diff --git a/lib/pure/strutils.nim b/lib/pure/strutils.nim index 361fa72eff..86f8df8011 100644 --- a/lib/pure/strutils.nim +++ b/lib/pure/strutils.nim @@ -1810,6 +1810,15 @@ func initSkipTable*(a: var SkipTable, sub: string) {.rtl, for i in 0 ..< m - 1: a[sub[i]] = m - 1 - i +func initSkipTable*(sub: string): SkipTable {.noinit, rtl, + extern: "nsuInitNewSkipTable".} = + ## Returns a new table initialized for `sub`. + ## + ## See also: + ## * `initSkipTable func<#initSkipTable,SkipTable,string>`_ + ## * `find func<#find,SkipTable,string,string,Natural,int>`_ + initSkipTable(result, sub) + func find*(a: SkipTable, s, sub: string, start: Natural = 0, last = 0): int {. rtl, extern: "nsuFindStrA".} = ## Searches for `sub` in `s` inside range `start..last` using preprocessed @@ -1842,9 +1851,6 @@ func find*(a: SkipTable, s, sub: string, start: Natural = 0, last = 0): int {. when not (defined(js) or defined(nimdoc) or defined(nimscript)): func c_memchr(cstr: pointer, c: char, n: csize_t): pointer {. importc: "memchr", header: "".} - func c_strstr(haystack, needle: cstring): cstring {. - importc: "strstr", header: "".} - const hasCStringBuiltin = true else: const hasCStringBuiltin = false @@ -1909,28 +1915,7 @@ func find*(s, sub: string, start: Natural = 0, last = 0): int {.rtl, if sub.len > s.len - start: return -1 if sub.len == 1: return find(s, sub[0], start, last) - template useSkipTable {.dirty.} = - var a {.noinit.}: SkipTable - initSkipTable(a, sub) - result = find(a, s, sub, start, last) - - when not hasCStringBuiltin: - useSkipTable() - else: - when nimvm: - useSkipTable() - else: - when hasCStringBuiltin: - if last == 0 and s.len > start: - let found = c_strstr(s[start].unsafeAddr, sub) - if not found.isNil: - result = cast[ByteAddress](found) -% cast[ByteAddress](s.cstring) - else: - result = -1 - else: - useSkipTable() - else: - useSkipTable() + result = find(initSkipTable(sub), s, sub, start, last) func rfind*(s: string, sub: char, start: Natural = 0, last = -1): int {.rtl, extern: "nsuRFindChar".} = diff --git a/lib/std/private/strimpl.nim b/lib/std/private/strimpl.nim index 7d42a7cf83..7d19825f4c 100644 --- a/lib/std/private/strimpl.nim +++ b/lib/std/private/strimpl.nim @@ -74,3 +74,40 @@ template endsWithImpl*[T: string | cstring](s, suffix: T) = func cmpNimIdentifier*[T: string | cstring](a, b: T): int = cmpIgnoreStyleImpl(a, b, true) + +func c_memchr(cstr: pointer, c: char, n: csize_t): pointer {. + importc: "memchr", header: "".} +func c_strstr(haystack, needle: cstring): cstring {. + importc: "strstr", header: "".} + + +func find*(s: cstring, sub: char, start: Natural = 0, last = 0): int = + ## Searches for `sub` in `s` inside the range `start..last` (both ends included). + ## If `last` is unspecified, it defaults to `s.high` (the last element). + ## + ## Searching is case-sensitive. If `sub` is not in `s`, -1 is returned. + ## Otherwise the index returned is relative to `s[0]`, not `start`. + ## Use `s[start..last].rfind` for a `start`-origin index. + let last = if last == 0: s.high else: last + let L = last-start+1 + if L > 0: + let found = c_memchr(s[start].unsafeAddr, sub, cast[csize_t](L)) + if not found.isNil: + return cast[ByteAddress](found) -% cast[ByteAddress](s) + return -1 + +func find*(s, sub: cstring, start: Natural = 0, last = 0): int = + ## Searches for `sub` in `s` inside the range `start..last` (both ends included). + ## If `last` is unspecified, it defaults to `s.high` (the last element). + ## + ## Searching is case-sensitive. If `sub` is not in `s`, -1 is returned. + ## Otherwise the index returned is relative to `s[0]`, not `start`. + ## Use `s[start..last].find` for a `start`-origin index. + if sub.len > s.len - start: return -1 + if sub.len == 1: return find(s, sub[0], start, last) + if last == 0 and s.len > start: + let found = c_strstr(s[start].unsafeAddr, sub) + if not found.isNil: + result = cast[ByteAddress](found) -% cast[ByteAddress](s) + else: + result = -1 diff --git a/tests/stdlib/tstrimpl.nim b/tests/stdlib/tstrimpl.nim new file mode 100644 index 0000000000..4d0ef827f0 --- /dev/null +++ b/tests/stdlib/tstrimpl.nim @@ -0,0 +1,6 @@ +import std/private/strimpl + +doAssert find(cstring"Hello Nim", cstring"Nim") == 6 +doAssert find(cstring"Hello Nim", cstring"N") == 6 +doAssert find(cstring"Hello Nim", cstring"I") == -1 +doAssert find(cstring"Hello Nim", cstring"O") == -1