Built motion from commit 6a09e18b.|2.6.11

[motion2.git] / legacy-libs / grpc / deps / grpc / src / core / lib / gprpp / string_view.h

diff --git a/legacy-libs/grpc/deps/grpc/src/core/lib/gprpp/string_view.h b/legacy-libs/grpc/deps/grpc/src/core/lib/gprpp/string_view.h
new file mode 100644 (file)
index 0000000..05a8106
--- /dev/null
+++ b/legacy-libs/grpc/deps/grpc/src/core/lib/gprpp/string_view.h
@@ -0,0 +1,143 @@
+/*
+ *
+ * Copyright 2019 gRPC authors.
+ *
+ * Licensed 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.
+ *
+ */
+#ifndef GRPC_CORE_LIB_GPRPP_STRING_VIEW_H
+#define GRPC_CORE_LIB_GPRPP_STRING_VIEW_H
+
+#include <grpc/support/port_platform.h>
+
+#include <grpc/impl/codegen/slice.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include <algorithm>
+#include <cstdint>
+#include <cstring>
+#include <limits>
+
+#include "src/core/lib/gpr/string.h"
+#include "src/core/lib/gpr/useful.h"
+#include "src/core/lib/gprpp/memory.h"
+
+namespace grpc_core {
+
+// Provides a light-weight view over a char array or a slice, similar but not
+// identical to absl::string_view.
+//
+// Any method that has the same name as absl::string_view MUST HAVE identical
+// semantics to what absl::string_view provides.
+//
+// Methods that are not part of absl::string_view API, must be clearly
+// annotated.
+//
+// StringView does not own the buffers that back the view. Callers must ensure
+// the buffer stays around while the StringView is accessible.
+//
+// Pass StringView by value in functions, since it is exactly two pointers in
+// size.
+//
+// The interface used here is not identical to absl::string_view. Notably, we
+// need to support slices while we cannot support std::string, and gpr string
+// style functions such as strdup() and cmp(). Once we switch to
+// absl::string_view this class will inherit from absl::string_view and add the
+// gRPC-specific APIs.
+class StringView final {
+ public:
+  static constexpr size_t npos = std::numeric_limits<size_t>::max();
+
+  constexpr StringView(const char* ptr, size_t size) : ptr_(ptr), size_(size) {}
+  constexpr StringView(const char* ptr)
+      : StringView(ptr, ptr == nullptr ? 0 : strlen(ptr)) {}
+  // Not part of absl::string_view API.
+  StringView(const grpc_slice& slice)
+      : StringView(reinterpret_cast<const char*>(GRPC_SLICE_START_PTR(slice)),
+                   GRPC_SLICE_LENGTH(slice)) {}
+  constexpr StringView() : StringView(nullptr, 0) {}
+
+  constexpr const char* data() const { return ptr_; }
+  constexpr size_t size() const { return size_; }
+  constexpr bool empty() const { return size_ == 0; }
+
+  StringView substr(size_t start, size_t size = npos) {
+    GPR_DEBUG_ASSERT(start + size <= size_);
+    return StringView(ptr_ + start, std::min(size, size_ - start));
+  }
+
+  constexpr const char& operator[](size_t i) const { return ptr_[i]; }
+
+  const char& front() const { return ptr_[0]; }
+  const char& back() const { return ptr_[size_ - 1]; }
+
+  void remove_prefix(size_t n) {
+    GPR_DEBUG_ASSERT(n <= size_);
+    ptr_ += n;
+    size_ -= n;
+  }
+
+  void remove_suffix(size_t n) {
+    GPR_DEBUG_ASSERT(n <= size_);
+    size_ -= n;
+  }
+
+  size_t find(char c, size_t pos = 0) const {
+    if (empty() || pos >= size_) return npos;
+    const char* result =
+        static_cast<const char*>(memchr(ptr_ + pos, c, size_ - pos));
+    return result != nullptr ? result - ptr_ : npos;
+  }
+
+  void clear() {
+    ptr_ = nullptr;
+    size_ = 0;
+  }
+
+  // Creates a dup of the string viewed by this class.
+  // Return value is null-terminated and never nullptr.
+  //
+  // Not part of absl::string_view API.
+  grpc_core::UniquePtr<char> dup() const {
+    char* str = static_cast<char*>(gpr_malloc(size_ + 1));
+    if (size_ > 0) memcpy(str, ptr_, size_);
+    str[size_] = '\0';
+    return grpc_core::UniquePtr<char>(str);
+  }
+
+  // Not part of absl::string_view API.
+  int cmp(StringView other) const {
+    const size_t len = GPR_MIN(size(), other.size());
+    const int ret = strncmp(data(), other.data(), len);
+    if (ret != 0) return ret;
+    if (size() == other.size()) return 0;
+    if (size() < other.size()) return -1;
+    return 1;
+  }
+
+ private:
+  const char* ptr_;
+  size_t size_;
+};
+
+inline bool operator==(StringView lhs, StringView rhs) {
+  return lhs.size() == rhs.size() &&
+         strncmp(lhs.data(), rhs.data(), lhs.size()) == 0;
+}
+
+inline bool operator!=(StringView lhs, StringView rhs) { return !(lhs == rhs); }
+
+}  // namespace grpc_core
+
+#endif /* GRPC_CORE_LIB_GPRPP_STRING_VIEW_H */