string: minor optimization (fix #8100) (#8106)

pull/8117/head
yuyi 2021-01-15 09:26:06 +08:00 committed by GitHub
parent c80cc917c7
commit aeddd5b559
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1 changed files with 60 additions and 31 deletions

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@ -43,8 +43,8 @@ NB: A V string should be/is immutable from the point of view of
*/
pub struct string {
pub:
str byteptr // points to a C style 0 terminated string of bytes.
len int // the length of the .str field, excluding the ending 0 byte. It is always equal to strlen(.str).
str byteptr // points to a C style 0 terminated string of bytes.
len int // the length of the .str field, excluding the ending 0 byte. It is always equal to strlen(.str).
mut:
is_lit int
}
@ -212,8 +212,11 @@ pub fn cstring_to_vstring(cstr byteptr) string {
// replace_once replaces the first occurence of `rep` with the string passed in `with`.
pub fn (s string) replace_once(rep string, with string) string {
index := s.index(rep) or { return s.clone() }
return s.substr(0, index) + with + s.substr(index + rep.len, s.len)
idx := s.index_(rep)
if idx == -1 {
return s.clone()
}
return s.substr(0, idx) + with + s.substr(idx + rep.len, s.len)
}
// replace replaces all occurences of `rep` with the string passed in `with`.
@ -643,11 +646,15 @@ pub fn (s string) substr(start int, end int) string {
return res
}
// TODO should probably be deprecated? Not used in the V code base (df4ec89a0)
pub fn (s string) index_old(p string) int {
// index returns the position of the first character of the input string.
// It will return `-1` if the input string can't be found.
fn (s string) index_(p string) int {
if p.len > s.len || p.len == 0 {
return -1
}
if p.len > 2 {
return s.index_kmp(p)
}
mut i := 0
for i < s.len {
mut j := 0
@ -665,21 +672,11 @@ pub fn (s string) index_old(p string) int {
// index returns the position of the first character of the input string.
// It will return `none` if the input string can't be found.
pub fn (s string) index(p string) ?int {
if p.len > s.len || p.len == 0 {
idx := s.index_(p)
if idx == -1 {
return none
}
mut i := 0
for i < s.len {
mut j := 0
for j < p.len && unsafe { s.str[i + j] == p.str[j] } {
j++
}
if j == p.len {
return i
}
i++
}
return none
return idx
}
// index_kmp does KMP search.
@ -716,16 +713,19 @@ fn (s string) index_kmp(p string) int {
// index_any returns the position of any of the characters in the input string - if found.
pub fn (s string) index_any(chars string) int {
for c in chars {
index := s.index(c.ascii_str()) or { continue }
return index
idx := s.index_(c.ascii_str())
if idx == -1 {
continue
}
return idx
}
return -1
}
// last_index returns the position of the last occurence of the input string.
pub fn (s string) last_index(p string) ?int {
fn (s string) last_index_(p string) int {
if p.len > s.len || p.len == 0 {
return none
return -1
}
mut i := s.len - p.len
for i >= 0 {
@ -738,7 +738,16 @@ pub fn (s string) last_index(p string) ?int {
}
i--
}
return none
return -1
}
// last_index returns the position of the last occurence of the input string.
pub fn (s string) last_index(p string) ?int {
idx := s.last_index_(p)
if idx == -1 {
return none
}
return idx
}
// index_after returns the position of the input string, starting search from `start` position.
@ -818,7 +827,9 @@ pub fn (s string) contains(substr string) bool {
if substr.len == 0 {
return true
}
s.index(substr) or { return false }
if s.index_(substr) == -1 {
return false
}
return true
}
@ -970,10 +981,16 @@ pub fn (s string) is_title() bool {
// find_between returns the string found between `start` string and `end` string.
// Example: assert 'hey [man] how you doin'.find_between('[', ']') == 'man'
pub fn (s string) find_between(start string, end string) string {
start_pos := s.index(start) or { return '' }
start_pos := s.index_(start)
if start_pos == -1 {
return ''
}
// First get everything to the right of 'start'
val := s.right(start_pos + start.len)
end_pos := val.index(end) or { return val }
end_pos := val.index_(end)
if end_pos == -1 {
return val
}
return val.left(end_pos)
}
@ -1407,28 +1424,40 @@ pub fn (s &string) free() {
// all_before returns the contents before `dot` in the string.
// Example: assert '23:34:45.234'.all_before('.') == '23:34:45'
pub fn (s string) all_before(dot string) string {
pos := s.index(dot) or { return s }
pos := s.index_(dot)
if pos == -1 {
return s
}
return s.left(pos)
}
// all_before_last returns the contents before the last occurence of `dot` in the string.
// Example: assert '23:34:45.234'.all_before_last(':') == '23:34'
pub fn (s string) all_before_last(dot string) string {
pos := s.last_index(dot) or { return s }
pos := s.last_index_(dot)
if pos == -1 {
return s
}
return s.left(pos)
}
// all_after returns the contents after `dot` in the string.
// Example: assert '23:34:45.234'.all_after('.') == '234'
pub fn (s string) all_after(dot string) string {
pos := s.index(dot) or { return s }
pos := s.index_(dot)
if pos == -1 {
return s
}
return s.right(pos + dot.len)
}
// all_after_last returns the contents after the last occurence of `dot` in the string.
// Example: assert '23:34:45.234'.all_after_last(':') == '45.234'
pub fn (s string) all_after_last(dot string) string {
pos := s.last_index(dot) or { return s }
pos := s.last_index_(dot)
if pos == -1 {
return s
}
return s.right(pos + dot.len)
}