else {
lua_remove(L, -2); /* remove only metatable */
return 1;
}
}
LUALIB_API int luaL_callmeta (lua_State *L, int obj, const char *event) {
obj = abs_index(L, obj);
if (!luaL_getmetafield(L, obj, event)) /* no metafield? */
return 0;
lua_pushvalue(L, obj);
lua_call(L, 1, 1);
return 1;
}
LUALIB_API int luaL_len (lua_State *L, int idx) {
int l;
lua_len(L, idx);
l = lua_tointeger(L, -1);
if (l == 0 && !lua_isnumber(L, -1))
luaL_error(L, "object length is not a number");
lua_pop(L, 1); /* remove object */
return l;
}
LUALIB_API const char *luaL_tolstring (lua_State *L, int idx, size_t *len) {
if (!luaL_callmeta(L, idx, "__tostring")) { /* no metafield? */
switch (lua_type(L, idx)) {
case LUA_TNUMBER:
case LUA_TSTRING:
lua_pushvalue(L, idx);
break;
case LUA_TBOOLEAN:
lua_pushstring(L, (lua_toboolean(L, idx) ? "true" : "false"));
break;
case LUA_TNIL:
lua_pushliteral(L, "nil");
break;
default:
lua_pushfstring(L, "%s: %p", luaL_typename(L, idx),
lua_topointer(L, idx));
break;
}
}
return lua_tolstring(L, -1, len);
}
static int libsize (const luaL_Reg *l) {
int size = 0;
for (; l->name; l++) size++;
return size;
}
LUALIB_API void luaL_register (lua_State *L, const char *libname,
const luaL_Reg *l) {
luaL_checkversion(L);
if (libname) {
/* check whether lib already exists */
luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 1);
lua_getfield(L, -1, libname); /* get _LOADED[libname] */
if (!lua_istable(L, -1)) { /* not found? */
lua_pop(L, 1); /* remove previous result */
/* try global variable (and create one if it does not exist) */
lua_pushglobaltable(L);
if (luaL_findtable(L, 0, libname, libsize(l)) != NULL)
luaL_error(L, "name conflict for module " LUA_QS, libname);
lua_pushvalue(L, -1);
lua_setfield(L, -3, libname); /* _LOADED[libname] = new table */
}
lua_remove(L, -2); /* remove _LOADED table */
}
if (l == NULL) return; /* nothing to register? */
for (; l->name; l++) { /* else fill the table with given functions */
lua_pushcfunction(L, l->func);
lua_setfield(L, -2, l->name);
}
}
LUALIB_API const char *luaL_gsub (lua_State *L, const char *s, const char *p,
const char *r) {
const char *wild;
size_t l = strlen(p);
luaL_Buffer b;
luaL_buffinit(L, &b);
while ((wild = strstr(s, p)) != NULL) {
luaL_addlstring(&b, s, wild - s); /* push prefix */
luaL_addstring(&b, r); /* push replacement in place of pattern */
s = wild + l; /* continue after `p' */
}
luaL_addstring(&b, s); /* push last suffix */
luaL_pushresult(&b);
return lua_tostring(L, -1);
}
LUALIB_API const char *luaL_findtable (lua_State *L, int idx,
const char *fname, int szhint) {
const char *e;
if (idx) lua_pushvalue(L, idx);
do {
e = strchr(fname, '.');
if (e == NULL) e = fname + strlen(fname);
lua_pushlstring(L, fname, e - fname);
lua_rawget(L, -2);
if (lua_isnil(L, -1)) { /* no such field? */
lua_pop(L, 1); /* remove this nil */
lua_createtable(L, 0, (*e == '.' ? 1 : szhint)); /* new table for field */
lua_pushlstring(L, fname, e - fname);
lua_pushvalue(L, -2);
lua_settable(L, -4); /* set new table into field */
}
else if (!lua_istable(L, -1)) { /* field has a non-table value? */
lua_pop(L, 2); /* remove table and value */
return fname; /* return problematic part of the name */
}
lua_remove(L, -2); /* remove previous table */
fname = e + 1;
} while (*e == '.');
return NULL;
}
static void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {
(void)ud;
(void)osize;
if (nsize == 0) {
free(ptr);
return NULL;
}
else
return realloc(ptr, nsize);
}
static int panic (lua_State *L) {
fprintf(stderr, "PANIC: unprotected error in call to Lua API (%s)\n",
lua_tostring(L, -1));
return 0; /* return to Lua to abort */
}
LUALIB_API lua_State *luaL_newstate (void) {
lua_State *L = lua_newstate(l_alloc, NULL);
if (L) lua_atpanic(L, &panic);
return L;
}
LUALIB_API void luaL_checkversion_ (lua_State *L, lua_Number ver) {
const lua_Number *v = lua_version(L);
if (v != lua_version(NULL))
luaL_error(L, "multiple Lua VMs detected");
else if (*v != ver)
luaL_error(L, "version mismatch: app. needs %d, Lua core provides %f",
ver, *v);
}
LUALIB_API int luaL_cpcall (lua_State *L, lua_CFunction f, int nargs,
int nresults) {
nargs++; /* to include function itself */
lua_rawgeti(L, LUA_REGISTRYINDEX, LUA_RIDX_CPCALL);
lua_insert(L, -nargs);
lua_pushlightuserdata(L, &f);
lua_insert(L, -nargs);
return lua_pcall(L, nargs, nresults, 0);
}
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