On Fri, May 18, 2012 at 04:42:36PM -0600, Eric Blake wrote:
> I'm tired of writing:
>
> bool sep = false;
> while (...) {
> if (sep)
> virBufferAddChar(buf, ',');
> sep = true;
> virBufferAdd(buf, str);
> }
>
> This makes it easier, allowing one to write:
>
> while (...)
> virBufferAsprintf(buf, "%s,", str);
> virBufferTrim(buf, ",", -1);
>
> to trim any remaining comma.
>
> * src/util/buf.h (virBufferTrim): Declare.
> * src/util/buf.c (virBufferTrim): New function.
> * tests/virbuftest.c (testBufTrim): Test it.
> ---
>
> I've threatened to do this enough times, so I finally carried through
> with my threat :)
>
> src/util/buf.c | 36 +++++++++++++++++++++++++++++++++
> src/util/buf.h | 2 +
> tests/virbuftest.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 94 insertions(+), 0 deletions(-)
>
> diff --git a/src/util/buf.c b/src/util/buf.c
> index d18f6af..630e4c9 100644
> --- a/src/util/buf.c
> +++ b/src/util/buf.c
> @@ -612,3 +612,39 @@ virBufferStrcat(virBufferPtr buf, ...)
> virBufferAdd(buf, str, -1);
> va_end(ap);
> }
> +
> +/**
> + * virBufferTrim:
> + * @buf: the buffer to trim
> + * @str: the optional string, to force an exact trim
> + * @len: the number of bytes to trim, or -1 to use @str
> + *
> + * Trim the tail of a buffer. If @str is provided, the trim only occurs
> + * if the current tail of the buffer matches @str; a non-negative @len
> + * further limits how much of the tail is trimmed. If @str is NULL, then
> + * @len must be non-negative.
> + *
> + * Returns -1 if @buf has previously encountered an error or if @len is
> + * invalid, 0 if there was nothing to trim (@buf was too short or @str
> + * didn't match), and 1 if the trim was successful.
> + */
> +int
> +virBufferTrim(virBufferPtr buf, const char *str, int len)
> +{
> + size_t len2 = 0;
> +
> + if (!buf || buf->error || (!str && len < 0))
> + return -1;
> +
> + if (len > 0 && len > buf->use)
> + return 0;
> + if (str) {
> + len2 = strlen(str);
> + if (len2 > buf->use ||
> + memcmp(&buf->content[buf->use - len2], str, len2) != 0)
> + return 0;
> + }
> + buf->use -= len < 0 ? len2 : len;
> + buf->content[buf->use] = '\0';
> + return 1;
> +}
> diff --git a/src/util/buf.h b/src/util/buf.h
> index d6bc8f3..a8e2eb5 100644
> --- a/src/util/buf.h
> +++ b/src/util/buf.h
> @@ -64,4 +64,6 @@ void virBufferURIEncodeString(virBufferPtr buf, const char *str);
> void virBufferAdjustIndent(virBufferPtr buf, int indent);
> int virBufferGetIndent(const virBufferPtr buf, bool dynamic);
>
> +int virBufferTrim(virBufferPtr buf, const char *trim, int len);
> +
> #endif /* __VIR_BUFFER_H__ */
> diff --git a/tests/virbuftest.c b/tests/virbuftest.c
> index 9058920..cd02db1 100644
> --- a/tests/virbuftest.c
> +++ b/tests/virbuftest.c
> @@ -133,6 +133,61 @@ static int testBufAutoIndent(const void *data ATTRIBUTE_UNUSED)
> return ret;
> }
>
> +static int testBufTrim(const void *data ATTRIBUTE_UNUSED)
> +{
> + virBuffer bufinit = VIR_BUFFER_INITIALIZER;
> + virBufferPtr buf = NULL;
> + char *result = NULL;
> + const char *expected = "a,b";
> + int ret = -1;
> + int i = 1;
> +
> +#define ACT(str, len, result) \
> + do { \
> + if (virBufferTrim(buf, str, len) != result) { \
> + TEST_ERROR("trim %d failed", i); \
> + goto cleanup; \
> + } \
> + i++; \
> + } while (0);
> +
> + if (virBufferTrim(buf, "", 0) != -1) {
> + TEST_ERROR("Wrong failure detection 1");
> + goto cleanup;
> + }
> + buf = &bufinit;
> + if (virBufferTrim(buf, NULL, -1) != -1) {
> + TEST_ERROR("Wrong failure detection 2");
> + goto cleanup;
> + }
> +
> + virBufferAddLit(buf, "a;");
> + ACT("", 0, 1);
> + ACT("", -1, 1);
> + ACT(NULL, 1, 1);
> + ACT(NULL, 5, 0);
> + ACT("a", 2, 0);
> +
> + virBufferAddLit(buf, ",b,,");
> + ACT("b", -1, 0);
> + ACT("b,,", 1, 1);
> + ACT(",", -1, 1);
> +
> + result = virBufferContentAndReset(buf);
> + if (!result || STRNEQ(result, expected)) {
> + virtTestDifference(stderr, expected, result);
> + goto cleanup;
> + }
> +
> + ret = 0;
> +
> +cleanup:
> + virBufferFreeAndReset(buf);
> + VIR_FREE(result);
> + return ret;
> +}
> +
> +
> static int
> mymain(void)
> {
> @@ -149,6 +204,7 @@ mymain(void)
> DO_TEST("EscapeString infinite loop", testBufInfiniteLoop, 1);
> DO_TEST("VSprintf infinite loop", testBufInfiniteLoop, 0);
> DO_TEST("Auto-indentation", testBufAutoIndent, 0);
> + DO_TEST("Trim", testBufTrim, 0);
>
> return ret==0 ? EXIT_SUCCESS : EXIT_FAILURE;
> }
ACK, interesting addition :-) Code looks fine,
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel@xxxxxxxxxxxx | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/
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