The current implementations of the AppendQuote functions use quoteWith
(through Quote) for quoting the given value and appends the returned
string to the dst byte slice. quoteWith internally creates a byte slice
on each call which gets converted to a string in Quote.
This means the AppendQuote functions always allocates a new byte slice
and a string only to append them to an existing byte slice. In the case
of (Append)QuoteRune the string passed to quoteWith will also needs to
be allocated from a rune first.
Split quoteWith into two functions (quoteWith and appendQuotedWith) and
replace the call to Quote inside AppendQuote with appendQuotedWith,
which appends directly to the byte slice passed to AppendQuote and also
avoids the []byte->string conversion.
Also introduce the 2 functions quoteRuneWith and appendQuotedRuneWith
that work the same way as quoteWith and appendQuotedWith, but take a
single rune instead of a string, to avoid allocating a new string when
appending a single rune, and use them in (Append)QuoteRune.
Also update the ToASCII and ToGraphic variants to use the new functions.
Benchmark results:
benchmark old ns/op new ns/op delta
BenchmarkQuote-8 428 503 +17.52%
BenchmarkQuoteRune-8 148 105 -29.05%
BenchmarkAppendQuote-8 435 307 -29.43%
BenchmarkAppendQuoteRune-8 158 23.5 -85.13%
benchmark old allocs new allocs delta
BenchmarkQuote-8 3 3 +0.00%
BenchmarkQuoteRune-8 3 2 -33.33%
BenchmarkAppendQuote-8 3 0 -100.00%
BenchmarkAppendQuoteRune-8 3 0 -100.00%
benchmark old bytes new bytes delta
BenchmarkQuote-8 144 144 +0.00%
BenchmarkQuoteRune-8 16 16 +0.00%
BenchmarkAppendQuote-8 144 0 -100.00%
BenchmarkAppendQuoteRune-8 16 0 -100.00%
Change-Id: I77c148d5c7242f1b0edbbeeea184878abb51a522
Reviewed-on: https://go-review.googlesource.com/18962
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This version of quoting allows runes in category Zs, such as the
ideographic space characters, to be passed through unquoted.
Still to do (maybe): A way to access this from Printf.
Updates #11511.
Change-Id: I3bae84b1aa0bc1b885318d3f67c5f451099a2a5a
Reviewed-on: https://go-review.googlesource.com/14184
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
