| Copyright | Copyright (c) 2010--2021 wren gayle romano |
|---|---|
| License | BSD2 |
| Maintainer | wren@cpan.org |
| Stability | provisional |
| Portability | BangPatterns |
| Safe Haskell | None |
| Language | Haskell2010 |
Data.ByteString.Lex.Integral
Description
Functions for parsing and producing Integral values from/to
ByteStrings based on the "Char8" encoding. That is, we assume
an ASCII-compatible encoding of alphanumeric characters.
Since: 0.3.0
Synopsis
- readSigned :: Num a => (ByteString -> Maybe (a, ByteString)) -> ByteString -> Maybe (a, ByteString)
- readDecimal :: Integral a => ByteString -> Maybe (a, ByteString)
- readDecimal_ :: Integral a => ByteString -> a
- packDecimal :: Integral a => a -> Maybe ByteString
- readHexadecimal :: Integral a => ByteString -> Maybe (a, ByteString)
- packHexadecimal :: Integral a => a -> Maybe ByteString
- asHexadecimal :: ByteString -> ByteString
- readOctal :: Integral a => ByteString -> Maybe (a, ByteString)
- packOctal :: Integral a => a -> Maybe ByteString
General combinators
readSigned :: Num a => (ByteString -> Maybe (a, ByteString)) -> ByteString -> Maybe (a, ByteString) Source #
Adjust a reading function to recognize an optional leading sign. As with the other functions, we assume an ASCII-compatible encoding of the sign characters.
Decimal conversions
readDecimal :: Integral a => ByteString -> Maybe (a, ByteString) Source #
Read an unsigned/non-negative integral value in ASCII decimal
format. Returns Nothing if there is no integer at the beginning
of the string, otherwise returns Just the integer read and the
remainder of the string.
If you are extremely concerned with performance, then it is more
performant to use this function at Int or Word and then to
call fromIntegral to perform the conversion at the end. However,
doing this will make your code succeptible to overflow bugs if
the target type is larger than Int.
readDecimal_ :: Integral a => ByteString -> a Source #
A variant of readDecimal which does not return the tail of
the string, and returns 0 instead of Nothing. This is twice
as fast for Int64 on 32-bit systems, but has identical performance
to readDecimal for all other types and architectures.
Since: 0.4.0
packDecimal :: Integral a => a -> Maybe ByteString Source #
Convert a non-negative integer into an (unsigned) ASCII decimal
string. Returns Nothing on negative inputs.
Hexadecimal conversions
readHexadecimal :: Integral a => ByteString -> Maybe (a, ByteString) Source #
Read a non-negative integral value in ASCII hexadecimal format.
Returns Nothing if there is no integer at the beginning of the
string, otherwise returns Just the integer read and the remainder
of the string.
This function does not recognize the various hexadecimal sigils like "0x", but because there are so many different variants, those are best handled by helper functions which then use this function for the actual numerical parsing. This function recognizes both upper-case, lower-case, and mixed-case hexadecimal.
packHexadecimal :: Integral a => a -> Maybe ByteString Source #
Convert a non-negative integer into a lower-case ASCII hexadecimal
string. Returns Nothing on negative inputs.
asHexadecimal :: ByteString -> ByteString Source #
Convert a bitvector into a lower-case ASCII hexadecimal string. This is helpful for visualizing raw binary data, rather than for parsing as such.
Octal conversions
readOctal :: Integral a => ByteString -> Maybe (a, ByteString) Source #
Read a non-negative integral value in ASCII octal format.
Returns Nothing if there is no integer at the beginning of the
string, otherwise returns Just the integer read and the remainder
of the string.
This function does not recognize the various octal sigils like "0o", but because there are different variants, those are best handled by helper functions which then use this function for the actual numerical parsing.