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GLib Reference Manual | ![]() |
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Top | Description |
Perl-compatible regular expressionsPerl-compatible regular expressions — matches strings against regular expressions |
#include <glib.h> enum GRegexError; #define G_REGEX_ERROR enum GRegexCompileFlags; enum GRegexMatchFlags; GRegex; gboolean (*GRegexEvalCallback) (const GMatchInfo *match_info, GString *result, gpointer user_data); GRegex * g_regex_new (const gchar *pattern, GRegexCompileFlags compile_options, GRegexMatchFlags match_options, GError **error); GRegex * g_regex_ref (GRegex *regex); void g_regex_unref (GRegex *regex); const gchar * g_regex_get_pattern (const GRegex *regex); gint g_regex_get_max_backref (const GRegex *regex); gint g_regex_get_capture_count (const GRegex *regex); gint g_regex_get_string_number (const GRegex *regex, const gchar *name); gchar * g_regex_escape_string (const gchar *string, gint length); gboolean g_regex_match_simple (const gchar *pattern, const gchar *string, GRegexCompileFlags compile_options, GRegexMatchFlags match_options); gboolean g_regex_match (const GRegex *regex, const gchar *string, GRegexMatchFlags match_options, GMatchInfo **match_info); 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); gboolean g_regex_match_all (const GRegex *regex, const gchar *string, GRegexMatchFlags match_options, GMatchInfo **match_info); 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); gchar ** g_regex_split_simple (const gchar *pattern, const gchar *string, GRegexCompileFlags compile_options, GRegexMatchFlags match_options); gchar ** g_regex_split (const GRegex *regex, const gchar *string, GRegexMatchFlags match_options); 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); gchar * g_regex_replace (const GRegex *regex, const gchar *string, gssize string_len, gint start_position, const gchar *replacement, GRegexMatchFlags match_options, GError **error); 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); 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); gboolean g_regex_check_replacement (const gchar *replacement, gboolean *has_references, GError **error); GMatchInfo; GRegex * g_match_info_get_regex (const GMatchInfo *match_info); const gchar * g_match_info_get_string (const GMatchInfo *match_info); void g_match_info_free (GMatchInfo *match_info); gboolean g_match_info_matches (const GMatchInfo *match_info); gboolean g_match_info_next (GMatchInfo *match_info, GError **error); gint g_match_info_get_match_count (const GMatchInfo *match_info); gboolean g_match_info_is_partial_match (const GMatchInfo *match_info); gchar * g_match_info_expand_references (const GMatchInfo *match_info, const gchar *string_to_expand, GError **error); gchar * g_match_info_fetch (const GMatchInfo *match_info, gint match_num); gboolean g_match_info_fetch_pos (const GMatchInfo *match_info, gint match_num, gint *start_pos, gint *end_pos); gchar * g_match_info_fetch_named (const GMatchInfo *match_info, const gchar *name); gboolean g_match_info_fetch_named_pos (const GMatchInfo *match_info, const gchar *name, gint *start_pos, gint *end_pos); gchar ** g_match_info_fetch_all (const GMatchInfo *match_info);
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.
typedef enum { G_REGEX_ERROR_COMPILE, G_REGEX_ERROR_OPTIMIZE, G_REGEX_ERROR_REPLACE, G_REGEX_ERROR_MATCH, G_REGEX_ERROR_INTERNAL, /* These are the error codes from PCRE + 100 */ G_REGEX_ERROR_STRAY_BACKSLASH = 101, G_REGEX_ERROR_MISSING_CONTROL_CHAR = 102, G_REGEX_ERROR_UNRECOGNIZED_ESCAPE = 103, G_REGEX_ERROR_QUANTIFIERS_OUT_OF_ORDER = 104, G_REGEX_ERROR_QUANTIFIER_TOO_BIG = 105, G_REGEX_ERROR_UNTERMINATED_CHARACTER_CLASS = 106, G_REGEX_ERROR_INVALID_ESCAPE_IN_CHARACTER_CLASS = 107, G_REGEX_ERROR_RANGE_OUT_OF_ORDER = 108, G_REGEX_ERROR_NOTHING_TO_REPEAT = 109, G_REGEX_ERROR_UNRECOGNIZED_CHARACTER = 112, G_REGEX_ERROR_POSIX_NAMED_CLASS_OUTSIDE_CLASS = 113, G_REGEX_ERROR_UNMATCHED_PARENTHESIS = 114, G_REGEX_ERROR_INEXISTENT_SUBPATTERN_REFERENCE = 115, G_REGEX_ERROR_UNTERMINATED_COMMENT = 118, G_REGEX_ERROR_EXPRESSION_TOO_LARGE = 120, G_REGEX_ERROR_MEMORY_ERROR = 121, G_REGEX_ERROR_VARIABLE_LENGTH_LOOKBEHIND = 125, G_REGEX_ERROR_MALFORMED_CONDITION = 126, G_REGEX_ERROR_TOO_MANY_CONDITIONAL_BRANCHES = 127, G_REGEX_ERROR_ASSERTION_EXPECTED = 128, G_REGEX_ERROR_UNKNOWN_POSIX_CLASS_NAME = 130, G_REGEX_ERROR_POSIX_COLLATING_ELEMENTS_NOT_SUPPORTED = 131, G_REGEX_ERROR_HEX_CODE_TOO_LARGE = 134, G_REGEX_ERROR_INVALID_CONDITION = 135, G_REGEX_ERROR_SINGLE_BYTE_MATCH_IN_LOOKBEHIND = 136, G_REGEX_ERROR_INFINITE_LOOP = 140, G_REGEX_ERROR_MISSING_SUBPATTERN_NAME_TERMINATOR = 142, G_REGEX_ERROR_DUPLICATE_SUBPATTERN_NAME = 143, G_REGEX_ERROR_MALFORMED_PROPERTY = 146, G_REGEX_ERROR_UNKNOWN_PROPERTY = 147, G_REGEX_ERROR_SUBPATTERN_NAME_TOO_LONG = 148, G_REGEX_ERROR_TOO_MANY_SUBPATTERNS = 149, G_REGEX_ERROR_INVALID_OCTAL_VALUE = 151, G_REGEX_ERROR_TOO_MANY_BRANCHES_IN_DEFINE = 154, G_REGEX_ERROR_DEFINE_REPETION = 155, G_REGEX_ERROR_INCONSISTENT_NEWLINE_OPTIONS = 156, G_REGEX_ERROR_MISSING_BACK_REFERENCE = 157 } GRegexError;
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. Since 2.16 | |
Inconsistent newline options. Since 2.16 | |
"\\g" is not followed by a braced name or an optionally braced non-zero number. Since 2.16 |
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
typedef enum { G_REGEX_CASELESS = 1 << 0, G_REGEX_MULTILINE = 1 << 1, G_REGEX_DOTALL = 1 << 2, G_REGEX_EXTENDED = 1 << 3, G_REGEX_ANCHORED = 1 << 4, G_REGEX_DOLLAR_ENDONLY = 1 << 5, G_REGEX_UNGREEDY = 1 << 9, G_REGEX_RAW = 1 << 11, G_REGEX_NO_AUTO_CAPTURE = 1 << 12, G_REGEX_OPTIMIZE = 1 << 13, G_REGEX_DUPNAMES = 1 << 19, G_REGEX_NEWLINE_CR = 1 << 20, G_REGEX_NEWLINE_LF = 1 << 21, G_REGEX_NEWLINE_CRLF = G_REGEX_NEWLINE_CR | G_REGEX_NEWLINE_LF } GRegexCompileFlags;
Flags specifying compile-time options.
Letters in the pattern match both upper and lower case letters. It 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 ("$") matches only at the end of the string, or before a terminating newline (unless G_REGEX_DOLLAR_ENDONLY is set). When G_REGEX_MULTILINE is set, the "start of line" and "end of line" constructs match immediately following or immediately before any newline in the string, respectively, as well as at the very start and end. This can be changed within a pattern by a "(?m)" option setting. | |
A dot metacharater (".") in the pattern matches all characters, including newlines. Without it, newlines are excluded. This option can be changed within a pattern by a ("?s") option setting. | |
Whitespace data characters in the pattern are totally ignored except when escaped or inside a character class. Whitespace does not include the VT character (code 11). In addition, characters between an unescaped "#" outside a character class and the next newline character, inclusive, are also ignored. This can be changed within a pattern by a "(?x)" option setting. | |
The pattern is forced to be "anchored", that is, it is constrained to match only at the first matching point in the string that is being searched. This effect can also be achieved by appropriate constructs in the pattern itself such as the "^" metacharater. | |
A dollar metacharacter ("$") 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 G_REGEX_MULTILINE is set. | |
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). | |
Optimize the regular expression. If the pattern will be used many times, then it may be worth the effort to optimize it to improve the speed of matches. | |
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 is recognized, if this option is set, the only recognized newline character is '\r'. | |
Usually any newline character is recognized, if this option is set, the only recognized newline character is '\n'. | |
Usually any newline character is recognized, if this option is set, the only recognized newline character sequence is '\r\n'. |
Since 2.14
typedef enum { G_REGEX_MATCH_ANCHORED = 1 << 4, G_REGEX_MATCH_NOTBOL = 1 << 7, G_REGEX_MATCH_NOTEOL = 1 << 8, G_REGEX_MATCH_NOTEMPTY = 1 << 10, G_REGEX_MATCH_PARTIAL = 1 << 15, G_REGEX_MATCH_NEWLINE_CR = 1 << 20, G_REGEX_MATCH_NEWLINE_LF = 1 << 21, G_REGEX_MATCH_NEWLINE_CRLF = G_REGEX_MATCH_NEWLINE_CR | G_REGEX_MATCH_NEWLINE_LF, G_REGEX_MATCH_NEWLINE_ANY = 1 << 22 } GRegexMatchFlags;
Flags specifying match-time options.
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 "^" metacharater. | |
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 G_REGEX_MULTILINE (at compile time) causes circumflex never to match. This option affects only the behaviour of the circumflex metacharacter, it does not affect "\A". | |
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 G_REGEX_MULTILINE (at compile time) causes dollar never to match. This option affects only the behaviour of the dollar metacharacter, it does not affect "\Z" or "\z". | |
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 g_match_info_is_partial_match() .
|
|
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 as line terminator. | |
Overrides the newline definition set when creating a new GRegex, any newline character or character sequence is recognized. |
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
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 occurance of the pattern in the string passed
to g_regex_replace_eval()
, and it should append the replacement to
result
.
|
the GMatchInfo generated by the match.
Use g_match_info_get_regex() and g_match_info_get_string() if you
need the GRegex or the matched string.
|
|
a GString containing the new string |
|
user data passed to g_regex_replace_eval()
|
Returns : |
%FALSE to continue the replacement process, TRUE to stop it
|
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.
|
the regular expression |
|
compile options for the regular expression, or 0 |
|
match options for the regular expression, or 0 |
|
return location for a GError |
Returns : |
a GRegex structure. Call g_regex_unref() when you
are done with it
|
Since 2.14
GRegex * g_regex_ref (GRegex *regex);
Increases reference count of regex
by 1.
|
a GRegex |
Returns : |
regex
|
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.
|
a GRegex |
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()
.
|
a GRegex structure |
Returns : |
the pattern of regex
|
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.
|
a GRegex |
Returns : |
the number of the highest back reference |
Since 2.14
gint g_regex_get_capture_count (const GRegex *regex);
Returns the number of capturing subpatterns in the pattern.
|
a GRegex |
Returns : |
the number of capturing subpatterns |
Since 2.14
gint g_regex_get_string_number (const GRegex *regex, const gchar *name);
Retrieves the number of the subexpression named name
.
|
GRegex structure |
|
name of the subexpression |
Returns : |
The number of the subexpression or -1 if name
does not exists
|
Since 2.14
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
.
|
the string to escape |
|
the length of string , or -1 if string is nul-terminated
|
Returns : |
a newly-allocated escaped string |
Since 2.14
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()
.
|
the regular expression |
|
the string to scan for matches |
|
compile options for the regular expression, or 0 |
|
match options, or 0 |
Returns : |
TRUE if the string matched, FALSE otherwise
|
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.
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()
.
static void print_uppercase_words (const gchar *string) { /* Print all uppercase-only words. */ GRegex *regex; GMatchInfo *match_info; regex = g_regex_new ("[A-Z]+", 0, 0, 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.
|
a GRegex structure from g_regex_new()
|
|
the string to scan for matches |
|
match options |
|
pointer to location where to store the GMatchInfo,
or NULL if you do not need it
|
Returns : |
TRUE is the string matched, FALSE otherwise
|
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".
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()
.
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]+", 0, 0, 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); } }
|
a GRegex structure from g_regex_new()
|
|
the string to scan for matches |
|
the length of string , or -1 if string is nul-terminated
|
|
starting index of the string to match |
|
match options |
|
pointer to location where to store the GMatchInfo,
or NULL if you do not need it
|
|
location to store the error occuring, or NULL to ignore errors
|
Returns : |
TRUE is the string matched, FALSE otherwise
|
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.
|
a GRegex structure from g_regex_new()
|
|
the string to scan for matches |
|
match options |
|
pointer to location where to store the GMatchInfo,
or NULL if you do not need it
|
Returns : |
TRUE is the string matched, FALSE otherwise
|
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 possibile 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".
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.
|
a GRegex structure from g_regex_new()
|
|
the string to scan for matches |
|
the length of string , or -1 if string is nul-terminated
|
|
starting index of the string to match |
|
match options |
|
pointer to location where to store the GMatchInfo,
or NULL if you do not need it
|
|
location to store the error occuring, or NULL to ignore errors
|
Returns : |
TRUE is the string matched, FALSE otherwise
|
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 a 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".
|
the regular expression |
|
the string to scan for matches |
|
compile options for the regular expression, or 0 |
|
match options, or 0 |
Returns : |
a NULL -terminated array of strings. Free it using g_strfreev()
|
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 a 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".
|
a GRegex structure |
|
the string to split with the pattern |
|
match time option flags |
Returns : |
a NULL -terminated gchar ** array. Free it using g_strfreev()
|
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 a 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".
|
a GRegex structure |
|
the string to split with the pattern |
|
the length of string , or -1 if string is nul-terminated
|
|
starting index of the string to match |
|
match time option flags |
|
the maximum number of tokens to split string into.
If this is less than 1, the string is split completely
|
|
return location for a GError |
Returns : |
a NULL -terminated gchar ** array. Free it using g_strfreev()
|
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 stings
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".
|
a GRegex structure |
|
the string to perform matches against |
|
the length of string , or -1 if string is nul-terminated
|
|
starting index of the string to match |
|
text to replace each match with |
|
options for the match |
|
location to store the error occuring, or NULL to ignore errors
|
Returns : |
a newly allocated string containing the replacements |
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".
|
a GRegex structure |
|
the string to perform matches against |
|
the length of string , or -1 if string is nul-terminated
|
|
starting index of the string to match |
|
text to replace each match with |
|
options for the match |
|
location to store the error occuring, or NULL to ignore errors
|
Returns : |
a newly allocated string containing the replacements |
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:
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", 0, 0, NULL); res = g_regex_replace_eval (reg, text, -1, 0, 0, eval_cb, h, NULL); g_hash_table_destroy (h); /* ... */
|
a GRegex structure from g_regex_new()
|
|
string to perform matches against |
|
the length of string , or -1 if string is nul-terminated
|
|
starting index of the string to match |
|
options for the match |
|
a function to call for each match |
|
user data to pass to the function |
|
location to store the error occuring, or NULL to ignore errors
|
Returns : |
a newly allocated string containing the replacements |
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.
|
the replacement string |
|
location to store information about
references in replacement or NULL
|
|
location to store error |
Returns : |
whether replacement is a valid replacement string
|
Since 2.14
typedef struct _GMatchInfo GMatchInfo;
GMatchInfo is used to retrieve information about the regular expression match which created it. This structure is opaque and its fields cannot be accessed directly.
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.
|
a GMatchInfo |
Returns : |
GRegex object used in match_info
|
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.
|
a GMatchInfo |
Returns : |
the string searched with match_info
|
Since 2.14
void g_match_info_free (GMatchInfo *match_info);
Frees all the memory associated with the GMatchInfo structure.
|
a GMatchInfo |
Since 2.14
gboolean g_match_info_matches (const GMatchInfo *match_info);
Returns whether the previous match operation succeeded.
|
a GMatchInfo structure |
Returns : |
TRUE if the previous match operation succeeded,
FALSE otherwise
|
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.
|
a GMatchInfo structure |
|
location to store the error occuring, or NULL to ignore errors
|
Returns : |
TRUE is the string matched, FALSE otherwise
|
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.
|
a GMatchInfo structure |
Returns : |
Number of matched substrings, or -1 if an error occurred |
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 flag. When this is set 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()
.
When using partial matching you cannot use g_match_info_fetch*().
Because of the way certain internal optimizations are implemented the partial matching algorithm cannot be used with all patterns. So repeated single characters such as "a{2,4}" and repeated single meta-sequences such as "\d+" are not permitted if the maximum number of occurrences is greater than one. Optional items such as "\d?" (where the maximum is one) are permitted. Quantifiers with any values are permitted after parentheses, so the invalid examples above can be coded thus "(a){2,4}" and "(\d)+". If G_REGEX_MATCH_PARTIAL is set for a pattern that does not conform to the restrictions, matching functions return an error.
|
a GMatchInfo structure |
Returns : |
TRUE if the match was partial, FALSE otherwise
|
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.
|
a GMatchInfo or NULL
|
|
the string to expand |
|
location to store the error occuring, or NULL to ignore errors
|
Returns : |
the expanded string, or NULL if an error occurred
|
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.
|
GMatchInfo structure |
|
number of the sub expression |
Returns : |
The matched substring, or NULL if an error occurred.
You have to free the string yourself
|
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.
|
GMatchInfo structure |
|
number of the sub expression |
|
pointer to location where to store the start position |
|
pointer to location where to store the end position |
Returns : |
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.
|
GMatchInfo structure |
|
name of the subexpression |
Returns : |
The matched substring, or NULL if an error occurred.
You have to free the string yourself
|
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.
|
GMatchInfo structure |
|
name of the subexpression |
|
pointer to location where to store the start position |
|
pointer to location where to store the end position |
Returns : |
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 GMatchInfo structure |
Returns : |
a NULL -terminated array of gchar * pointers. It must be
freed using g_strfreev() . If the previous match failed NULL is
returned
|
Since 2.14