GI.GLib.Structs.String

A GString is an object that handles the memory management of a C string.

The emphasis of GString is on text, typically UTF-8. Crucially, the "str" member of a GString is guaranteed to have a trailing nul character, and it is therefore always safe to call functions such as strchr() or strdup() on it.

However, a GString can also hold arbitrary binary data, because it has a "len" member, which includes any possible embedded nul characters in the data. Conceptually then, GString is like a GByteArray with the addition of many convenience methods for text, and a guaranteed nul terminator.

Exported types

newtype String

Memory-managed wrapper type.

Constructors

String (ManagedPtr String)

Instances

Eq String

Defined in GI.GLib.Structs.String

Methods

(==) :: String -> String -> Bool

(/=) :: String -> String -> Bool

GBoxed String

Defined in GI.GLib.Structs.String

ManagedPtrNewtype String

Defined in GI.GLib.Structs.String

Methods

toManagedPtr :: String -> ManagedPtr String

TypedObject String

Defined in GI.GLib.Structs.String

Methods

glibType :: IO GType

HasParentTypes String

Defined in GI.GLib.Structs.String

tag ~ 'AttrSet => Constructible String tag

Defined in GI.GLib.Structs.String

Methods

new :: MonadIO m => (ManagedPtr String -> String) -> [AttrOp String tag] -> m String

IsGValue (Maybe String)

Convert String to and from GValue. See toGValue and fromGValue.

Defined in GI.GLib.Structs.String

Methods

gvalueGType_ :: IO GType

gvalueSet_ :: Ptr GValue -> Maybe String -> IO ()

gvalueGet_ :: Ptr GValue -> IO (Maybe String)

type ParentTypes String

Defined in GI.GLib.Structs.String

type ParentTypes String = '[] :: [Type]

newZeroString :: MonadIO m => m String

Construct a String struct initialized to zero.

Methods

Click to display all available methods, including inherited ones

Methods

append, appendC, appendLen, appendUnichar, appendUriEscaped, asciiDown, asciiUp, assign, down, equal, erase, free, freeAndSteal, freeToBytes, hash, insert, insertC, insertLen, insertUnichar, overwrite, overwriteLen, prepend, prependC, prependLen, prependUnichar, replace, truncate, up.

Getters

None.

Setters

setSize.

append

stringAppend

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Text

val: the string to append onto the end of string

-> m String

Returns: string

Adds a string onto the end of a String, expanding it if necessary.

appendC

stringAppendC

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Int8

c: the byte to append onto the end of string

-> m String

Returns: string

Adds a byte onto the end of a String, expanding it if necessary.

appendLen

stringAppendLen

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Text

val: bytes to append

-> Int64

len: number of bytes of val to use, or -1 for all of val

-> m String

Returns: string

Appends len bytes of val to string.

If len is positive, val may contain embedded nuls and need not be nul-terminated. It is the caller's responsibility to ensure that val has at least len addressable bytes.

If len is negative, val must be nul-terminated and len is considered to request the entire string length. This makes stringAppendLen equivalent to stringAppend.

appendUnichar

stringAppendUnichar

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Char

wc: a Unicode character

-> m String

Returns: string

Converts a Unicode character into UTF-8, and appends it to the string.

appendUriEscaped

stringAppendUriEscaped

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Text

unescaped: a string

-> Text

reservedCharsAllowed: a string of reserved characters allowed to be used, or Nothing

-> Bool

allowUtf8: set True if the escaped string may include UTF8 characters

-> m String

Returns: string

Appends unescaped to string, escaping any characters that are reserved in URIs using URI-style escape sequences.

Since: 2.16

asciiDown

stringAsciiDown

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a GString

-> m String

Returns: passed-in string pointer, with all the uppercase characters converted to lowercase in place, with semantics that exactly match asciiTolower.

Converts all uppercase ASCII letters to lowercase ASCII letters.

asciiUp

stringAsciiUp

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a GString

-> m String

Returns: passed-in string pointer, with all the lowercase characters converted to uppercase in place, with semantics that exactly match asciiToupper.

Converts all lowercase ASCII letters to uppercase ASCII letters.

assign

stringAssign

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: the destination String. Its current contents are destroyed.

-> Text

rval: the string to copy into string

-> m String

Returns: string

Copies the bytes from a string into a String, destroying any previous contents. It is rather like the standard strcpy() function, except that you do not have to worry about having enough space to copy the string.

down

stringDown

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> m String

Returns: the String

Deprecated: (Since version 2.2)This function uses the locale-specific tolower() function, which is almost never the right thing. Use stringAsciiDown or utf8Strdown instead.

Converts a String to lowercase.

equal

stringEqual

Arguments

:: (HasCallStack, MonadIO m)

=> String

v: a String

-> String

v2: another String

-> m Bool

Returns: True if the strings are the same length and contain the same bytes

Compares two strings for equality, returning True if they are equal. For use with HashTable.

erase

stringErase

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Int64

pos: the position of the content to remove

-> Int64

len: the number of bytes to remove, or -1 to remove all following bytes

-> m String

Returns: string

Removes len bytes from a String, starting at position pos. The rest of the String is shifted down to fill the gap.

free

stringFree

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Bool

freeSegment: if True, the actual character data is freed as well

-> m (Maybe Text)

Returns: the character data of string (i.e. Nothing if freeSegment is True)

Frees the memory allocated for the String. If freeSegment is True it also frees the character data. If it's False, the caller gains ownership of the buffer and must free it after use with free.

Instead of passing False to this function, consider using stringFreeAndSteal.

freeAndSteal

stringFreeAndSteal

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> m Text

Returns: the character data of string

Frees the memory allocated for the String.

The caller gains ownership of the buffer and must free it after use with free.

Since: 2.76

freeToBytes

stringFreeToBytes

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> m Bytes

Returns: A newly allocated Bytes containing contents of string; string itself is freed

Transfers ownership of the contents of string to a newly allocated Bytes. The String structure itself is deallocated, and it is therefore invalid to use string after invoking this function.

Note that while String ensures that its buffer always has a trailing nul character (not reflected in its "len"), the returned Bytes does not include this extra nul; i.e. it has length exactly equal to the "len" member.

Since: 2.34

hash

stringHash

Arguments

:: (HasCallStack, MonadIO m)

=> String

str: a string to hash

-> m Word32

Returns: hash code for str

Creates a hash code for str; for use with HashTable.

insert

stringInsert

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Int64

pos: the position to insert the copy of the string

-> Text

val: the string to insert

-> m String

Returns: string

Inserts a copy of a string into a String, expanding it if necessary.

insertC

stringInsertC

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Int64

pos: the position to insert the byte

-> Int8

c: the byte to insert

-> m String

Returns: string

Inserts a byte into a String, expanding it if necessary.

insertLen

stringInsertLen

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Int64

pos: position in string where insertion should happen, or -1 for at the end

-> Text

val: bytes to insert

-> Int64

len: number of bytes of val to insert, or -1 for all of val

-> m String

Returns: string

Inserts len bytes of val into string at pos.

If len is positive, val may contain embedded nuls and need not be nul-terminated. It is the caller's responsibility to ensure that val has at least len addressable bytes.

If len is negative, val must be nul-terminated and len is considered to request the entire string length.

If pos is -1, bytes are inserted at the end of the string.

insertUnichar

stringInsertUnichar

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Int64

pos: the position at which to insert character, or -1 to append at the end of the string

-> Char

wc: a Unicode character

-> m String

Returns: string

Converts a Unicode character into UTF-8, and insert it into the string at the given position.

new

stringNew

Arguments

:: (HasCallStack, MonadIO m)

=> Maybe Text

init: the initial text to copy into the string, or Nothing to start with an empty string

-> m String

Returns: the new String

Creates a new String, initialized with the given string.

newLen

stringNewLen

Arguments

:: (HasCallStack, MonadIO m)

=> Text

init: initial contents of the string

-> Int64

len: length of init to use

-> m String

Returns: a new String

Creates a new String with len bytes of the init buffer. Because a length is provided, init need not be nul-terminated, and can contain embedded nul bytes.

Since this function does not stop at nul bytes, it is the caller's responsibility to ensure that init has at least len addressable bytes.

newTake

stringNewTake

Arguments

:: (HasCallStack, MonadIO m)

=> Maybe Text

init: initial text used as the string. Ownership of the string is transferred to the String. Passing Nothing creates an empty string.

-> m String

Returns: the new String

Creates a new String, initialized with the given string.

After this call, init belongs to the String and may no longer be modified by the caller. The memory of data has to be dynamically allocated and will eventually be freed with free.

Since: 2.78

overwrite

stringOverwrite

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> CSize

pos: the position at which to start overwriting

-> Text

val: the string that will overwrite the string starting at pos

-> m String

Returns: string

Overwrites part of a string, lengthening it if necessary.

Since: 2.14

overwriteLen

stringOverwriteLen

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> CSize

pos: the position at which to start overwriting

-> Text

val: the string that will overwrite the string starting at pos

-> Int64

len: the number of bytes to write from val

-> m String

Returns: string

Overwrites part of a string, lengthening it if necessary. This function will work with embedded nuls.

Since: 2.14

prepend

stringPrepend

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Text

val: the string to prepend on the start of string

-> m String

Returns: string

Adds a string on to the start of a String, expanding it if necessary.

prependC

stringPrependC

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Int8

c: the byte to prepend on the start of the String

-> m String

Returns: string

Adds a byte onto the start of a String, expanding it if necessary.

prependLen

stringPrependLen

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Text

val: bytes to prepend

-> Int64

len: number of bytes in val to prepend, or -1 for all of val

-> m String

Returns: string

Prepends len bytes of val to string.

If len is positive, val may contain embedded nuls and need not be nul-terminated. It is the caller's responsibility to ensure that val has at least len addressable bytes.

If len is negative, val must be nul-terminated and len is considered to request the entire string length. This makes stringPrependLen equivalent to stringPrepend.

prependUnichar

stringPrependUnichar

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Char

wc: a Unicode character

-> m String

Returns: string

Converts a Unicode character into UTF-8, and prepends it to the string.

replace

stringReplace

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> Text

find: the string to find in string

-> Text

replace: the string to insert in place of find

-> Word32

limit: the maximum instances of find to replace with replace, or 0 for no limit

-> m Word32

Returns: the number of find and replace operations performed.

Replaces the string find with the string replace in a String up to limit times. If the number of instances of find in the String is less than limit, all instances are replaced. If limit is 0, all instances of find are replaced.

If find is the empty string, since versions 2.69.1 and 2.68.4 the replacement will be inserted no more than once per possible position (beginning of string, end of string and between characters). This did not work correctly in earlier versions.

Since: 2.68

setSize

stringSetSize

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> CSize

len: the new length

-> m String

Returns: string

Sets the length of a String. If the length is less than the current length, the string will be truncated. If the length is greater than the current length, the contents of the newly added area are undefined. (However, as always, string->str[string->len] will be a nul byte.)

sizedNew

stringSizedNew

Arguments

:: (HasCallStack, MonadIO m)

=> CSize

dflSize: the default size of the space allocated to hold the string

-> m String

Returns: the new String

Creates a new String, with enough space for dflSize bytes. This is useful if you are going to add a lot of text to the string and don't want it to be reallocated too often.

truncate

stringTruncate

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> CSize

len: the new size of string

-> m String

Returns: string

Cuts off the end of the GString, leaving the first len bytes.

up

stringUp

Arguments

:: (HasCallStack, MonadIO m)

=> String

string: a String

-> m String

Returns: string

Deprecated: (Since version 2.2)This function uses the locale-specific toupper() function, which is almost never the right thing. Use stringAsciiUp or utf8Strup instead.

Converts a String to uppercase.

Properties

allocatedLen

the number of bytes that can be stored in the string before it needs to be reallocated. May be larger than len.

getStringAllocatedLen :: MonadIO m => String -> m CSize

Get the value of the “allocated_len” field. When overloading is enabled, this is equivalent to

get string #allocatedLen

setStringAllocatedLen :: MonadIO m => String -> CSize -> m ()

Set the value of the “allocated_len” field. When overloading is enabled, this is equivalent to

set string [ #allocatedLen := value ]

len

contains the length of the string, not including the terminating nul byte.

getStringLen :: MonadIO m => String -> m CSize

Get the value of the “len” field. When overloading is enabled, this is equivalent to

get string #len

setStringLen :: MonadIO m => String -> CSize -> m ()

Set the value of the “len” field. When overloading is enabled, this is equivalent to

set string [ #len := value ]

str

points to the character data. It may move as text is added. The str field is null-terminated and so can be used as an ordinary C string.

clearStringStr :: MonadIO m => String -> m ()

Set the value of the “str” field to Nothing. When overloading is enabled, this is equivalent to

clear #str

getStringStr :: MonadIO m => String -> m (Maybe Text)

Get the value of the “str” field. When overloading is enabled, this is equivalent to

get string #str

setStringStr :: MonadIO m => String -> CString -> m ()

Set the value of the “str” field. When overloading is enabled, this is equivalent to

set string [ #str := value ]