function recombineTagsAndDecorations()

in src/site/resources/js/prettify.js [1062:1156]
69 lines of code
15 McCabe index (conditional complexity)

  function recombineTagsAndDecorations(job) {
    var isIE = /\bMSIE\b/.test(navigator.userAgent);
    var newlineRe = /\n/g;
  
    var source = job.sourceCode;
    var sourceLength = source.length;
    // Index into source after the last code-unit recombined.
    var sourceIndex = 0;
  
    var spans = job.spans;
    var nSpans = spans.length;
    // Index into spans after the last span which ends at or before sourceIndex.
    var spanIndex = 0;
  
    var decorations = job.decorations;
    var nDecorations = decorations.length;
    // Index into decorations after the last decoration which ends at or before
    // sourceIndex.
    var decorationIndex = 0;
  
    // Remove all zero-length decorations.
    decorations[nDecorations] = sourceLength;
    var decPos, i;
    for (i = decPos = 0; i < nDecorations;) {
      if (decorations[i] !== decorations[i + 2]) {
        decorations[decPos++] = decorations[i++];
        decorations[decPos++] = decorations[i++];
      } else {
        i += 2;
      }
    }
    nDecorations = decPos;
  
    // Simplify decorations.
    for (i = decPos = 0; i < nDecorations;) {
      var startPos = decorations[i];
      // Conflate all adjacent decorations that use the same style.
      var startDec = decorations[i + 1];
      var end = i + 2;
      while (end + 2 <= nDecorations && decorations[end + 1] === startDec) {
        end += 2;
      }
      decorations[decPos++] = startPos;
      decorations[decPos++] = startDec;
      i = end;
    }
  
    nDecorations = decorations.length = decPos;
  
    var decoration = null;
    while (spanIndex < nSpans) {
      var spanStart = spans[spanIndex];
      var spanEnd = spans[spanIndex + 2] || sourceLength;
  
      var decStart = decorations[decorationIndex];
      var decEnd = decorations[decorationIndex + 2] || sourceLength;
  
      var end = Math.min(spanEnd, decEnd);
  
      var textNode = spans[spanIndex + 1];
      var styledText;
      if (textNode.nodeType !== 1  // Don't muck with <BR>s or <LI>s
          // Don't introduce spans around empty text nodes.
          && (styledText = source.substring(sourceIndex, end))) {
        // This may seem bizarre, and it is.  Emitting LF on IE causes the
        // code to display with spaces instead of line breaks.
        // Emitting Windows standard issue linebreaks (CRLF) causes a blank
        // space to appear at the beginning of every line but the first.
        // Emitting an old Mac OS 9 line separator makes everything spiffy.
        if (isIE) { styledText = styledText.replace(newlineRe, '\r'); }
        textNode.nodeValue = styledText;
        var document = textNode.ownerDocument;
        var span = document.createElement('SPAN');
        span.className = decorations[decorationIndex + 1];
        var parentNode = textNode.parentNode;
        parentNode.replaceChild(span, textNode);
        span.appendChild(textNode);
        if (sourceIndex < spanEnd) {  // Split off a text node.
          spans[spanIndex + 1] = textNode
              // TODO: Possibly optimize by using '' if there's no flicker.
              = document.createTextNode(source.substring(end, spanEnd));
          parentNode.insertBefore(textNode, span.nextSibling);
        }
      }
  
      sourceIndex = end;
  
      if (sourceIndex >= spanEnd) {
        spanIndex += 2;
      }
      if (sourceIndex >= decEnd) {
        decorationIndex += 2;
      }
    }
  }