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-rw-r--r--include/common.h25
1 files changed, 25 insertions, 0 deletions
diff --git a/include/common.h b/include/common.h
index 32b5d23..2812f49 100644
--- a/include/common.h
+++ b/include/common.h
@@ -181,6 +181,31 @@ static inline int is_power_of_2(unsigned long long n)
return (n != 0 && ((n & (n - 1)) == 0));
}
+/* Check whether buffer is filled with character 'pattern' */
+static inline int buffer_check_pattern(unsigned char *buffer, size_t size,
+ unsigned char pattern)
+{
+ /* Invalid input */
+ if (!buffer || (size == 0))
+ return 0;
+
+ /* No match on first byte */
+ if (*buffer != pattern)
+ return 0;
+
+ /* First byte matched and buffer is 1 byte long, OK. */
+ if (size == 1)
+ return 1;
+
+ /*
+ * Check buffer longer than 1 byte. We already know that buffer[0]
+ * matches the pattern, so the test below only checks whether the
+ * buffer[0...size-2] == buffer[1...size-1] , which is a test for
+ * whether the buffer is filled with constant value.
+ */
+ return !memcmp(buffer, buffer + 1, size - 1);
+}
+
/**
* simple_strtoX - convert a hex/dec/oct string into a number
* @snum: buffer to convert