util: introduce virBufferTrimLen

Just like the existing virBufferTrim, but only
does one thing at a time.
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NPeter Krempa <pkrempa@redhat.com>

src/libvirt_private.syms

@@ -1646,6 +1646,7 @@ virBufferStrcat;
 virBufferStrcatVArgs;
 virBufferTrim;
 virBufferTrimChars;
+virBufferTrimLen;
 virBufferURIEncodeString;
 virBufferUse;
 virBufferVasprintf;

src/util/virbuffer.c

@@ -700,6 +700,25 @@ virBufferTrimChars(virBufferPtr buf, const char *trim)
     g_string_truncate(buf->str, i + 1);
 }
 
+/**
+ * virBufferTrimLen:
+ * @buf: the buffer to trim
+ * @len: the number of bytes to trim
+ *
+ * Trim the tail of a buffer.
+ */
+void
+virBufferTrimLen(virBufferPtr buf, int len)
+{
+    if (!buf || !buf->str)
+        return;
+
+    if (len > buf->str->len)
+        return;
+
+    g_string_truncate(buf->str, buf->str->len - len);
+}
+
 /**
  * virBufferAddStr:
  * @buf: the buffer to append to

src/util/virbuffer.h

@@ -93,4 +93,5 @@ size_t virBufferGetEffectiveIndent(const virBuffer *buf);
 
 void virBufferTrim(virBufferPtr buf, const char *trim, int len);
 void virBufferTrimChars(virBufferPtr buf, const char *trim);
+void virBufferTrimLen(virBufferPtr buf, int len);
 void virBufferAddStr(virBufferPtr buf, const char *str);