Making xtob take two byte arguments avoids a lot of slicing. This makes
the Parse function faster. In addition, because so much slicing is
avoiding, duplicating the parse logic to ParseBytes resulted in the
function being faster than Parse (<1ns).
The BenchmarkParseBytesNative function has been removed (parseBytes was
identical to ParseBytes). And a new benchmark,
BenchmarkParseBytesUnsafe, has been added to benchmark the old way of
parsing []byte (which is slightly slower than Parse and thus the new
ParseBytes implementation).
benchmark old ns/op new ns/op delta
BenchmarkUUID_MarshalJSON-4 685 667 -2.63%
BenchmarkUUID_UnmarshalJSON-4 1145 1162 +1.48%
BenchmarkParse-4 61.6 56.5 -8.28%
BenchmarkParseBytes-4 65.7 55.9 -14.92%
BenchmarkParseBytesCopy-4 121 115 -4.96%
BenchmarkNew-4 1665 1643 -1.32%
BenchmarkUUID_String-4 112 113 +0.89%
BenchmarkUUID_URN-4 117 119 +1.71%
benchmark old allocs new allocs delta
BenchmarkUUID_MarshalJSON-4 4 4 +0.00%
BenchmarkUUID_UnmarshalJSON-4 2 2 +0.00%
BenchmarkParse-4 0 0 +0.00%
BenchmarkParseBytes-4 0 0 +0.00%
BenchmarkParseBytesCopy-4 1 1 +0.00%
BenchmarkNew-4 1 1 +0.00%
BenchmarkUUID_String-4 1 1 +0.00%
BenchmarkUUID_URN-4 1 1 +0.00%
benchmark old bytes new bytes delta
BenchmarkUUID_MarshalJSON-4 248 248 +0.00%
BenchmarkUUID_UnmarshalJSON-4 248 248 +0.00%
BenchmarkParse-4 0 0 +0.00%
BenchmarkParseBytes-4 0 0 +0.00%
BenchmarkParseBytesCopy-4 48 48 +0.00%
BenchmarkNew-4 16 16 +0.00%
BenchmarkUUID_String-4 48 48 +0.00%
BenchmarkUUID_URN-4 48 48 +0.00%
The MustParse and MustNewUUID functions have been removed since they
can be replaced simply using the new function.
uuid.Must(uuid.Parse(s))
uuid.Must(uuid.NewUUID())
This also fixes a spurious bug in the UnmarshalJSON method that
prevented compiling the json.go file.
A common helper function is used for UUID.String(), UUID.URN(), and
UUID.MarshalJSON(). Any perforance hit in UUID.String() and
UUID.Marshal() appears to be negligable. The benefit to
UUID.MarshalJSON() is several hundred nanoseconds (23% faster) and 2
allocations (21% fewer bytes).
Some redundant checks are removed from UUID.UnmarshalJSON() method. The
"encoding/json".Unmarshaler interface specifies that implementations can
assume input is valid JSON content. This allows one to assume that (1)
input is not empty and (2) if index 0 is a quote, then the content is a
json string and the last index will contain a terminating quote. The
second point is not completely explicit in the documentation but it is
true in practice (and it is safe to assume -- errors will be caught).
A single array is used as a buffer and "encoding/hex".Encode() hex
encodes directly its final destination. Loops are avoided because they
are simple enough to unroll manually.
