diff options
| -rw-r--r-- | src/lutf8lib.js | 44 |
1 files changed, 18 insertions, 26 deletions
diff --git a/src/lutf8lib.js b/src/lutf8lib.js index de97bec..3c9147a 100644 --- a/src/lutf8lib.js +++ b/src/lutf8lib.js @@ -21,18 +21,17 @@ const u_posrelat = function(pos, len) { /* ** Decode one UTF-8 sequence, returning NULL if byte sequence is invalid. */ -const utf8_decode = function(s) { - let limits = [0xFF, 0x7F, 0x7FF, 0xFFFF]; - let c = s[0]; +const limits = [0xFF, 0x7F, 0x7FF, 0xFFFF]; +const utf8_decode = function(s, pos) { + let c = s[pos]; let res = 0; /* final result */ - let pos = 0; if (c < 0x80) /* ascii? */ res = c; else { let count = 0; /* to count number of continuation bytes */ while (c & 0x40) { /* still have continuation bytes? */ - let cc = s[++count]; /* read next byte */ - if ((cc & 0xC0) != 0x80) /* not a continuation byte? */ + let cc = s[pos + (++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 */ @@ -40,12 +39,10 @@ const utf8_decode = function(s) { res |= ((c & 0x7F) << (count * 5)); /* add first byte */ if (count > 3 || res > MAXUNICODE || res <= limits[count]) return null; /* invalid byte sequence */ - s = s.slice(count); /* skip continuation bytes read */ - pos += count; + pos += count; /* skip continuation bytes read */ } return { - string: s.slice(1), /* +1 to include first byte */ code: res, pos: pos + 1 }; @@ -63,19 +60,17 @@ const utflen = function(L) { let posi = u_posrelat(lauxlib.luaL_optinteger(L, 2, 1), len); let posj = u_posrelat(lauxlib.luaL_optinteger(L, 3, -1), len); - lauxlib.luaL_argcheck(L, 1 <= posi && --posi <= len, 2, "initial position out of string"); - lauxlib.luaL_argcheck(L, --posj < len, 3, "final position out of string"); + lauxlib.luaL_argcheck(L, 1 <= posi && --posi <= len, 2, lua.to_luastring("initial position out of string")); + lauxlib.luaL_argcheck(L, --posj < len, 3, lua.to_luastring("final position out of string")); while (posi <= posj) { - let dec = utf8_decode(s.slice(posi)); - let s1 = dec ? dec.string : null; - if (s1 === null) { - /* conversion error? */ + let dec = utf8_decode(s, posi); + if (dec === null) { /* conversion error? */ lua.lua_pushnil(L); /* return nil ... */ lua.lua_pushinteger(L, posi + 1); /* ... and current position */ return 2; } - posi = s.length - s1.length; + posi = dec.pos; n++; } lua.lua_pushinteger(L, n); @@ -170,13 +165,12 @@ const codepoint = function(L) { let n = (pose - posi) + 1; lauxlib.luaL_checkstack(L, n, lua.to_luastring("string slice too long", true)); n = 0; - for (s = s.slice(posi - 1); n < pose - posi;) { - let dec = utf8_decode(s); + for (posi -= 1; posi < pose;) { + let dec = utf8_decode(s, posi); if (dec === null) return lauxlib.luaL_error(L, lua.to_luastring("invalid UTF-8 code", true)); - s = dec.string; - let code = dec.code; - lua.lua_pushinteger(L, code); + lua.lua_pushinteger(L, dec.code); + posi = dec.pos; n++; } return n; @@ -197,13 +191,11 @@ const iter_aux = function(L) { if (n >= len) return 0; /* no more codepoints */ else { - let dec = utf8_decode(s.slice(n)); - let code = dec ? dec.code : null; - let next = dec ? dec.string : null; - if (next === null || iscont(next[0])) + let dec = utf8_decode(s, n); + if (dec === null || iscont(s[dec.pos])) return lauxlib.luaL_error(L, lua.to_luastring("invalid UTF-8 code", true)); lua.lua_pushinteger(L, n + 1); - lua.lua_pushinteger(L, code); + lua.lua_pushinteger(L, dec.code); return 2; } }; |