#
#
# Nim's Runtime Library
# (c) Copyright 2017 Nim contributors
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## This module supports helper routines for working with `cstring`
## without having to convert `cstring` to `string`, in order to
## save allocations.
##
## See also
## ========
## * `strutils module <strutils.html>`_ for working with `string`
include system/inclrtl
import std/private/strimpl
when defined(js):
func jsStartsWith(s, prefix: cstring): bool {.importjs: "#.startsWith(#)".}
func jsEndsWith(s, suffix: cstring): bool {.importjs: "#.endsWith(#)".}
func startsWith*(s, prefix: cstring): bool {.rtl, extern: "csuStartsWith".} =
## Returns true if `s` starts with `prefix`.
##
## The JS backend uses the native `String.prototype.startsWith` function.
runnableExamples:
assert startsWith(cstring"Hello, Nimion", cstring"Hello")
assert not startsWith(cstring"Hello, Nimion", cstring"Nimion")
assert startsWith(cstring"Hello", cstring"")
when nimvm:
startsWithImpl(s, prefix)
else:
when defined(js):
result = jsStartsWith(s, prefix)
else:
var i = 0
while true:
if prefix[i] == '\0': return true
if s[i] != prefix[i]: return false
inc(i)
func endsWith*(s, suffix: cstring): bool {.rtl, extern: "csuEndsWith".} =
## Returns true if `s` ends with `suffix`.
##
## The JS backend uses the native `String.prototype.endsWith` function.
runnableExamples:
assert endsWith(cstring"Hello, Nimion", cstring"Nimion")
assert not endsWith(cstring"Hello, Nimion", cstring"Hello")
assert endsWith(cstring"Hello", cstring"")
when nimvm:
endsWithImpl(s, suffix)
else:
when defined(js):
result = jsEndsWith(s, suffix)
else:
let slen = s.len
var i = 0
var j = slen - len(suffix)
while i + j <% slen:
if s[i + j] != suffix[i]: return false
inc(i)
if suffix[i] == '\0': return true
func cmpIgnoreStyle*(a, b: cstring): int {.rtl, extern: "csuCmpIgnoreStyle".} =
## Semantically the same as `cmp(normalize($a), normalize($b))`. It
## is just optimized to not allocate temporary strings. This should
## NOT be used to compare Nim identifier names, use `macros.eqIdent`
## for that. Returns:
## * 0 if `a == b`
## * < 0 if `a < b`
## * > 0 if `a > b`
runnableExamples:
assert cmpIgnoreStyle(cstring"hello", cstring"H_e_L_Lo") == 0
when nimvm:
cmpIgnoreStyleImpl(a, b)
else:
when defined(js):
cmpIgnoreStyleImpl(a, b)
else:
var i = 0
var j = 0
while true:
while a[i] == '_': inc(i)
while b[j] == '_': inc(j) # BUGFIX: typo
var aa = toLowerAscii(a[i])
var bb = toLowerAscii(b[j])
result = ord(aa) - ord(bb)
if result != 0 or aa == '\0': break
inc(i)
inc(j)
func cmpIgnoreCase*(a, b: cstring): int {.rtl, extern: "csuCmpIgnoreCase".} =
## Compares two strings in a case insensitive manner. Returns:
## * 0 if `a == b`
## * < 0 if `a < b`
## * > 0 if `a > b`
runnableExamples:
assert cmpIgnoreCase(cstring"hello", cstring"HeLLo") == 0
assert cmpIgnoreCase(cstring"echo", cstring"hello") < 0
assert cmpIgnoreCase(cstring"yellow", cstring"hello") > 0
when nimvm:
cmpIgnoreCaseImpl(a, b)
else:
when defined(js):
cmpIgnoreCaseImpl(a, b)
else:
var i = 0
while true:
var aa = toLowerAscii(a[i])
var bb = toLowerAscii(b[i])
result = ord(aa) - ord(bb)
if result != 0 or aa == '\0': break
inc(i)