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// Process *this* and _that_
//
'use strict';
var isWhiteSpace = require('../common/utils').isWhiteSpace;
var isPunctChar = require('../common/utils').isPunctChar;
var isMdAsciiPunct = require('../common/utils').isMdAsciiPunct;
// parse sequence of emphasis 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);
// treat beginning of the line as a whitespace
lastChar = start > 0 ? state.src.charCodeAt(start - 1) : 0x20;
while (pos < max && state.src.charCodeAt(pos) === marker) { pos++; }
if (pos >= max) {
can_open = false;
}
count = pos - start;
// treat end of the line as a whitespace
nextChar = pos < max ? state.src.charCodeAt(pos) : 0x20;
isLastPunctChar = isMdAsciiPunct(lastChar) || isPunctChar(String.fromCharCode(lastChar));
isNextPunctChar = isMdAsciiPunct(nextChar) || isPunctChar(String.fromCharCode(nextChar));
isLastWhiteSpace = isWhiteSpace(lastChar);
isNextWhiteSpace = isWhiteSpace(nextChar);
if (isNextWhiteSpace) {
can_open = false;
} else if (isNextPunctChar) {
if (!(isLastWhiteSpace || isLastPunctChar)) {
can_open = false;
}
}
if (isLastWhiteSpace) {
can_close = false;
} else if (isLastPunctChar) {
if (!(isNextWhiteSpace || isNextPunctChar)) {
can_close = false;
}
}
if (marker === 0x5F /* _ */) {
if (can_open && can_close) {
// "_" inside a word can neither open nor close an emphasis
can_open = false;
can_close = isNextPunctChar;
}
}
return {
can_open: can_open,
can_close: can_close,
delims: count
};
}
module.exports = function emphasis(state, silent) {
var startCount,
count,
found,
oldCount,
newCount,
stack,
res,
token,
max = state.posMax,
start = state.pos,
marker = state.src.charCodeAt(start);
if (marker !== 0x5F/* _ */ && marker !== 0x2A /* * */) { 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;
}
state.pos = start + startCount;
stack = [ startCount ];
while (state.pos < max) {
if (state.src.charCodeAt(state.pos) === marker) {
res = scanDelims(state, state.pos);
count = res.delims;
if (res.can_close) {
oldCount = stack.pop();
newCount = count;
while (oldCount !== newCount) {
if (newCount < oldCount) {
stack.push(oldCount - newCount);
break;
}
// assert(newCount > oldCount)
newCount -= oldCount;
if (stack.length === 0) { break; }
state.pos += oldCount;
oldCount = stack.pop();
}
if (stack.length === 0) {
startCount = oldCount;
found = true;
break;
}
state.pos += count;
continue;
}
if (res.can_open) { stack.push(count); }
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 + startCount;
// Earlier we checked !silent, but this implementation does not need it
// we have `startCount` starting and ending markers,
// now trying to serialize them into tokens
for (count = startCount; count > 1; count -= 2) {
token = state.push('strong_open', 'strong', 1);
token.markup = String.fromCharCode(marker) + String.fromCharCode(marker);
}
if (count % 2) {
token = state.push('em_open', 'em', 1);
token.markup = String.fromCharCode(marker);
}
state.md.inline.tokenize(state);
if (count % 2) {
token = state.push('em_close', 'em', -1);
token.markup = String.fromCharCode(marker);
}
for (count = startCount; count > 1; count -= 2) {
token = state.push('strong_close', 'strong', -1);
token.markup = String.fromCharCode(marker) + String.fromCharCode(marker);
}
state.pos = state.posMax + startCount;
state.posMax = max;
return true;
};