| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell2010 |
Data.Text.Internal.Validate
Contents
Description
Test whether or not a sequence of bytes is a valid UTF-8 byte sequence.
In the GHC Haskell ecosystem, there are several representations of byte
sequences. The only one that the stable text API concerns itself with is
ByteString. Part of bytestring-to-text decoding is isValidUtf8ByteString,
a high-performance UTF-8 validation routine written in C++ with fallbacks
for various platforms. The C++ code backing this routine is nontrivial,
so in the interest of reuse, this module additionally exports functions
for working with the GC-managed ByteArray type. These ByteArray
functions are not used anywhere else in text. They are for the benefit
of library and application authors who do not use ByteString but still
need to interoperate with text.
Synopsis
- isValidUtf8ByteString :: ByteString -> Bool
- isValidUtf8ByteArray :: ByteArray -> Int -> Int -> Bool
- isValidUtf8ByteArrayUnpinned :: ByteArray -> Int -> Int -> Bool
- isValidUtf8ByteArrayPinned :: ByteArray -> Int -> Int -> Bool
ByteString
isValidUtf8ByteString :: ByteString -> Bool Source #
Is the ByteString a valid UTF-8 byte sequence?
ByteArray
Is the slice of a byte array a valid UTF-8 byte sequence? These functions all accept an offset and a length.
For pinned byte arrays larger than 128KiB, this switches to the safe FFI so that it does not prevent GC. This threshold (128KiB) was chosen somewhat arbitrarily and may change in the future.
isValidUtf8ByteArrayUnpinned Source #
This uses the unsafe FFI. GC waits for all unsafe FFI calls
to complete before starting. Consequently, an unsafe FFI call does not
run concurrently with GC and is not interrupted by GC. Since relocation
cannot happen concurrently with an unsafe FFI call, it is safe
to call this function with an unpinned byte array argument.
It is also safe to call this with a pinned ByteArray argument.
isValidUtf8ByteArrayPinned Source #
This uses the safe FFI. GC may run concurrently with safe
FFI calls. Consequently, unpinned objects may be relocated while a
safe FFI call is executing. The byte array argument must be pinned,
and the calling context is responsible for enforcing this. If the
byte array is not pinned, this function's behavior is undefined.