diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/linit.js | 2 | ||||
| -rw-r--r-- | src/lstrlib.js | 2 | ||||
| -rw-r--r-- | src/lutf8lib.js | 79 |
3 files changed, 81 insertions, 2 deletions
diff --git a/src/linit.js b/src/linit.js index f9f8296..4d50f8b 100644 --- a/src/linit.js +++ b/src/linit.js @@ -9,6 +9,7 @@ const lcorolib = require('./lcorolib.js'); const lmathlib = require('./lmathlib.js'); const lstrlib = require('./lstrlib.js'); const ltablib = require('./ltablib.js'); +const lutf8lib = require('./lutf8lib.js'); const lualib = require('./lualib.js'); const loadedlibs = { @@ -16,6 +17,7 @@ const loadedlibs = { [lualib.LUA_MATHLIBNAME]: lmathlib.luaopen_math, [lualib.LUA_STRLIBNAME]: lstrlib.luaopen_string, [lualib.LUA_TABLIBNAME]: ltablib.luaopen_table, + [lualib.LUA_UTF8LIBNAME]: lutf8lib.luaopen_utf8, "_G": lbaselib.luaopen_base }; diff --git a/src/lstrlib.js b/src/lstrlib.js index 2f89777..3db3e5e 100644 --- a/src/lstrlib.js +++ b/src/lstrlib.js @@ -5,8 +5,6 @@ const assert = require('assert'); const lua = require('./lua.js'); const lapi = require('./lapi.js'); const lauxlib = require('./lauxlib.js'); -const CT = lua.constant_types; -const TS = lua.thread_status; const str_len = function(L) { lapi.lua_pushinteger(L, lauxlib.luaL_checkstring(L, 1).length); diff --git a/src/lutf8lib.js b/src/lutf8lib.js new file mode 100644 index 0000000..bc43d54 --- /dev/null +++ b/src/lutf8lib.js @@ -0,0 +1,79 @@ +"use strict"; + +const assert = require('assert'); + +const lua = require('./lua.js'); +const lapi = require('./lapi.js'); +const lauxlib = require('./lauxlib.js'); + + +const iscont = function(p) { + return p & 0xC0 === 0x80; +}; + +/* translate a relative string position: negative means back from end */ +const u_posrelat = function(pos, len) { + if (pos >= 0) return pos; + else if (0 - pos > len) return 0; + else return len + pos + 1; +}; + +/* +** offset(s, n, [i]) -> index where n-th character counting from +** position 'i' starts; 0 means character at 'i'. +*/ +const byteoffset = function(L) { + let s = lauxlib.luaL_checkstring(L, 1); + let n = lauxlib.luaL_checkinteger(L, 2); + let posi = n >= 0 ? 1 : s.length + 1; + posi = u_posrelat(lauxlib.luaL_optinteger(L, 3, posi), s.length); + lauxlib.luaL_argcheck(L, 1 <= posi && --posi <= s.length, 3, "position ot ouf range"); + + if (n === 0) { + /* find beginning of current byte sequence */ + while (posi > 0 && iscont(s.slice(posi))) posi--; + } else { + if (iscont(s.slice(posi))) + lauxlib.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.slice(posi))); + n++; + } + } else { + n--; /* do not move for 1st character */ + while (n > 0 && posi < s.length) { + do { /* find beginning of next character */ + posi++; + } while (iscont(s.slice(posi))); /* (cannot pass final '\0') */ + n--; + } + } + } + + if (n === 0) /* did it find given character? */ + lapi.lua_pushinteger(L, posi + 1); + else /* no such character */ + lapi.lua_pushnil(L); + + return 1; +}; + +const funcs = { + "offset": byteoffset +}; + +/* pattern to match a single UTF-8 character */ +const UTF8PATT = "[\0-\x7F\xC2-\xF4][\x80-\xBF]*"; + +const luaopen_utf8 = function(L) { + lauxlib.luaL_newlib(L, funcs); + lapi.lua_pushstring(L, UTF8PATT); + lapi.lua_setfield(L, -2, "charpattern"); + return 1; +}; + +module.exports.luaopen_utf8 = luaopen_utf8;
\ No newline at end of file |