ref: 8b4a3db418e246dc07abd839776df99dfc38498d
dir: /lauxlib.c/
/*
** $Id: lauxlib.c $
** Auxiliary functions for building Lua libraries
** See Copyright Notice in lua.h
*/
#define lauxlib_c
#define LUA_LIB
#include "lprefix.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.
*/
#include "lua.h"
#include "lauxlib.h"
#if !defined(MAX_SIZET)
/* maximum value for size_t */
#define MAX_SIZET ((size_t)(~(size_t)0))
#endif
/*
** {======================================================
** Traceback
** =======================================================
*/
#define LEVELS1 10 /* size of the first part of the stack */
#define LEVELS2 11 /* size of the second part of the stack */
/*
** Search for 'objidx' in table at index -1. ('objidx' must be an
** absolute index.) Return 1 + string at top if it found a good name.
*/
static int findfield (lua_State *L, int objidx, int level) {
if (level == 0 || !lua_istable(L, -1))
return 0; /* not found */
lua_pushnil(L); /* start 'next' loop */
while (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 */
/* stack: lib_name, lib_table, field_name (top) */
lua_pushliteral(L, "."); /* place '.' between the two names */
lua_replace(L, -3); /* (in the slot occupied by table) */
lua_concat(L, 3); /* lib_name.field_name */
return 1;
}
}
lua_pop(L, 1); /* remove value */
}
return 0; /* not found */
}
/*
** Search for a name for a function in all loaded modules
*/
static int pushglobalfuncname (lua_State *L, lua_Debug *ar) {
int top = lua_gettop(L);
lua_getinfo(L, "f", ar); /* push function */
lua_getfield(L, LUA_REGISTRYINDEX, LUA_LOADED_TABLE);
if (findfield(L, top + 1, 2)) {
const char *name = lua_tostring(L, -1);
if (strncmp(name, LUA_GNAME ".", 3) == 0) { /* name start with '_G.'? */
lua_pushstring(L, name + 3); /* push name without prefix */
lua_remove(L, -2); /* remove original name */
}
lua_copy(L, -1, top + 1); /* copy name to proper place */
lua_settop(L, top + 1); /* remove table "loaded" and name copy */
return 1;
}
else {
lua_settop(L, top); /* remove function and global table */
return 0;
}
}
static void pushfuncname (lua_State *L, lua_Debug *ar) {
if (pushglobalfuncname(L, ar)) { /* try first a global name */
lua_pushfstring(L, "function '%s'", lua_tostring(L, -1));
lua_remove(L, -2); /* remove name */
}
else if (*ar->namewhat != '\0') /* is there a name from code? */
lua_pushfstring(L, "%s '%s'", ar->namewhat, ar->name); /* use it */
else if (*ar->what == 'm') /* main? */
lua_pushliteral(L, "main chunk");
else if (*ar->what != 'C') /* for Lua functions, use <file:line> */
lua_pushfstring(L, "function <%s:%d>", ar->short_src, ar->linedefined);
else /* nothing left... */
lua_pushliteral(L, "?");
}
static int lastlevel (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) {
luaL_Buffer b;
lua_Debug ar;
int last = lastlevel(L1);
int limit2show = (last - level > LEVELS1 + LEVELS2) ? LEVELS1 : -1;
luaL_buffinit(L, &b);
if (msg) {
luaL_addstring(&b, msg);
luaL_addchar(&b, '\n');
}
luaL_addstring(&b, "stack traceback:");
while (lua_getstack(L1, level++, &ar)) {
if (limit2show-- == 0) { /* too many levels? */
int n = last - level - LEVELS2 + 1; /* number of levels to skip */
lua_pushfstring(L, "\n\t...\t(skipping %d levels)", n);
luaL_addvalue(&b); /* add warning about skip */
level += n; /* and skip to last levels */
}
else {
lua_getinfo(L1, "Slnt", &ar);
if (ar.currentline <= 0)
lua_pushfstring(L, "\n\t%s: in ", ar.short_src);
else
lua_pushfstring(L, "\n\t%s:%d: in ", ar.short_src, ar.currentline);
luaL_addvalue(&b);
pushfuncname(L, &ar);
luaL_addvalue(&b);
if (ar.istailcall)
luaL_addstring(&b, "\n\t(...tail calls...)");
}
}
luaL_pushresult(&b);
}
/* }====================================================== */
/*
** {======================================================
** Error-report functions
** =======================================================
*/
LUALIB_API int luaL_argerror (lua_State *L, int arg, const char *extramsg) {
lua_Debug ar;
if (!lua_getstack(L, 0, &ar)) /* no stack frame? */
return luaL_error(L, "bad argument #%d (%s)", arg, extramsg);
lua_getinfo(L, "n", &ar);
if (strcmp(ar.namewhat, "method") == 0) {
arg--; /* do not count 'self' */
if (arg == 0) /* error is in the self argument itself? */
return luaL_error(L, "calling '%s' on bad self (%s)",
ar.name, extramsg);
}
if (ar.name == NULL)
ar.name = (pushglobalfuncname(L, &ar)) ? lua_tostring(L, -1) : "?";
return luaL_error(L, "bad argument #%d to '%s' (%s)",
arg, ar.name, extramsg);
}
int luaL_typeerror (lua_State *L, int arg, const char *tname) {
const char *msg;
const char *typearg; /* name for the type of the actual argument */
if (luaL_getmetafield(L, arg, "__name") == LUA_TSTRING)
typearg = lua_tostring(L, -1); /* use the given type name */
else if (lua_type(L, arg) == LUA_TLIGHTUSERDATA)
typearg = "light userdata"; /* special name for messages */
else
typearg = luaL_typename(L, arg); /* standard name */
msg = lua_pushfstring(L, "%s expected, got %s", tname, typearg);
return luaL_argerror(L, arg, msg);
}
static void tag_error (lua_State *L, int arg, int tag) {
luaL_typeerror(L, arg, lua_typename(L, tag));
}
/*
** The use of 'lua_pushfstring' ensures this function does not
** need reserved stack space when called.
*/
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_pushfstring(L, ""); /* else, no information available... */
}
/*
** Again, the use of 'lua_pushvfstring' ensures this function does
** not need reserved stack space when called. (At worst, it generates
** an error with "stack overflow" instead of the given message.)
*/
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);
}
LUALIB_API int luaL_fileresult (lua_State *L, int stat, const char *fname) {
int en = errno; /* calls to Lua API may change this value */
if (stat) {
lua_pushboolean(L, 1);
return 1;
}
else {
luaL_pushfail(L);
if (fname)
lua_pushfstring(L, "%s: %s", fname, strerror(en));
else
lua_pushstring(L, strerror(en));
lua_pushinteger(L, en);
return 3;
}
}
#if !defined(l_inspectstat) /* { */
#if defined(LUA_USE_POSIX)
#include <sys/wait.h>
/*
** use appropriate macros to interpret 'pclose' return status
*/
#define l_inspectstat(stat,what) \
if (WIFEXITED(stat)) { stat = WEXITSTATUS(stat); } \
else if (WIFSIGNALED(stat)) { stat = WTERMSIG(stat); what = "signal"; }
#else
#define l_inspectstat(stat,what) /* no op */
#endif
#endif /* } */
LUALIB_API int luaL_execresult (lua_State *L, int stat) {
if (stat != 0 && errno != 0) /* error with an 'errno'? */
return luaL_fileresult(L, 0, NULL);
else {
const char *what = "exit"; /* type of termination */
l_inspectstat(stat, what); /* interpret result */
if (*what == 'e' && stat == 0) /* successful termination? */
lua_pushboolean(L, 1);
else
luaL_pushfail(L);
lua_pushstring(L, what);
lua_pushinteger(L, stat);
return 3; /* return true/fail,what,code */
}
}
/* }====================================================== */
/*
** {======================================================
** Userdata's metatable manipulation
** =======================================================
*/
LUALIB_API int luaL_newmetatable (lua_State *L, const char *tname) {
if (luaL_getmetatable(L, tname) != LUA_TNIL) /* name already in use? */
return 0; /* leave previous value on top, but return 0 */
lua_pop(L, 1);
lua_createtable(L, 0, 2); /* create metatable */
lua_pushstring(L, tname);
lua_setfield(L, -2, "__name"); /* metatable.__name = tname */
lua_pushvalue(L, -1);
lua_setfield(L, LUA_REGISTRYINDEX, tname); /* registry.name = metatable */
return 1;
}
LUALIB_API void luaL_setmetatable (lua_State *L, const char *tname) {
luaL_getmetatable(L, tname);
lua_setmetatable(L, -2);
}
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? */
luaL_getmetatable(L, 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);
luaL_argexpected(L, p != NULL, ud, tname);
return p;
}
/* }====================================================== */
/*
** {======================================================
** Argument check functions
** =======================================================
*/
LUALIB_API int luaL_checkoption (lua_State *L, int arg, const char *def,
const char *const lst[]) {
const char *name = (def) ? luaL_optstring(L, arg, def) :
luaL_checkstring(L, arg);
int i;
for (i=0; lst[i]; i++)
if (strcmp(lst[i], name) == 0)
return i;
return luaL_argerror(L, arg,
lua_pushfstring(L, "invalid option '%s'", name));
}
/*
** Ensures the stack has at least 'space' extra slots, raising an error
** if it cannot fulfill the request. (The error handling needs a few
** extra slots to format the error message. In case of an error without
** this extra space, Lua will generate the same 'stack overflow' error,
** but without 'msg'.)
*/
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 arg, int t) {
if (lua_type(L, arg) != t)
tag_error(L, arg, t);
}
LUALIB_API void luaL_checkany (lua_State *L, int arg) {
if (lua_type(L, arg) == LUA_TNONE)
luaL_argerror(L, arg, "value expected");
}
LUALIB_API const char *luaL_checklstring (lua_State *L, int arg, size_t *len) {
const char *s = lua_tolstring(L, arg, len);
if (!s) tag_error(L, arg, LUA_TSTRING);
return s;
}
LUALIB_API const char *luaL_optlstring (lua_State *L, int arg,
const char *def, size_t *len) {
if (lua_isnoneornil(L, arg)) {
if (len)
*len = (def ? strlen(def) : 0);
return def;
}
else return luaL_checklstring(L, arg, len);
}
LUALIB_API lua_Number luaL_checknumber (lua_State *L, int arg) {
int isnum;
lua_Number d = lua_tonumberx(L, arg, &isnum);
if (!isnum)
tag_error(L, arg, LUA_TNUMBER);
return d;
}
LUALIB_API lua_Number luaL_optnumber (lua_State *L, int arg, lua_Number def) {
return luaL_opt(L, luaL_checknumber, arg, def);
}
static void interror (lua_State *L, int arg) {
if (lua_isnumber(L, arg))
luaL_argerror(L, arg, "number has no integer representation");
else
tag_error(L, arg, LUA_TNUMBER);
}
LUALIB_API lua_Integer luaL_checkinteger (lua_State *L, int arg) {
int isnum;
lua_Integer d = lua_tointegerx(L, arg, &isnum);
if (!isnum) {
interror(L, arg);
}
return d;
}
LUALIB_API lua_Integer luaL_optinteger (lua_State *L, int arg,
lua_Integer def) {
return luaL_opt(L, luaL_checkinteger, arg, def);
}
/* }====================================================== */
/*
** {======================================================
** Generic Buffer manipulation
** =======================================================
*/
/* userdata to box arbitrary data */
typedef struct UBox {
void *box;
size_t bsize;
} UBox;
static void *resizebox (lua_State *L, int idx, size_t newsize) {
void *ud;
lua_Alloc allocf = lua_getallocf(L, &ud);
UBox *box = (UBox *)lua_touserdata(L, idx);
void *temp = allocf(ud, box->box, box->bsize, newsize);
if (temp == NULL && newsize > 0) { /* allocation error? */
lua_pushliteral(L, "not enough memory");
lua_error(L); /* raise a memory error */
}
box->box = temp;
box->bsize = newsize;
return temp;
}
static int boxgc (lua_State *L) {
resizebox(L, 1, 0);
return 0;
}
static const luaL_Reg boxmt[] = { /* box metamethods */
{"__gc", boxgc},
{"__close", boxgc},
{NULL, NULL}
};
static void newbox (lua_State *L) {
UBox *box = (UBox *)lua_newuserdatauv(L, sizeof(UBox), 0);
box->box = NULL;
box->bsize = 0;
if (luaL_newmetatable(L, "_UBOX*")) /* creating metatable? */
luaL_setfuncs(L, boxmt, 0); /* set its metamethods */
lua_setmetatable(L, -2);
}
/*
** check whether buffer is using a userdata on the stack as a temporary
** buffer
*/
#define buffonstack(B) ((B)->b != (B)->init.b)
/*
** Compute new size for buffer 'B', enough to accommodate extra 'sz'
** bytes.
*/
static size_t newbuffsize (luaL_Buffer *B, size_t sz) {
size_t newsize = B->size * 2; /* double buffer size */
if (MAX_SIZET - sz < B->n) /* overflow in (B->n + sz)? */
return luaL_error(B->L, "buffer too large");
if (newsize < B->n + sz) /* double is not big enough? */
newsize = B->n + sz;
return newsize;
}
/*
** Returns a pointer to a free area with at least 'sz' bytes in buffer
** 'B'. 'boxidx' is the relative position in the stack where the
** buffer's box is or should be.
*/
static char *prepbuffsize (luaL_Buffer *B, size_t sz, int boxidx) {
if (B->size - B->n >= sz) /* enough space? */
return B->b + B->n;
else {
lua_State *L = B->L;
char *newbuff;
size_t newsize = newbuffsize(B, sz);
/* create larger buffer */
if (buffonstack(B)) /* buffer already has a box? */
newbuff = (char *)resizebox(L, boxidx, newsize); /* resize it */
else { /* no box yet */
lua_pushnil(L); /* reserve slot for final result */
newbox(L); /* create a new box */
/* move box (and slot) to its intended position */
lua_rotate(L, boxidx - 1, 2);
lua_toclose(L, boxidx);
newbuff = (char *)resizebox(L, boxidx, newsize);
memcpy(newbuff, B->b, B->n * sizeof(char)); /* copy original content */
}
B->b = newbuff;
B->size = newsize;
return newbuff + B->n;
}
}
/*
** returns a pointer to a free area with at least 'sz' bytes
*/
LUALIB_API char *luaL_prepbuffsize (luaL_Buffer *B, size_t sz) {
return prepbuffsize(B, sz, -1);
}
LUALIB_API void luaL_addlstring (luaL_Buffer *B, const char *s, size_t l) {
if (l > 0) { /* avoid 'memcpy' when 's' can be NULL */
char *b = prepbuffsize(B, l, -1);
memcpy(b, s, l * sizeof(char));
luaL_addsize(B, l);
}
}
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) {
lua_State *L = B->L;
lua_pushlstring(L, B->b, B->n);
if (buffonstack(B)) {
lua_copy(L, -1, -3); /* move string to reserved slot */
lua_pop(L, 2); /* pop string and box (closing the box) */
}
}
LUALIB_API void luaL_pushresultsize (luaL_Buffer *B, size_t sz) {
luaL_addsize(B, sz);
luaL_pushresult(B);
}
/*
** 'luaL_addvalue' is the only function in the Buffer system where the
** box (if existent) is not on the top of the stack. So, instead of
** calling 'luaL_addlstring', it replicates the code using -2 as the
** last argument to 'prepbuffsize', signaling that the box is (or will
** be) bellow the string being added to the buffer. (Box creation can
** trigger an emergency GC, so we should not remove the string from the
** stack before we have the space guaranteed.)
*/
LUALIB_API void luaL_addvalue (luaL_Buffer *B) {
lua_State *L = B->L;
size_t len;
const char *s = lua_tolstring(L, -1, &len);
char *b = prepbuffsize(B, len, -2);
memcpy(b, s, len * sizeof(char));
luaL_addsize(B, len);
lua_pop(L, 1); /* pop string */
}
LUALIB_API void luaL_buffinit (lua_State *L, luaL_Buffer *B) {
B->L = L;
B->b = B->init.b;
B->n = 0;
B->size = LUAL_BUFFERSIZE;
}
LUALIB_API char *luaL_buffinitsize (lua_State *L, luaL_Buffer *B, size_t sz) {
luaL_buffinit(L, B);
return prepbuffsize(B, sz, -1);
}
/* }====================================================== */
/*
** {======================================================
** Reference system
** =======================================================
*/
/* index of free-list header */
#define freelist 0
LUALIB_API int luaL_ref (lua_State *L, int t) {
int ref;
if (lua_isnil(L, -1)) {
lua_pop(L, 1); /* remove from stack */
return LUA_REFNIL; /* 'nil' has a unique fixed reference */
}
t = lua_absindex(L, t);
lua_rawgeti(L, t, freelist); /* get first free element */
ref = (int)lua_tointeger(L, -1); /* ref = t[freelist] */
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); /* (t[freelist] = t[ref]) */
}
else /* no free elements */
ref = (int)lua_rawlen(L, t) + 1; /* get a new reference */
lua_rawseti(L, t, ref);
return ref;
}
LUALIB_API void luaL_unref (lua_State *L, int t, int ref) {
if (ref >= 0) {
t = lua_absindex(L, t);
lua_rawgeti(L, t, freelist);
lua_rawseti(L, t, ref); /* t[ref] = t[freelist] */
lua_pushinteger(L, ref);
lua_rawseti(L, t, freelist); /* t[freelist] = ref */
}
}
/* }====================================================== */
/*
** {======================================================
** Load functions
** =======================================================
*/
typedef struct LoadF {
int n; /* number of pre-read characters */
FILE *f; /* file being read */
char buff[BUFSIZ]; /* area for reading file */
} LoadF;
static const char *getF (lua_State *L, void *ud, size_t *size) {
LoadF *lf = (LoadF *)ud;
(void)L; /* not used */
if (lf->n > 0) { /* are there pre-read characters to be read? */
*size = lf->n; /* return them (chars already in buffer) */
lf->n = 0; /* no more pre-read characters */
}
else { /* read a block from file */
/* 'fread' can return > 0 *and* set the EOF flag. If next call to
'getF' called 'fread', it might 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); /* read block */
}
return lf->buff;
}
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;
}
static int skipBOM (LoadF *lf) {
const char *p = "\xEF\xBB\xBF"; /* UTF-8 BOM mark */
int c;
lf->n = 0;
do {
c = getc(lf->f);
if (c == EOF || c != *(const unsigned char *)p++) return c;
lf->buff[lf->n++] = c; /* to be read by the parser */
} while (*p != '\0');
lf->n = 0; /* prefix matched; discard it */
return getc(lf->f); /* return next character */
}
/*
** reads the first character of file 'f' and skips an optional BOM mark
** in its beginning plus its first line if it starts with '#'. Returns
** true if it skipped the first line. In any case, '*cp' has the
** first "valid" character of the file (after the optional BOM and
** a first-line comment).
*/
static int skipcomment (LoadF *lf, int *cp) {
int c = *cp = skipBOM(lf);
if (c == '#') { /* first line is a comment (Unix exec. file)? */
do { /* skip first line */
c = getc(lf->f);
} while (c != EOF && c != '\n');
*cp = getc(lf->f); /* skip end-of-line, if present */
return 1; /* there was a comment */
}
else return 0; /* no comment */
}
LUALIB_API int luaL_loadfilex (lua_State *L, const char *filename,
const char *mode) {
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);
}
if (skipcomment(&lf, &c)) /* read initial portion */
lf.buff[lf.n++] = '\n'; /* add line to correct line numbers */
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);
skipcomment(&lf, &c); /* re-read initial portion */
}
if (c != EOF)
lf.buff[lf.n++] = c; /* 'c' is the first character of the stream */
status = lua_load(L, getF, &lf, lua_tostring(L, -1), mode);
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; /* not used */
if (ls->size == 0) return NULL;
*size = ls->size;
ls->size = 0;
return ls->s;
}
LUALIB_API int luaL_loadbufferx (lua_State *L, const char *buff, size_t size,
const char *name, const char *mode) {
LoadS ls;
ls.s = buff;
ls.size = size;
return lua_load(L, getS, &ls, name, mode);
}
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 LUA_TNIL;
else {
int tt;
lua_pushstring(L, event);
tt = lua_rawget(L, -2);
if (tt == LUA_TNIL) /* is metafield nil? */
lua_pop(L, 2); /* remove metatable and metafield */
else
lua_remove(L, -2); /* remove only metatable */
return tt; /* return metafield type */
}
}
LUALIB_API int luaL_callmeta (lua_State *L, int obj, const char *event) {
obj = lua_absindex(L, obj);
if (luaL_getmetafield(L, obj, event) == LUA_TNIL) /* no metafield? */
return 0;
lua_pushvalue(L, obj);
lua_call(L, 1, 1);
return 1;
}
LUALIB_API lua_Integer luaL_len (lua_State *L, int idx) {
lua_Integer l;
int isnum;
lua_len(L, idx);
l = lua_tointegerx(L, -1, &isnum);
if (!isnum)
luaL_error(L, "object length is not an integer");
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")) { /* metafield? */
if (!lua_isstring(L, -1))
luaL_error(L, "'__tostring' must return a string");
}
else {
switch (lua_type(L, idx)) {
case LUA_TNUMBER: {
if (lua_isinteger(L, idx))
lua_pushfstring(L, "%I", (LUAI_UACINT)lua_tointeger(L, idx));
else
lua_pushfstring(L, "%f", (LUAI_UACNUMBER)lua_tonumber(L, idx));
break;
}
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: {
int tt = luaL_getmetafield(L, idx, "__name"); /* try name */
const char *kind = (tt == LUA_TSTRING) ? lua_tostring(L, -1) :
luaL_typename(L, idx);
lua_pushfstring(L, "%s: %p", kind, lua_topointer(L, idx));
if (tt != LUA_TNIL)
lua_remove(L, -2); /* remove '__name' */
break;
}
}
}
return lua_tolstring(L, -1, len);
}
/*
** set functions from list 'l' into table at top - 'nup'; each
** function gets the 'nup' elements at the top as upvalues.
** Returns with only the table at the stack.
*/
LUALIB_API void luaL_setfuncs (lua_State *L, const luaL_Reg *l, int nup) {
luaL_checkstack(L, nup, "too many upvalues");
for (; l->name != NULL; l++) { /* fill the table with given functions */
if (l->func == NULL) /* place holder? */
lua_pushboolean(L, 0);
else {
int i;
for (i = 0; i < nup; i++) /* copy upvalues to the top */
lua_pushvalue(L, -nup);
lua_pushcclosure(L, l->func, nup); /* closure with those upvalues */
}
lua_setfield(L, -(nup + 2), l->name);
}
lua_pop(L, nup); /* remove upvalues */
}
/*
** ensure that stack[idx][fname] has a table and push that table
** into the stack
*/
LUALIB_API int luaL_getsubtable (lua_State *L, int idx, const char *fname) {
if (lua_getfield(L, idx, fname) == LUA_TTABLE)
return 1; /* table already there */
else {
lua_pop(L, 1); /* remove previous result */
idx = lua_absindex(L, idx);
lua_newtable(L);
lua_pushvalue(L, -1); /* copy to be left at top */
lua_setfield(L, idx, fname); /* assign new table to field */
return 0; /* false, because did not find table there */
}
}
/*
** Stripped-down 'require': After checking "loaded" table, calls 'openf'
** to open a module, registers the result in 'package.loaded' table and,
** if 'glb' is true, also registers the result in the global table.
** Leaves resulting module on the top.
*/
LUALIB_API void luaL_requiref (lua_State *L, const char *modname,
lua_CFunction openf, int glb) {
luaL_getsubtable(L, LUA_REGISTRYINDEX, LUA_LOADED_TABLE);
lua_getfield(L, -1, modname); /* LOADED[modname] */
if (!lua_toboolean(L, -1)) { /* package not already loaded? */
lua_pop(L, 1); /* remove field */
lua_pushcfunction(L, openf);
lua_pushstring(L, modname); /* argument to open function */
lua_call(L, 1, 1); /* call 'openf' to open module */
lua_pushvalue(L, -1); /* make copy of module (call result) */
lua_setfield(L, -3, modname); /* LOADED[modname] = module */
}
lua_remove(L, -2); /* remove LOADED table */
if (glb) {
lua_pushvalue(L, -1); /* copy of module */
lua_setglobal(L, modname); /* _G[modname] = module */
}
}
LUALIB_API void luaL_addgsub (luaL_Buffer *b, const char *s,
const char *p, const char *r) {
const char *wild;
size_t l = strlen(p);
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 */
}
LUALIB_API const char *luaL_gsub (lua_State *L, const char *s,
const char *p, const char *r) {
luaL_Buffer b;
luaL_buffinit(L, &b);
luaL_addgsub(&b, s, p, r);
luaL_pushresult(&b);
return lua_tostring(L, -1);
}
static void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {
(void)ud; (void)osize; /* not used */
if (nsize == 0) {
free(ptr);
return NULL;
}
else
return realloc(ptr, nsize);
}
static int panic (lua_State *L) {
const char *msg = lua_tostring(L, -1);
if (msg == NULL) msg = "error object is not a string";
lua_writestringerror("PANIC: unprotected error in call to Lua API (%s)\n",
msg);
return 0; /* return to Lua to abort */
}
/*
** Warning functions:
** warnfoff: warning system is off
** warnfon: ready to start a new message
** warnfcont: previous message is to be continued
*/
static void warnfoff (void *ud, const char *message, int tocont);
static void warnfon (void *ud, const char *message, int tocont);
static void warnfcont (void *ud, const char *message, int tocont);
/*
** Check whether message is a control message. If so, execute the
** control or ignore it if unknown.
*/
static int checkcontrol (lua_State *L, const char *message, int tocont) {
if (tocont || *(message++) != '@') /* not a control message? */
return 0;
else {
if (strcmp(message, "off") == 0)
lua_setwarnf(L, warnfoff, L); /* turn warnings off */
else if (strcmp(message, "on") == 0)
lua_setwarnf(L, warnfon, L); /* turn warnings on */
return 1; /* it was a control message */
}
}
static void warnfoff (void *ud, const char *message, int tocont) {
checkcontrol((lua_State *)ud, message, tocont);
}
/*
** Writes the message and handle 'tocont', finishing the message
** if needed and setting the next warn function.
*/
static void warnfcont (void *ud, const char *message, int tocont) {
lua_State *L = (lua_State *)ud;
lua_writestringerror("%s", message); /* write message */
if (tocont) /* not the last part? */
lua_setwarnf(L, warnfcont, L); /* to be continued */
else { /* last part */
lua_writestringerror("%s", "\n"); /* finish message with end-of-line */
lua_setwarnf(L, warnfon, L); /* next call is a new message */
}
}
static void warnfon (void *ud, const char *message, int tocont) {
if (checkcontrol((lua_State *)ud, message, tocont)) /* control message? */
return; /* nothing else to be done */
lua_writestringerror("%s", "Lua warning: "); /* start a new warning */
warnfcont(ud, message, tocont); /* finish processing */
}
LUALIB_API lua_State *luaL_newstate (void) {
lua_State *L = lua_newstate(l_alloc, NULL);
if (L) {
lua_atpanic(L, &panic);
lua_setwarnf(L, warnfoff, L); /* default is warnings off */
}
return L;
}
LUALIB_API void luaL_checkversion_ (lua_State *L, lua_Number ver, size_t sz) {
lua_Number v = lua_version(L);
if (sz != LUAL_NUMSIZES) /* check numeric types */
luaL_error(L, "core and library have incompatible numeric types");
else if (v != ver)
luaL_error(L, "version mismatch: app. needs %f, Lua core provides %f",
(LUAI_UACNUMBER)ver, (LUAI_UACNUMBER)v);
}