System.OsString.Windows

Commonly used windows string as wide character bytes.

This represents a "wide char" on windows.

A better name would maybe have been WindowsWord, since this is just Word16 in a UCS-2 sequence.

Partial unicode friendly encoding.

This encodes as UTF16-LE (strictly), which is a pretty good guess.

Throws an EncodingException if encoding fails. If the input does not contain surrogate chars, you can use unsafeEncodeUtf.

Unsafe unicode friendly encoding.

Like encodeUtf, except it crashes when the input contains surrogate chars. For sanitized input, this can be useful.

Encode a String with the specified encoding.

Note: We expect a "wide char" encoding (e.g. UCS-2 or UTF-16). Anything that works with Word16 boundaries. Picking an incompatible encoding may crash filepath operations.

This mimics the behavior of the base library when doing filesystem operations (usually filepaths), which does permissive UTF-16 encoding, where coding errors generate Chars in the surrogate range.

The reason this is in IO is because it unifies with the Posix counterpart, which does require IO. This is safe to unsafePerformIO/unsafeDupablePerformIO.

This mimics the behavior of the base library when doing string operations, which does permissive UTF-16 encoding, where coding errors generate Chars in the surrogate range.

The reason this is in IO is because it unifies with the Posix counterpart, which does require IO. This is safe to unsafePerformIO/unsafeDupablePerformIO.

Like 'encodeLE but not in IO.

encodeLE was designed to have a symmetric type signature on unix and windows, but morally the function has no IO effects on windows, so we provide this variant without breaking existing API.

On windows, encodeLE is equivalent to encodeFS.

This function does not exist on unix.

Constructs a platform string from a ByteString.

This ensures valid UCS-2LE. Note that this doesn't expand Word8 to Word16 on windows, so you may get invalid UTF-16.

Throws EncodingException on invalid UCS-2LE (although unlikely).

Constructs a platform string from a ShortByteString.

This ensures valid UCS-2LE. Note that this doesn't expand Word8 to Word16 on windows, so you may get invalid UTF-16.

Throws EncodingException on invalid UCS-2LE (although unlikely).

QuasiQuote a WindowsString. This accepts Unicode characters and encodes as UTF-16LE on windows.

Pack a list of platform words to a platform string.

Note that using this in conjunction with unsafeFromChar to convert from [Char] to platform string is probably not what you want, because it will truncate unicode code points.

Additionally, a platform word is a byte (or wide char on windows) in an encoded byte sequence, so we're not operating on unicode code points or graphemes here.

Partial unicode friendly decoding.

This decodes as UTF16-LE (strictly), which is a pretty good.

Throws a EncodingException if decoding fails.

Decode a WindowsString with the specified encoding.

The String is forced into memory to catch all exceptions.

Like decodeUtf, except this mimics the behavior of the base library when doing filesystem operations (usually filepaths), which does permissive UTF-16 encoding, where coding errors generate Chars in the surrogate range.

The reason this is in IO is because it unifies with the Posix counterpart, which does require IO. unsafePerformIO/unsafeDupablePerformIO are safe, however.

Like decodeUtf, except this mimics the behavior of the base library when doing filesystem operations, which does permissive UTF-16 encoding, where coding errors generate Chars in the surrogate range.

The reason this is in IO is because it unifies with the Posix counterpart, which does require IO. unsafePerformIO/unsafeDupablePerformIO are safe, however.

Unpack a platform string to a list of platform words.

Truncates to 2 octets.

Note that WindowsChar is a "wide char" in a UCS-2 encoded byte sequence and is not morally a unicode code point by any means, so this conversion is rarely what you want.

Consider using fromWord instead.

Convert from Word16.

Converts back to a unicode codepoint (total).

O(n) Append a byte to the end of a OsString

O(n) cons is analogous to (:) for lists.

O(1) Extract the last element of a OsString, which must be finite and non-empty. An exception will be thrown in the case of an empty OsString.

This is a partial function, consider using unsnoc instead.

O(n) Extract the elements after the head of a OsString, which must be non-empty. An exception will be thrown in the case of an empty OsString.

This is a partial function, consider using uncons instead.

O(n) Extract the head and tail of a OsString, returning Nothing if it is empty.

O(1) Extract the first element of a OsString, which must be non-empty. An exception will be thrown in the case of an empty OsString.

This is a partial function, consider using uncons instead.

O(n) Return all the elements of a OsString except the last one. An exception will be thrown in the case of an empty OsString.

This is a partial function, consider using unsnoc instead.

O(n) Extract the init and last of a OsString, returning Nothing if it is empty.

O(1). The empty OsString.

O(1) The length of a OsString.

This returns the number of code units (Word8 on unix and Word16 on windows), not bytes.

>>> length "abc"3

O(n) map f xs is the OsString obtained by applying f to each element of xs.

O(n) reverse xs efficiently returns the elements of xs in reverse order.

O(n) The intercalate function takes a OsString and a list of OsStrings and concatenates the list after interspersing the first argument between each element of the list.

foldl, applied to a binary operator, a starting value (typically the left-identity of the operator), and a OsString, reduces the OsString using the binary operator, from left to right.

foldl' is like foldl, but strict in the accumulator.

foldl1 is a variant of foldl that has no starting value argument, and thus must be applied to non-empty OsStrings. An exception will be thrown in the case of an empty OsString.

foldl1' is like foldl1, but strict in the accumulator. An exception will be thrown in the case of an empty OsString.

foldr, applied to a binary operator, a starting value (typically the right-identity of the operator), and a OsString, reduces the OsString using the binary operator, from right to left.

foldr' is like foldr, but strict in the accumulator.

foldr1 is a variant of foldr that has no starting value argument, and thus must be applied to non-empty OsStrings An exception will be thrown in the case of an empty OsString.

foldr1' is a variant of foldr1, but is strict in the accumulator.

Check whether one string is a substring of another.

O(n) The isPrefixOf function takes two OsStrings and returns True

O(n) The isSuffixOf function takes two OsStrings and returns True iff the first is a suffix of the second.

The following holds:

isSuffixOf x y == reverse x `isPrefixOf` reverse y

O(1) OsString index (subscript) operator, starting from 0.

O(1) OsString index, starting from 0, that returns Just if:

0 <= n < length bs

O(1) OsString index, starting from 0, that returns Just if:

0 <= n < length bs

O(n) The elemIndex function returns the index of the first element in the given OsString which is equal to the query element, or Nothing if there is no such element.

O(n) The elemIndices function extends elemIndex, by returning the indices of all elements equal to the query element, in ascending order.

count returns the number of times its argument appears in the OsString

O(n) The findIndex function takes a predicate and a OsString and returns the index of the first element in the OsString satisfying the predicate.

O(n) The findIndices function extends findIndex, by returning the indices of all elements satisfying the predicate, in ascending order.