Adding grpc::string_ref class.

- Strict subset of
  http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3442.html
- Useful to avoid unnecessary string copies.

1 files changed, 111 insertions, 0 deletions

diff --git a/src/cpp/util/string_ref.cc b/src/cpp/util/string_ref.cc
new file mode 100644
index 0000000000..7f91ca95b4
--- /dev/null
+++ b/src/cpp/util/string_ref.cc
@@ -0,0 +1,111 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc++/string_ref.h>
+
+#include <string.h>
+
+#include <algorithm>
+
+namespace grpc {
+
+constexpr size_t string_ref::npos;
+
+string_ref& string_ref::operator=(const string_ref& rhs) {
+  data_ = rhs.data_;
+  length_ = rhs.length_;
+  return *this;
+}
+
+string_ref::string_ref(const char* s) : data_(s), length_(strlen(s)) {}
+
+string_ref string_ref::substr(size_t pos, size_t n) const {
+  if (pos > length_) pos = length_;
+  if (n > (length_ - pos)) n = length_ - pos;
+  return string_ref(data_ + pos, n);
+}
+
+int string_ref::compare(string_ref x) const {
+  size_t min_size = length_ < x.length_ ? length_ : x.length_;
+  int r = memcmp(data_, x.data_, min_size);
+  if (r < 0) return -1;
+  if (r > 0) return 1;
+  if (length_ < x.length_) return -1;
+  if (length_ > x.length_) return 1;
+  return 0;
+}
+
+bool string_ref::starts_with(string_ref x) const {
+  return length_ >= x.length_ && (memcmp(data_, x.data_, x.length_) == 0);
+}
+
+bool string_ref::ends_with(string_ref x) const {
+  return length_ >= x.length_ &&
+         (memcmp(data_ + (length_ - x.length_), x.data_, x.length_) == 0);
+}
+
+size_t string_ref::find(string_ref s) const {
+  auto it = std::search(cbegin(), cend(), s.cbegin(), s.cend());
+  return it == cend() ? npos : std::distance(cbegin(), it);
+}
+
+size_t string_ref::find(char c) const {
+  auto it = std::find_if(cbegin(), cend(), [c](char cc) { return cc == c; });
+  return it == cend() ? npos : std::distance(cbegin(), it);
+}
+
+bool operator==(string_ref x, string_ref y) {
+  return x.compare(y) == 0;
+}
+
+bool operator!=(string_ref x, string_ref y) {
+  return x.compare(y) != 0;
+}
+
+bool operator<(string_ref x, string_ref y) {
+  return x.compare(y) < 0;
+}
+
+bool operator<=(string_ref x, string_ref y) {
+  return x.compare(y) <= 0;
+}
+
+bool operator>(string_ref x, string_ref y) {
+  return x.compare(y) > 0;
+}
+
+bool operator>=(string_ref x, string_ref y) {
+  return x.compare(y) >= 0;
+}
+
+}  // namespace grpc