/* ** $Id: lutf8lib.c,v 1.16.1.1 2017/04/19 17:29:57 roberto Exp $ ** Standard library for UTF-8 manipulation ** See Copyright Notice in lua.h */ #define lutf8lib_c #define LUA_LIB #include "lprefix.h" #include #include #include #include #include "lua.h" #include "lauxlib.h" #include "lualib.h" #define MAXUNICODE 0x10FFFF #define iscont(p) ((*(p) & 0xC0) == 0x80) /* from strlib */ /* translate a relative string position: negative means back from end */ static lua_Integer u_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; } /* ** Decode one UTF-8 sequence, returning NULL if byte sequence is invalid. */ static const char *utf8_decode (const char *o, int *val) { static const unsigned int limits[] = {0xFF, 0x7F, 0x7FF, 0xFFFF}; const unsigned char *s = (const unsigned char *)o; unsigned int c = s[0]; unsigned int res = 0; /* final result */ if (c < 0x80) /* ascii? */ res = c; else { int count = 0; /* to count number of continuation bytes */ while (c & 0x40) { /* still have continuation bytes? */ int cc = s[++count]; /* read next byte */ if ((cc & 0xC0) != 0x80) /* not a continuation byte? */ return NULL; /* invalid byte sequence */ res = (res << 6) | (cc & 0x3F); /* add lower 6 bits from cont. byte */ c <<= 1; /* to test next bit */ } res |= ((c & 0x7F) << (count * 5)); /* add first byte */ if (count > 3 || res > MAXUNICODE || res <= limits[count]) return NULL; /* invalid byte sequence */ s += count; /* skip continuation bytes read */ } if (val) *val = res; return (const char *)s + 1; /* +1 to include first byte */ } /* ** utf8len(s [, i [, j]]) --> number of characters that start in the ** range [i,j], or nil + current position if 's' is not well formed in ** that interval */ static int utflen (lua_State *L) { int n = 0; size_t len; const char *s = luaL_checklstring(L, 1, &len); lua_Integer posi = u_posrelat(luaL_optinteger(L, 2, 1), len); lua_Integer posj = u_posrelat(luaL_optinteger(L, 3, -1), len); luaL_argcheck(L, 1 <= posi && --posi <= (lua_Integer)len, 2, "initial position out of string"); luaL_argcheck(L, --posj < (lua_Integer)len, 3, "final position out of string"); while (posi <= posj) { const char *s1 = utf8_decode(s + posi, NULL); if (s1 == NULL) { /* conversion error? */ lua_pushnil(L); /* return nil ... */ lua_pushinteger(L, posi + 1); /* ... and current position */ return 2; } posi = s1 - s; n++; } lua_pushinteger(L, n); return 1; } /* ** codepoint(s, [i, [j]]) -> returns codepoints for all characters ** that start in the range [i,j] */ static int codepoint (lua_State *L) { size_t len; const char *s = luaL_checklstring(L, 1, &len); lua_Integer posi = u_posrelat(luaL_optinteger(L, 2, 1), len); lua_Integer pose = u_posrelat(luaL_optinteger(L, 3, posi), len); int n; const char *se; luaL_argcheck(L, posi >= 1, 2, "out of range"); luaL_argcheck(L, pose <= (lua_Integer)len, 3, "out of range"); if (posi > pose) return 0; /* empty interval; return no values */ if (pose - posi >= INT_MAX) /* (lua_Integer -> int) overflow? */ return luaL_error(L, "string slice too long"); n = (int)(pose - posi) + 1; luaL_checkstack(L, n, "string slice too long"); n = 0; se = s + pose; for (s += posi - 1; s < se;) { int code; s = utf8_decode(s, &code); if (s == NULL) return luaL_error(L, "invalid UTF-8 code"); lua_pushinteger(L, code); n++; } return n; } static void pushutfchar (lua_State *L, int arg) { lua_Integer code = luaL_checkinteger(L, arg); luaL_argcheck(L, 0 <= code && code <= MAXUNICODE, arg, "value out of range"); lua_pushfstring(L, "%U", (long)code); } /* ** utfchar(n1, n2, ...) -> char(n1)..char(n2)... */ static int utfchar (lua_State *L) { int n = lua_gettop(L); /* number of arguments */ if (n == 1) /* optimize common case of single char */ pushutfchar(L, 1); else { int i; luaL_Buffer b; luaL_buffinit(L, &b); for (i = 1; i <= n; i++) { pushutfchar(L, i); luaL_addvalue(&b); } luaL_pushresult(&b); } return 1; } /* ** offset(s, n, [i]) -> index where n-th character counting from ** position 'i' starts; 0 means character at 'i'. */ static int byteoffset (lua_State *L) { size_t len; const char *s = luaL_checklstring(L, 1, &len); lua_Integer n = luaL_checkinteger(L, 2); lua_Integer posi = (n >= 0) ? 1 : len + 1; posi = u_posrelat(luaL_optinteger(L, 3, posi), len); luaL_argcheck(L, 1 <= posi && --posi <= (lua_Integer)len, 3, "position out of range"); if (n == 0) { /* find beginning of current byte sequence */ while (posi > 0 && iscont(s + posi)) posi--; } else { if (iscont(s + posi)) return luaL_error(L, "initial position is a continuation byte"); if (n < 0) { while (n < 0 && posi > 0) { /* move back */ do { /* find beginning of previous character */ posi--; } while (posi > 0 && iscont(s + posi)); n++; } } else { n--; /* do not move for 1st character */ while (n > 0 && posi < (lua_Integer)len) { do { /* find beginning of next character */ posi++; } while (iscont(s + posi)); /* (cannot pass final '\0') */ n--; } } } if (n == 0) /* did it find given character? */ lua_pushinteger(L, posi + 1); else /* no such character */ lua_pushnil(L); return 1; } static int iter_aux (lua_State *L) { size_t len; const char *s = luaL_checklstring(L, 1, &len); lua_Integer n = lua_tointeger(L, 2) - 1; if (n < 0) /* first iteration? */ n = 0; /* start from here */ else if (n < (lua_Integer)len) { n++; /* skip current byte */ while (iscont(s + n)) n++; /* and its continuations */ } if (n >= (lua_Integer)len) return 0; /* no more codepoints */ else { int code; const char *next = utf8_decode(s + n, &code); if (next == NULL || iscont(next)) return luaL_error(L, "invalid UTF-8 code"); lua_pushinteger(L, n + 1); lua_pushinteger(L, code); return 2; } } static int iter_codes (lua_State *L) { luaL_checkstring(L, 1); lua_pushcfunction(L, iter_aux); lua_pushvalue(L, 1); lua_pushinteger(L, 0); return 3; } /* pattern to match a single UTF-8 character */ #define UTF8PATT "[\0-\x7F\xC2-\xF4][\x80-\xBF]*" static const luaL_Reg funcs[] = { {"offset", byteoffset}, {"codepoint", codepoint}, {"char", utfchar}, {"len", utflen}, {"codes", iter_codes}, /* placeholders */ {"charpattern", NULL}, {NULL, NULL} }; LUAMOD_API int luaopen_utf8 (lua_State *L) { luaL_newlib(L, funcs); lua_pushlstring(L, UTF8PATT, sizeof(UTF8PATT)/sizeof(char) - 1); lua_setfield(L, -2, "charpattern"); return 1; }