[ccan] [PATCH 02/11] bytestring: Add bytestring_slice function
David Gibson
david at gibson.dropbear.id.au
Sun Oct 12 03:43:27 AEDT 2014
Add a bytestring_slice() function to take a sub(byte)string of a
bytestring.
Signed-off-by: David Gibson <david at gibson.dropbear.id.au>
---
ccan/bytestring/bytestring.h | 23 +++++++++++++++++++++++
ccan/bytestring/test/run.c | 11 +++++++++--
2 files changed, 32 insertions(+), 2 deletions(-)
diff --git a/ccan/bytestring/bytestring.h b/ccan/bytestring/bytestring.h
index 77435c9..34ab505 100644
--- a/ccan/bytestring/bytestring.h
+++ b/ccan/bytestring/bytestring.h
@@ -95,4 +95,27 @@ static inline char bytestring_byte(struct bytestring s, size_t n)
return s.ptr[n];
}
+/**
+ * bytestring_slice - extract a substring from a bytestring
+ * @s: bytestring
+ * @start, @end: indexes
+ *
+ * Return a sub-bytestring of @s, starting at byte index @start, and
+ * running to, but not including byte @end. If @end is before start,
+ * returns a zero-length bytestring. If @start is out of range,
+ * return a zero length bytestring at the end of @s.
+ */
+static inline struct bytestring bytestring_slice(struct bytestring s,
+ size_t start, size_t end)
+{
+ if (start > s.len)
+ start = s.len;
+ if (end > s.len)
+ end = s.len;
+ if (end < start)
+ end = start;
+
+ return bytestring(s.ptr + start, end - start);
+}
+
#endif /* CCAN_BYTESTRING_H_ */
diff --git a/ccan/bytestring/test/run.c b/ccan/bytestring/test/run.c
index 2d86926..97fa8c5 100644
--- a/ccan/bytestring/test/run.c
+++ b/ccan/bytestring/test/run.c
@@ -12,7 +12,7 @@ int main(void)
struct bytestring bs, bs1, bs2, bs3, bs4, bs5;
/* This is how many tests you plan to run */
- plan_tests(16);
+ plan_tests(22);
bs = bytestring(str1, sizeof(str1) - 1);
ok1(bs.ptr == str1);
@@ -42,7 +42,14 @@ int main(void)
ok1(bytestring_byte(bs2, 4) == 'd');
ok1(bytestring_byte(bs2, 5) == 'e');
ok1(bytestring_byte(bs2, 6) == 'f');
-
+
+ ok1(bytestring_eq(bytestring_slice(bs, 0, 4), BYTESTRING("test")));
+ ok1(bytestring_eq(bytestring_slice(bs, 5, 8), BYTESTRING("str")));
+ ok1(bytestring_eq(bytestring_slice(bs2, 2, 5), BYTESTRING("c\0d")));
+ ok1(bytestring_eq(bytestring_slice(bs2, 0, -1U), bs2));
+ ok1(bytestring_eq(bytestring_slice(bs2, 10, 20), bytestring_NULL));
+ ok1(bytestring_eq(bytestring_slice(bs2, 2, 1), bytestring_NULL));
+
/* This exits depending on whether all tests passed */
return exit_status();
}
--
1.9.3
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