X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=lib%2Frand.c;h=a79fb9c17c321a94e8e4bcfe030193003c80d93f;hb=52c0cea392321740cba72f65b9cf5d2102658edf;hp=7c6fed1fabbcc01f1803f00521d881a9c9662603;hpb=3545a109a2cfe5ab22969ef453dc049db47f0b68;p=fio.git

diff --git a/lib/rand.c b/lib/rand.c
index 7c6fed1f..a79fb9c1 100644
--- a/lib/rand.c
+++ b/lib/rand.c
@@ -33,6 +33,7 @@
 
 */
 
+#include <string.h>
 #include "rand.h"
 #include "../hash.h"
 
@@ -88,3 +89,45 @@ unsigned long fill_random_buf(struct frand_state *fs, void *buf,
 	__fill_random_buf(buf, len, r);
 	return r;
 }
+
+unsigned long fill_random_buf_percentage(struct frand_state *fs, void *buf,
+					 unsigned int percentage,
+					 unsigned int segment, unsigned int len)
+{
+	unsigned long r = __rand(fs);
+	unsigned int this_len;
+
+	if (percentage == 100) {
+		memset(buf, 0, len);
+		return 0;
+	}
+
+	if (segment > len)
+		segment = len;
+
+	if (sizeof(int) != sizeof(long *))
+		r *= (unsigned long) __rand(fs);
+
+	while (len) {
+		/*
+		 * Fill random chunk
+		 */
+		this_len = (segment * (100 - percentage)) / 100;
+		if (this_len > len)
+			this_len = len;
+
+		__fill_random_buf(buf, this_len, r);
+
+		len -= this_len;
+		buf += this_len;
+
+		if (this_len > len)
+			this_len = len;
+
+		memset(buf, 0, this_len);
+		len -= this_len;
+		buf += this_len;
+	}
+
+	return r;
+}