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// ~~strike through~~
//
'use strict';
var isWhiteSpace = require('../common/utils').isWhiteSpace;
var isPunctChar = require('../common/utils').isPunctChar;
var isMdAsciiPunct = require('../common/utils').isMdAsciiPunct;
// parse sequence of markers,
// "start" should point at a valid marker
function scanDelims(state, start) {
var pos = start, lastChar, nextChar, count,
isLastWhiteSpace, isLastPunctChar,
isNextWhiteSpace, isNextPunctChar,
can_open = true,
can_close = true,
max = state.posMax,
marker = state.src.charCodeAt(start);
lastChar = start > 0 ? state.src.charCodeAt(start - 1) : -1;
while (pos < max && state.src.charCodeAt(pos) === marker) { pos++; }
if (pos >= max) { can_open = false; }
count = pos - start;
nextChar = pos < max ? state.src.charCodeAt(pos) : -1;
isLastPunctChar = lastChar >= 0 &&
(isMdAsciiPunct(lastChar) || isPunctChar(String.fromCharCode(lastChar)));
isNextPunctChar = nextChar >= 0 &&
(isMdAsciiPunct(nextChar) || isPunctChar(String.fromCharCode(nextChar)));
isLastWhiteSpace = lastChar >= 0 && isWhiteSpace(lastChar);
isNextWhiteSpace = nextChar >= 0 && isWhiteSpace(nextChar);
if (isNextWhiteSpace) {
can_open = false;
} else if (isNextPunctChar) {
if (!(isLastWhiteSpace || isLastPunctChar || lastChar === -1)) {
can_open = false;
}
}
if (isLastWhiteSpace) {
can_close = false;
} else if (isLastPunctChar) {
if (!(isNextWhiteSpace || isNextPunctChar || nextChar === -1)) {
can_close = false;
}
}
return {
can_open: can_open,
can_close: can_close,
delims: count
};
}
module.exports = function strikethrough(state, silent) {
var startCount,
count,
tagCount,
found,
stack,
res,
max = state.posMax,
start = state.pos,
marker = state.src.charCodeAt(start);
if (marker !== 0x7E/* ~ */) { return false; }
if (silent) { return false; } // don't run any pairs in validation mode
res = scanDelims(state, start);
startCount = res.delims;
if (!res.can_open) {
state.pos += startCount;
// Earlier we checked !silent, but this implementation does not need it
state.pending += state.src.slice(start, state.pos);
return true;
}
stack = Math.floor(startCount / 2);
if (stack <= 0) { return false; }
state.pos = start + startCount;
while (state.pos < max) {
if (state.src.charCodeAt(state.pos) === marker) {
res = scanDelims(state, state.pos);
count = res.delims;
tagCount = Math.floor(count / 2);
if (res.can_close) {
if (tagCount >= stack) {
state.pos += count - 2;
found = true;
break;
}
stack -= tagCount;
state.pos += count;
continue;
}
if (res.can_open) { stack += tagCount; }
state.pos += count;
continue;
}
state.md.inline.skipToken(state);
}
if (!found) {
// parser failed to find ending tag, so it's not valid emphasis
state.pos = start;
return false;
}
// found!
state.posMax = state.pos;
state.pos = start + 2;
// Earlier we checked !silent, but this implementation does not need it
state.push({ type: 's_open', level: state.level++ });
state.md.inline.tokenize(state);
state.push({ type: 's_close', level: --state.level });
state.pos = state.posMax + 2;
state.posMax = max;
return true;
};