Revision: 6286
Author: [email protected]
Date: Wed Jan 12 06:16:19 2011
Log: Optimize JSON stringify for arrays.
Review URL: http://codereview.chromium.org/6164004
http://code.google.com/p/v8/source/detail?r=6286
Modified:
/branches/bleeding_edge/src/json.js
=======================================
--- /branches/bleeding_edge/src/json.js Wed Dec 22 05:19:25 2010
+++ /branches/bleeding_edge/src/json.js Wed Jan 12 06:16:19 2011
@@ -179,24 +179,60 @@
function BasicSerializeArray(value, stack, builder) {
+ var len = value.length;
+ if (len == 0) {
+ builder.push("[]");
+ return;
+ }
if (!%PushIfAbsent(stack, value)) {
throw MakeTypeError('circular_structure', []);
}
builder.push("[");
- var len = value.length;
- for (var i = 0; i < len; i++) {
+ var val = value[0];
+ if (IS_STRING(val)) {
+ // First entry is a string. Remaining entries are likely to be strings
too.
+ builder.push(%QuoteJSONString(val));
+ for (var i = 1; i < len; i++) {
+ builder.push(",");
+ val = value[i];
+ if (IS_STRING(val)) {
+ builder.push(%QuoteJSONString(val));
+ } else {
+ var before = builder.length;
+ BasicJSONSerialize(i, value[i], stack, builder);
+ if (before == builder.length) builder.push("null");
+ }
+ }
+ } else if (IS_NUMBER(val)) {
+ // First entry is a number. Remaining entries are likely to be numbers
too.
+ builder.push(NUMBER_IS_FINITE(val) ? %_NumberToString(val) : "null");
+ for (var i = 1; i < len; i++) {
+ builder.push(",");
+ val = value[i];
+ if (IS_NUMBER(val)) {
+ builder.push(NUMBER_IS_FINITE(val)
+ ? %_NumberToString(val)
+ : "null");
+ } else {
+ var before = builder.length;
+ BasicJSONSerialize(i, value[i], stack, builder);
+ if (before == builder.length) builder.push("null");
+ }
+ }
+ } else {
var before = builder.length;
- BasicJSONSerialize(i, value, stack, builder);
+ BasicJSONSerialize(0, val, stack, builder);
if (before == builder.length) builder.push("null");
- builder.push(",");
+ for (var i = 1; i < len; i++) {
+ builder.push(",");
+ before = builder.length;
+ val = value[i];
+ BasicJSONSerialize(i, val, stack, builder);
+ if (before == builder.length) builder.push("null");
+ }
}
stack.pop();
- if (builder.pop() != ",") {
- builder.push("[]"); // Zero length array. Push "[" back on.
- } else {
- builder.push("]");
- }
-
+ builder.push("]");
}
@@ -210,7 +246,7 @@
builder.push(%QuoteJSONString(p));
builder.push(":");
var before = builder.length;
- BasicJSONSerialize(p, value, stack, builder);
+ BasicJSONSerialize(p, value[p], stack, builder);
if (before == builder.length) {
builder.pop();
builder.pop();
@@ -228,8 +264,7 @@
}
-function BasicJSONSerialize(key, holder, stack, builder) {
- var value = holder[key];
+function BasicJSONSerialize(key, value, stack, builder) {
if (IS_SPEC_OBJECT(value)) {
var toJSON = value.toJSON;
if (IS_FUNCTION(toJSON)) {
@@ -266,7 +301,7 @@
function JSONStringify(value, replacer, space) {
if (%_ArgumentsLength() == 1) {
var builder = [];
- BasicJSONSerialize('', {'': value}, [], builder);
+ BasicJSONSerialize('', value, [], builder);
if (builder.length == 0) return;
var result = %_FastAsciiArrayJoin(builder, "");
if (!IS_UNDEFINED(result)) return result;
--
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