From: "Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>
To: git@vger.kernel.org
Cc: "Junio C Hamano" <gitster@pobox.com>, "Jeff King" <peff@peff.net>,
sschuberth@gmail.com, "Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>
Subject: [PATCH v2 1/2] add skip_prefix_mem helper
Date: Tue, 28 Jun 2016 19:26:40 +0200 [thread overview]
Message-ID: <20160628172641.26381-2-pclouds@gmail.com> (raw)
In-Reply-To: <20160628172641.26381-1-pclouds@gmail.com>
From: Jeff King <peff@peff.net>
The skip_prefix function has been very useful for
simplifying pointer arithmetic and avoiding repeated magic
numbers, but we have no equivalent for length-limited
buffers. So we're stuck with:
if (3 <= len && skip_prefix(buf, "foo", &buf))
len -= 3;
That's not that complicated, but it needs to use magic
numbers for the length of the prefix (or else write out
strlen("foo"), repeating the string). By using a helper, we
can get the string length behind the scenes (and often at
compile time for string literals).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
git-compat-util.h | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/git-compat-util.h b/git-compat-util.h
index 49d4029..c99cddc 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -473,6 +473,23 @@ static inline int skip_prefix(const char *str, const char *prefix,
return 0;
}
+/*
+ * Like skip_prefix, but promises never to read past "len" bytes of the input
+ * buffer, and returns the remaining number of bytes in "out" via "outlen".
+ */
+static inline int skip_prefix_mem(const char *buf, size_t len,
+ const char *prefix,
+ const char **out, size_t *outlen)
+{
+ size_t prefix_len = strlen(prefix);
+ if (prefix_len <= len && !memcmp(buf, prefix, prefix_len)) {
+ *out = buf + prefix_len;
+ *outlen = len - prefix_len;
+ return 1;
+ }
+ return 0;
+}
+
/*
* If buf ends with suffix, return 1 and subtract the length of the suffix
* from *len. Otherwise, return 0 and leave *len untouched.
--
2.8.2.531.gd073806
next prev parent reply other threads:[~2016-06-28 17:45 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-26 7:06 [PATCH] config: add conditional include Nguyễn Thái Ngọc Duy
2016-06-26 18:27 ` Jeff King
2016-06-27 16:14 ` Duy Nguyen
2016-06-27 16:20 ` Jeff King
2016-06-27 16:32 ` Duy Nguyen
2016-06-27 16:35 ` Jeff King
2016-06-28 17:26 ` [PATCH v2 0/2] Config " Nguyễn Thái Ngọc Duy
2016-06-28 17:26 ` Nguyễn Thái Ngọc Duy [this message]
2016-06-28 17:26 ` [PATCH v2 2/2] config: add " Nguyễn Thái Ngọc Duy
2016-06-28 20:49 ` Jeff King
2016-06-29 4:06 ` Duy Nguyen
2016-06-28 23:11 ` Eric Sunshine
2016-07-12 16:42 ` [PATCH v3] " Nguyễn Thái Ngọc Duy
2016-07-13 7:21 ` Matthieu Moy
2016-07-13 7:26 ` Jeff King
2016-07-13 12:48 ` Matthieu Moy
2016-07-13 15:57 ` Duy Nguyen
2016-07-14 15:33 ` [PATCH v4] " Nguyễn Thái Ngọc Duy
2016-07-14 15:53 ` Johannes Schindelin
2016-07-14 16:13 ` Duy Nguyen
2016-07-16 13:30 ` Johannes Schindelin
2016-07-16 14:48 ` Duy Nguyen
2016-07-16 15:08 ` Jeff King
2016-07-16 16:36 ` Johannes Schindelin
2016-07-16 16:47 ` Jeff King
2016-07-17 8:15 ` Johannes Schindelin
2016-07-20 13:31 ` Jeff King
2016-07-20 22:07 ` Junio C Hamano
2016-07-20 16:39 ` Jakub Narębski
2016-08-13 8:40 ` Duy Nguyen
2016-08-19 13:54 ` Jeff King
2016-08-20 21:08 ` Jakub Narębski
2016-08-22 12:43 ` Duy Nguyen
2016-08-22 12:59 ` Matthieu Moy
2016-08-22 13:09 ` Duy Nguyen
2016-08-22 13:22 ` Matthieu Moy
2016-08-22 13:32 ` Duy Nguyen
2016-08-23 13:42 ` Johannes Schindelin
2016-08-24 9:37 ` Duy Nguyen
2016-08-24 12:44 ` Jakub Narębski
2016-08-24 14:17 ` Jeff King
2016-06-28 20:28 ` [PATCH v2 0/2] Config " Jeff King
2016-06-28 20:51 ` Matthieu Moy
2016-06-28 21:03 ` Jeff King
2016-06-29 4:09 ` Duy Nguyen
2016-06-28 22:11 ` Junio C Hamano
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