Strings

Strings — text buffers which grow automatically as text is added

Synopsis


#include <glib.h>

                    GString;
GString*            g_string_new                        (const gchar *init);
GString*            g_string_new_len                    (const gchar *init,
                                                         gssize len);
GString*            g_string_sized_new                  (gsize dfl_size);
GString*            g_string_assign                     (GString *string,
                                                         const gchar *rval);
#define             g_string_sprintf
#define             g_string_sprintfa
void                g_string_vprintf                    (GString *string,
                                                         const gchar *format,
                                                         va_list args);
void                g_string_append_vprintf             (GString *string,
                                                         const gchar *format,
                                                         va_list args);
void                g_string_printf                     (GString *string,
                                                         const gchar *format,
                                                         ...);
void                g_string_append_printf              (GString *string,
                                                         const gchar *format,
                                                         ...);
GString*            g_string_append                     (GString *string,
                                                         const gchar *val);
GString*            g_string_append_c                   (GString *string,
                                                         gchar c);
GString*            g_string_append_unichar             (GString *string,
                                                         gunichar wc);
GString*            g_string_append_len                 (GString *string,
                                                         const gchar *val,
                                                         gssize len);
GString*            g_string_append_uri_escaped         (GString *string,
                                                         const char *unescaped,
                                                         const char *reserved_chars_allowed,
                                                         gboolean allow_utf8);
GString*            g_string_prepend                    (GString *string,
                                                         const gchar *val);
GString*            g_string_prepend_c                  (GString *string,
                                                         gchar c);
GString*            g_string_prepend_unichar            (GString *string,
                                                         gunichar wc);
GString*            g_string_prepend_len                (GString *string,
                                                         const gchar *val,
                                                         gssize len);
GString*            g_string_insert                     (GString *string,
                                                         gssize pos,
                                                         const gchar *val);
GString*            g_string_insert_c                   (GString *string,
                                                         gssize pos,
                                                         gchar c);
GString*            g_string_insert_unichar             (GString *string,
                                                         gssize pos,
                                                         gunichar wc);
GString*            g_string_insert_len                 (GString *string,
                                                         gssize pos,
                                                         const gchar *val,
                                                         gssize len);
GString*            g_string_overwrite                  (GString *string,
                                                         gsize pos,
                                                         const gchar *val);
GString*            g_string_overwrite_len              (GString *string,
                                                         gsize pos,
                                                         const gchar *val,
                                                         gssize len);
GString*            g_string_erase                      (GString *string,
                                                         gssize pos,
                                                         gssize len);
GString*            g_string_truncate                   (GString *string,
                                                         gsize len);
GString*            g_string_set_size                   (GString *string,
                                                         gsize len);
gchar*              g_string_free                       (GString *string,
                                                         gboolean free_segment);

GString*            g_string_up                         (GString *string);
GString*            g_string_down                       (GString *string);

guint               g_string_hash                       (const GString *str);
gboolean            g_string_equal                      (const GString *v,
                                                         const GString *v2);

Description

A GString is similar to a standard C string, except that it grows automatically as text is appended or inserted. Also, it stores the length of the string, so can be used for binary data with embedded nul bytes.

Details

GString

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

The GString struct contains the public fields of a GString.

gchar *str;

points to the character data. It may move as text is added. The str field is nul-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_new ()

GString*            g_string_new                        (const gchar *init);

Creates a new GString, initialized with the given string.

init :

the initial text to copy into the string

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.

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.

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.

string :

the destination GString. Its current contents are destroyed.

rval :

the string to copy into string

Returns :

string

g_string_sprintf

#define             g_string_sprintf

Warning

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.

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

Warning

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.

string :

a GString

format :

the string format. See the sprintf() documentation

... :

the parameters to insert into the format string

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.

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.

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.

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.

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.

string :

a GString

val :

the string to append onto the end of string

Returns :

string

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.

string :

a GString

c :

the byte to append onto the end of string

Returns :

string

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.

string :

a GString

wc :

a Unicode character

Returns :

string

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.

string :

a GString

val :

bytes to append

len :

number of bytes of val to use

Returns :

string

g_string_append_uri_escaped ()

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

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

string :

a GString

unescaped :

a string

reserved_chars_allowed :

a string of reserved characters allowed to be used

allow_utf8 :

set TRUE if the escaped string may include UTF8 characters

Returns :

string

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.

string :

a GString

val :

the string to prepend on the start of string

Returns :

string

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.

string :

a GString

c :

the byte to prepend on the start of the GString

Returns :

string

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.

string :

a GString

wc :

a Unicode character

Returns :

string

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.

string :

a GString

val :

bytes to prepend

len :

number of bytes in val to prepend

Returns :

string

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.

string :

a GString

pos :

the position to insert the copy of the string

val :

the string to insert

Returns :

string

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.

string :

a GString

pos :

the position to insert the byte

c :

the byte to insert

Returns :

string

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.

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

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.

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

g_string_overwrite ()

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

Overwrites part of a string, lengthening it if necessary.

string :

a GString

pos :

the position at which to start overwriting

val :

the string that will overwrite the string starting at pos

Returns :

string

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.

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

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.

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

g_string_truncate ()

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

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

string :

a GString

len :

the new size of string

Returns :

string

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.)

string :

a GString

len :

the new length

Returns :

string

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.

string :

a GString

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)

g_string_up ()

GString*            g_string_up                         (GString *string);

Warning

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.

string :

a GString

Returns :

string

g_string_down ()

GString*            g_string_down                       (GString *string);

Warning

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.

string :

a GString

Returns :

the GString.

g_string_hash ()

guint               g_string_hash                       (const GString *str);

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

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.

v :

a GString

v2 :

another GString

Returns :

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