Strings

Strings — text buffers which grow automatically as text is added

Types and Values

struct GString
#define g_string_sprintf
#define g_string_sprintfa

Includes

#include <glib.h>

Description

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

Functions

g_string_new ()

GString *
g_string_new (const gchar *init);

Creates a new GString, initialized with the given string.

Parameters

init

the initial text to copy into the string, or NULL to start with an empty string.

[nullable]

Returns

the new GString


g_string_new_len ()

GString *
g_string_new_len (const gchar *init,
                  gssize len);

Creates a new GString 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.

Parameters

init

initial contents of the string

 

len

length of init to use

 

Returns

a new GString


g_string_sized_new ()

GString *
g_string_sized_new (gsize dfl_size);

Creates a new GString, with enough space for dfl_size 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.

Parameters

dfl_size

the default size of the space allocated to hold the string

 

Returns

the new GString


g_string_assign ()

GString *
g_string_assign (GString *string,
                 const gchar *rval);

Copies the bytes from a string into a GString, 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.

Parameters

string

the destination GString. Its current contents are destroyed.

 

rval

the string to copy into string

 

Returns

string .

[transfer none]


g_string_vprintf ()

void
g_string_vprintf (GString *string,
                  const gchar *format,
                  va_list args);

Writes a formatted string into a GString. This function is similar to g_string_printf() except that the arguments to the format string are passed as a va_list.

Parameters

string

a GString

 

format

the string format. See the printf() documentation

 

args

the parameters to insert into the format string

 

Since: 2.14


g_string_append_vprintf ()

void
g_string_append_vprintf (GString *string,
                         const gchar *format,
                         va_list args);

Appends a formatted string onto the end of a GString. This function is similar to g_string_append_printf() except that the arguments to the format string are passed as a va_list.

Parameters

string

a GString

 

format

the string format. See the printf() documentation

 

args

the list of arguments to insert in the output

 

Since: 2.14


g_string_printf ()

void
g_string_printf (GString *string,
                 const gchar *format,
                 ...);

Writes a formatted string into a GString. This is similar to the standard sprintf() function, except that the GString buffer automatically expands to contain the results. The previous contents of the GString are destroyed.

Parameters

string

a GString

 

format

the string format. See the printf() documentation

 

...

the parameters to insert into the format string

 

g_string_append_printf ()

void
g_string_append_printf (GString *string,
                        const gchar *format,
                        ...);

Appends a formatted string onto the end of a GString. This function is similar to g_string_printf() except that the text is appended to the GString.

Parameters

string

a GString

 

format

the string format. See the printf() documentation

 

...

the parameters to insert into the format string

 

g_string_append ()

GString *
g_string_append (GString *string,
                 const gchar *val);

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

Parameters

string

a GString

 

val

the string to append onto the end of string

 

Returns

string .

[transfer none]


g_string_append_c ()

GString *
g_string_append_c (GString *string,
                   gchar c);

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

Parameters

string

a GString

 

c

the byte to append onto the end of string

 

Returns

string .

[transfer none]


g_string_append_unichar ()

GString *
g_string_append_unichar (GString *string,
                         gunichar wc);

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

Parameters

string

a GString

 

wc

a Unicode character

 

Returns

string .

[transfer none]


g_string_append_len ()

GString *
g_string_append_len (GString *string,
                     const gchar *val,
                     gssize len);

Appends len bytes of val to string . Because len is provided, val may contain embedded nuls and need not be nul-terminated.

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

Parameters

string

a GString

 

val

bytes to append

 

len

number of bytes of val to use

 

Returns

string .

[transfer none]


g_string_append_uri_escaped ()

GString *
g_string_append_uri_escaped (GString *string,
                             const gchar *unescaped,
                             const gchar *reserved_chars_allowed,
                             gboolean allow_utf8);

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

Parameters

string

a GString

 

unescaped

a string

 

reserved_chars_allowed

a string of reserved characters allowed to be used, or NULL

 

allow_utf8

set TRUE if the escaped string may include UTF8 characters

 

Returns

string .

[transfer none]

Since: 2.16


g_string_prepend ()

GString *
g_string_prepend (GString *string,
                  const gchar *val);

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

Parameters

string

a GString

 

val

the string to prepend on the start of string

 

Returns

string .

[transfer none]


g_string_prepend_c ()

GString *
g_string_prepend_c (GString *string,
                    gchar c);

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

Parameters

string

a GString

 

c

the byte to prepend on the start of the GString

 

Returns

string .

[transfer none]


g_string_prepend_unichar ()

GString *
g_string_prepend_unichar (GString *string,
                          gunichar wc);

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

Parameters

string

a GString

 

wc

a Unicode character

 

Returns

string .

[transfer none]


g_string_prepend_len ()

GString *
g_string_prepend_len (GString *string,
                      const gchar *val,
                      gssize len);

Prepends len bytes of val to string . Because len is provided, val may contain embedded nuls and need not be nul-terminated.

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

Parameters

string

a GString

 

val

bytes to prepend

 

len

number of bytes in val to prepend

 

Returns

string .

[transfer none]


g_string_insert ()

GString *
g_string_insert (GString *string,
                 gssize pos,
                 const gchar *val);

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

Parameters

string

a GString

 

pos

the position to insert the copy of the string

 

val

the string to insert

 

Returns

string .

[transfer none]


g_string_insert_c ()

GString *
g_string_insert_c (GString *string,
                   gssize pos,
                   gchar c);

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

Parameters

string

a GString

 

pos

the position to insert the byte

 

c

the byte to insert

 

Returns

string .

[transfer none]


g_string_insert_unichar ()

GString *
g_string_insert_unichar (GString *string,
                         gssize pos,
                         gunichar wc);

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

Parameters

string

a GString

 

pos

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

 

wc

a Unicode character

 

Returns

string .

[transfer none]


g_string_insert_len ()

GString *
g_string_insert_len (GString *string,
                     gssize pos,
                     const gchar *val,
                     gssize len);

Inserts len bytes of val into string at pos . Because len is provided, val may contain embedded nuls and need not be nul-terminated. If pos is -1, bytes are inserted at the end of the string.

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

Parameters

string

a GString

 

pos

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

 

val

bytes to insert

 

len

number of bytes of val to insert

 

Returns

string .

[transfer none]


g_string_overwrite ()

GString *
g_string_overwrite (GString *string,
                    gsize pos,
                    const gchar *val);

Overwrites part of a string, lengthening it if necessary.

Parameters

string

a GString

 

pos

the position at which to start overwriting

 

val

the string that will overwrite the string starting at pos

 

Returns

string .

[transfer none]

Since: 2.14


g_string_overwrite_len ()

GString *
g_string_overwrite_len (GString *string,
                        gsize pos,
                        const gchar *val,
                        gssize len);

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

Parameters

string

a GString

 

pos

the position at which to start overwriting

 

val

the string that will overwrite the string starting at pos

 

len

the number of bytes to write from val

 

Returns

string .

[transfer none]

Since: 2.14


g_string_erase ()

GString *
g_string_erase (GString *string,
                gssize pos,
                gssize len);

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

Parameters

string

a GString

 

pos

the position of the content to remove

 

len

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

 

Returns

string .

[transfer none]


g_string_truncate ()

GString *
g_string_truncate (GString *string,
                   gsize len);

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

Parameters

string

a GString

 

len

the new size of string

 

Returns

string .

[transfer none]


g_string_set_size ()

GString *
g_string_set_size (GString *string,
                   gsize len);

Sets the length of a GString. 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.)

Parameters

string

a GString

 

len

the new length

 

Returns

string .

[transfer none]


g_string_free ()

gchar *
g_string_free (GString *string,
               gboolean free_segment);

Frees the memory allocated for the GString. If free_segment 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 g_free().

Parameters

string

a GString.

[transfer full]

free_segment

if TRUE, the actual character data is freed as well

 

Returns

the character data of string (i.e. NULL if free_segment is TRUE).

[nullable]


g_string_free_to_bytes ()

GBytes *
g_string_free_to_bytes (GString *string);

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

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

Parameters

string

a GString.

[transfer full]

Returns

A newly allocated GBytes containing contents of string ; string itself is freed.

[transfer full]

Since: 2.34


g_string_up ()

GString *
g_string_up (GString *string);

g_string_up has been deprecated since version 2.2 and should not be used in newly-written code.

This function uses the locale-specific toupper() function, which is almost never the right thing. Use g_string_ascii_up() or g_utf8_strup() instead.

Converts a GString to uppercase.

Parameters

string

a GString

 

Returns

string .

[transfer none]


g_string_down ()

GString *
g_string_down (GString *string);

g_string_down has been deprecated since version 2.2 and should not be used in newly-written code.

This function uses the locale-specific tolower() function, which is almost never the right thing. Use g_string_ascii_down() or g_utf8_strdown() instead.

Converts a GString to lowercase.

Parameters

string

a GString

 

Returns

the GString.

[transfer none]


g_string_hash ()

guint
g_string_hash (const GString *str);

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

Parameters

str

a string to hash

 

Returns

hash code for str


g_string_equal ()

gboolean
g_string_equal (const GString *v,
                const GString *v2);

Compares two strings for equality, returning TRUE if they are equal. For use with GHashTable.

Parameters

v

a GString

 

v2

another GString

 

Returns

TRUE if the strings are the same length and contain the same bytes

Types and Values

struct GString

struct GString {
  gchar  *str;
  gsize len;
  gsize allocated_len;
};

The GString struct contains the public fields of a GString.

Members

gchar *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.

 

gsize len;

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

 

gsize allocated_len;

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

 

g_string_sprintf

#define             g_string_sprintf

g_string_sprintf is deprecated and should not be used in newly-written code.

This function has been renamed to g_string_printf().

Writes a formatted string into a GString. This is similar to the standard sprintf() function, except that the GString buffer automatically expands to contain the results. The previous contents of the GString are destroyed.

Parameters

string

a GString

 

format

the string format. See the sprintf() documentation

 

...

the parameters to insert into the format string

 

g_string_sprintfa

#define             g_string_sprintfa

g_string_sprintfa is deprecated and should not be used in newly-written code.

This function has been renamed to g_string_append_printf()

Appends a formatted string onto the end of a GString. This function is similar to g_string_sprintf() except that the text is appended to the GString.

Parameters

string

a GString

 

format

the string format. See the sprintf() documentation

 

...

the parameters to insert into the format string