diff options
Diffstat (limited to 'lib/pure/parseutils.nim')
-rw-r--r-- | lib/pure/parseutils.nim | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/lib/pure/parseutils.nim b/lib/pure/parseutils.nim index 698bde42a..3e25eba22 100644 --- a/lib/pure/parseutils.nim +++ b/lib/pure/parseutils.nim @@ -234,6 +234,47 @@ proc parseInt*(s: string, number: var int, start = 0): int {. elif result != 0: number = int(res) +# overflowChecks doesn't work with uint64 +proc rawParseUInt(s: string, b: var uint64, start = 0): int = + var + res = 0'u64 + prev = 0'u64 + i = start + if s[i] == '+': inc(i) # Allow + if s[i] in {'0'..'9'}: + b = 0 + while s[i] in {'0'..'9'}: + prev = res + res = res * 10 + (ord(s[i]) - ord('0')).uint64 + if prev > res: + return 0 # overflowChecks emulation + inc(i) + while s[i] == '_': inc(i) # underscores are allowed and ignored + b = res + result = i - start + +proc parseBiggestUInt*(s: string, number: var uint64, start = 0): int {. + rtl, extern: "npuParseBiggestUInt", noSideEffect.} = + ## parses an unsigned integer starting at `start` and stores the value into `number`. + ## Result is the number of processed chars or 0 if there is no integer or overflow detected. + var res: uint64 + # use 'res' for exception safety (don't write to 'number' in case of an + # overflow exception): + result = rawParseUInt(s, res, start) + number = res + +proc parseUInt*(s: string, number: var uint, start = 0): int {. + rtl, extern: "npuParseUInt", noSideEffect.} = + ## parses an unsigned integer starting at `start` and stores the value into `number`. + ## Result is the number of processed chars or 0 if there is no integer or overflow detected. + var res: uint64 + result = parseBiggestUInt(s, res, start) + if (sizeof(uint) <= 4) and + (res > 0xFFFF_FFFF'u64): + raise newException(OverflowError, "overflow") + elif result != 0: + number = uint(res) + proc parseBiggestFloat*(s: string, number: var BiggestFloat, start = 0): int {. magic: "ParseBiggestFloat", importc: "nimParseBiggestFloat", noSideEffect.} ## parses a float starting at `start` and stores the value into `number`. |