lexing

1 files changed, 124 insertions, 9 deletions

diff --git a/src/lobject.js b/src/lobject.js
index 086af00..93e23c2 100644
--- a/src/lobject.js
+++ b/src/lobject.js
@@ -1,8 +1,11 @@
-/*jshint esversion: 6 */
+ /*jshint esversion: 6 */
 "use strict";
 
-const CT    = require('./lua.js').constant_types;
-const UpVal = require('./lfunc.js').UpVal;
+const assert = require('assert');
+
+const ljstype = require('./ljstype.js');
+const CT      = require('./lua.js').constant_types;
+const UpVal   = require('./lfunc.js').UpVal;
 
 class TValue {
 
@@ -223,7 +226,7 @@ const luaO_chunkid = function(source, bufflen) {
         let nli = source.indexOf('\n');  /* find first new line (if any) */
         let nl = nli ? source.slice(nli) : null;
         out = `${PRE}`;  /* add prefix */
-        bufflen -= PRE.length - RETS.length; - POS.length + 1;  /* save space for prefix+suffix+'\0' */
+        bufflen -= PRE.length + RETS.length + POS.length + 1;  /* save space for prefix+suffix+'\0' */
         if (l < bufflen && nl === null) {  /* small one-line source? */
             out += `${source}`;  /* keep it */
         } else {
@@ -237,8 +240,120 @@ const luaO_chunkid = function(source, bufflen) {
     return out;
 };
 
-module.exports.LClosure     = LClosure;
-module.exports.CClosure     = CClosure;
-module.exports.TValue       = TValue;
-module.exports.Table        = Table;
-module.exports.luaO_chunkid = luaO_chunkid;
\ No newline at end of file
+const luaO_hexavalue = function(c) {
+    if (ljstype.lisdigit(c)) return c.charCodeAt(0) - '0'.charCodeAt(0);
+    else return (c.toLowerCase().charCodeAt(0) - 'a'.charCodeAt(0)) + 10;
+};
+
+const UTF8BUFFSZ = 8;
+
+const luaO_utf8desc = function(buff, x) {
+    let n = 1;  /* number of bytes put in buffer (backwards) */
+    assert(x <= 0x10FFFF);
+    if (x < 0x80)  /* ascii? */
+        buff[UTF8BUFFSZ - 1] = String.fromCharCode(x);
+    else {  /* need continuation bytes */
+        let mfb = 0x3f;  /* maximum that fits in first byte */
+        do {
+            buff[UTF8BUFFSZ - (n++)] = String.fromCharCode(0x80 | (x & 0x3f));
+            x >>= 6;  /* remove added bits */
+            mfb >>= 1;  /* now there is one less bit available in first byte */
+        } while (x > mfb);  /* still needs continuation byte? */
+        buff[UTF8BUFFSZ - n] = String.fromCharCode((~mfb << 1) | x);  /* add first byte */
+    }
+    return n;
+};
+
+const l_str2dloc = function(s, result, mode) {
+    result[0] = mode === 'x' ? parseInt(s, '16') : parseInt(s);
+    if (isNaN(result[0])) return null;  /* nothing recognized? */
+    while (ljstype.lisspace(result[0])) result[0] = result[0].slice(1);  /* skip trailing spaces */
+    return result[0] === '\0' ? result : null;  /* OK if no trailing characters */
+};
+
+const l_str2d = function(s) {
+    let result = [null, null];
+    let pidx = /[.xXnN]/g.exec(s).index;
+    let pmode = pidx ? s.slice(pidx) : null;
+    let mode = pmode ? pmode.toLowerCase() : 0;
+    if (mode === 'n')  /* reject 'inf' and 'nan' */
+        return null;
+    let end = l_str2dloc(s, result, mode)[0];  /* try to convert */
+    if (end === null) {   /* failed? may be a different locale */
+        throw new Error("Locale not available to handle number"); // TODO
+    }
+    return [end, result[1]];
+};
+
+const MAXBY10  = Number.MAX_SAFE_INTEGER / 10;
+const MAXLASTD = Number.MAX_SAFE_INTEGER % 10;
+
+const l_str2int = function(s) {
+    let result = [null, null];
+    let a = 0;
+    let empty = true;
+    let neg;
+
+    while (ljstype.lisspace(s.charAt(0))) s = s.slice(1);  /* skip initial spaces */
+    neg = s.charAt(0) === '-';
+
+    if (neg || s.charAt(0) === '+')
+        s = s.slice(1);
+
+    if (s[0] === '0' && (s[1] === 'x' || s[1] === 'X')) {  /* hex? */
+        s = s.slice(2);  /* skip '0x' */
+
+        for (; ljstype.lisxdigit(s); s = s.slice(1)) {
+            a = a * 16 + luaO_hexavalue(s);
+            empty = false;
+        }
+    } else {  /* decimal */
+        for (; ljstype.lisdigit(s); s = s.slice(1)) {
+            let d = parseInt(s.charAt(0));
+            if (a >= MAXBY10 && (a > MAXBY10 || d > MAXLASTD + neg))  /* overflow? */
+                return null;  /* do not accept it (as integer) */
+            a = a * 10 + d;
+            empty = false;
+        }
+    }
+
+    while (ljstype.lisspace(s.charAt(0))) s = s.slice(1);  /* skip trailing spaces */
+
+    if (empty || s.charAt(0) !== "") return null;  /* something wrong in the numeral */
+    else {
+        result[1] = neg ? -a : a;
+        result[0] = s;
+        return result;
+    }
+};
+
+const luaO_str2num = function(s) {
+    let s2i = l_str2int(s);
+    let e = s2i[0];
+    let i = s2i[1];
+
+    let o;
+    if (e !== null)   /* try as an integer */
+        o = new TValue(CT.LUA_TNUMINT, i);
+    else {   /* else try as a float */
+        s2i = l_str2d(s);
+        e = s2i[0];
+        i = s2i[1];
+
+        if (e !== null) {
+            o = new TValue(CT.LUA_TNUMFLT, i);
+        } else
+            return false;  /* conversion failed */
+        return (e - s) + 1; // TODO: wrong
+    }
+};
+
+module.exports.CClosure       = CClosure;
+module.exports.LClosure       = LClosure;
+module.exports.TValue         = TValue;
+module.exports.Table          = Table;
+module.exports.UTF8BUFFSZ     = UTF8BUFFSZ;
+module.exports.luaO_chunkid   = luaO_chunkid;
+module.exports.luaO_hexavalue = luaO_hexavalue;
+module.exports.luaO_str2num   = luaO_str2num;
+module.exports.luaO_utf8desc  = luaO_utf8desc;
\ No newline at end of file