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Early specialize sorting functions depending if there is a custom comparator or not.

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Review URL: http://codereview.chromium.org/1513020

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4356 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
antonm@chromium.org 2010-04-07 13:13:06 +00:00
parent c0976e9276
commit a4df380ffa
1 changed files with 74 additions and 13 deletions
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87
src/array.js
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@ -644,16 +644,77 @@ function ArraySort(comparefn) {
// In-place QuickSort algorithm.
// For short (length <= 22) arrays, insertion sort is used for efficiency.
var custom_compare = IS_FUNCTION(comparefn);
function InsertionSortWithFunc(a, from, to) {
for (var i = from + 1; i < to; i++) {
var element = a[i];
// place element in a[from..i[
// binary search
var min = from;
var max = i;
// The search interval is a[min..max[
while (min < max) {
var mid = min + ((max - min) >> 1);
var order = (a[mid] === element) ?
0 : comparefn.call(null, a[mid], element);
if (order == 0) {
min = max = mid;
break;
}
if (order < 0) {
min = mid + 1;
} else {
max = mid;
}
}
// place element at position min==max.
for (var j = i; j > min; j--) {
a[j] = a[j - 1];
}
a[min] = element;
}
}
function QuickSortWithFunc(a, from, to) {
// Insertion sort is faster for short arrays.
if (to - from <= 22) {
InsertionSortWithFunc(a, from, to);
return;
}
var pivot_index = $floor($random() * (to - from)) + from;
var pivot = a[pivot_index];
// Issue 95: Keep the pivot element out of the comparisons to avoid
// infinite recursion if comparefn(pivot, pivot) != 0.
a[pivot_index] = a[from];
a[from] = pivot;
var low_end = from; // Upper bound of the elements lower than pivot.
var high_start = to; // Lower bound of the elements greater than pivot.
// From low_end to i are elements equal to pivot.
// From i to high_start are elements that haven't been compared yet.
for (var i = from + 1; i < high_start; ) {
var element = a[i];
var order = (element === pivot) ?
0 : comparefn.call(null, element, pivot);
if (order < 0) {
a[i] = a[low_end];
a[low_end] = element;
i++;
low_end++;
} else if (order > 0) {
high_start--;
a[i] = a[high_start];
a[high_start] = element;
} else { // order == 0
i++;
}
}
QuickSortWithFunc(a, from, low_end);
QuickSortWithFunc(a, high_start, to);
}
function Compare(x,y) {
// Assume the comparefn, if any, is a consistent comparison function.
// If it isn't, we are allowed arbitrary behavior by ECMA 15.4.4.11.
if (x === y) return 0;
if (custom_compare) {
// Don't call directly to avoid exposing the builtin's global object.
return comparefn.call(null, x, y);
}
if (%_IsSmi(x) && %_IsSmi(y)) {
return %SmiLexicographicCompare(x, y);
}
@ -668,8 +729,7 @@ function ArraySort(comparefn) {
var element = a[i];
// Pre-convert the element to a string for comparison if we know
// it will happen on each compare anyway.
var key =
(custom_compare || %_IsSmi(element)) ? element : ToString(element);
var key = %_IsSmi(element) ? element : ToString(element);
// place element in a[from..i[
// binary search
var min = from;
@ -706,8 +766,7 @@ function ArraySort(comparefn) {
var pivot = a[pivot_index];
// Pre-convert the element to a string for comparison if we know
// it will happen on each compare anyway.
var pivot_key =
(custom_compare || %_IsSmi(pivot)) ? pivot : ToString(pivot);
var pivot_key = %_IsSmi(pivot) ? pivot : ToString(pivot);
// Issue 95: Keep the pivot element out of the comparisons to avoid
// infinite recursion if comparefn(pivot, pivot) != 0.
a[pivot_index] = a[from];
@ -736,8 +795,6 @@ function ArraySort(comparefn) {
QuickSort(a, high_start, to);
}
var length;
// Copies elements in the range 0..length from obj's prototype chain
// to obj itself, if obj has holes. Returns one more than the maximal index
// of a prototype property.
@ -855,7 +912,7 @@ function ArraySort(comparefn) {
return first_undefined;
}
length = TO_UINT32(this.length);
var length = TO_UINT32(this.length);
if (length < 2) return this;
var is_array = IS_ARRAY(this);
@ -880,7 +937,11 @@ function ArraySort(comparefn) {
num_non_undefined = SafeRemoveArrayHoles(this);
}
QuickSort(this, 0, num_non_undefined);
if(IS_FUNCTION(comparefn)) {
QuickSortWithFunc(this, 0, num_non_undefined);
} else {
QuickSort(this, 0, num_non_undefined);
}
if (!is_array && (num_non_undefined + 1 < max_prototype_element)) {
// For compatibility with JSC, we shadow any elements in the prototype