update source to Ceph Pacific 16.2.2

[ceph.git] / ceph / src / jaegertracing / thrift / lib / d / src / thrift / internal / ctfe.d

diff --git a/ceph/src/jaegertracing/thrift/lib/d/src/thrift/internal/ctfe.d b/ceph/src/jaegertracing/thrift/lib/d/src/thrift/internal/ctfe.d
new file mode 100644 (file)
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--- /dev/null
+++ b/ceph/src/jaegertracing/thrift/lib/d/src/thrift/internal/ctfe.d
@@ -0,0 +1,98 @@
+/*
+ * 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.
+ */
+
+module thrift.internal.ctfe;
+
+import std.conv : to;
+import std.traits;
+
+/*
+ * Simple eager join() for strings, std.algorithm.join isn't CTFEable yet.
+ */
+string ctfeJoin(string[] strings, string separator = ", ") {
+  string result;
+  if (strings.length > 0) {
+    result ~= strings[0];
+    foreach (s; strings[1..$]) {
+      result ~= separator ~ s;
+    }
+  }
+  return result;
+}
+
+/*
+ * A very primitive to!string() implementation for floating point numbers that
+ * is evaluatable at compile time.
+ *
+ * There is a wealth of problems associated with the algorithm used (e.g. 5.0
+ * prints as 4.999…, incorrect rounding, etc.), but a better alternative should
+ * be included with the D standard library instead of implementing it here.
+ */
+string ctfeToString(T)(T val) if (isFloatingPoint!T) {
+  if (val is T.nan) return "nan";
+  if (val is T.infinity) return "inf";
+  if (val is -T.infinity) return "-inf";
+  if (val is 0.0) return "0";
+  if (val is -0.0) return "-0";
+
+  auto b = val;
+
+  string result;
+  if (b < 0) {
+    result ~= '-';
+    b *= -1;
+  }
+
+  short magnitude;
+  while (b >= 10) {
+    ++magnitude;
+    b /= 10;
+  }
+  while (b < 1) {
+    --magnitude;
+    b *= 10;
+  }
+
+  foreach (i; 0 .. T.dig) {
+    if (i == 1) result ~= '.';
+
+    auto first = cast(ubyte)b;
+    result ~= to!string(first);
+
+    b -= first;
+    import std.math;
+    if (b < pow(10.0, i - T.dig)) break;
+    b *= 10;
+  }
+
+  if (magnitude != 0) result ~= "e" ~ to!string(magnitude);
+  return result;
+}
+
+unittest {
+  import std.algorithm;
+  static assert(ctfeToString(double.infinity) == "inf");
+  static assert(ctfeToString(-double.infinity) == "-inf");
+  static assert(ctfeToString(double.nan) == "nan");
+  static assert(ctfeToString(0.0) == "0");
+  static assert(ctfeToString(-0.0) == "-0");
+  static assert(ctfeToString(2.5) == "2.5");
+  static assert(ctfeToString(3.1415).startsWith("3.141"));
+  static assert(ctfeToString(2e-200) == "2e-200");
+}