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// For each opening emphasis-like marker find a matching closing one
//
'use strict';
function processDelimiters(state, delimiters) {
var closerIdx, openerIdx, closer, opener, minOpenerIdx, newMinOpenerIdx,
isOddMatch, lastJump,
openersBottom = {},
max = delimiters.length;
for (closerIdx = 0; closerIdx < max; closerIdx++) {
closer = delimiters[closerIdx];
// Length is only used for emphasis-specific "rule of 3",
// if it's not defined (in strikethrough or 3rd party plugins),
// we can default it to 0 to disable those checks.
//
closer.length = closer.length || 0;
if (!closer.close) continue;
// Previously calculated lower bounds (previous fails)
// for each marker and each delimiter length modulo 3.
if (!openersBottom.hasOwnProperty(closer.marker)) {
openersBottom[closer.marker] = [ -1, -1, -1 ];
}
minOpenerIdx = openersBottom[closer.marker][closer.length % 3];
newMinOpenerIdx = -1;
openerIdx = closerIdx - closer.jump - 1;
for (; openerIdx > minOpenerIdx; openerIdx -= opener.jump + 1) {
opener = delimiters[openerIdx];
if (opener.marker !== closer.marker) continue;
if (newMinOpenerIdx === -1) newMinOpenerIdx = openerIdx;
if (opener.open && opener.end < 0) {
isOddMatch = false;
// from spec:
//
// If one of the delimiters can both open and close emphasis, then the
// sum of the lengths of the delimiter runs containing the opening and
// closing delimiters must not be a multiple of 3 unless both lengths
// are multiples of 3.
//
if (opener.close || closer.open) {
if ((opener.length + closer.length) % 3 === 0) {
if (opener.length % 3 !== 0 || closer.length % 3 !== 0) {
isOddMatch = true;
}
}
}
if (!isOddMatch) {
// If previous delimiter cannot be an opener, we can safely skip
// the entire sequence in future checks. This is required to make
// sure algorithm has linear complexity (see *_*_*_*_*_... case).
//
lastJump = openerIdx > 0 && !delimiters[openerIdx - 1].open ?
delimiters[openerIdx - 1].jump + 1 :
0;
closer.jump = closerIdx - openerIdx + lastJump;
closer.open = false;
opener.end = closerIdx;
opener.jump = lastJump;
opener.close = false;
newMinOpenerIdx = -1;
break;
}
}
}
if (newMinOpenerIdx !== -1) {
// If match for this delimiter run failed, we want to set lower bound for
// future lookups. This is required to make sure algorithm has linear
// complexity.
//
// See details here:
// https://github.com/commonmark/cmark/issues/178#issuecomment-270417442
//
openersBottom[closer.marker][(closer.length || 0) % 3] = newMinOpenerIdx;
}
}
}
module.exports = function link_pairs(state) {
var curr,
tokens_meta = state.tokens_meta,
max = state.tokens_meta.length;
processDelimiters(state, state.delimiters);
for (curr = 0; curr < max; curr++) {
if (tokens_meta[curr] && tokens_meta[curr].delimiters) {
processDelimiters(state, tokens_meta[curr].delimiters);
}
}
};