/*
** $Id: lauxlib.c,v 1.159.1.3 2008/01/21 13:20:51 roberto Exp $
** Auxiliary functions for building Lua libraries
** See Copyright Notice in lua.h
*/

#include <ctype.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"

#define FREELIST_REF 0 /* free list of references */

/* convert a stack index to positive */
#define abs_index(L, i)                                                        \
    ((i) > 0 || (i) <= LUA_REGISTRYINDEX ? (i) : lua_gettop(L) + (i) + 1)

/*
** {======================================================
** 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 (%s)", ar.name,
                              extramsg);
    }
    if (ar.name == NULL)
        ar.name = "?";
    return luaL_error(L, "bad argument #%d to " LUA_QS " (%s)", narg, ar.name,
                      extramsg);
}

LUALIB_API int luaL_typerror(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_typerror(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);
}

/* }====================================================== */

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 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_checkudata(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)) { /* does it have the correct mt? */
                lua_pop(L, 2);             /* remove both metatables */
                return p;
            }
        }
    }
    luaL_typerror(L, ud, tname); /* else error */
    return NULL;                 /* to avoid warnings */
}

LUALIB_API void luaL_checkstack(lua_State *L, int space, const char *mes)
{
    if (!lua_checkstack(L, space))
        luaL_error(L, "stack overflow (%s)", mes);
}

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);
}

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 void(luaL_register)(lua_State *L, const char *libname,
                               const luaL_Reg *l)
{
    luaI_openlib(L, libname, l, 0);
}

static int libsize(const luaL_Reg *l)
{
    int size = 0;
    for (; l->name; l++)
        size++;
    return size;
}

LUALIB_API void luaI_openlib(lua_State *L, const char *libname,
                             const luaL_Reg *l, int nup)
{
    if (libname) {
        int size = libsize(l);
        /* 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) */
            if (luaL_findtable(L, LUA_GLOBALSINDEX, libname, size) != 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 */
        lua_insert(L, -(nup + 1)); /* move library table to below upvalues */
    }
    for (; l->name; l++) {
        int i;
        for (i = 0; i < nup; i++) /* copy upvalues to the top */
            lua_pushvalue(L, -nup);
        lua_pushcclosure(L, l->func, nup);
        lua_setfield(L, -(nup + 2), l->name);
    }
    lua_pop(L, nup); /* remove upvalues */
}

/*
** {======================================================
** getn-setn: size for arrays
** =======================================================
*/

#if defined(LUA_COMPAT_GETN)

static int checkint(lua_State *L, int topop)
{
    int n = (lua_type(L, -1) == LUA_TNUMBER) ? lua_tointeger(L, -1) : -1;
    lua_pop(L, topop);
    return n;
}

static void getsizes(lua_State *L)
{
    lua_getfield(L, LUA_REGISTRYINDEX, "LUA_SIZES");
    if (lua_isnil(L, -1)) {   /* no `size' table? */
        lua_pop(L, 1);        /* remove nil */
        lua_newtable(L);      /* create it */
        lua_pushvalue(L, -1); /* `size' will be its own metatable */
        lua_setmetatable(L, -2);
        lua_pushliteral(L, "kv");
        lua_setfield(L, -2, "__mode"); /* metatable(N).__mode = "kv" */
        lua_pushvalue(L, -1);
        lua_setfield(L, LUA_REGISTRYINDEX, "LUA_SIZES"); /* store in register */
    }
}

LUALIB_API void luaL_setn(lua_State *L, int t, int n)
{
    t = abs_index(L, t);
    lua_pushliteral(L, "n");
    lua_rawget(L, t);
    if (checkint(L, 1) >= 0) {   /* is there a numeric field `n'? */
        lua_pushliteral(L, "n"); /* use it */
        lua_pushinteger(L, n);
        lua_rawset(L, t);
    }
    else { /* use `sizes' */
        getsizes(L);
        lua_pushvalue(L, t);
        lua_pushinteger(L, n);
        lua_rawset(L, -3); /* sizes[t] = n */
        lua_pop(L, 1);     /* remove `sizes' */
    }
}

LUALIB_API int luaL_getn(lua_State *L, int t)
{
    int n;
    t = abs_index(L, t);
    lua_pushliteral(L, "n"); /* try t.n */
    lua_rawget(L, t);
    if ((n = checkint(L, 1)) >= 0)
        return n;
    getsizes(L); /* else try sizes[t] */
    lua_pushvalue(L, t);
    lua_rawget(L, -2);
    if ((n = checkint(L, 2)) >= 0)
        return n;
    return (int)lua_objlen(L, t);
}

#endif

/* }====================================================== */

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;
    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;
}

/*
** {======================================================
** 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_strlen(L, -1);
        do {
            size_t l = lua_strlen(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)
{
    B->L = L;
    B->p = B->buffer;
    B->lvl = 0;
}

/* }====================================================== */

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_objlen(L, t);
        ref++; /* create 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 = 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 {
    int extraline;
    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;
    if (lf->extraline) {
        lf->extraline = 0;
        *size = 1;
        return "\n";
    }
    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 */
    lf.extraline = 0;
    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? */
        lf.extraline = 1;
        while ((c = getc(lf.f)) != EOF && c != '\n')
            ; /* skip first line */
        if (c == '\n')
            c = getc(lf.f);
    }
    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);
        /* skip eventual `#!...' */
        while ((c = getc(lf.f)) != EOF && c != LUA_SIGNATURE[0])
            ;
        lf.extraline = 0;
    }
    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);
}

/* }====================================================== */

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)
{
    (void)L; /* to avoid warnings */
    fprintf(stderr, "PANIC: unprotected error in call to Lua API (%s)\n",
            lua_tostring(L, -1));
    return 0;
}

LUALIB_API lua_State *luaL_newstate(void)
{
    lua_State *L = lua_newstate(l_alloc, NULL);
    if (L)
        lua_atpanic(L, &panic);
    return L;
}
