diff options
Diffstat (limited to 'lib/pure/includes')
| -rw-r--r-- | lib/pure/includes/decode_helpers.nim | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/lib/pure/includes/decode_helpers.nim b/lib/pure/includes/decode_helpers.nim new file mode 100644 index 000000000..74fe37d07 --- /dev/null +++ b/lib/pure/includes/decode_helpers.nim @@ -0,0 +1,24 @@ +# Include file that implements 'decodePercent' and friends. Do not import it! + +proc handleHexChar(c: char, x: var int, f: var bool) {.inline.} = + case c + of '0'..'9': x = (x shl 4) or (ord(c) - ord('0')) + of 'a'..'f': x = (x shl 4) or (ord(c) - ord('a') + 10) + of 'A'..'F': x = (x shl 4) or (ord(c) - ord('A') + 10) + else: f = true + +proc decodePercent(s: string, i: var int): char = + ## Converts `%xx` hexadecimal to the charracter with ordinal number `xx`. + ## + ## If `xx` is not a valid hexadecimal value, it is left intact: only the + ## leading `%` is returned as-is, and `xx` characters will be processed in the + ## next step (e.g. in `uri.decodeUrl`) as regular characters. + result = '%' + if i+2 < s.len: + var x = 0 + var failed = false + handleHexChar(s[i+1], x, failed) + handleHexChar(s[i+2], x, failed) + if not failed: + result = chr(x) + inc(i, 2) |