strings and bytes.Split: make count of 0 mean 0, not infinite.

Use a count of -1 for infinity.  Ditto for Replace.

R=rsc
CC=golang-dev
https://golang.org/cl/1704044
This commit is contained in:
Rob Pike 2010-07-01 14:08:14 -07:00
parent 285312a05c
commit 38f1231f3e
24 changed files with 123 additions and 98 deletions

View file

@ -154,10 +154,13 @@ func IndexAny(s []byte, chars string) int {
// Generic split: splits after each instance of sep,
// including sepSave bytes of sep in the subarrays.
func genSplit(s, sep []byte, sepSave, n int) [][]byte {
if n == 0 {
return nil
}
if len(sep) == 0 {
return explode(s, n)
}
if n <= 0 {
if n < 0 {
n = Count(s, sep) + 1
}
c := sep[0]
@ -178,13 +181,15 @@ func genSplit(s, sep []byte, sepSave, n int) [][]byte {
// Split splits the array s around each instance of sep, returning an array of subarrays of s.
// If sep is empty, Split splits s after each UTF-8 sequence.
// If n > 0, Split splits s into at most n subarrays; the last subarray will contain an unsplit remainder.
// If n >= 0, Split splits s into at most n subarrays; the last subarray will contain an unsplit remainder.
// Thus if n == 0, the result will ne nil.
func Split(s, sep []byte, n int) [][]byte { return genSplit(s, sep, 0, n) }
// SplitAfter splits the array s after each instance of sep, returning an array of subarrays of s.
// If sep is empty, SplitAfter splits s after each UTF-8 sequence.
// If n > 0, SplitAfter splits s into at most n subarrays; the last subarray will contain an
// If n >= 0, SplitAfter splits s into at most n subarrays; the last subarray will contain an
// unsplit remainder.
// Thus if n == 0, the result will ne nil.
func SplitAfter(s, sep []byte, n int) [][]byte {
return genSplit(s, sep, len(sep), n)
}
@ -465,8 +470,11 @@ func Runes(s []byte) []int {
// Replace returns a copy of the slice s with the first n
// non-overlapping instances of old replaced by new.
// If n <= 0, there is no limit on the number of replacements.
// If n < 0, there is no limit on the number of replacements.
func Replace(s, old, new []byte, n int) []byte {
if n == 0 {
return s // avoid allocation
}
// Compute number of replacements.
if m := Count(s, old); m == 0 {
return s // avoid allocation