diff --git a/src/core/obj.js b/src/core/obj.js index cc2e36dd6..babfdaf8a 100644 --- a/src/core/obj.js +++ b/src/core/obj.js @@ -485,15 +485,7 @@ var Catalog = (function CatalogClosure() { } if (nameTreeRef) { var nameTree = new NameTree(nameTreeRef, xref); - var names = nameTree.getAll(); - for (var name in names) { - if (!names.hasOwnProperty(name)) { - continue; - } - if (name === destinationId) { - dest = fetchDestination(names[name]); - } - } + dest = fetchDestination(nameTree.get(destinationId)); } return dest; }, @@ -1398,6 +1390,76 @@ var NameTree = (function NameTreeClosure() { } } return dict; + }, + + get: function NameTree_get(destinationId) { + if (!this.root) { + return null; + } + + var xref = this.xref; + var kidsOrNames = xref.fetchIfRef(this.root); + var loopCount = 0; + var MAX_NAMES_LEVELS = 10; + var l, r, m; + + // Perform a binary search to quickly find the entry that + // contains the named destination we are looking for. + while (kidsOrNames.has('Kids')) { + loopCount++; + if (loopCount > MAX_NAMES_LEVELS) { + warn('Search depth limit for named destionations has been reached.'); + return null; + } + + var kids = kidsOrNames.get('Kids'); + if (!isArray(kids)) { + return null; + } + + l = 0; + r = kids.length - 1; + while (l <= r) { + m = (l + r) >> 1; + var kid = xref.fetchIfRef(kids[m]); + var limits = kid.get('Limits'); + + if (destinationId < limits[0]) { + r = m - 1; + } else if (destinationId > limits[1]) { + l = m + 1; + } else { + kidsOrNames = xref.fetchIfRef(kids[m]); + break; + } + } + if (l > r) { + return null; + } + } + + // If we get here, then we have found the right entry. Now + // go through the named destinations in the Named dictionary + // until we find the exact destination we're looking for. + var names = kidsOrNames.get('Names'); + if (isArray(names)) { + // Perform a binary search to reduce the lookup time. + l = 0; + r = names.length - 2; + while (l <= r) { + // Check only even indices (0, 2, 4, ...) because the + // odd indices contain the actual D array. + m = (l + r) & ~1; + if (destinationId < names[m]) { + r = m - 2; + } else if (destinationId > names[m]) { + l = m + 2; + } else { + return xref.fetchIfRef(names[m + 1]); + } + } + } + return null; } }; return NameTree;