LUA脚本语言的实现C代码

/* ** $Id: lstrlib.c,v 1.256 2017/05/19 16:29:40 roberto Exp roberto $ ** Standard library for string operations and pattern-matching ** See Copyright Notice in lua.h */ #define lstrlib_c #define LUA_LIB #include "lprefix.h" #include <ctype.h> #include <float.h> #include <limits.h> #include <locale.h> #include <math.h> #include <stddef.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include "lua.h" #include "lauxlib.h" #include "lualib.h" /* ** maximum number of captures that a pattern can do during ** pattern-matching. This limit is arbitrary, but must fit in ** an unsigned char. */ #if !defined(LUA_MAXCAPTURES) #define LUA_MAXCAPTURES 32 #endif /* macro to 'unsign' a character */ #define uchar(c) ((unsigned char)(c)) /* ** Some sizes are better limited to fit in 'int', but must also fit in ** 'size_t'. (We assume that 'lua_Integer' cannot be smaller than 'int'.) */ #define MAX_SIZET ((size_t)(~(size_t)0)) #define MAXSIZE \ (sizeof(size_t) < sizeof(int) ? MAX_SIZET : (size_t)(INT_MAX)) static int str_len (lua_State *L) { size_t l; luaL_checklstring(L, 1, &l); lua_pushinteger(L, (lua_Integer)l); return 1; } /* translate a relative string position: negative means back from end */ static lua_Integer posrelat (lua_Integer pos, size_t len) { if (pos >= 0) return pos; else if (0u - (size_t)pos > len) return 0; else return (lua_Integer)len + pos + 1; } static int str_sub (lua_State *L) { size_t l; const char *s = luaL_checklstring(L, 1, &l); lua_Integer start = posrelat(luaL_checkinteger(L, 2), l); lua_Integer end = posrelat(luaL_optinteger(L, 3, -1), l); if (start < 1) start = 1; if (end > (lua_Integer)l) end = l; if (start <= end) lua_pushlstring(L, s + start - 1, (size_t)(end - start) + 1); else lua_pushliteral(L, ""); return 1; } static int str_reverse (lua_State *L) { size_t l, i; luaL_Buffer b; const char *s = luaL_checklstring(L, 1, &l); char *p = luaL_buffinitsize(L, &b, l); for (i = 0; i < l; i++) p[i] = s[l - i - 1]; luaL_pushresultsize(&b, l); return 1; } static int str_lower (lua_State *L) { size_t l; size_t i; luaL_Buffer b; const char *s = luaL_checklstring(L, 1, &l); char *p = luaL_buffinitsize(L, &b, l); for (i=0; i<l; i++) p[i] = tolower(uchar(s[i])); luaL_pushresultsize(&b, l); return 1; } static int str_upper (lua_State *L) { size_t l; size_t i; luaL_Buffer b; const char *s = luaL_checklstring(L, 1, &l); char *p = luaL_buffinitsize(L, &b, l); for (i=0; i<l; i++) p[i] = toupper(uchar(s[i])); luaL_pushresultsize(&b, l); return 1; } static int str_rep (lua_State *L) { size_t l, lsep; const char *s = luaL_checklstring(L, 1, &l); lua_Integer n = luaL_checkinteger(L, 2); const char *sep = luaL_optlstring(L, 3, "", &lsep); if (n <= 0) lua_pushliteral(L, ""); else if (l + lsep < l || l + lsep > MAXSIZE / n) /* may overflow? */ return luaL_error(L, "resulting string too large"); else { size_t totallen = (size_t)n * l + (size_t)(n - 1) * lsep; luaL_Buffer b; char *p = luaL_buffinitsize(L, &b, totallen); while (n-- > 1) { /* first n-1 copies (followed by separator) */ memcpy(p, s, l * sizeof(char)); p += l; if (lsep > 0) { /* empty 'memcpy' is not that cheap */ memcpy(p, sep, lsep * sizeof(char)); p += lsep; } } memcpy(p, s, l * sizeof(char)); /* last copy (not followed by separator) */ luaL_pushresultsize(&b, totallen); } return 1; } static int str_byte (lua_State *L) { size_t l; const char *s = luaL_checklstring(L, 1, &l); lua_Integer posi = posrelat(luaL_optinteger(L, 2, 1), l); lua_Integer pose = posrelat(luaL_optinteger(L, 3, posi), l); int n, i; if (posi < 1) posi = 1; if (pose > (lua_Integer)l) pose = l; if (posi > pose) return 0; /* empty interval; return no values */ if (pose - posi >= INT_MAX) /* arithmetic overflow? */ return luaL_error(L, "string slice too long"); n = (int)(pose - posi) + 1; luaL_checkstack(L, n, "string slice too long"); for (i=0; i<n; i++) lua_pushinteger(L, uchar(s[posi+i-1])); return n; } static int str_char (lua_State *L) { int n = lua_gettop(L); /* number of arguments */ int i; luaL_Buffer b; char *p = luaL_buffinitsize(L, &b, n); for (i=1; i<=n; i++) { lua_Integer c = luaL_checkinteger(L, i); luaL_argcheck(L, uchar(c) == c, i, "value out of range"); p[i - 1] = uchar(c); } luaL_pushresultsize(&b, n); 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; } static int str_dump (lua_State *L) { luaL_Buffer b; int strip = lua_toboolean(L, 2); luaL_checktype(L, 1, LUA_TFUNCTION); lua_settop(L, 1); luaL_buffinit(L,&b); if (lua_dump(L, writer, &b, strip) != 0) return luaL_error(L, "unable to dump given function"); luaL_pushresult(&b); return 1; } /* ** {====================================================== ** METAMETHODS ** ======================================================= */ static int tonum (lua_State *L, int arg) { if (lua_type(L, arg) == LUA_TNUMBER) { /* already a number? */ lua_pushvalue(L, arg); return 1; } else { /* check whether it is a numerical string */ size_t len; const char *s = lua_tolstring(L, arg, &len); return (s != NULL && lua_stringtonumber(L, s) == len + 1); } } static int arith (lua_State *L, int op, const char *mtname) { if (tonum(L, 1) && tonum(L, 2)) lua_arith(L, op); /* result will be on the top */ else { lua_settop(L, 2); /* back to the original arguments */ if (lua_type(L, 2) == LUA_TSTRING || !luaL_getmetafield(L, 2, mtname)) return luaL_error(L, "attempt to %s a '%s' with a '%s'", mtname + 2, luaL_typename(L, -2), luaL_typename(L, -1)); lua_insert(L, -3); /* put metamethod before arguments */ lua_call(L, 2, 1); /* call metamethod */ } return 1; } static int arith_add (lua_State *L) { return arith(L, LUA_OPADD, "__add"); } static int arith_sub (lua_State *L) { return arith(L, LUA_OPSUB, "__sub"); } static int arith_mul (lua_State *L) { return arith(L, LUA_OPMUL, "__mul"); } static int arith_mod (lua_State *L) { return arith(L, LUA_OPMOD, "__mod"); } static int arith_pow (lua_State *L) { return arith(L, LUA_OPPOW, "__pow"); } static int arith_div (lua_State *L) { return arith(L, LUA_OPDIV, "__div"); } static int arith_idiv (lua_State *L) { return arith(L, LUA_OPIDIV, "__idiv"); } static int arith_unm (lua_State *L) { return arith(L, LUA_OPUNM, "__unm"); } static const luaL_Reg stringmetamethods[] = { {"__add", arith_add}, {"__sub", arith_sub}, {"__mul", arith_mul}, {"__mod", arith_mod}, {"__pow", arith_pow}, {"__div", arith_div}, {"__idiv", arith_idiv}, {"__unm", arith_unm}, {"__index", NULL}, /* placeholder */ {NULL, NULL} }; /* }====================================================== */ /* ** {====================================================== ** 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 */ const char *p_end; /* end ('\0') of pattern */ lua_State *L; int matchdepth; /* control for recursive depth (to avoid C stack overflow) */ unsigned char level; /* total number of captures (finished or unfinished) */ struct { const char *init; ptrdiff_t len; } capture[LUA_MAXCAPTURES]; } MatchState; /* recursive function */ static const char *match (MatchState *ms, const char *s, const char *p); /* maximum recursion depth for 'match' */ #if !defined(MAXCCALLS) #define MAXCCALLS 200 #endif #define L_ESC '%' #define SPECIALS "^$*+?.([%-" static int check_capture