}
~~~
-The *DefineRegex* allows substring extraction like:
+The *DefineRegex* allows substring extraction using regular expressions (POSIX extended regex).
+It can match patterns in strings and extract matched substrings into UCM variables.
+
+#### DefineRegex Structure
+
+~~~{.html}
+DefineRegex.name {
+ String "text to match against"
+ Regex "regex_pattern"
+ Flags "e"
+ Scheme "first"
+}
+~~~
+
+Field | Description
+---------------------|---------------------
+String | The input string to match the regex pattern against
+Regex | POSIX extended regular expression pattern
+Flags | Optional regex flags (see below)
+Scheme | Matching scheme: "first" (default) or "all" [**Syntax 9**]
+
+#### Regex Flags
+
+The Flags field is optional and accepts the following characters:
+
+Flag | Description
+-------|---------------------
+e | Extended POSIX regex (REG_EXTENDED) - default recommended
+i | Case-insensitive matching (REG_ICASE)
+s | Report only success/fail (REG_NOSUB)
+n | Newline-sensitive matching (REG_NEWLINE)
+
+Multiple flags can be combined, e.g., "ei" for extended and case-insensitive.
+
+#### Matching Schemes
+
+**Scheme "first"** (default): Matches the pattern once and extracts capture groups
+
+The variables created are:
+- `name` - the full matched string
+- `name1` - first capture group (parentheses in regex)
+- `name2` - second capture group
+- `nameN` - Nth capture group
+
+Example with "first" scheme:
+
+~~~{.html}
+DefineRegex.hwdev {
+ String "hw:2,0"
+ Regex "hw:([0-9]+),([0-9]+)"
+ Flags "e"
+ Scheme "first"
+}
+~~~
+
+This creates variables:
+- `hwdev` = "hw:2,0" (full match)
+- `hwdev1` = "2" (first capture group - card number)
+- `hwdev2` = "0" (second capture group - device number)
+
+**Scheme "all"** [**Syntax 9**]: Matches the pattern multiple times and extracts all matches
+
+The variables created are:
+- `nameN` - Nth full match (N starts at 1)
+- `nameN_1` - Nth match, first capture group
+- `nameN_2` - Nth match, second capture group
+- `nameN_M` - Nth match, Mth capture group
+
+Example with "all" scheme:
+
+~~~{.html}
+DefineRegex.devices {
+ String "device1 device2 device3"
+ Regex "device([0-9]+)"
+ Flags "e"
+ Scheme "all"
+}
+~~~
+
+This creates variables:
+- `devices1` = "device1" (first full match)
+- `devices1_1` = "1" (first match, capture group 1)
+- `devices2` = "device2" (second full match)
+- `devices2_1` = "2" (second match, capture group 1)
+- `devices3` = "device3" (third full match)
+- `devices3_1` = "3" (third match, capture group 1)
+
+#### Practical Examples
+
+Extract USB device vendor and product IDs:
+
+~~~{.html}
+DefineRegex.usbids {
+ String "${sys:bus/usb/devices/1-1/uevent}"
+ Regex "PRODUCT=([0-9a-f]+)/([0-9a-f]+)"
+ Flags "e"
+ Scheme "first"
+}
+# Creates: usbids (full match), usbids1 (vendor), usbids2 (product)
+~~~
+
+Parse multiple key=value pairs:
~~~{.html}
-DefineRegex.rval {
- Regex "(hello)|(regex)"
- String "hello, it's my regex"
+DefineRegex.params {
+ String "rate=48000,channels=2,format=S16_LE"
+ Regex "([a-z]+)=([^,]+)"
+ Flags "e"
+ Scheme "all"
}
+# Creates: params1="rate=48000", params1_1="rate", params1_2="48000"
+# params2="channels=2", params2_1="channels", params2_2="2"
+# params3="format=S16_LE", params3_1="format", params3_2="S16_LE"
~~~
-The result will be stored to variables *rval1* as *hello* and *rval2* as *regex* (every matched
-substrings are stored to a separate variable with the sequence number postfix.
+Extract text components:
+
+~~~{.html}
+DefineRegex.model {
+ String "USB Audio Device Model XYZ123"
+ Regex "([A-Z]+).*Model ([A-Z0-9]+)"
+ Flags "e"
+ Scheme "first"
+}
+# Creates: model (full match), model1="USB", model2="XYZ123"
+~~~
-Variables can be substituted using the `${var:rval1}` reference for example.
+Variables can be substituted using `${var:name}` reference. For example, to use the extracted
+card number: `PlaybackPCM "hw:${var:hwdev1},0"`
### Macros
}
static int set_variables(snd_use_case_mgr_t *uc_mgr, const char *data,
- unsigned int match_size, regmatch_t *match,
- const char *name)
+ regex_t *re, const char *name, int scheme_all)
{
- size_t name2_len = strlen(name) + 16;
- char *name2 = alloca(name2_len);
+ size_t name_len = strlen(name) + 32;
+ char *var_name = alloca(name_len);
+ regmatch_t match[20];
char *s;
+ unsigned int match_idx = 1;
unsigned int i;
int err;
+ const char *pos;
- if (match[0].rm_so < 0 || match[0].rm_eo < 0)
- return 0;
- s = extract_substring(data, &match[0]);
- if (s == NULL)
- return -ENOMEM;
- err = uc_mgr_set_variable(uc_mgr, name, s);
- free(s);
- if (err < 0)
- return err;
- for (i = 1; i < match_size; i++) {
- if (match[i].rm_so < 0 || match[i].rm_eo < 0)
- return 0;
- s = extract_substring(data, &match[i]);
+ pos = data;
+ while (1) {
+ err = regexec(re, pos, ARRAY_SIZE(match), match, 0);
+ if (err == REG_NOMATCH)
+ break;
+ if (err != 0)
+ return -EINVAL;
+
+ if (match[0].rm_so < 0 || match[0].rm_eo < 0)
+ break;
+
+ s = extract_substring(pos, &match[0]);
if (s == NULL)
return -ENOMEM;
- snprintf(name2, name2_len, "%s%u", name, i);
- err = uc_mgr_set_variable(uc_mgr, name2, s);
+ if (scheme_all) {
+ snprintf(var_name, name_len, "%s%u", name, match_idx);
+ err = uc_mgr_set_variable(uc_mgr, var_name, s);
+ } else {
+ err = uc_mgr_set_variable(uc_mgr, name, s);
+ }
free(s);
if (err < 0)
return err;
+
+ for (i = 1; i < ARRAY_SIZE(match); i++) {
+ if (match[i].rm_so < 0 || match[i].rm_eo < 0)
+ break;
+ s = extract_substring(pos, &match[i]);
+ if (s == NULL)
+ return -ENOMEM;
+ if (scheme_all)
+ snprintf(var_name, name_len, "%s%u_%u", name, match_idx, i);
+ else
+ snprintf(var_name, name_len, "%s%u", name, i);
+ err = uc_mgr_set_variable(uc_mgr, var_name, s);
+ free(s);
+ if (err < 0)
+ return err;
+ }
+
+ if (!scheme_all)
+ break;
+
+ pos += match[0].rm_eo;
+ match_idx++;
+
+ if (*pos == '\0')
+ break;
}
+
return 0;
}
int uc_mgr_define_regex(snd_use_case_mgr_t *uc_mgr, const char *name,
snd_config_t *eval)
{
- const char *string, *regex_string, *flags_string;
+ const char *string, *regex_string, *flags_string, *scheme_string;
char *s;
regex_t re;
int options = 0;
- regmatch_t match[20];
+ int use_scheme_all = 0;
int err;
if (uc_mgr->conf_format < 3) {
return -EINVAL;
}
+ err = get_string(eval, "Scheme", &scheme_string);
+ if (err == -ENOENT) {
+ use_scheme_all = 0;
+ } else if (err < 0) {
+ snd_error(UCM, "DefineRegex error (Scheme string)");
+ return -EINVAL;
+ } else {
+ if (strcmp(scheme_string, "first") == 0) {
+ use_scheme_all = 0;
+ } else if (strcmp(scheme_string, "all") == 0) {
+ if (uc_mgr->conf_format < 9) {
+ snd_error(UCM, "DefineRegex 'all' scheme is supported in v9+ syntax");
+ return -EINVAL;
+ }
+ use_scheme_all = 1;
+ } else {
+ snd_error(UCM, "DefineRegex error (unknown scheme '%s')", scheme_string);
+ return -EINVAL;
+ }
+ }
+
err = get_string(eval, "Flags", &flags_string);
if (err == -ENOENT) {
options = REG_EXTENDED;
regfree(&re);
return err;
}
- err = regexec(&re, s, ARRAY_SIZE(match), match, 0);
- if (err < 0)
- err = -errno;
- else if (err == REG_NOMATCH)
- err = 0;
- else
- err = set_variables(uc_mgr, s, ARRAY_SIZE(match), match, name);
+
+ err = set_variables(uc_mgr, s, &re, name, use_scheme_all);
free(s);
regfree(&re);
return err;
projects / alsa-lib.git / commitdiff