[libvirt] [PATCH 08/11] util: Add util to pad string

[Osier Yang]

The string can be padded either on the left (@from_right=false) or right
(@from_right=true).
---
 src/libvirt_private.syms |  1 +
 src/util/virstring.c     | 38 ++++++++++++++++++++++++++++++++++++++
 src/util/virstring.h     |  6 ++++++
 tests/utiltest.c         | 28 ++++++++++++++++++++++++++++
 4 files changed, 73 insertions(+)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index ce39cc6..27fb0b5 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1822,6 +1822,7 @@ virStringArrayHasString;
 virStringFreeList;
 virStringJoin;
 virStringListLength;
+virStringPad;
 virStringSplit;
 virStrncpy;
 virStrndup;
diff --git a/src/util/virstring.c b/src/util/virstring.c
index 1937f82..498daab 100644
--- a/src/util/virstring.c
+++ b/src/util/virstring.c
@@ -608,3 +608,41 @@ size_t virStringListLength(char **strings)
 
     return i;
 }
+
+char *
+virStringPad(const char *src,
+             char padchar,
+             unsigned int length,
+             bool from_right)
+{
+    virBuffer buf = VIR_BUFFER_INITIALIZER;
+    int len;
+    int i;
+
+    len = strlen(src);
+
+    if (len > length)
+        return NULL;
+
+    if (!from_right) {
+        for (i = 0; i < length - len; i++) {
+            virBufferAsprintf(&buf, "%c", padchar);
+        }
+
+        virBufferAsprintf(&buf, "%s", src);
+    } else {
+        virBufferAsprintf(&buf, "%s", src);
+
+        for (i = 0; i < length - len; i++) {
+            virBufferAsprintf(&buf, "%c", padchar);
+        }
+    }
+
+    if (virBufferError(&buf)) {
+        virBufferFreeAndReset(&buf);
+        virReportOOMError();
+        return NULL;
+    }
+
+    return virBufferContentAndReset(&buf);
+}
diff --git a/src/util/virstring.h b/src/util/virstring.h
index 34ffae1..5809167 100644
--- a/src/util/virstring.h
+++ b/src/util/virstring.h
@@ -166,4 +166,10 @@ int virStrndup(char **dest, const char *src, ssize_t n, bool report, int domcode
 
 size_t virStringListLength(char **strings);
 
+char *virStringPad(const char *src,
+                   char padchar,
+                   unsigned int length,
+                   bool from_right)
+    ATTRIBUTE_NONNULL(1);
+
 #endif /* __VIR_STRING_H__ */
diff --git a/tests/utiltest.c b/tests/utiltest.c
index 41fdd7e..d567ecc 100644
--- a/tests/utiltest.c
+++ b/tests/utiltest.c
@@ -226,6 +226,33 @@ cleanup:
 }
 
 static int
+testStringPad(const void *data ATTRIBUTE_UNUSED)
+{
+    const char *str = "1ff2";
+    char *lpadstr = NULL;
+    char *rpadstr = NULL;
+    int ret = -1;
+
+    if (!(lpadstr = virStringPad(str, '0', 7, false)))
+        return -1;
+
+    if (STRNEQ(lpadstr, "0001ff2"))
+        goto cleanup;
+
+    if (!(rpadstr = virStringPad(str, '0', 7, true)))
+        goto cleanup;
+
+    if (STRNEQ(rpadstr, "1ff2000"))
+        goto cleanup;
+
+    ret = 0;
+cleanup:
+    VIR_FREE(lpadstr);
+    VIR_FREE(rpadstr);
+    return ret;
+}
+
+static int
 mymain(void)
 {
     int result = 0;
@@ -251,6 +278,7 @@ mymain(void)
     DO_TEST(ParseVersionString);
     DO_TEST(FindPCIDeviceByVPD);
     DO_TEST(ParseStableScsiHostAddress);
+    DO_TEST(StringPad);
 
 cleanup:
     VIR_FREE(test_sysfs);
-- 
1.8.1.4