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c62513049c
* fix #14082, don't crash on incorrectly formatted input * address code review * remove duplication
25 lines
890 B
Nim
25 lines
890 B
Nim
# Include file that implements 'decodePercent' and friends. Do not import it!
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proc handleHexChar(c: char, x: var int, f: var bool) {.inline.} =
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case c
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of '0'..'9': x = (x shl 4) or (ord(c) - ord('0'))
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of 'a'..'f': x = (x shl 4) or (ord(c) - ord('a') + 10)
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of 'A'..'F': x = (x shl 4) or (ord(c) - ord('A') + 10)
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else: f = true
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proc decodePercent(s: string, i: var int): char =
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## Converts `%xx` hexadecimal to the charracter with ordinal number `xx`.
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##
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## If `xx` is not a valid hexadecimal value, it is left intact: only the
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## leading `%` is returned as-is, and `xx` characters will be processed in the
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## next step (e.g. in `uri.decodeUrl`) as regular characters.
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result = '%'
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if i+2 < s.len:
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var x = 0
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var failed = false
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handleHexChar(s[i+1], x, failed)
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handleHexChar(s[i+2], x, failed)
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if not failed:
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result = chr(x)
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inc(i, 2)
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