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authorJohn MacFarlane <jgm@berkeley.edu>2014-10-02 10:33:49 -0700
committerJohn MacFarlane <jgm@berkeley.edu>2014-10-02 11:03:17 -0700
commitfb0c0cc2741120e3706c7698b15a510c40fc71c0 (patch)
tree5080a644487710b86c0aa42b7ee74ade9cdfb1e0
parent669ea14fdbf12c25693706502f8dae6b1cf4e033 (diff)
Changed peek() to return char code.
Test char codes instead of strings. Small optimization (about 1% speed boost).
-rwxr-xr-xjs/stmd.js106
1 files changed, 64 insertions, 42 deletions
diff --git a/js/stmd.js b/js/stmd.js
index 04d7360..788809b 100755
--- a/js/stmd.js
+++ b/js/stmd.js
@@ -2137,6 +2137,22 @@
zwj: '‍',
zwnj: '‌' };
+ // Constants for character codes:
+
+ var C_NEWLINE = 10;
+ var C_SPACE = 32;
+ var C_ASTERISK = 42;
+ var C_UNDERSCORE = 95;
+ var C_BACKTICK = 96;
+ var C_OPEN_BRACKET = 91;
+ var C_CLOSE_BRACKET = 93;
+ var C_LESSTHAN = 60;
+ var C_BANG = 33;
+ var C_BACKSLASH = 92;
+ var C_AMPERSAND = 38;
+ var C_OPEN_PAREN = 40;
+ var C_COLON = 58;
+
// Some regexps used in inline parser:
var ESCAPABLE = '[!"#$%&\'()*+,./:;<=>?@[\\\\\\]^_`{|}~-]';
@@ -2286,10 +2302,14 @@
}
};
- // Returns the character at the current subject position, or null if
+ // Returns the code for the character at the current subject position, or -1
// there are no more characters.
var peek = function() {
- return this.subject.charAt(this.pos) || null;
+ if (this.pos < this.subject.length) {
+ return this.subject.charCodeAt(this.pos);
+ } else {
+ return -1;
+ }
};
// Parse zero or more space characters, including at most one newline
@@ -2377,29 +2397,34 @@
}
};
- // Scan a sequence of characters == c, and return information about
+ // Scan a sequence of characters with code cc, and return information about
// the number of delimiters and whether they are positioned such that
// they can open and/or close emphasis or strong emphasis. A utility
// function for strong/emph parsing.
- var scanDelims = function(c) {
+ var scanDelims = function(cc) {
var numdelims = 0;
var first_close_delims = 0;
- var char_before, char_after;
+ var char_before, char_after, cc_after;
var startpos = this.pos;
char_before = this.pos === 0 ? '\n' :
this.subject.charAt(this.pos - 1);
- while (this.peek() === c) {
+ while (this.peek() === cc) {
numdelims++;
this.pos++;
}
- char_after = this.peek() || '\n';
+ cc_after = this.peek();
+ if (cc_after === -1) {
+ char_after = '\n';
+ } else {
+ char_after = String.fromCharCode(cc_after);
+ }
var can_open = numdelims > 0 && numdelims <= 3 && !(/\s/.test(char_after));
var can_close = numdelims > 0 && numdelims <= 3 && !(/\s/.test(char_before));
- if (c === '_') {
+ if (cc === C_UNDERSCORE) {
can_open = can_open && !((/[a-z0-9]/i).test(char_before));
can_close = can_close && !((/[a-z0-9]/i).test(char_after));
}
@@ -2422,21 +2447,18 @@
}
// Attempt to parse emphasis or strong emphasis.
- var parseEmphasis = function() {
+ var parseEmphasis = function(cc) {
var startpos = this.pos;
var c ;
var first_close = 0;
- c = this.peek();
- if (!(c === '*' || c === '_')) {
- return null;
- }
+ c = String.fromCharCode(cc);
var numdelims;
var delimpos;
var inlines = [];
// Get opening delimiters.
- res = this.scanDelims(c);
+ res = this.scanDelims(cc);
numdelims = res.numdelims;
if (numdelims === 0) {
@@ -2472,10 +2494,10 @@
}
while (true) {
- if (this.last_emphasis_closer[c] < this.pos) {
+ if (this.last_emphasis_closer[cc] < this.pos) {
break;
}
- res = this.scanDelims(c);
+ res = this.scanDelims(cc);
if (res) {
numdelims = res.numdelims;
@@ -2615,7 +2637,7 @@
// we didn't match emphasis: fallback
this.pos = fallbackpos;
if (last_emphasis_closer) {
- this.last_emphasis_closer[c] = last_emphasis_closer;
+ this.last_emphasis_closer[cc] = last_emphasis_closer;
}
return [fallback];
@@ -2651,7 +2673,7 @@
// Attempt to parse a link label, returning number of characters parsed.
var parseLinkLabel = function() {
- if (this.peek() != '[') {
+ if (this.peek() != C_OPEN_BRACKET) {
return 0;
}
var startpos = this.pos;
@@ -2668,36 +2690,36 @@
}
this.pos++; // advance past [
var c;
- while ((c = this.peek()) && (c != ']' || nest_level > 0)) {
+ while ((c = this.peek()) && c != -1 && (c != C_CLOSE_BRACKET || nest_level > 0)) {
switch (c) {
- case '`':
+ case C_BACKTICK:
this.parseBackticks();
break;
- case '<':
+ case C_LESSTHAN:
this.parseAutolink() || this.parseHtmlTag() ||
this.pos++;
break;
- case '[': // nested []
+ case C_OPEN_BRACKET: // nested []
nest_level++;
this.pos++;
break;
- case ']': // nested []
+ case C_CLOSE_BRACKET: // nested []
nest_level--;
this.pos++;
break;
- case '\\':
+ case C_BACKSLASH:
this.parseBackslash();
break;
default:
this.parseString();
}
}
- if (c === ']') {
+ if (c === C_CLOSE_BRACKET) {
this.label_nest_level = 0;
this.pos++; // advance past ]
return this.pos - startpos;
} else {
- if (!c) {
+ if (c === -1) {
this.label_nest_level = nest_level;
}
this.pos = startpos;
@@ -2730,7 +2752,7 @@
// if we got this far, we've parsed a label.
// Try to parse an explicit link: [label](url "title")
- if (this.peek() == '(') {
+ if (this.peek() == C_OPEN_PAREN) {
this.pos++;
if (this.spnl() &&
((dest = this.parseLinkDestination()) !== null) &&
@@ -2851,7 +2873,7 @@
}
// colon:
- if (this.peek() === ':') {
+ if (this.peek() === C_COLON) {
this.pos++;
} else {
this.pos = startpos;
@@ -2902,35 +2924,35 @@
}
var c = this.peek();
- if (!c) {
+ if (c === -1) {
return null;
}
var res;
switch(c) {
- case '\n':
- case ' ':
+ case C_NEWLINE:
+ case C_SPACE:
res = this.parseNewline();
break;
- case '\\':
+ case C_BACKSLASH:
res = this.parseBackslash();
break;
- case '`':
+ case C_BACKTICK:
res = this.parseBackticks();
break;
- case '*':
- case '_':
- res = this.parseEmphasis();
+ case C_ASTERISK:
+ case C_UNDERSCORE:
+ res = this.parseEmphasis(c);
break;
- case '[':
+ case C_OPEN_BRACKET:
res = this.parseLink();
break;
- case '!':
+ case C_BANG:
res = this.parseImage();
break;
- case '<':
+ case C_LESSTHAN:
res = this.parseAutolink() || this.parseHtmlTag();
break;
- case '&':
+ case C_AMPERSAND:
res = this.parseEntity();
break;
default:
@@ -2939,7 +2961,7 @@
}
if (res === null) {
this.pos += 1;
- res = [{t: 'Str', c: c}];
+ res = [{t: 'Str', c: String.fromCharCode(c)}];
}
if (res && memoize) {
@@ -2956,7 +2978,7 @@
this.pos = 0;
this.refmap = refmap || {};
this.memo = {};
- this.last_emphasis_closer = { '*': s.length, '_': s.length };
+ this.last_emphasis_closer = { C_ASTERISK: s.length, C_UNDERSCORE: s.length };
var inlines = [];
var next_inline;
while ((next_inline = this.parseInline())) {