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authordaurnimator <quae@daurnimator.com>2017-06-01 18:05:11 +1000
committerdaurnimator <quae@daurnimator.com>2017-06-01 18:10:40 +1000
commit9fea5d9d6b32a8694d150398c2fff55c6696ba5f (patch)
treed55dad0199eeaa9729b3289eb767472bc9e59855
parent82694d3d46b6488982407de6218e5c7b768287cd (diff)
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src/lobject.js: Remove .slice operations from lua_strx2number
-rw-r--r--src/lobject.js42
1 files changed, 19 insertions, 23 deletions
diff --git a/src/lobject.js b/src/lobject.js
index 7174ef6..32fdba5 100644
--- a/src/lobject.js
+++ b/src/lobject.js
@@ -363,6 +363,7 @@ const MAXSIGDIG = 30;
** C99 specification for 'strtod'
*/
const lua_strx2number = function(s) {
+ let i = 0;
let dot = char[luaconf.lua_getlocaledecpoint()];
let r = 0.0; /* result (accumulator) */
let sigdig = 0; /* number of significant digits */
@@ -370,23 +371,20 @@ const lua_strx2number = function(s) {
let e = 0; /* exponent correction */
let neg; /* 1 if number is negative */
let hasdot = false; /* true after seen a dot */
-
- while (ljstype.lisspace(s[0])) s = s.slice(1); /* skip initial spaces */
-
- neg = s[0] === char['-']; /* check signal */
- s = neg || s[0] === char['+'] ? s.slice(1) : s; /* skip sign if one */
- if (!(s[0] === char['0'] && (s[1] === char['x'] || s[1] === char['X']))) /* check '0x' */
+ while (ljstype.lisspace(s[i])) i++; /* skip initial spaces */
+ if ((neg = (s[i] === char['-']))) i++; /* check signal */
+ else if (s[i] === char['+']) i++;
+ if (!(s[i] === char['0'] && (s[i+1] === char['x'] || s[i+1] === char['X']))) /* check '0x' */
return null; /* invalid format (no '0x') */
-
- for (s = s.slice(2); ; s = s.slice(1)) { /* skip '0x' and read numeral */
- if (s[0] === dot) {
+ for (i += 2; ; i++) { /* skip '0x' and read numeral */
+ if (s[i] === dot) {
if (hasdot) break; /* second dot? stop loop */
else hasdot = true;
- } else if (ljstype.lisxdigit(s[0])) {
- if (sigdig === 0 && s[0] === char['0']) /* non-significant digit (zero)? */
+ } else if (ljstype.lisxdigit(s[i])) {
+ if (sigdig === 0 && s[i] === char['0']) /* non-significant digit (zero)? */
nosigdig++;
else if (++sigdig <= MAXSIGDIG) /* can read it without overflow? */
- r = (r * 16) + luaO_hexavalue(s[0]);
+ r = (r * 16) + luaO_hexavalue(s[i]);
else e++; /* too many digits; ignore, but still count for exponent */
if (hasdot) e--; /* decimal digit? correct exponent */
} else break; /* neither a dot nor a digit */
@@ -395,24 +393,22 @@ const lua_strx2number = function(s) {
if (nosigdig + sigdig === 0) /* no digits? */
return null; /* invalid format */
e *= 4; /* each digit multiplies/divides value by 2^4 */
- if (s[0] === char['p'] || s[0] === char['P']) { /* exponent part? */
+ if (s[i] === char['p'] || s[i] === char['P']) { /* exponent part? */
let exp1 = 0; /* exponent value */
let neg1; /* exponent signal */
- s = s.slice(1); /* skip 'p' */
- neg1 = s[0] === char['-']; /* check signal */
- s = neg1 || s[0] === char['+'] ? s.slice(1) : s; /* skip sign if one */
- if (!ljstype.lisdigit(s[0]))
+ i++; /* skip 'p' */
+ if ((neg1 = (s[i] === char['-']))) i++; /* signal */
+ else if (s[i] === char['+']) i++;
+ if (!ljstype.lisdigit(s[i]))
return null; /* invalid; must have at least one digit */
- while (ljstype.lisdigit(s[0])) { /* read exponent */
- exp1 = exp1 * 10 + s[0] - char['0'];
- s = s.slice(1);
- }
+ while (ljstype.lisdigit(s[i])) /* read exponent */
+ exp1 = exp1 * 10 + s[i++] - char['0'];
if (neg1) exp1 = -exp1;
e += exp1;
}
if (neg) r = -r;
- while (ljstype.lisspace(s[0])) s = s.slice(1); /* skip trailing spaces */
- return s.length === 0 ? luaconf.ldexp(r, e) : null; /* Only valid if nothing left is s*/
+ while (ljstype.lisspace(s[i])) i++; /* skip trailing spaces */
+ return i === s.length ? luaconf.ldexp(r, e) : null; /* Only valid if nothing left is s*/
};
const lua_str2number = function(s) {