util: Don't output too many zeros from virBitmapToString

Truncate the output so that it is only as big as is needed to fit all
the bits, not all the units from the map.  This will be needed in the
future in order to properly format bitmaps for kernel's sysfs files.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>

src/qemu/qemu_capabilities.c

@@ -1510,7 +1510,7 @@ int virQEMUCapsParseHelpStr(const char *qemu,
                                    qemuCaps, check_yajl) < 0)
         goto cleanup;
 
-    strflags = virBitmapToString(qemuCaps->flags, true);
+    strflags = virBitmapToString(qemuCaps->flags, true, false);
     VIR_DEBUG("Version %u.%u.%u, cooked version %u, flags %s",
               major, minor, micro, *version, NULLSTR(strflags));
     VIR_FREE(strflags);
@@ -2377,7 +2377,7 @@ virQEMUCapsClear(virQEMUCapsPtr qemuCaps,
 
 char *virQEMUCapsFlagsString(virQEMUCapsPtr qemuCaps)
 {
-    return virBitmapToString(qemuCaps->flags, true);
+    return virBitmapToString(qemuCaps->flags, true, false);
 }
 
 

src/util/virbitmap.c

@@ -313,6 +313,7 @@ int virBitmapGetBit(virBitmapPtr bitmap, size_t b, bool *result)
  * virBitmapToString:
  * @bitmap: Pointer to bitmap
  * @prefix: Whether to prepend "0x"
+ * @trim: Whether to output only the minimum required characters
  *
  * Convert @bitmap to printable string.
  *
@@ -320,10 +321,14 @@ int virBitmapGetBit(virBitmapPtr bitmap, size_t b, bool *result)
  */
 char *
 virBitmapToString(virBitmapPtr bitmap,
-                  bool prefix)
+                  bool prefix,
+                  bool trim)
 {
     virBuffer buf = VIR_BUFFER_INITIALIZER;
     size_t sz;
+    size_t len;
+    size_t diff;
+    char *ret = NULL;
 
     if (prefix)
         virBufferAddLit(&buf, "0x");
@@ -337,7 +342,28 @@ virBitmapToString(virBitmapPtr bitmap,
     }
 
     virBufferCheckError(&buf);
-    return virBufferContentAndReset(&buf);
+    ret = virBufferContentAndReset(&buf);
+    if (!ret)
+        return NULL;
+
+    if (!trim)
+        return ret;
+
+    if (bitmap->max_bit != bitmap->map_len * VIR_BITMAP_BITS_PER_UNIT) {
+        char *tmp = ret;
+
+        if (prefix)
+            tmp += 2;
+
+        len = strlen(tmp);
+        sz = VIR_DIV_UP(bitmap->max_bit, 4);
+        diff = len - sz;
+
+        if (diff)
+            memmove(tmp, tmp + diff, sz + 1);
+    }
+
+    return ret;
 }
 
 /**

src/util/virbitmap.h

@@ -80,7 +80,7 @@ bool virBitmapIsBitSet(virBitmapPtr bitmap, size_t b)
 int virBitmapGetBit(virBitmapPtr bitmap, size_t b, bool *result)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(3) ATTRIBUTE_RETURN_CHECK;
 
-char *virBitmapToString(virBitmapPtr bitmap, bool prefix)
+char *virBitmapToString(virBitmapPtr bitmap, bool prefix, bool trim)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
 
 char *virBitmapFormat(virBitmapPtr bitmap);