On Thu, Jan 23, 2014 at 10:28:29AM +0100, Manuel VIVES wrote:
> ---
> po/POTFILES.in | 1 +
> src/libvirt_private.syms | 1 +
> src/util/virstring.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++
> src/util/virstring.h | 3 ++
> 4 files changed, 102 insertions(+)
Can you add something to tests/virstringtest.c to validate your
new method with various interesting input strings.
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index d1a58f9..68ca39d 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1763,6 +1763,7 @@ virStorageFileResize;
> # util/virstring.h
> virArgvToString;
> virAsprintfInternal;
> +virSearchRegex;
Lets call this new method 'virStringSearchRegex' so we have a normal
name prefix
> diff --git a/src/util/virstring.c b/src/util/virstring.c
> index 8d0ca70..3c93450 100644
> --- a/src/util/virstring.c
> +++ b/src/util/virstring.c
> @@ -23,6 +23,7 @@
>
> #include <stdlib.h>
> #include <stdio.h>
> +#include <regex.h>
>
> #include "c-ctype.h"
> #include "virstring.h"
> @@ -645,3 +646,99 @@ int virStringSortRevCompare(const void *a, const void *b)
>
> return strcmp(*sb, *sa);
> }
> +
> +/**
> + * virSearchRegex:
> + * Allows you to get the nth occurrence of a substring in sourceString which matches
> + * a POSIX Extended regular expression pattern.
> + * If there is no substring, result is not modified.
> + * return -1 on error, 0 if not found and 1 if found.
> + *
> + * @sourceString: String to parse
> + * @occurrence: return occurrence 'n' (starting from 0) of a sub-string that
> + * matches the pattern.
> + * @regexp: POSIX Extended regular expression pattern used for matching
> + * @result: nth occurrence substring matching the @regexp pattern
> + * @code
> + char *source = "6853a496-1c10-472e-867a-8244937bd6f0
> + 773ab075-4cd7-4fc2-8b6e-21c84e9cb391
> + bbb3c75c-d60f-43b0-b802-fd56b84a4222
> + 60c04aa1-0375-4654-8d9f-e149d9885273
> + 4548d465-9891-4c34-a184-3b1c34a26aa8";
> + char *ret1=NULL;
> + char *ret2=NULL;
> + char *ret3=NULL;
> + virSearchRegex(source,
> + 4,
> + "([a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12})",
> + &ret1);
> + //ret1 = "4548d465-9891-4c34-a184-3b1c34a26aa8"
> + virSearchRegex(source,
> + 0,
> + "([a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12})",
> + &ret2);
> + //ret2 = "6853a496-1c10-472e-867a-8244937bd6f0"
> + virSearchRegex(source,
> + 1,
> + "([a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12})",
> + &ret3);
> + //ret3 = "773ab075-4cd7-4fc2-8b6e-21c84e9cb391"
> + * @endcode
> +int
> +virSearchRegex(const char *sourceString,
> + unsigned int occurrence,
> + const char *regexp,
> + char **result)
This kind of usage leads to pretty inefficient code. Why not just
change it to return 'char ***matches' and thus give the caller all
possible matches in one call. And 'unsigned int occurrence' could
be 'size_t maxMatches' to limit it.
> +{
> + regex_t pregUuidBracket;
This variable name is a little odd - lets just call it 're'.
> + size_t i = 0;
> + size_t nmatch = 0;
> + regmatch_t *pmatch = NULL;
> + int ret = -1;
> + int regError = -1;
> +
> + regError = regcomp(&pregUuidBracket, regexp, REG_EXTENDED);
> + if (regError != 0) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + _("Error while compiling regular expression: %d"),
> + regError);
> + goto cleanup;
> + }
> + nmatch = pregUuidBracket.re_nsub;
> + if (VIR_ALLOC_N(pmatch, nmatch) < 0)
> + goto cleanup;
> +
> + while (i < (occurrence+1)) {
> + if (regexec(&pregUuidBracket, sourceString, nmatch, pmatch, 0) == 0) {
> + regoff_t start = pmatch[0].rm_so;
> + regoff_t end = pmatch[0].rm_eo;
> + if (i == occurrence ||
> + (occurrence > i && regexec(&pregUuidBracket, &sourceString[end],
> + nmatch, pmatch, 0) != 0)) {
> + /* We copy only if i == position (so that it is the uuid we're looking for),
> + * or position > i AND there is no matches left in the rest of the string
> + * (this is the case where we give a biggest @occurence than the
> + * number of matches and we want to return the last one)
> + */
> + if (VIR_STRNDUP(*result, sourceString + start, end - start) < 0)
> + goto cleanup;
> +
> + ret = 1;
> + goto cleanup;
> + }
> + sourceString = &sourceString[end];
> + } else {
> + break;
> + ret = 0;
> + goto cleanup;
> + }
> + ++i;
> + }
> +
> +cleanup:
> + regfree(&pregUuidBracket);
> + VIR_FREE(pmatch);
> + return ret;
> +}
Daniel
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