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43 lines
1.4 KiB
Nim
43 lines
1.4 KiB
Nim
proc handleHexChar*(c: char, x: var int): bool {.inline.} =
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## Converts `%xx` hexadecimal to the ordinal number and adds the result to `x`.
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## Returns `true` if `c` is hexadecimal.
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##
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## When `c` is hexadecimal, the proc is equal to `x = x shl 4 + hex2Int(c)`.
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runnableExamples:
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var x = 0
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assert handleHexChar('a', x)
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assert x == 10
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assert handleHexChar('B', x)
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assert x == 171 # 10 shl 4 + 11
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assert not handleHexChar('?', x)
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assert x == 171 # unchanged
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result = true
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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:
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result = false
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proc handleHexChar*(c: char): int {.inline.} =
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case c
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of '0'..'9': result = (ord(c) - ord('0'))
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of 'a'..'f': result = (ord(c) - ord('a') + 10)
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of 'A'..'F': result = (ord(c) - ord('A') + 10)
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else: discard
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proc decodePercent*(s: openArray[char], i: var int): char =
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## Converts `%xx` hexadecimal to the character 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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if handleHexChar(s[i+1], x) and handleHexChar(s[i+2], x):
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result = chr(x)
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inc(i, 2)
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