1 files changed, 107 insertions, 0 deletions
diff --git a/subversion/libsvn_subr/encode.c b/subversion/libsvn_subr/encode.c
new file mode 100644
index 000000000000..503277cd9e2f
--- /dev/null
+++ b/subversion/libsvn_subr/encode.c
@@ -0,0 +1,107 @@
+/*
+ * encode.c:  various data encoding routines
+ *
+ * ====================================================================
+ *    Licensed to the Apache Software Foundation (ASF) under one
+ *    or more contributor license agreements.  See the NOTICE file
+ *    distributed with this work for additional information
+ *    regarding copyright ownership.  The ASF licenses this file
+ *    to you under the Apache License, Version 2.0 (the
+ *    "License"); you may not use this file except in compliance
+ *    with the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing,
+ *    software distributed under the License is distributed on an
+ *    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *    KIND, either express or implied.  See the License for the
+ *    specific language governing permissions and limitations
+ *    under the License.
+ * ====================================================================
+ */
+
+#include "private/svn_subr_private.h"
+
+#include "svn_private_config.h"
+
+unsigned char *
+svn__encode_uint(unsigned char *p, apr_uint64_t val)
+{
+  int n;
+  apr_uint64_t v;
+
+  /* Figure out how many bytes we'll need.  */
+  v = val >> 7;
+  n = 1;
+  while (v > 0)
+    {
+      v = v >> 7;
+      n++;
+    }
+
+  /* Encode the remaining bytes; n is always the number of bytes
+     coming after the one we're encoding.  */
+  while (--n >= 1)
+    *p++ = (unsigned char)(((val >> (n * 7)) | 0x80) & 0xff);
+
+  *p++ = (unsigned char)(val & 0x7f);
+
+  return p;
+}
+
+unsigned char *
+svn__encode_int(unsigned char *p, apr_int64_t val)
+{
+  apr_uint64_t value = val;
+  value = value & APR_UINT64_C(0x8000000000000000)
+        ? APR_UINT64_MAX - (2 * value)
+        : 2 * value;
+
+  return svn__encode_uint(p, value);
+}
+
+const unsigned char *
+svn__decode_uint(apr_uint64_t *val,
+                 const unsigned char *p,
+                 const unsigned char *end)
+{
+  apr_uint64_t temp = 0;
+
+  if (end - p > SVN__MAX_ENCODED_UINT_LEN)
+    end = p + SVN__MAX_ENCODED_UINT_LEN;
+
+  /* Decode bytes until we're done. */
+  while (SVN__PREDICT_TRUE(p < end))
+    {
+      unsigned int c = *p++;
+
+      if (c < 0x80)
+        {
+          *val = (temp << 7) | c;
+          return p;
+        }
+      else
+        {
+          temp = (temp << 7) | (c & 0x7f);
+        }
+    }
+
+  return NULL;
+}
+
+const unsigned char *
+svn__decode_int(apr_int64_t *val,
+                const unsigned char *p,
+                const unsigned char *end)
+{
+  apr_uint64_t value;
+  const unsigned char *result = svn__decode_uint(&value, p, end);
+
+  value = value & 1
+        ? (APR_UINT64_MAX - value / 2)
+        : value / 2;
+  *val = (apr_int64_t)value;
+
+  return result;
+}