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src: only memcmp if length > 0 in Buffer::Compare 

Both pointer arguments to memcmp are defined as non-null
and compiler optimizes upon that.

PR-URL: https://github.com/nodejs/node/pull/2544
Reviewed-By: trevnorris - Trevor Norris <trev.norris@gmail.com>
Reviewed-By: thefourtheye - Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
pull/2620/head
Karl Skomski 2015-08-21 13:31:24 +02:00 committed by Alexis Campailla
parent 37ee43efd5
commit e3740e4524
2 changed files with 4 additions and 1 deletions
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2
src/node_buffer.cc
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@ -835,7 +835,7 @@ void Compare(const FunctionCallbackInfo<Value> &args) {
size_t cmp_length = MIN(obj_a_length, obj_b_length);
int32_t val = memcmp(obj_a_data, obj_b_data, cmp_length);
int val = cmp_length > 0 ? memcmp(obj_a_data, obj_b_data, cmp_length) : 0;
// Normalize val to be an integer in the range of [1, -1] since
// implementations of memcmp() can vary by platform.

3
test/parallel/test-buffer.js
View File

@ -1137,6 +1137,9 @@ assert.equal(Buffer.compare(d, b), 1);
assert.equal(Buffer.compare(b, d), -1);
assert.equal(Buffer.compare(c, c), 0);
assert.equal(Buffer.compare(Buffer(0), Buffer(0)), 0);
assert.equal(Buffer.compare(Buffer(0), Buffer(1)), -1);
assert.equal(Buffer.compare(Buffer(1), Buffer(0)), 1);
assert.throws(function() {
var b = new Buffer(1);