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|
use "types"
use "option"
pkg std =
const strfind : (haystack : byte[:], needle : byte[:] -> option(size))
const strrfind : (haystack : byte[:], needle : byte[:] -> option(size))
const strhas : (haystack : byte[:], needle : byte[:] -> bool)
;;
const strfind = {haystack, needle
-> strfindin(haystack, needle, 0, haystack.len)
}
const strrfind = {haystack, needle
-> strfindin(haystack, needle, haystack.len - 1, -1)
}
const strfindin = {haystack, needle, start, end
var inc : size
inc = 1
if start > end
inc = -1
;;
for var i = start; i != end; i += inc
/*
if we knew the direction we could terminate early,
but we allow the start and end to be passed in.
*/
if i + needle.len > haystack.len
continue
;;
if haystack[i] == needle[0]
for var j = 0; j < needle.len; j++
if haystack[i + j] != needle[j]
goto nextiter
;;
;;
-> `Some i
;;
:nextiter
;;
-> `None
}
const strhas = {haystack, needle
match strfind(haystack, needle)
| `Some _: -> true
| `None: -> false
;;
}
|
