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hex byte: raise instead of assert on hex-to-byte odd lengths

This commit is contained in:
Jacek Sieka 2020-04-09 11:20:21 +02:00 committed by zah
parent 3e1fa974a4
commit 87ccf8e66b
2 changed files with 18 additions and 6 deletions
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13
stew/byteutils.nim
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@ -51,7 +51,7 @@ proc readHexChar*(c: char): byte {.noSideEffect, inline.}=
template skip0xPrefix(hexStr: string): int =
## Returns the index of the first meaningful char in `hexStr` by skipping
## "0x" prefix
if hexStr[0] == '0' and hexStr[1] in {'x', 'X'}: 2
if hexStr.len > 1 and hexStr[0] == '0' and hexStr[1] in {'x', 'X'}: 2
else: 0
func hexToByteArray*(hexStr: string, output: var openArray[byte], fromIdx, toIdx: int) =
@ -62,8 +62,8 @@ func hexToByteArray*(hexStr: string, output: var openArray[byte], fromIdx, toIdx
doAssert(fromIdx >= 0 and toIdx >= fromIdx and fromIdx < output.len and toIdx < output.len)
let sz = toIdx - fromIdx + 1
doAssert hexStr.len - sIdx >= 2*sz
if hexStr.len - sIdx < 2*sz:
raise (ref ValueError)(msg: "hex string too short")
sIdx += fromIdx * 2
for bIdx in fromIdx ..< sz + fromIdx:
output[bIdx] = hexStr[sIdx].readHexChar shl 4 or hexStr[sIdx + 1].readHexChar
@ -89,7 +89,9 @@ func hexToPaddedByteArray*[N: static[int]](hexStr: string): array[N, byte] =
bIdx: int
shift = 4
doAssert hexStr.len - p <= maxStrSize
if hexStr.len - p > maxStrSize:
# TODO this is a bit strange, compared to the hexToByteArray above...
raise (ref ValueError)(msg: "hex string too long")
if sz < maxStrSize:
# include extra byte if odd length
@ -105,7 +107,8 @@ func hexToPaddedByteArray*[N: static[int]](hexStr: string): array[N, byte] =
func hexToSeqByte*(hexStr: string): seq[byte] =
## Read an hex string and store it in a sequence of bytes. No "endianness" reordering is done.
doAssert (hexStr.len and 1) == 0
if (hexStr.len and 1) == 1:
raise (ref ValueError)(msg: "hex string must have even length")
let skip = skip0xPrefix(hexStr)
let N = (hexStr.len - skip) div 2

11
tests/test_byteutils.nim
View File

@ -33,8 +33,17 @@ suite "Byte utils":
a = hexToByteArray[4](s)
check a == simpleBArray
expect(ValueError): discard hexToByteArray[1]("")
expect(ValueError): discard hexToByteArray[1]("1")
test "toHex":
check simpleBArray.toHex == "12345678"
check hexToSeqByte("12345678") == simpleBArray
check hexToSeqByte("00") == [byte 0]
check hexToSeqByte("0x") == []
expect(ValueError): discard hexToSeqByte("1234567")
expect(ValueError): discard hexToSeqByte("X")
expect(ValueError): discard hexToSeqByte("0")
test "Array concatenation":
check simpleBArray & simpleBArray ==
@ -57,7 +66,7 @@ suite "Byte utils":
let a = hexToPaddedByteArray[32]("0x68656c6c6f20776f726c64")
check a.toHex == "00000000000000000000000000000000000000000068656c6c6f20776f726c64"
block:
expect AssertionError:
expect ValueError:
discard hexToPaddedByteArray[2]("0x12345")
test "lessThan":