/*** $Id: lstrlib.c,v 1.132.1.5 2010/05/14 15:34:19 roberto Exp $** Standard library for string Operations and pattern-matching** See Copyright Notice in lua.h*/#include <ctype.h>#include <stddef.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#define lstrlib_c#define LUA_LIB#include "lua.h"#include "lauxlib.h"#include "lualib.h"/* macro to `unsign' a character */#define uchar(c) ((unsigned char)(c))//获取字符串的长度static int str_len (lua_State *L) { size_t l; luaL_checklstring(L, 1, &l);//判断所得到的值是否为字符串，是的话返回字符串，并修改l为字符串长度 lua_pushinteger(L, l); return 1;}//ptrdiff_t是C/C++标准库中定义的一个与机器相关的数据类型。ptrdiff_t类型变量通常用来保存两个指针减法操作的结果//ptrdiff_t定义在stddef.h（cstddef）这个文件内// 在lua里面索引是从1开始的，-1是从后面开始的，这个函数的作用就是，提供以负数这种方式，// 来访问堆栈以及字符串、table等。其原理还是根据下面的函数把负数根据长度转换成整数的形式，其本质和正数是一样的// （这个函数不是用来让lua代码直接调用的，而是实现给C代码调用的，所以这个函数的书写形式不同于平常的被Lua调用的C代码）static ptrdiff_t posrelat (ptrdiff_t pos, size_t len) { /* relative string position: negative means back from end */ if (pos < 0) pos += (ptrdiff_t)len + 1; return (pos >= 0) ? pos : 0;}// 截取字符串static int str_sub (lua_State *L) { size_t l; const char *s = luaL_checklstring(L, 1, &l); ptrdiff_t start = posrelat(luaL_checkinteger(L, 2), l); ptrdiff_t end = posrelat(luaL_optinteger(L, 3, -1), l); if (start < 1) start = 1; if (end > (ptrdiff_t)l) end = (ptrdiff_t)l; if (start <= end) lua_pushlstring(L, s+start-1, end-start+1); else lua_pushliteral(L, ""); return 1;}// 翻转字符串// luaL_Buffer创建一个允许C代码编译的Lua字符串块，它的使用模式如下：// 1、首先定义一个luaL_Buffer类型的变量// 2、然后用luaL_buffinit(L, &b)初始化一下// 3、然后用luaL_addchar(&b, s[l])来add一下string// 4、最后用luaL_pushresult(&b)来压入栈顶static int str_reverse (lua_State *L) { size_t l; luaL_Buffer b; const char *s = luaL_checklstring(L, 1, &l); luaL_buffinit(L, &b); while (l--) luaL_addchar(&b, s[l]); luaL_pushresult(&b); return 1;}// 字符串转换小写static int str_lower (lua_State *L) { size_t l; size_t i; luaL_Buffer b; const char *s = luaL_checklstring(L, 1, &l); luaL_buffinit(L, &b); for (i=0; i<l; i++) luaL_addchar(&b, tolower(uchar(s[i]))); luaL_pushresult(&b); return 1;}// 字符串转换大写static int str_upper (lua_State *L) { size_t l; size_t i; luaL_Buffer b; const char *s = luaL_checklstring(L, 1, &l); luaL_buffinit(L, &b); for (i=0; i<l; i++) luaL_addchar(&b, toupper(uchar(s[i]))); luaL_pushresult(&b); return 1;}// 复制n段字符串static int str_rep (lua_State *L) { size_t l; luaL_Buffer b; const char *s = luaL_checklstring(L, 1, &l); int n = luaL_checkint(L, 2); luaL_buffinit(L, &b); while (n-- > 0) luaL_addlstring(&b, s, l); luaL_pushresult(&b); return 1;}// 返回某个字符的内部数值表示static int str_byte (lua_State *L) { size_t l; const char *s = luaL_checklstring(L, 1, &l); ptrdiff_t posi = posrelat(luaL_optinteger(L, 2, 1), l); ptrdiff_t pose = posrelat(luaL_optinteger(L, 3, posi), l); int n, i; if (posi <= 0) posi = 1; if ((size_t)pose > l) pose = l; if (posi > pose) return 0; /* empty interval; return no values */ n = (int)(pose - posi + 1); if (posi + n <= pose) /* overflow? */ luaL_error(L, "string slice too long"); luaL_checkstack(L, n, "string slice too long"); for (i=0; i<n; i++) lua_pushinteger(L, uchar(s[posi+i-1])); return n;}// 将整数转换为字符// luaL_argcheck检查参数是否满足条件，不满足的话抛出一条错误// #define uchar(c) ((unsigned char)(c)) 这个宏将整数转换为字符static int str_char (lua_State *L) { int n = lua_gettop(L); /* number of arguments */ int i; luaL_Buffer b; luaL_buffinit(L, &b); for (i=1; i<=n; i++) { int c = luaL_checkint(L, i); luaL_argcheck(L, uchar(c) == c, i, "invalid value"); luaL_addchar(&b, uchar(c)); } luaL_pushresult(&b); return 1;}static int writer (lua_State *L, const void* b, size_t size, void* B) { (void)L; luaL_addlstring((luaL_Buffer*) B, (const char *)b, size); return 0;} // lua_settop(L, 1);把栈顶位置设置为1static int str_dump (lua_State *L) { luaL_Buffer b; luaL_checktype(L, 1, LUA_TFUNCTION); lua_settop(L, 1); luaL_buffinit(L,&b); if (lua_dump(L, writer, &b) != 0) luaL_error(L, "unable to dump given function"); luaL_pushresult(&b); return 1;}/*** {======================================================** PATTERN MATCHING** =======================================================*/#define CAP_UNFINISHED (-1)#define CAP_POSITION (-2)typedef struct MatchState { const char *src_init; /* init of source string */ const char *src_end; /* end (`/0') of source string */ lua_State *L; int level; /* total number of captures (finished or unfinished) */ struct { const char *init; ptrdiff_t len; } capture[LUA_MAXCAPTURES];} MatchState;#define L_ESC '%'#define SPECIALS "^$*+?.([%-"static int check_capture (MatchState *ms, int l) { l -= '1'; if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED) return luaL_error(ms->L, "invalid capture index"); return l;}static int capture_to_close (MatchState *ms) { int level = ms->level; for (level--; level>=0; level--) if (ms->capture[level].len == CAP_UNFINISHED) return level; return luaL_error(ms->L, "invalid pattern capture");}static const char *classend (MatchState *ms, const char *p) { switch (*p++) { case L_ESC: { if (*p == '/0') luaL_error(ms->L, "malformed pattern (ends with " LUA_QL("%%") ")"); return p+1; } case '[': { if (*p == '^') p++; do { /* look for a `]' */ if (*p == '/0') luaL_error(ms->L, "malformed pattern (missing " LUA_QL("]") ")"); if (*(p++) == L_ESC && *p != '/0') p++; /* skip escapes (e.g. `%]') */ } while (*p != ']'); return p+1; } default: { return p; } }}static int match_class (int c, int cl) { int res; switch (tolower(cl)) { case 'a' : res = isalpha(c); break; case 'c' : res = iscntrl(c); break; case 'd' : res = isdigit(c); break; case 'l' : res = islower(c); break; case 'p' : res = ispunct(c); break; case 's' : res = isspace(c); break; case 'u' : res = isupper(c); break; case 'w' : res = isalnum(c); break; case 'x' : res = isxdigit(c); break; case 'z' : res = (c == 0); break; default: return (cl == c); } return (islower(cl) ? res : !res);}static int matchbracketclass (int c, const char *p, const char *ec) { int sig = 1; if (*(p+1) == '^') { sig = 0; p++; /* skip the `^' */ } while (++p < ec) { if (*p == L_ESC) { p++; if (match_class(c, uchar(*p))) return sig; } else if ((*(p+1) == '-') && (p+2 < ec)) { p+=2; if (uchar(*(p-2)) <= c && c <= uchar(*p)) return sig; } else if (uchar(*p) == c) return sig; } return !sig;}static int singlematch (int c, const char *p, const char *ep) { switch (*p) { case '.': return 1; /* matches any char */ case L_ESC: return match_class(c, uchar(*(p+1))); case '[': return matchbracketclass(c, p, ep-1); default: return (uchar(*p) == c); }}static const char *match (MatchState *ms, const char *s, const char *p);static const char *matchbalance (MatchState *ms, const char *s, const char *p) { if (*p == 0 || *(p+1) == 0) luaL_error(ms->L, "unbalanced pattern"); if (*s != *p) return NULL; else { int b = *p; int e = *(p+1); int cont = 1; while (++s < ms->src_end) { if (*s == e) { if (--cont == 0) return s+1; } else if (*s == b) cont++; } } return NULL; /* string ends out of balance */}static const char *max_expand (MatchState *ms, const char *s, const char *p, const char *ep) { ptrdiff_t i = 0; /* counts maximum expand for item */ while ((s+i)<ms->src_end && singlematch(uchar(*(s+i)), p, ep)) i++; /* keeps trying to match with the maximum repetitions */ while (i>=0) { const char *res = match(ms, (s+i), ep+1); if (res) return res; i--; /* else didn't match; reduce 1 repetition to try again */ } return NULL;}static const char *min_expand (MatchState *ms, const char *s, const char *p, const char *ep) { for (;;) { const char *res = match(ms, s, ep+1); if (res != NULL) return res; else if (s<ms->src_end && singlematch(uchar(*s), p, ep)) s++; /* try with one more repetition */ else return NULL; }}static const char *start_capture (MatchState *ms, const char *s, const char *p, int what) { const char *res; int level = ms->level; if (level >= LUA_MAXCAPTURES) luaL_error(ms->L, "too many captures"); ms->capture[level].init = s; ms->capture[level].len = what; ms->level = level+1; if ((res=match(ms, s, p)) == NULL) /* match failed? */ ms->level--; /* undo capture */ return res;}static const char *end_capture (MatchState *ms, const char *s, const char *p) { int l = capture_to_close(ms); const char *res; ms->capture[l].len = s - ms->capture[l].init; /* close capture */ if ((res = match(ms, s, p)) == NULL) /* match failed? */ ms->capture[l].len = CAP_UNFINISHED; /* undo capture */ return res;}static const char *match_capture (MatchState *ms, const char *s, int l) { size_t len; l = check_capture(ms, l); len = ms->capture[l].len; if ((size_t)(ms->src_end-s) >= len && memcmp(ms->capture[l].init, s, len) == 0) return s+len; else return NULL;}static const char *match (MatchState *ms, const char *s, const char *p) { init: /* using goto's to optimize tail recursion */ switch (*p) { case '(': { /* start capture */ if (*(p+1) == ')') /* position capture? */ return start_capture(ms, s, p+2, CAP_POSITION); else return start_capture(ms, s, p+1, CAP_UNFINISHED); } case ')': { /* end capture */ return end_capture(ms, s, p+1); } case L_ESC: { switch (*(p+1)) { case 'b': { /* balanced string? */ s = matchbalance(ms, s, p+2); if (s == NULL) return NULL; p+=4; goto init; /* else return match(ms, s, p+4); */ } case 'f': { /* frontier? */ const char *ep; char PRevious; p += 2; if (*p != '[') luaL_error(ms->L, "missing " LUA_QL("[") " after " LUA_QL("%%f") " in pattern"); ep = classend(ms, p); /* points to what is next */ previous = (s == ms->src_init) ? '/0' : *(s-1); if (matchbracketclass(uchar(previous), p, ep-1) || !matchbracketclass(uchar(*s), p, ep-1)) return NULL; p=ep; goto init; /* else return match(ms, s, ep); */ } default: { if (isdigit(uchar(*(p+1)))) { /* capture results (%0-%9)? */ s = match_capture(ms, s, uchar(*(p+1))); if (s == NULL) return NULL; p+=2; goto init; /* else return match(ms, s, p+2) */ } goto dflt; /* case default */ } } } case '/0': { /* end of pattern */ return s; /* match succeeded */ } case '$': { if (*(p+1) == '/0') /* is the `$' the last char in pattern? */ return (s == ms->src_end) ? s : NULL; /* check end of string */ else goto dflt; } default: dflt: { /* it is a pattern item */ const char *ep = classend(ms, p); /* points to what is next */ int m = s<ms->src_end && singlematch(uchar(*s), p, ep); switch (*ep) { case '?': { /* optional */ const char *res; if (m && ((res=match(ms, s+1, ep+1)) != NULL)) return res; p=ep+1; goto init; /* else return match(ms, s, ep+1); */ } case '*': { /* 0 or more repetitions */ return max_expand(ms, s, p, ep); } case '+': { /* 1 or more repetitions */ return (m ? max_expand(ms, s+1, p, ep) : NULL); } case '-': { /* 0 or more repetitions (minimum) */ return min_expand(ms, s, p, ep); } default: { if (!m) return NULL; s++; p=ep; goto init; /* else return match(ms, s+1, ep); */ } } } }}static const char *lmemfind (const char *s1, size_t l1, const char *s2, size_t l2) { if (l2 == 0) return s1; /* empty strings are everywhere */ else if (l2 > l1) return NULL; /* avoids a negative `l1' */ else { const char *init; /* to search for a `*s2' inside `s1' */ l2--; /* 1st char will be checked by `memchr' */ l1 = l1-l2; /* `s2' cannot be found after that */ while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) { init++; /* 1st char is already checked */ if (memcmp(init, s2+1, l2) == 0) return init-1; else { /* correct `l1' and `s1' to try again */ l1 -= init-s1; s1 = init; } } return NULL; /* not found */ }}static void push_onecapture (MatchState *ms, int i, const char *s, const char *e) { if (i >= ms->level) { if (i == 0) /* ms->level == 0, too */ lua_pushlstring(ms->L, s, e - s); /* add whole match */ else luaL_error(ms->L, "invalid capture index"); } else { ptrdiff_t l = ms->capture[i].len; if (l == CAP_UNFINISHED) luaL_error(ms->L, "unfinished capture"); if (l == CAP_POSITION) lua_pushinteger(ms->L, ms->capture[i].init - ms->src_init + 1); else lua_pushlstring(ms->L, ms->capture[i].init, l); }}static int push_captures (MatchState *ms, const char *s, const char *e) { int i; int nlevels = (ms->level == 0 && s) ? 1 : ms->level; luaL_checkstack(ms->L, nlevels, "too many captures"); for (i = 0; i < nlevels; i++) push_onecapture(ms, i, s, e); return nlevels; /* number of strings pushed */} //若调用的是string.find()并且第四个参数为true，表明忽略模式中的特殊字符，只做简单的原始匹配 //或者模式中，不存在特殊字符，也是做简单的原始匹配，这些特殊字符，包括"^$*+?.([%-"，它是用 //宏SPECIALS来定义的，利用内部接口nospecials来判断模式中是否有特殊字符static int str_find_aux (lua_State *L, int find) { size_t l1, l2; const char *s = luaL_checklstring(L, 1, &l1);////获取原始数据字符串 const char *p = luaL_checklstring(L, 2, &l2);////获取模式字符串 ptrdiff_t init = posrelat(luaL_optinteger(L, 3, 1), l1) - 1;//获取开始匹配的位置 if (init < 0) init = 0; else if ((size_t)(init) > l1) init = (ptrdiff_t)l1; if (find && (lua_toboolean(L, 4) || /* explicit request? */ strpbrk(p, SPECIALS) == NULL)) { /* or no special characters? */ /* do a plain search */ const char *s2 = lmemfind(s+init, l1-init, p, l2); if (s2) { lua_pushinteger(L, s2-s+1); lua_pushinteger(L, s2-s+l2); return 2; } } else { MatchState ms; int anchor = (*p == '^') ? (p++, 1) : 0; const char *s1=s+init; ms.L = L; ms.src_init = s; ms.src_end = s+l1; do { const char *res; ms.level = 0; if ((res=match(&ms, s1, p)) != NULL) { if (find) { lua_pushinteger(L, s1-s+1); /* start */ lua_pushinteger(L, res-s); /* end */ return push_captures(&ms, NULL, 0) + 2; } else return push_captures(&ms, s1, res); } } while (s1++ < ms.src_end && !anchor); } lua_pushnil(L); /* not found */ return 1;}static int str_find (lua_State *L) { return str_find_aux(L, 1);}static int str_match (lua_State *L) { return str_find_aux(L, 0);}static int gmatch_aux (lua_State *L) { MatchState ms; size_t ls; const char *s = lua_tolstring(L, lua_upvalueindex(1), &ls); const char *p = lua_tostring(L, lua_upvalueindex(2)); const char *src; ms.L = L; ms.src_init = s; ms.src_end = s+ls; for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3)); src <= ms.src_end; src++) { const char *e; ms.level = 0; if ((e = match(&ms, src, p)) != NULL) { lua_Integer newstart = e-s; if (e == src) newstart++; /* empty match? go at least one position */ lua_pushinteger(L, newstart); lua_replace(L, lua_upvalueindex(3)); return push_captures(&ms, src, e); } } return 0; /* not found */}static int gmatch (lua_State *L) { luaL_checkstring(L, 1); luaL_checkstring(L, 2); lua_settop(L, 2); lua_pushinteger(L, 0); lua_pushcclosure(L, gmatch_aux, 3); return 1;}static int gfind_nodef (lua_State *L) { return luaL_error(L, LUA_QL("string.gfind") " was renamed to " LUA_QL("string.gmatch"));}static void add_s (MatchState *ms, luaL_Buffer *b, const char *s, const char *e) { size_t l, i; const char *news = lua_tolstring(ms->L, 3, &l); for (i = 0; i < l; i++) { if (news[i] != L_ESC) luaL_addchar(b, news[i]); else { i++; /* skip ESC */ if (!isdigit(uchar(news[i]))) luaL_addchar(b, news[i]); else if (news[i] == '0') luaL_addlstring(b, s, e - s); else { push_onecapture(ms, news[i] - '1', s, e); luaL_addvalue(b); /* add capture to accumulated result */ } } }}static void add_value (MatchState *ms, luaL_Buffer *b, const char *s, const char *e) { lua_State *L = ms->L; switch (lua_type(L, 3)) { case LUA_TNUMBER: case LUA_TSTRING: { add_s(ms, b, s, e); return; } case LUA_TFUNCTION: { int n; lua_pushvalue(L, 3); n = push_captures(ms, s, e); lua_call(L, n, 1); break; } case LUA_TTABLE: { push_onecapture(ms, 0, s, e); lua_gettable(L, 3); break; } } if (!lua_toboolean(L, -1)) { /* nil or false? */ lua_pop(L, 1); lua_pushlstring(L, s, e - s); /* keep original text */ } else if (!lua_isstring(L, -1)) luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1)); luaL_addvalue(b); /* add result to accumulator */}static int str_gsub (lua_State *L) { size_t srcl; const char *src = luaL_checklstring(L, 1, &srcl); const char *p = luaL_checkstring(L, 2); int tr = lua_type(L, 3); int max_s = luaL_optint(L, 4, srcl+1); int anchor = (*p == '^') ? (p++, 1) : 0; int n = 0; MatchState ms; luaL_Buffer b; luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING || tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3, "string/function/table expected"); luaL_buffinit(L, &b); ms.L = L; ms.src_init = src; ms.src_end = src+srcl; while (n < max_s) { const char *e; ms.level = 0; e = match(&ms, src, p); if (e) { n++; add_value(&ms, &b, src, e); } if (e && e>src) /* non empty match? */ src = e; /* skip it */ else if (src < ms.src_end) luaL_addchar(&b, *src++); else break; if (anchor) break; } luaL_addlstring(&b, src, ms.src_end-src); luaL_pushresult(&b); lua_pushinteger(L, n); /* number of substitutions */ return 2;}/* }====================================================== *//* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */#define MAX_ITEM 512/* valid flags in a format specification */#define FLAGS "-+ #0"/*** maximum size of each format specification (such as '%-099.99d')** (+10 accounts for %99.99x plus margin of error)*/#define MAX_FORMAT (sizeof(FLAGS) + sizeof(LUA_INTFRMLEN) + 10)static void addquoted (lua_State *L, luaL_Buffer *b, int arg) { size_t l; const char *s = luaL_checklstring(L, arg, &l); luaL_addchar(b, '"'); while (l--) { switch (*s) { case '"': case '//': case '/n': { luaL_addchar(b, '//'); luaL_addchar(b, *s); break; } case '/r': { luaL_addlstring(b, "//r", 2); break; } case '/0': { luaL_addlstring(b, "//000", 4); break; } default: { luaL_addchar(b, *s); break; } } s++; } luaL_addchar(b, '"');}static const char *scanformat (lua_State *L, const char *strfrmt, char *form) { const char *p = strfrmt; while (*p != '/0' && strchr(FLAGS, *p) != NULL) p++; /* skip flags */ if ((size_t)(p - strfrmt) >= sizeof(FLAGS)) luaL_error(L, "invalid format (repeated flags)"); if (isdigit(uchar(*p))) p++; /* skip width */ if (isdigit(uchar(*p))) p++; /* (2 digits at most) */ if (*p == '.') { p++; if (isdigit(uchar(*p))) p++; /* skip precision */ if (isdigit(uchar(*p))) p++; /* (2 digits at most) */ } if (isdigit(uchar(*p))) luaL_error(L, "invalid format (width or precision too long)"); *(form++) = '%'; strncpy(form, strfrmt, p - strfrmt + 1); form += p - strfrmt + 1; *form = '/0'; return p;}static void addintlen (char *form) { size_t l = strlen(form); char spec = form[l - 1]; strcpy(form + l - 1, LUA_INTFRMLEN); form[l + sizeof(LUA_INTFRMLEN) - 2] = spec; form[l + sizeof(LUA_INTFRMLEN) - 1] = '/0';}// 控制字符串的输出格式static int str_format (lua_State *L) { int top = lua_gettop(L); int arg = 1; size_t sfl; const char *strfrmt = luaL_checklstring(L, arg, &sfl); const char *strfrmt_end = strfrmt+sfl; luaL_Buffer b; luaL_buffinit(L, &b); while (strfrmt < strfrmt_end) { if (*strfrmt != L_ESC) luaL_addchar(&b, *strfrmt++); else if (*++strfrmt == L_ESC) luaL_addchar(&b, *strfrmt++); /* %% */ else { /* format item */ char form[MAX_FORMAT]; /* to store the format (`%...') */ char buff[MAX_ITEM]; /* to store the formatted item */ if (++arg > top) luaL_argerror(L, arg, "no value"); strfrmt = scanformat(L, strfrmt, form); switch (*strfrmt++) { case 'c': { sprintf(buff, form, (int)luaL_checknumber(L, arg)); break; } case 'd': case 'i': { addintlen(form); sprintf(buff, form, (LUA_INTFRM_T)luaL_checknumber(L, arg)); break; } case 'o': case 'u': case 'x': case 'X': { addintlen(form); sprintf(buff, form, (unsigned LUA_INTFRM_T)luaL_checknumber(L, arg)); break; } case 'e': case 'E': case 'f': case 'g': case 'G': { sprintf(buff, form, (double)luaL_checknumber(L, arg)); break; } case 'q': { addquoted(L, &b, arg); continue; /* skip the 'addsize' at the end */ } case 's': { size_t l; const char *s = luaL_checklstring(L, arg, &l); if (!strchr(form, '.') && l >= 100) { /* no precision and string is too long to be formatted; keep original string */ lua_pushvalue(L, arg); luaL_addvalue(&b); continue; /* skip the `addsize' at the end */ } else { sprintf(buff, form, s); break; } } default: { /* also treat cases `pnLlh' */ return luaL_error(L, "invalid option " LUA_QL("%%%c") " to " LUA_QL("format"), *(strfrmt - 1)); } } luaL_addlstring(&b, buff, strlen(buff)); } } luaL_pushresult(&b); return 1;}static const luaL_Reg strlib[] = { {"byte", str_byte}, {"char", str_char}, {"dump", str_dump}, {"find", str_find}, {"format", str_format}, {"gfind", gfind_nodef}, {"gmatch", gmatch}, {"gsub", str_gsub}, {"len", str_len}, {"lower", str_lower}, {"match", str_match}, {"rep", str_rep}, {"reverse", str_reverse}, {"sub", str_sub}, {"upper", str_upper}, {NULL, NULL}};static void createmetatable (lua_State *L) { lua_createtable(L, 0, 1); /* create metatable for strings */ lua_pushliteral(L, ""); /* dummy string */ lua_pushvalue(L, -2); lua_setmetatable(L, -2); /* set string metatable */ lua_pop(L, 1); /* pop dummy string */ lua_pushvalue(L, -2); /* string library... */ lua_setfield(L, -2, "__index"); /* ...is the __index metamethod */ lua_pop(L, 1); /* pop metatable */}/*** Open string library*/LUALIB_API int luaopen_string (lua_State *L) { luaL_register(L, LUA_STRLIBNAME, strlib);#if defined(LUA_COMPAT_GFIND) lua_getfield(L, -1, "gmatch"); lua_setfield(L, -2, "gfind");#endif createmetatable(L); return 1;}
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