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buffer: normalize compare() output

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Because of differences in memcmp() implementation, normalize output to
return -1, 0 or 1 only.

Signed-off-by: Timothy J Fontaine <tjfontaine@gmail.com>
This commit is contained in:
Trevor Norris 2014-04-29 14:46:58 -07:00 committed by Timothy J Fontaine
parent 3d3d48d4b7
commit d1fe6857ba
2 changed files with 18 additions and 6 deletions
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16
src/node_buffer.cc
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@ -621,8 +621,20 @@ void Compare(const FunctionCallbackInfo<Value> &args) {
size_t cmp_length = MIN(obj_a_len, obj_b_len); size_t cmp_length = MIN(obj_a_len, obj_b_len);
int32_t val = memcmp(obj_a_data, obj_b_data, cmp_length); int32_t val = memcmp(obj_a_data, obj_b_data, cmp_length);
if (!val)
val = obj_a_len - obj_b_len; // Normalize val to be an integer in the range of [1, -1] since
// implementations of memcmp() can vary by platform.
if (val == 0) {
if (obj_a_len > obj_b_len)
val = 1;
else if (obj_a_len < obj_b_len)
val = -1;
} else {
if (val > 0)
val = 1;
else
val = -1;
}
args.GetReturnValue().Set(val); args.GetReturnValue().Set(val);
} }

8
test/simple/test-buffer.js
View File

@ -1043,13 +1043,13 @@ var b = new Buffer(1).fill('a');
var c = new Buffer(1).fill('c'); var c = new Buffer(1).fill('c');
var d = new Buffer(2).fill('aa'); var d = new Buffer(2).fill('aa');
assert.equal(b.compare(c), -2); assert.equal(b.compare(c), -1);
assert.equal(c.compare(d), 2); assert.equal(c.compare(d), 1);
assert.equal(d.compare(b), 1); assert.equal(d.compare(b), 1);
assert.equal(b.compare(d), -1); assert.equal(b.compare(d), -1);
assert.equal(Buffer.compare(b, c), 2); assert.equal(Buffer.compare(b, c), 1);
assert.equal(Buffer.compare(c, d), -2); assert.equal(Buffer.compare(c, d), -1);
assert.equal(Buffer.compare(d, b), -1); assert.equal(Buffer.compare(d, b), -1);
assert.equal(Buffer.compare(b, d), 1); assert.equal(Buffer.compare(b, d), 1);