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Perl-compatible regular expressionsPerl-compatible regular expressions — matches strings against regular expressions |
enum | GRegexError |
#define | G_REGEX_ERROR |
enum | GRegexCompileFlags |
enum | GRegexMatchFlags |
GRegex | |
GMatchInfo |
The g_regex_*() functions implement regular expression pattern matching using syntax and semantics similar to Perl regular expression.
Some functions accept a start_position
argument, setting it differs
from just passing over a shortened string and setting G_REGEX_MATCH_NOTBOL
in the case of a pattern that begins with any kind of lookbehind assertion.
For example, consider the pattern "\Biss\B" which finds occurrences of "iss"
in the middle of words. ("\B" matches only if the current position in the
subject is not a word boundary.) When applied to the string "Mississipi"
from the fourth byte, namely "issipi", it does not match, because "\B" is
always false at the start of the subject, which is deemed to be a word
boundary. However, if the entire string is passed , but with
start_position
set to 4, it finds the second occurrence of "iss" because
it is able to look behind the starting point to discover that it is
preceded by a letter.
Note that, unless you set the G_REGEX_RAW
flag, all the strings passed
to these functions must be encoded in UTF-8. The lengths and the positions
inside the strings are in bytes and not in characters, so, for instance,
"\xc3\xa0" (i.e. "à") is two bytes long but it is treated as a
single character. If you set G_REGEX_RAW
the strings can be non-valid
UTF-8 strings and a byte is treated as a character, so "\xc3\xa0" is two
bytes and two characters long.
When matching a pattern, "\n" matches only against a "\n" character in the string, and "\r" matches only a "\r" character. To match any newline sequence use "\R". This particular group matches either the two-character sequence CR + LF ("\r\n"), or one of the single characters LF (linefeed, U+000A, "\n"), VT vertical tab, U+000B, "\v"), FF (formfeed, U+000C, "\f"), CR (carriage return, U+000D, "\r"), NEL (next line, U+0085), LS (line separator, U+2028), or PS (paragraph separator, U+2029).
The behaviour of the dot, circumflex, and dollar metacharacters are
affected by newline characters, the default is to recognize any newline
character (the same characters recognized by "\R"). This can be changed
with G_REGEX_NEWLINE_CR
, G_REGEX_NEWLINE_LF
and G_REGEX_NEWLINE_CRLF
compile options, and with G_REGEX_MATCH_NEWLINE_ANY
,
G_REGEX_MATCH_NEWLINE_CR
, G_REGEX_MATCH_NEWLINE_LF
and
G_REGEX_MATCH_NEWLINE_CRLF
match options. These settings are also
relevant when compiling a pattern if G_REGEX_EXTENDED
is set, and an
unescaped "#" outside a character class is encountered. This indicates
a comment that lasts until after the next newline.
Creating and manipulating the same GRegex structure from different threads is not a problem as GRegex does not modify its internal state between creation and destruction, on the other hand GMatchInfo is not threadsafe.
The regular expressions low-level functionalities are obtained through the excellent PCRE library written by Philip Hazel.
gboolean (*GRegexEvalCallback) (const GMatchInfo *match_info
,GString *result
,gpointer user_data
);
Specifies the type of the function passed to g_regex_replace_eval()
.
It is called for each occurrence of the pattern in the string passed
to g_regex_replace_eval()
, and it should append the replacement to
result
.
match_info |
the GMatchInfo generated by the match.
Use |
|
result |
a GString containing the new string |
|
user_data |
user data passed to |
Since: 2.14
GRegex * g_regex_new (const gchar *pattern
,GRegexCompileFlags compile_options
,GRegexMatchFlags match_options
,GError **error
);
Compiles the regular expression to an internal form, and does the initial setup of the GRegex structure.
pattern |
the regular expression |
|
compile_options |
compile options for the regular expression, or 0 |
|
match_options |
match options for the regular expression, or 0 |
|
error |
return location for a GError |
a GRegex structure or NULL
if an error occurred. Call
g_regex_unref()
when you are done with it.
[nullable]
Since: 2.14
GRegex *
g_regex_ref (GRegex *regex
);
Increases reference count of regex
by 1.
Since: 2.14
void
g_regex_unref (GRegex *regex
);
Decreases reference count of regex
by 1. When reference count drops
to zero, it frees all the memory associated with the regex structure.
Since: 2.14
const gchar *
g_regex_get_pattern (const GRegex *regex
);
Gets the pattern string associated with regex
, i.e. a copy of
the string passed to g_regex_new()
.
Since: 2.14
gint
g_regex_get_max_backref (const GRegex *regex
);
Returns the number of the highest back reference in the pattern, or 0 if the pattern does not contain back references.
Since: 2.14
gint
g_regex_get_capture_count (const GRegex *regex
);
Returns the number of capturing subpatterns in the pattern.
Since: 2.14
gboolean
g_regex_get_has_cr_or_lf (const GRegex *regex
);
Checks whether the pattern contains explicit CR or LF references.
Since: 2.34
gint
g_regex_get_max_lookbehind (const GRegex *regex
);
Gets the number of characters in the longest lookbehind assertion in the pattern. This information is useful when doing multi-segment matching using the partial matching facilities.
Since: 2.38
gint g_regex_get_string_number (const GRegex *regex
,const gchar *name
);
Retrieves the number of the subexpression named name
.
Since: 2.14
GRegexCompileFlags
g_regex_get_compile_flags (const GRegex *regex
);
Returns the compile options that regex
was created with.
Depending on the version of PCRE that is used, this may or may not
include flags set by option expressions such as (?i)
found at the
top-level within the compiled pattern.
Since: 2.26
GRegexMatchFlags
g_regex_get_match_flags (const GRegex *regex
);
Returns the match options that regex
was created with.
Since: 2.26
gchar * g_regex_escape_string (const gchar *string
,gint length
);
Escapes the special characters used for regular expressions
in string
, for instance "a.b*c" becomes "a.b*c". This
function is useful to dynamically generate regular expressions.
string
can contain nul characters that are replaced with "\0",
in this case remember to specify the correct length of string
in length
.
string |
the string to escape. |
[array length=length] |
length |
the length of |
Since: 2.14
gchar * g_regex_escape_nul (const gchar *string
,gint length
);
Escapes the nul characters in string
to "\x00". It can be used
to compile a regex with embedded nul characters.
For completeness, length
can be -1 for a nul-terminated string.
In this case the output string will be of course equal to string
.
Since: 2.30
gboolean g_regex_match_simple (const gchar *pattern
,const gchar *string
,GRegexCompileFlags compile_options
,GRegexMatchFlags match_options
);
Scans for a match in string
for pattern
.
This function is equivalent to g_regex_match()
but it does not
require to compile the pattern with g_regex_new()
, avoiding some
lines of code when you need just to do a match without extracting
substrings, capture counts, and so on.
If this function is to be called on the same pattern
more than
once, it's more efficient to compile the pattern once with
g_regex_new()
and then use g_regex_match()
.
pattern |
the regular expression |
|
string |
the string to scan for matches |
|
compile_options |
compile options for the regular expression, or 0 |
|
match_options |
match options, or 0 |
Since: 2.14
gboolean g_regex_match (const GRegex *regex
,const gchar *string
,GRegexMatchFlags match_options
,GMatchInfo **match_info
);
Scans for a match in string
for the pattern in regex
.
The match_options
are combined with the match options specified
when the regex
structure was created, letting you have more
flexibility in reusing GRegex structures.
Unless G_REGEX_RAW
is specified in the options, string
must be valid UTF-8.
A GMatchInfo structure, used to get information on the match,
is stored in match_info
if not NULL
. Note that if match_info
is not NULL
then it is created even if the function returns FALSE
,
i.e. you must free it regardless if regular expression actually matched.
To retrieve all the non-overlapping matches of the pattern in
string you can use g_match_info_next()
.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 |
static void print_uppercase_words (const gchar *string) { // Print all uppercase-only words. GRegex *regex; GMatchInfo *match_info; regex = g_regex_new ("[A-Z]+", G_REGEX_DEFAULT, G_REGEX_MATCH_DEFAULT, NULL); g_regex_match (regex, string, 0, &match_info); while (g_match_info_matches (match_info)) { gchar *word = g_match_info_fetch (match_info, 0); g_print ("Found: %s\n", word); g_free (word); g_match_info_next (match_info, NULL); } g_match_info_free (match_info); g_regex_unref (regex); } |
string
is not copied and is used in GMatchInfo internally. If
you use any GMatchInfo method (except g_match_info_free()
) after
freeing or modifying string
then the behaviour is undefined.
regex |
a GRegex structure from |
|
string |
the string to scan for matches |
|
match_options |
match options |
|
match_info |
pointer to location where to store
the GMatchInfo, or |
[out][optional] |
Since: 2.14
gboolean g_regex_match_full (const GRegex *regex
,const gchar *string
,gssize string_len
,gint start_position
,GRegexMatchFlags match_options
,GMatchInfo **match_info
,GError **error
);
Scans for a match in string
for the pattern in regex
.
The match_options
are combined with the match options specified
when the regex
structure was created, letting you have more
flexibility in reusing GRegex structures.
Setting start_position
differs from just passing over a shortened
string and setting G_REGEX_MATCH_NOTBOL
in the case of a pattern
that begins with any kind of lookbehind assertion, such as "\b".
Unless G_REGEX_RAW
is specified in the options, string
must be valid UTF-8.
A GMatchInfo structure, used to get information on the match, is
stored in match_info
if not NULL
. Note that if match_info
is
not NULL
then it is created even if the function returns FALSE
,
i.e. you must free it regardless if regular expression actually
matched.
string
is not copied and is used in GMatchInfo internally. If
you use any GMatchInfo method (except g_match_info_free()
) after
freeing or modifying string
then the behaviour is undefined.
To retrieve all the non-overlapping matches of the pattern in
string you can use g_match_info_next()
.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 |
static void print_uppercase_words (const gchar *string) { // Print all uppercase-only words. GRegex *regex; GMatchInfo *match_info; GError *error = NULL; regex = g_regex_new ("[A-Z]+", G_REGEX_DEFAULT, G_REGEX_MATCH_DEFAULT, NULL); g_regex_match_full (regex, string, -1, 0, 0, &match_info, &error); while (g_match_info_matches (match_info)) { gchar *word = g_match_info_fetch (match_info, 0); g_print ("Found: %s\n", word); g_free (word); g_match_info_next (match_info, &error); } g_match_info_free (match_info); g_regex_unref (regex); if (error != NULL) { g_printerr ("Error while matching: %s\n", error->message); g_error_free (error); } } |
regex |
a GRegex structure from |
|
string |
the string to scan for matches. |
[array length=string_len] |
string_len |
the length of |
|
start_position |
starting index of the string to match, in bytes |
|
match_options |
match options |
|
match_info |
pointer to location where to store
the GMatchInfo, or |
[out][optional] |
error |
location to store the error occurring, or |
Since: 2.14
gboolean g_regex_match_all (const GRegex *regex
,const gchar *string
,GRegexMatchFlags match_options
,GMatchInfo **match_info
);
Using the standard algorithm for regular expression matching only
the longest match in the string is retrieved. This function uses
a different algorithm so it can retrieve all the possible matches.
For more documentation see g_regex_match_all_full()
.
A GMatchInfo structure, used to get information on the match, is
stored in match_info
if not NULL
. Note that if match_info
is
not NULL
then it is created even if the function returns FALSE
,
i.e. you must free it regardless if regular expression actually
matched.
string
is not copied and is used in GMatchInfo internally. If
you use any GMatchInfo method (except g_match_info_free()
) after
freeing or modifying string
then the behaviour is undefined.
regex |
a GRegex structure from |
|
string |
the string to scan for matches |
|
match_options |
match options |
|
match_info |
pointer to location where to store
the GMatchInfo, or |
[out][optional] |
Since: 2.14
gboolean g_regex_match_all_full (const GRegex *regex
,const gchar *string
,gssize string_len
,gint start_position
,GRegexMatchFlags match_options
,GMatchInfo **match_info
,GError **error
);
Using the standard algorithm for regular expression matching only
the longest match in the string
is retrieved, it is not possible
to obtain all the available matches. For instance matching
"<a> <b> <c>" against the pattern "<.*>"
you get "<a> <b> <c>".
This function uses a different algorithm (called DFA, i.e. deterministic finite automaton), so it can retrieve all the possible matches, all starting at the same point in the string. For instance matching "<a> <b> <c>" against the pattern "<.*>;" you would obtain three matches: "<a> <b> <c>", "<a> <b>" and "<a>".
The number of matched strings is retrieved using
g_match_info_get_match_count()
. To obtain the matched strings and
their position you can use, respectively, g_match_info_fetch()
and
g_match_info_fetch_pos()
. Note that the strings are returned in
reverse order of length; that is, the longest matching string is
given first.
Note that the DFA algorithm is slower than the standard one and it is not able to capture substrings, so backreferences do not work.
Setting start_position
differs from just passing over a shortened
string and setting G_REGEX_MATCH_NOTBOL
in the case of a pattern
that begins with any kind of lookbehind assertion, such as "\b".
Unless G_REGEX_RAW
is specified in the options, string
must be valid UTF-8.
A GMatchInfo structure, used to get information on the match, is
stored in match_info
if not NULL
. Note that if match_info
is
not NULL
then it is created even if the function returns FALSE
,
i.e. you must free it regardless if regular expression actually
matched.
string
is not copied and is used in GMatchInfo internally. If
you use any GMatchInfo method (except g_match_info_free()
) after
freeing or modifying string
then the behaviour is undefined.
regex |
a GRegex structure from |
|
string |
the string to scan for matches. |
[array length=string_len] |
string_len |
the length of |
|
start_position |
starting index of the string to match, in bytes |
|
match_options |
match options |
|
match_info |
pointer to location where to store
the GMatchInfo, or |
[out][optional] |
error |
location to store the error occurring, or |
Since: 2.14
gchar ** g_regex_split_simple (const gchar *pattern
,const gchar *string
,GRegexCompileFlags compile_options
,GRegexMatchFlags match_options
);
Breaks the string on the pattern, and returns an array of the tokens. If the pattern contains capturing parentheses, then the text for each of the substrings will also be returned. If the pattern does not match anywhere in the string, then the whole string is returned as the first token.
This function is equivalent to g_regex_split()
but it does
not require to compile the pattern with g_regex_new()
, avoiding
some lines of code when you need just to do a split without
extracting substrings, capture counts, and so on.
If this function is to be called on the same pattern
more than
once, it's more efficient to compile the pattern once with
g_regex_new()
and then use g_regex_split()
.
As a special case, the result of splitting the empty string "" is an empty vector, not a vector containing a single string. The reason for this special case is that being able to represent an empty vector is typically more useful than consistent handling of empty elements. If you do need to represent empty elements, you'll need to check for the empty string before calling this function.
A pattern that can match empty strings splits string
into
separate characters wherever it matches the empty string between
characters. For example splitting "ab c" using as a separator
"\s*", you will get "a", "b" and "c".
pattern |
the regular expression |
|
string |
the string to scan for matches |
|
compile_options |
compile options for the regular expression, or 0 |
|
match_options |
match options, or 0 |
Since: 2.14
gchar ** g_regex_split (const GRegex *regex
,const gchar *string
,GRegexMatchFlags match_options
);
Breaks the string on the pattern, and returns an array of the tokens. If the pattern contains capturing parentheses, then the text for each of the substrings will also be returned. If the pattern does not match anywhere in the string, then the whole string is returned as the first token.
As a special case, the result of splitting the empty string "" is an empty vector, not a vector containing a single string. The reason for this special case is that being able to represent an empty vector is typically more useful than consistent handling of empty elements. If you do need to represent empty elements, you'll need to check for the empty string before calling this function.
A pattern that can match empty strings splits string
into separate
characters wherever it matches the empty string between characters.
For example splitting "ab c" using as a separator "\s*", you will get
"a", "b" and "c".
regex |
a GRegex structure |
|
string |
the string to split with the pattern |
|
match_options |
match time option flags |
Since: 2.14
gchar ** g_regex_split_full (const GRegex *regex
,const gchar *string
,gssize string_len
,gint start_position
,GRegexMatchFlags match_options
,gint max_tokens
,GError **error
);
Breaks the string on the pattern, and returns an array of the tokens. If the pattern contains capturing parentheses, then the text for each of the substrings will also be returned. If the pattern does not match anywhere in the string, then the whole string is returned as the first token.
As a special case, the result of splitting the empty string "" is an empty vector, not a vector containing a single string. The reason for this special case is that being able to represent an empty vector is typically more useful than consistent handling of empty elements. If you do need to represent empty elements, you'll need to check for the empty string before calling this function.
A pattern that can match empty strings splits string
into separate
characters wherever it matches the empty string between characters.
For example splitting "ab c" using as a separator "\s*", you will get
"a", "b" and "c".
Setting start_position
differs from just passing over a shortened
string and setting G_REGEX_MATCH_NOTBOL
in the case of a pattern
that begins with any kind of lookbehind assertion, such as "\b".
regex |
a GRegex structure |
|
string |
the string to split with the pattern. |
[array length=string_len] |
string_len |
the length of |
|
start_position |
starting index of the string to match, in bytes |
|
match_options |
match time option flags |
|
max_tokens |
the maximum number of tokens to split |
|
error |
return location for a GError |
Since: 2.14
gchar * g_regex_replace (const GRegex *regex
,const gchar *string
,gssize string_len
,gint start_position
,const gchar *replacement
,GRegexMatchFlags match_options
,GError **error
);
Replaces all occurrences of the pattern in regex
with the
replacement text. Backreferences of the form '\number' or
'\g<number>' in the replacement text are interpolated by the
number-th captured subexpression of the match, '\g<name>' refers
to the captured subexpression with the given name. '\0' refers
to the complete match, but '\0' followed by a number is the octal
representation of a character. To include a literal '\' in the
replacement, write '\\'.
There are also escapes that changes the case of the following text:
\l: Convert to lower case the next character
\u: Convert to upper case the next character
\L: Convert to lower case till \E
\U: Convert to upper case till \E
\E: End case modification
If you do not need to use backreferences use g_regex_replace_literal()
.
The replacement
string must be UTF-8 encoded even if G_REGEX_RAW
was
passed to g_regex_new()
. If you want to use not UTF-8 encoded strings
you can use g_regex_replace_literal()
.
Setting start_position
differs from just passing over a shortened
string and setting G_REGEX_MATCH_NOTBOL
in the case of a pattern that
begins with any kind of lookbehind assertion, such as "\b".
regex |
a GRegex structure |
|
string |
the string to perform matches against. |
[array length=string_len] |
string_len |
the length of |
|
start_position |
starting index of the string to match, in bytes |
|
replacement |
text to replace each match with |
|
match_options |
options for the match |
|
error |
location to store the error occurring, or |
Since: 2.14
gchar * g_regex_replace_literal (const GRegex *regex
,const gchar *string
,gssize string_len
,gint start_position
,const gchar *replacement
,GRegexMatchFlags match_options
,GError **error
);
Replaces all occurrences of the pattern in regex
with the
replacement text. replacement
is replaced literally, to
include backreferences use g_regex_replace()
.
Setting start_position
differs from just passing over a
shortened string and setting G_REGEX_MATCH_NOTBOL
in the
case of a pattern that begins with any kind of lookbehind
assertion, such as "\b".
regex |
a GRegex structure |
|
string |
the string to perform matches against. |
[array length=string_len] |
string_len |
the length of |
|
start_position |
starting index of the string to match, in bytes |
|
replacement |
text to replace each match with |
|
match_options |
options for the match |
|
error |
location to store the error occurring, or |
Since: 2.14
gchar * g_regex_replace_eval (const GRegex *regex
,const gchar *string
,gssize string_len
,gint start_position
,GRegexMatchFlags match_options
,GRegexEvalCallback eval
,gpointer user_data
,GError **error
);
Replaces occurrences of the pattern in regex with the output of
eval
for that occurrence.
Setting start_position
differs from just passing over a shortened
string and setting G_REGEX_MATCH_NOTBOL
in the case of a pattern
that begins with any kind of lookbehind assertion, such as "\b".
The following example uses g_regex_replace_eval()
to replace multiple
strings at once:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 |
static gboolean eval_cb (const GMatchInfo *info, GString *res, gpointer data) { gchar *match; gchar *r; match = g_match_info_fetch (info, 0); r = g_hash_table_lookup ((GHashTable *)data, match); g_string_append (res, r); g_free (match); return FALSE; } ... GRegex *reg; GHashTable *h; gchar *res; h = g_hash_table_new (g_str_hash, g_str_equal); g_hash_table_insert (h, "1", "ONE"); g_hash_table_insert (h, "2", "TWO"); g_hash_table_insert (h, "3", "THREE"); g_hash_table_insert (h, "4", "FOUR"); reg = g_regex_new ("1|2|3|4", G_REGEX_DEFAULT, G_REGEX_MATCH_DEFAULT, NULL); res = g_regex_replace_eval (reg, text, -1, 0, 0, eval_cb, h, NULL); g_hash_table_destroy (h); ... |
regex |
a GRegex structure from |
|
string |
string to perform matches against. |
[array length=string_len] |
string_len |
the length of |
|
start_position |
starting index of the string to match, in bytes |
|
match_options |
options for the match |
|
eval |
a function to call for each match |
|
user_data |
user data to pass to the function |
|
error |
location to store the error occurring, or |
Since: 2.14
gboolean g_regex_check_replacement (const gchar *replacement
,gboolean *has_references
,GError **error
);
Checks whether replacement
is a valid replacement string
(see g_regex_replace()
), i.e. that all escape sequences in
it are valid.
If has_references
is not NULL
then replacement
is checked
for pattern references. For instance, replacement text 'foo\n'
does not contain references and may be evaluated without information
about actual match, but '\0\1' (whole match followed by first
subpattern) requires valid GMatchInfo object.
replacement |
the replacement string |
|
has_references |
location to store information about
references in |
[out][optional] |
error |
location to store error |
Since: 2.14
GRegex *
g_match_info_get_regex (const GMatchInfo *match_info
);
Returns GRegex object used in match_info
. It belongs to Glib
and must not be freed. Use g_regex_ref()
if you need to keep it
after you free match_info
object.
Since: 2.14
const gchar *
g_match_info_get_string (const GMatchInfo *match_info
);
Returns the string searched with match_info
. This is the
string passed to g_regex_match()
or g_regex_replace()
so
you may not free it before calling this function.
Since: 2.14
GMatchInfo *
g_match_info_ref (GMatchInfo *match_info
);
Increases reference count of match_info
by 1.
Since: 2.30
void
g_match_info_unref (GMatchInfo *match_info
);
Decreases reference count of match_info
by 1. When reference count drops
to zero, it frees all the memory associated with the match_info structure.
Since: 2.30
void
g_match_info_free (GMatchInfo *match_info
);
If match_info
is not NULL
, calls g_match_info_unref()
; otherwise does
nothing.
Since: 2.14
gboolean
g_match_info_matches (const GMatchInfo *match_info
);
Returns whether the previous match operation succeeded.
Since: 2.14
gboolean g_match_info_next (GMatchInfo *match_info
,GError **error
);
Scans for the next match using the same parameters of the previous
call to g_regex_match_full()
or g_regex_match()
that returned
match_info
.
The match is done on the string passed to the match function, so you cannot free it before calling this function.
match_info |
a GMatchInfo structure |
|
error |
location to store the error occurring, or |
Since: 2.14
gint
g_match_info_get_match_count (const GMatchInfo *match_info
);
Retrieves the number of matched substrings (including substring 0, that is the whole matched text), so 1 is returned if the pattern has no substrings in it and 0 is returned if the match failed.
If the last match was obtained using the DFA algorithm, that is
using g_regex_match_all()
or g_regex_match_all_full()
, the retrieved
count is not that of the number of capturing parentheses but that of
the number of matched substrings.
Since: 2.14
gboolean
g_match_info_is_partial_match (const GMatchInfo *match_info
);
Usually if the string passed to g_regex_match*() matches as far as
it goes, but is too short to match the entire pattern, FALSE
is
returned. There are circumstances where it might be helpful to
distinguish this case from other cases in which there is no match.
Consider, for example, an application where a human is required to type in data for a field with specific formatting requirements. An example might be a date in the form ddmmmyy, defined by the pattern "^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$". If the application sees the user’s keystrokes one by one, and can check that what has been typed so far is potentially valid, it is able to raise an error as soon as a mistake is made.
GRegex supports the concept of partial matching by means of the
G_REGEX_MATCH_PARTIAL_SOFT
and G_REGEX_MATCH_PARTIAL_HARD
flags.
When they are used, the return code for
g_regex_match()
or g_regex_match_full()
is, as usual, TRUE
for a complete match, FALSE
otherwise. But, when these functions
return FALSE
, you can check if the match was partial calling
g_match_info_is_partial_match()
.
The difference between G_REGEX_MATCH_PARTIAL_SOFT
and
G_REGEX_MATCH_PARTIAL_HARD
is that when a partial match is encountered
with G_REGEX_MATCH_PARTIAL_SOFT
, matching continues to search for a
possible complete match, while with G_REGEX_MATCH_PARTIAL_HARD
matching
stops at the partial match.
When both G_REGEX_MATCH_PARTIAL_SOFT
and G_REGEX_MATCH_PARTIAL_HARD
are set, the latter takes precedence.
There were formerly some restrictions on the pattern for partial matching. The restrictions no longer apply.
See pcrepartial(3) for more information on partial matching.
Since: 2.14
gchar * g_match_info_expand_references (const GMatchInfo *match_info
,const gchar *string_to_expand
,GError **error
);
Returns a new string containing the text in string_to_expand
with
references and escape sequences expanded. References refer to the last
match done with string
against regex
and have the same syntax used by
g_regex_replace()
.
The string_to_expand
must be UTF-8 encoded even if G_REGEX_RAW
was
passed to g_regex_new()
.
The backreferences are extracted from the string passed to the match function, so you cannot call this function after freeing the string.
match_info
may be NULL
in which case string_to_expand
must not
contain references. For instance "foo\n" does not refer to an actual
pattern and '\n' merely will be replaced with \n character,
while to expand "\0" (whole match) one needs the result of a match.
Use g_regex_check_replacement()
to find out whether string_to_expand
contains references.
match_info |
a GMatchInfo or |
[nullable] |
string_to_expand |
the string to expand |
|
error |
location to store the error occurring, or |
Since: 2.14
gchar * g_match_info_fetch (const GMatchInfo *match_info
,gint match_num
);
Retrieves the text matching the match_num
'th capturing
parentheses. 0 is the full text of the match, 1 is the first paren
set, 2 the second, and so on.
If match_num
is a valid sub pattern but it didn't match anything
(e.g. sub pattern 1, matching "b" against "(a)?b") then an empty
string is returned.
If the match was obtained using the DFA algorithm, that is using
g_regex_match_all()
or g_regex_match_all_full()
, the retrieved
string is not that of a set of parentheses but that of a matched
substring. Substrings are matched in reverse order of length, so
0 is the longest match.
The string is fetched from the string passed to the match function, so you cannot call this function after freeing the string.
The matched substring, or NULL
if an error
occurred. You have to free the string yourself.
[nullable]
Since: 2.14
gboolean g_match_info_fetch_pos (const GMatchInfo *match_info
,gint match_num
,gint *start_pos
,gint *end_pos
);
Retrieves the position in bytes of the match_num
'th capturing
parentheses. 0 is the full text of the match, 1 is the first
paren set, 2 the second, and so on.
If match_num
is a valid sub pattern but it didn't match anything
(e.g. sub pattern 1, matching "b" against "(a)?b") then start_pos
and end_pos
are set to -1 and TRUE
is returned.
If the match was obtained using the DFA algorithm, that is using
g_regex_match_all()
or g_regex_match_all_full()
, the retrieved
position is not that of a set of parentheses but that of a matched
substring. Substrings are matched in reverse order of length, so
0 is the longest match.
match_info |
GMatchInfo structure |
|
match_num |
number of the sub expression |
|
start_pos |
pointer to location where to store
the start position, or |
[out][optional] |
end_pos |
pointer to location where to store
the end position, or |
[out][optional] |
TRUE
if the position was fetched, FALSE
otherwise. If
the position cannot be fetched, start_pos
and end_pos
are left
unchanged
Since: 2.14
gchar * g_match_info_fetch_named (const GMatchInfo *match_info
,const gchar *name
);
Retrieves the text matching the capturing parentheses named name
.
If name
is a valid sub pattern name but it didn't match anything
(e.g. sub pattern "X", matching "b" against "(?P<X>a)?b")
then an empty string is returned.
The string is fetched from the string passed to the match function, so you cannot call this function after freeing the string.
The matched substring, or NULL
if an error
occurred. You have to free the string yourself.
[nullable]
Since: 2.14
gboolean g_match_info_fetch_named_pos (const GMatchInfo *match_info
,const gchar *name
,gint *start_pos
,gint *end_pos
);
Retrieves the position in bytes of the capturing parentheses named name
.
If name
is a valid sub pattern name but it didn't match anything
(e.g. sub pattern "X", matching "b" against "(?P<X>a)?b")
then start_pos
and end_pos
are set to -1 and TRUE
is returned.
match_info |
GMatchInfo structure |
|
name |
name of the subexpression |
|
start_pos |
pointer to location where to store
the start position, or |
[out][optional] |
end_pos |
pointer to location where to store
the end position, or |
[out][optional] |
TRUE
if the position was fetched, FALSE
otherwise.
If the position cannot be fetched, start_pos
and end_pos
are left unchanged.
Since: 2.14
gchar **
g_match_info_fetch_all (const GMatchInfo *match_info
);
Bundles up pointers to each of the matching substrings from a match and stores them in an array of gchar pointers. The first element in the returned array is the match number 0, i.e. the entire matched text.
If a sub pattern didn't match anything (e.g. sub pattern 1, matching "b" against "(a)?b") then an empty string is inserted.
If the last match was obtained using the DFA algorithm, that is using
g_regex_match_all()
or g_regex_match_all_full()
, the retrieved
strings are not that matched by sets of parentheses but that of the
matched substring. Substrings are matched in reverse order of length,
so the first one is the longest match.
The strings are fetched from the string passed to the match function, so you cannot call this function after freeing the string.
a NULL
-terminated array of gchar *
pointers. It must be freed using g_strfreev()
. If the previous
match failed NULL
is returned.
[transfer full]
Since: 2.14
Error codes returned by regular expressions functions.
Compilation of the regular expression failed. |
||
Optimization of the regular expression failed. |
||
Replacement failed due to an ill-formed replacement string. |
||
The match process failed. |
||
Internal error of the regular expression engine. Since 2.16 |
||
"\" at end of pattern. Since 2.16 |
||
"\c" at end of pattern. Since 2.16 |
||
Unrecognized character follows "\". Since 2.16 |
||
Numbers out of order in "{}" quantifier. Since 2.16 |
||
Number too big in "{}" quantifier. Since 2.16 |
||
Missing terminating "]" for character class. Since 2.16 |
||
Invalid escape sequence in character class. Since 2.16 |
||
Range out of order in character class. Since 2.16 |
||
Nothing to repeat. Since 2.16 |
||
Unrecognized character after "(?", "(?<" or "(?P". Since 2.16 |
||
POSIX named classes are supported only within a class. Since 2.16 |
||
Missing terminating ")" or ")" without opening "(". Since 2.16 |
||
Reference to non-existent subpattern. Since 2.16 |
||
Missing terminating ")" after comment. Since 2.16 |
||
Regular expression too large. Since 2.16 |
||
Failed to get memory. Since 2.16 |
||
Lookbehind assertion is not fixed length. Since 2.16 |
||
Malformed number or name after "(?(". Since 2.16 |
||
Conditional group contains more than two branches. Since 2.16 |
||
Assertion expected after "(?(". Since 2.16 |
||
Unknown POSIX class name. Since 2.16 |
||
POSIX collating elements are not supported. Since 2.16 |
||
Character value in "\x{...}" sequence is too large. Since 2.16 |
||
Invalid condition "(?(0)". Since 2.16 |
||
\C not allowed in lookbehind assertion. Since 2.16 |
||
Recursive call could loop indefinitely. Since 2.16 |
||
Missing terminator in subpattern name. Since 2.16 |
||
Two named subpatterns have the same name. Since 2.16 |
||
Malformed "\P" or "\p" sequence. Since 2.16 |
||
Unknown property name after "\P" or "\p". Since 2.16 |
||
Subpattern name is too long (maximum 32 characters). Since 2.16 |
||
Too many named subpatterns (maximum 10,000). Since 2.16 |
||
Octal value is greater than "\377". Since 2.16 |
||
"DEFINE" group contains more than one branch. Since 2.16 |
||
Repeating a "DEFINE" group is not allowed. This error is never raised. Since: 2.16 Deprecated: 2.34 |
||
Inconsistent newline options. Since 2.16 |
||
"\g" is not followed by a braced, angle-bracketed, or quoted name or number, or by a plain number. Since: 2.16 |
||
relative reference must not be zero. Since: 2.34 |
||
the backtracing control verb used does not allow an argument. Since: 2.34 |
||
unknown backtracing control verb. Since: 2.34 |
||
number is too big in escape sequence. Since: 2.34 |
||
Missing subpattern name. Since: 2.34 |
||
Missing digit. Since 2.34 |
||
In JavaScript compatibility mode, "[" is an invalid data character. Since: 2.34 |
||
different names for subpatterns of the same number are not allowed. Since: 2.34 |
||
the backtracing control verb requires an argument. Since: 2.34 |
||
"\c" must be followed by an ASCII character. Since: 2.34 |
||
"\k" is not followed by a braced, angle-bracketed, or quoted name. Since: 2.34 |
||
"\N" is not supported in a class. Since: 2.34 |
||
too many forward references. Since: 2.34 |
||
the name is too long in "(*MARK)", "(*PRUNE)", "(*SKIP)", or "(*THEN)". Since: 2.34 |
||
the character value in the \u sequence is too large. Since: 2.34 |
Since: 2.14
#define G_REGEX_ERROR g_regex_error_quark ()
Error domain for regular expressions. Errors in this domain will be from the GRegexError enumeration. See GError for information on error domains.
Since: 2.14
Flags specifying compile-time options.
No special options set. Since: 2.74 |
||
Letters in the pattern match both upper- and lowercase letters. This option can be changed within a pattern by a "(?i)" option setting. |
||
By default, GRegex treats the strings as consisting
of a single line of characters (even if it actually contains
newlines). The "start of line" metacharacter ("^") matches only
at the start of the string, while the "end of line" metacharacter
("$") matches only at the end of the string, or before a terminating
newline (unless |
||
A dot metacharacter (".") in the pattern matches all characters, including newlines. Without it, newlines are excluded. This option can be changed within a pattern by a ("?s") option setting. |
||
Whitespace data characters in the pattern are totally ignored except when escaped or inside a character class. Whitespace does not include the VT character (code 11). In addition, characters between an unescaped "#" outside a character class and the next newline character, inclusive, are also ignored. This can be changed within a pattern by a "(?x)" option setting. |
||
The pattern is forced to be "anchored", that is, it is constrained to match only at the first matching point in the string that is being searched. This effect can also be achieved by appropriate constructs in the pattern itself such as the "^" metacharacter. |
||
A dollar metacharacter ("$") in the pattern
matches only at the end of the string. Without this option, a
dollar also matches immediately before the final character if
it is a newline (but not before any other newlines). This option
is ignored if |
||
Inverts the "greediness" of the quantifiers so that they are not greedy by default, but become greedy if followed by "?". It can also be set by a "(?U)" option setting within the pattern. |
||
Usually strings must be valid UTF-8 strings, using this flag they are considered as a raw sequence of bytes. |
||
Disables the use of numbered capturing parentheses in the pattern. Any opening parenthesis that is not followed by "?" behaves as if it were followed by "?:" but named parentheses can still be used for capturing (and they acquire numbers in the usual way). |
||
Since 2.74 and the port to pcre2, requests JIT compilation, which, if the just-in-time compiler is available, further processes a compiled pattern into machine code that executes much faster. However, it comes at the cost of extra processing before the match is performed, so it is most beneficial to use this when the same compiled pattern is used for matching many times. Before 2.74 this option used the built-in non-JIT optimizations in pcre1. |
||
Limits an unanchored pattern to match before (or at) the first newline. Since: 2.34 |
||
Names used to identify capturing subpatterns need not be unique. This can be helpful for certain types of pattern when it is known that only one instance of the named subpattern can ever be matched. |
||
Usually any newline character or character sequence is recognized. If this option is set, the only recognized newline character is '\r'. |
||
Usually any newline character or character sequence is recognized. If this option is set, the only recognized newline character is '\n'. |
||
Usually any newline character or character sequence is recognized. If this option is set, the only recognized newline character sequence is '\r\n'. |
||
Usually any newline character or character sequence is recognized. If this option is set, the only recognized newline character sequences are '\r', '\n', and '\r\n'. Since: 2.34 |
||
Usually any newline character or character sequence is recognised. If this option is set, then "\R" only recognizes the newline characters '\r', '\n' and '\r\n'. Since: 2.34 |
||
Changes behaviour so that it is compatible with JavaScript rather than PCRE. Since GLib 2.74 this is no longer supported, as libpcre2 does not support it. Since: 2.34 Deprecated: 2.74 |
Since: 2.14
Flags specifying match-time options.
No special options set. Since: 2.74 |
||
The pattern is forced to be "anchored", that is, it is constrained to match only at the first matching point in the string that is being searched. This effect can also be achieved by appropriate constructs in the pattern itself such as the "^" metacharacter. |
||
Specifies that first character of the string is
not the beginning of a line, so the circumflex metacharacter should
not match before it. Setting this without |
||
Specifies that the end of the subject string is
not the end of a line, so the dollar metacharacter should not match
it nor (except in multiline mode) a newline immediately before it.
Setting this without |
||
An empty string is not considered to be a valid match if this option is set. If there are alternatives in the pattern, they are tried. If all the alternatives match the empty string, the entire match fails. For example, if the pattern "a?b?" is applied to a string not beginning with "a" or "b", it matches the empty string at the start of the string. With this flag set, this match is not valid, so GRegex searches further into the string for occurrences of "a" or "b". |
||
Turns on the partial matching feature, for more
documentation on partial matching see |
||
Overrides the newline definition set when creating a new GRegex, setting the '\r' character as line terminator. |
||
Overrides the newline definition set when creating a new GRegex, setting the '\n' character as line terminator. |
||
Overrides the newline definition set when creating a new GRegex, setting the '\r\n' characters sequence as line terminator. |
||
Overrides the newline definition set when creating a new GRegex, any Unicode newline sequence is recognised as a newline. These are '\r', '\n' and '\rn', and the single characters U+000B LINE TABULATION, U+000C FORM FEED (FF), U+0085 NEXT LINE (NEL), U+2028 LINE SEPARATOR and U+2029 PARAGRAPH SEPARATOR. |
||
Overrides the newline definition set when creating a new GRegex; any '\r', '\n', or '\r\n' character sequence is recognized as a newline. Since: 2.34 |
||
Overrides the newline definition for "\R" set when creating a new GRegex; only '\r', '\n', or '\r\n' character sequences are recognized as a newline by "\R". Since: 2.34 |
||
Overrides the newline definition for "\R" set when creating a new GRegex; any Unicode newline character or character sequence are recognized as a newline by "\R". These are '\r', '\n' and '\rn', and the single characters U+000B LINE TABULATION, U+000C FORM FEED (FF), U+0085 NEXT LINE (NEL), U+2028 LINE SEPARATOR and U+2029 PARAGRAPH SEPARATOR. Since: 2.34 |
||
An alias for |
||
Turns on the partial matching feature. In contrast to
to |
||
Like |
Since: 2.14
typedef struct _GRegex GRegex;
A GRegex is the "compiled" form of a regular expression pattern. This structure is opaque and its fields cannot be accessed directly.
Since: 2.14