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