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strings: make parameters names less confusing

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Using 'sep' as parameter name for strings functions that take a
separator argument is fine, but for functions like Index or Count that
look for a substring it's better to use 'substr' (like Contains
already does).

Fixes #19039

Change-Id: Idd557409c8fea64ce830ab0e3fec37d3d56a79f0
Reviewed-on: https://go-review.googlesource.com/36874
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This commit is contained in:
Alberto Donizetti 2017-02-11 20:06:54 +01:00 • committed by Brad Fitzpatrick
parent 2ceeb7b090
commit 272ec231b7
4 changed files with 48 additions and 48 deletions
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28
src/strings/strings.go
View file

@ -72,21 +72,21 @@ func hashStrRev(sep string) (uint32, uint32) {
return hash, pow
}
// Count counts the number of non-overlapping instances of sep in s.
// If sep is an empty string, Count returns 1 + the number of Unicode code points in s.
func Count(s, sep string) int {
// Count counts the number of non-overlapping instances of substr in s.
// If substr is an empty string, Count returns 1 + the number of Unicode code points in s.
func Count(s, substr string) int {
n := 0
// special case
if len(sep) == 0 {
if len(substr) == 0 {
return utf8.RuneCountInString(s) + 1
}
for {
i := Index(s, sep)
i := Index(s, substr)
if i == -1 {
return n
}
n++
s = s[i+len(sep):]
s = s[i+len(substr):]
}
}
@ -105,16 +105,16 @@ func ContainsRune(s string, r rune) bool {
return IndexRune(s, r) >= 0
}
// LastIndex returns the index of the last instance of sep in s, or -1 if sep is not present in s.
func LastIndex(s, sep string) int {
n := len(sep)
// LastIndex returns the index of the last instance of substr in s, or -1 if substr is not present in s.
func LastIndex(s, substr string) int {
n := len(substr)
switch {
case n == 0:
return len(s)
case n == 1:
return LastIndexByte(s, sep[0])
return LastIndexByte(s, substr[0])
case n == len(s):
if sep == s {
if substr == s {
return 0
}
return -1
@ -122,20 +122,20 @@ func LastIndex(s, sep string) int {
return -1
}
// Rabin-Karp search from the end of the string
hashsep, pow := hashStrRev(sep)
hashss, pow := hashStrRev(substr)
last := len(s) - n
var h uint32
for i := len(s) - 1; i >= last; i-- {
h = h*primeRK + uint32(s[i])
}
if h == hashsep && s[last:] == sep {
if h == hashss && s[last:] == substr {
return last
}
for i := last - 1; i >= 0; i-- {
h *= primeRK
h += uint32(s[i])
h -= pow * uint32(s[i+n])
if h == hashsep && s[i:i+n] == sep {
if h == hashss && s[i:i+n] == substr {
return i
}
}

26
src/strings/strings_amd64.go
View file

@ -21,27 +21,27 @@ func init() {
}
}
// Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.
func Index(s, sep string) int {
n := len(sep)
// Index returns the index of the first instance of substr in s, or -1 if substr is not present in s.
func Index(s, substr string) int {
n := len(substr)
switch {
case n == 0:
return 0
case n == 1:
return IndexByte(s, sep[0])
return IndexByte(s, substr[0])
case n == len(s):
if sep == s {
if substr == s {
return 0
}
return -1
case n > len(s):
return -1
case n <= shortStringLen:
// Use brute force when s and sep both are small
// Use brute force when s and substr both are small
if len(s) <= 64 {
return indexShortStr(s, sep)
return indexShortStr(s, substr)
}
c := sep[0]
c := substr[0]
i := 0
t := s[:len(s)-n+1]
fails := 0
@ -55,7 +55,7 @@ func Index(s, sep string) int {
}
i += o
}
if s[i:i+n] == sep {
if s[i:i+n] == substr {
return i
}
fails++
@ -64,7 +64,7 @@ func Index(s, sep string) int {
// Too many means more that 1 error per 8 characters.
// Allow some errors in the beginning.
if fails > (i+16)/8 {
r := indexShortStr(s[i:], sep)
r := indexShortStr(s[i:], substr)
if r >= 0 {
return r + i
}
@ -74,12 +74,12 @@ func Index(s, sep string) int {
return -1
}
// Rabin-Karp search
hashsep, pow := hashStr(sep)
hashss, pow := hashStr(substr)
var h uint32
for i := 0; i < n; i++ {
h = h*primeRK + uint32(s[i])
}
if h == hashsep && s[:n] == sep {
if h == hashss && s[:n] == substr {
return 0
}
for i := n; i < len(s); {
@ -87,7 +87,7 @@ func Index(s, sep string) int {
h += uint32(s[i])
h -= pow * uint32(s[i-n])
i++
if h == hashsep && s[i-n:i] == sep {
if h == hashss && s[i-n:i] == substr {
return i - n
}
}

16
src/strings/strings_generic.go
View file

@ -9,16 +9,16 @@ package strings
// TODO: implements short string optimization on non amd64 platforms
// and get rid of strings_amd64.go
// Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.
func Index(s, sep string) int {
n := len(sep)
// Index returns the index of the first instance of substr in s, or -1 if substr is not present in s.
func Index(s, substr string) int {
n := len(substr)
switch {
case n == 0:
return 0
case n == 1:
return IndexByte(s, sep[0])
return IndexByte(s, substr[0])
case n == len(s):
if sep == s {
if substr == s {
return 0
}
return -1
@ -26,12 +26,12 @@ func Index(s, sep string) int {
return -1
}
// Rabin-Karp search
hashsep, pow := hashStr(sep)
hashss, pow := hashStr(substr)
var h uint32
for i := 0; i < n; i++ {
h = h*primeRK + uint32(s[i])
}
if h == hashsep && s[:n] == sep {
if h == hashss && s[:n] == substr {
return 0
}
for i := n; i < len(s); {
@ -39,7 +39,7 @@ func Index(s, sep string) int {
h += uint32(s[i])
h -= pow * uint32(s[i-n])
i++
if h == hashsep && s[i-n:i] == sep {
if h == hashss && s[i-n:i] == substr {
return i - n
}
}

26
src/strings/strings_s390x.go
View file

@ -24,27 +24,27 @@ func init() {
}
}
// Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.
func Index(s, sep string) int {
n := len(sep)
// Index returns the index of the first instance of substr in s, or -1 if substr is not present in s.
func Index(s, substr string) int {
n := len(substr)
switch {
case n == 0:
return 0
case n == 1:
return IndexByte(s, sep[0])
return IndexByte(s, substr[0])
case n == len(s):
if sep == s {
if substr == s {
return 0
}
return -1
case n > len(s):
return -1
case n <= shortStringLen:
// Use brute force when s and sep both are small
// Use brute force when s and substr both are small
if len(s) <= 64 {
return indexShortStr(s, sep)
return indexShortStr(s, substr)
}
c := sep[0]
c := substr[0]
i := 0
t := s[:len(s)-n+1]
fails := 0
@ -58,7 +58,7 @@ func Index(s, sep string) int {
}
i += o
}
if s[i:i+n] == sep {
if s[i:i+n] == substr {
return i
}
fails++
@ -67,7 +67,7 @@ func Index(s, sep string) int {
// Too many means more that 1 error per 8 characters.
// Allow some errors in the beginning.
if fails > (i+16)/8 {
r := indexShortStr(s[i:], sep)
r := indexShortStr(s[i:], substr)
if r >= 0 {
return r + i
}
@ -77,12 +77,12 @@ func Index(s, sep string) int {
return -1
}
// Rabin-Karp search
hashsep, pow := hashStr(sep)
hashss, pow := hashStr(substr)
var h uint32
for i := 0; i < n; i++ {
h = h*primeRK + uint32(s[i])
}
if h == hashsep && s[:n] == sep {
if h == hashss && s[:n] == substr {
return 0
}
for i := n; i < len(s); {
@ -90,7 +90,7 @@ func Index(s, sep string) int {
h += uint32(s[i])
h -= pow * uint32(s[i-n])
i++
if h == hashsep && s[i-n:i] == sep {
if h == hashss && s[i-n:i] == substr {
return i - n
}
}