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v/vlib/strings/strings.v
2022-02-15 15:12:15 +02:00

129 lines
4.4 KiB
V

module strings
// import rand
// random returns a random string with `n` characters
/*
pub fn random(n int) string {
buf := vmalloc(n)
for i in 0..n {
buf[i] = rand.next()
}
return tos(buf)
}
*/
// find_between_pair_byte returns the string found between the pair of marks defined
// by `start` and `end`.
// As opposed to the `find_between`, `all_after*`, `all_before*` methods defined on the
// `string` type, this function can extract content between *nested* marks in `input`.
// If `start` and `end` marks are nested in `input`, the characters
// between the *outermost* mark pair is returned. It is expected that `start` and `end`
// marks are *balanced*, meaning that the amount of `start` marks equal the
// amount of `end` marks in the `input`. An empty string is returned otherwise.
// Using two identical marks as `start` and `end` results in undefined output behavior.
// find_between_pair_byte is the fastest in the find_between_pair_* family of functions.
// Example: assert strings.find_between_pair_byte('(V) (NOT V)',`(`,`)`) == 'V'
// Example: assert strings.find_between_pair_byte('s {X{Y}} s',`{`,`}`) == 'X{Y}'
pub fn find_between_pair_byte(input string, start byte, end byte) string {
mut marks := 0
mut start_index := -1
for i, b in input {
if b == start {
if start_index == -1 {
start_index = i + 1
}
marks++
continue
}
if start_index > 0 {
if b == end {
marks--
if marks == 0 {
return input[start_index..i]
}
}
}
}
return ''
}
// find_between_pair_rune returns the string found between the pair of marks defined
// by `start` and `end`.
// As opposed to the `find_between`, `all_after*`, `all_before*` methods defined on the
// `string` type, this function can extract content between *nested* marks in `input`.
// If `start` and `end` marks are nested in `input`, the characters
// between the *outermost* mark pair is returned. It is expected that `start` and `end`
// marks are *balanced*, meaning that the amount of `start` marks equal the
// amount of `end` marks in the `input`. An empty string is returned otherwise.
// Using two identical marks as `start` and `end` results in undefined output behavior.
// find_between_pair_rune is inbetween the fastest and slowest in the find_between_pair_* family of functions.
// Example: assert strings.find_between_pair_rune('(V) (NOT V)',`(`,`)`) == 'V'
// Example: assert strings.find_between_pair_rune('s {X{Y}} s',`{`,`}`) == 'X{Y}'
pub fn find_between_pair_rune(input string, start rune, end rune) string {
mut marks := 0
mut start_index := -1
runes := input.runes()
for i, r in runes {
if r == start {
if start_index == -1 {
start_index = i + 1
}
marks++
continue
}
if start_index > 0 {
if r == end {
marks--
if marks == 0 {
return runes[start_index..i].string()
}
}
}
}
return ''
}
// find_between_pair_string returns the string found between the pair of marks defined
// by `start` and `end`.
// As opposed to the `find_between`, `all_after*`, `all_before*` methods defined on the
// `string` type, this function can extract content between *nested* marks in `input`.
// If `start` and `end` marks are nested in `input`, the characters
// between the *outermost* mark pair is returned. It is expected that `start` and `end`
// marks are *balanced*, meaning that the amount of `start` marks equal the
// amount of `end` marks in the `input`. An empty string is returned otherwise.
// Using two identical marks as `start` and `end` results in undefined output behavior.
// find_between_pair_string is the slowest in the find_between_pair_* function family.
// Example: assert strings.find_between_pair_string('/*V*/ /*NOT V*/','/*','*/') == 'V'
// Example: assert strings.find_between_pair_string('s {{X{{Y}}}} s','{{','}}') == 'X{{Y}}'
pub fn find_between_pair_string(input string, start string, end string) string {
mut start_index := -1
mut marks := 0
start_runes := start.runes()
end_runes := end.runes()
runes := input.runes()
mut i := 0
for ; i < runes.len; i++ {
start_slice := runes#[i..i + start_runes.len]
if start_slice == start_runes {
i = i + start_runes.len - 1
if start_index < 0 {
start_index = i + 1
}
marks++
continue
}
if start_index > 0 {
end_slice := runes#[i..i + end_runes.len]
if end_slice == end_runes {
marks--
if marks == 0 {
return runes[start_index..i].string()
}
i = i + end_runes.len - 1
continue
}
}
}
return ''
}