Coverage Report

Created: 2024-09-23 06:29

/src/abseil-cpp/absl/strings/cord.h
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// Copyright 2020 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//      https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// -----------------------------------------------------------------------------
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// File: cord.h
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// -----------------------------------------------------------------------------
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//
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// This file defines the `absl::Cord` data structure and operations on that data
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// structure. A Cord is a string-like sequence of characters optimized for
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// specific use cases. Unlike a `std::string`, which stores an array of
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// contiguous characters, Cord data is stored in a structure consisting of
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// separate, reference-counted "chunks."
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//
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// Because a Cord consists of these chunks, data can be added to or removed from
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// a Cord during its lifetime. Chunks may also be shared between Cords. Unlike a
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// `std::string`, a Cord can therefore accommodate data that changes over its
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// lifetime, though it's not quite "mutable"; it can change only in the
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// attachment, detachment, or rearrangement of chunks of its constituent data.
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//
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// A Cord provides some benefit over `std::string` under the following (albeit
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// narrow) circumstances:
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//
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//   * Cord data is designed to grow and shrink over a Cord's lifetime. Cord
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//     provides efficient insertions and deletions at the start and end of the
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//     character sequences, avoiding copies in those cases. Static data should
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//     generally be stored as strings.
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//   * External memory consisting of string-like data can be directly added to
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//     a Cord without requiring copies or allocations.
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//   * Cord data may be shared and copied cheaply. Cord provides a copy-on-write
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//     implementation and cheap sub-Cord operations. Copying a Cord is an O(1)
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//     operation.
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//
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// As a consequence to the above, Cord data is generally large. Small data
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// should generally use strings, as construction of a Cord requires some
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// overhead. Small Cords (<= 15 bytes) are represented inline, but most small
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// Cords are expected to grow over their lifetimes.
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//
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// Note that because a Cord is made up of separate chunked data, random access
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// to character data within a Cord is slower than within a `std::string`.
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//
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// Thread Safety
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//
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// Cord has the same thread-safety properties as many other types like
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// std::string, std::vector<>, int, etc -- it is thread-compatible. In
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// particular, if threads do not call non-const methods, then it is safe to call
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// const methods without synchronization. Copying a Cord produces a new instance
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// that can be used concurrently with the original in arbitrary ways.
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#ifndef ABSL_STRINGS_CORD_H_
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#define ABSL_STRINGS_CORD_H_
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#include <algorithm>
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#include <cstddef>
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#include <cstdint>
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#include <cstring>
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#include <iosfwd>
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#include <iterator>
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#include <string>
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#include <type_traits>
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#include "absl/base/attributes.h"
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#include "absl/base/config.h"
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#include "absl/base/internal/endian.h"
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#include "absl/base/internal/per_thread_tls.h"
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#include "absl/base/macros.h"
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#include "absl/base/nullability.h"
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#include "absl/base/optimization.h"
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#include "absl/base/port.h"
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#include "absl/container/inlined_vector.h"
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#include "absl/crc/internal/crc_cord_state.h"
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#include "absl/functional/function_ref.h"
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#include "absl/meta/type_traits.h"
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#include "absl/strings/cord_analysis.h"
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#include "absl/strings/cord_buffer.h"
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#include "absl/strings/internal/cord_data_edge.h"
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#include "absl/strings/internal/cord_internal.h"
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#include "absl/strings/internal/cord_rep_btree.h"
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#include "absl/strings/internal/cord_rep_btree_reader.h"
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#include "absl/strings/internal/cord_rep_crc.h"
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#include "absl/strings/internal/cordz_functions.h"
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#include "absl/strings/internal/cordz_info.h"
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#include "absl/strings/internal/cordz_statistics.h"
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#include "absl/strings/internal/cordz_update_scope.h"
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#include "absl/strings/internal/cordz_update_tracker.h"
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#include "absl/strings/internal/resize_uninitialized.h"
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#include "absl/strings/internal/string_constant.h"
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#include "absl/strings/string_view.h"
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#include "absl/types/compare.h"
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#include "absl/types/optional.h"
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namespace absl {
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ABSL_NAMESPACE_BEGIN
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class Cord;
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class CordTestPeer;
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template <typename Releaser>
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Cord MakeCordFromExternal(absl::string_view, Releaser&&);
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void CopyCordToString(const Cord& src, absl::Nonnull<std::string*> dst);
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void AppendCordToString(const Cord& src, absl::Nonnull<std::string*> dst);
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// Cord memory accounting modes
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enum class CordMemoryAccounting {
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  // Counts the *approximate* number of bytes held in full or in part by this
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  // Cord (which may not remain the same between invocations). Cords that share
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  // memory could each be "charged" independently for the same shared memory.
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  // See also comment on `kTotalMorePrecise` on internally shared memory.
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  kTotal,
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  // Counts the *approximate* number of bytes held in full or in part by this
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  // Cord for the distinct memory held by this cord. This option is similar
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  // to `kTotal`, except that if the cord has multiple references to the same
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  // memory, that memory is only counted once.
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  //
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  // For example:
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  //   absl::Cord cord;
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  //   cord.Append(some_other_cord);
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  //   cord.Append(some_other_cord);
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  //   // Counts `some_other_cord` twice:
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  //   cord.EstimatedMemoryUsage(kTotal);
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  //   // Counts `some_other_cord` once:
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  //   cord.EstimatedMemoryUsage(kTotalMorePrecise);
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  //
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  // The `kTotalMorePrecise` number is more expensive to compute as it requires
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  // deduplicating all memory references. Applications should prefer to use
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  // `kFairShare` or `kTotal` unless they really need a more precise estimate
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  // on "how much memory is potentially held / kept alive by this cord?"
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  kTotalMorePrecise,
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  // Counts the *approximate* number of bytes held in full or in part by this
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  // Cord weighted by the sharing ratio of that data. For example, if some data
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  // edge is shared by 4 different Cords, then each cord is attributed 1/4th of
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  // the total memory usage as a 'fair share' of the total memory usage.
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  kFairShare,
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};
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// Cord
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//
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// A Cord is a sequence of characters, designed to be more efficient than a
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// `std::string` in certain circumstances: namely, large string data that needs
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// to change over its lifetime or shared, especially when such data is shared
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// across API boundaries.
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//
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// A Cord stores its character data in a structure that allows efficient prepend
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// and append operations. This makes a Cord useful for large string data sent
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// over in a wire format that may need to be prepended or appended at some point
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// during the data exchange (e.g. HTTP, protocol buffers). For example, a
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// Cord is useful for storing an HTTP request, and prepending an HTTP header to
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// such a request.
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//
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// Cords should not be used for storing general string data, however. They
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// require overhead to construct and are slower than strings for random access.
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//
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// The Cord API provides the following common API operations:
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//
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// * Create or assign Cords out of existing string data, memory, or other Cords
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// * Append and prepend data to an existing Cord
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// * Create new Sub-Cords from existing Cord data
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// * Swap Cord data and compare Cord equality
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// * Write out Cord data by constructing a `std::string`
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//
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// Additionally, the API provides iterator utilities to iterate through Cord
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// data via chunks or character bytes.
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//
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class Cord {
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 private:
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  template <typename T>
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  using EnableIfString =
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      absl::enable_if_t<std::is_same<T, std::string>::value, int>;
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 public:
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  // Cord::Cord() Constructors.
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  // Creates an empty Cord.
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  constexpr Cord() noexcept;
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  // Creates a Cord from an existing Cord. Cord is copyable and efficiently
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  // movable. The moved-from state is valid but unspecified.
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  Cord(const Cord& src);
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  Cord(Cord&& src) noexcept;
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  Cord& operator=(const Cord& x);
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  Cord& operator=(Cord&& x) noexcept;
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  // Creates a Cord from a `src` string. This constructor is marked explicit to
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  // prevent implicit Cord constructions from arguments convertible to an
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  // `absl::string_view`.
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  explicit Cord(absl::string_view src);
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  Cord& operator=(absl::string_view src);
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  // Creates a Cord from a `std::string&&` rvalue. These constructors are
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  // templated to avoid ambiguities for types that are convertible to both
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  // `absl::string_view` and `std::string`, such as `const char*`.
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  template <typename T, EnableIfString<T> = 0>
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  explicit Cord(T&& src);
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  template <typename T, EnableIfString<T> = 0>
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  Cord& operator=(T&& src);
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  // Cord::~Cord()
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  //
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  // Destructs the Cord.
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0
  ~Cord() {
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0
    if (contents_.is_tree()) DestroyCordSlow();
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0
  }
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  // MakeCordFromExternal()
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  //
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  // Creates a Cord that takes ownership of external string memory. The
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  // contents of `data` are not copied to the Cord; instead, the external
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  // memory is added to the Cord and reference-counted. This data may not be
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  // changed for the life of the Cord, though it may be prepended or appended
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  // to.
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  //
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  // `MakeCordFromExternal()` takes a callable "releaser" that is invoked when
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  // the reference count for `data` reaches zero. As noted above, this data must
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  // remain live until the releaser is invoked. The callable releaser also must:
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  //
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  //   * be move constructible
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  //   * support `void operator()(absl::string_view) const` or `void operator()`
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  //
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  // Example:
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  //
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  // Cord MakeCord(BlockPool* pool) {
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  //   Block* block = pool->NewBlock();
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  //   FillBlock(block);
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  //   return absl::MakeCordFromExternal(
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  //       block->ToStringView(),
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  //       [pool, block](absl::string_view v) {
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  //         pool->FreeBlock(block, v);
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  //       });
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  // }
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  //
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  // WARNING: Because a Cord can be reference-counted, it's likely a bug if your
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  // releaser doesn't do anything. For example, consider the following:
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  //
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  // void Foo(const char* buffer, int len) {
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  //   auto c = absl::MakeCordFromExternal(absl::string_view(buffer, len),
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  //                                       [](absl::string_view) {});
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  //
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  //   // BUG: If Bar() copies its cord for any reason, including keeping a
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  //   // substring of it, the lifetime of buffer might be extended beyond
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  //   // when Foo() returns.
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  //   Bar(c);
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  // }
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  template <typename Releaser>
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  friend Cord MakeCordFromExternal(absl::string_view data, Releaser&& releaser);
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  // Cord::Clear()
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  //
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  // Releases the Cord data. Any nodes that share data with other Cords, if
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  // applicable, will have their reference counts reduced by 1.
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  ABSL_ATTRIBUTE_REINITIALIZES void Clear();
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  // Cord::Append()
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  //
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  // Appends data to the Cord, which may come from another Cord or other string
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  // data.
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  void Append(const Cord& src);
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  void Append(Cord&& src);
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  void Append(absl::string_view src);
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  template <typename T, EnableIfString<T> = 0>
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  void Append(T&& src);
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  // Appends `buffer` to this cord, unless `buffer` has a zero length in which
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  // case this method has no effect on this cord instance.
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  // This method is guaranteed to consume `buffer`.
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  void Append(CordBuffer buffer);
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  // Returns a CordBuffer, re-using potential existing capacity in this cord.
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  //
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  // Cord instances may have additional unused capacity in the last (or first)
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  // nodes of the underlying tree to facilitate amortized growth. This method
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  // allows applications to explicitly use this spare capacity if available,
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  // or create a new CordBuffer instance otherwise.
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  // If this cord has a final non-shared node with at least `min_capacity`
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  // available, then this method will return that buffer including its data
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  // contents. I.e.; the returned buffer will have a non-zero length, and
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  // a capacity of at least `buffer.length + min_capacity`. Otherwise, this
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  // method will return `CordBuffer::CreateWithDefaultLimit(capacity)`.
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  //
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  // Below an example of using GetAppendBuffer. Notice that in this example we
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  // use `GetAppendBuffer()` only on the first iteration. As we know nothing
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  // about any initial extra capacity in `cord`, we may be able to use the extra
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  // capacity. But as we add new buffers with fully utilized contents after that
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  // we avoid calling `GetAppendBuffer()` on subsequent iterations: while this
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  // works fine, it results in an unnecessary inspection of cord contents:
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  //
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  //   void AppendRandomDataToCord(absl::Cord &cord, size_t n) {
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  //     bool first = true;
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  //     while (n > 0) {
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  //       CordBuffer buffer = first ? cord.GetAppendBuffer(n)
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  //                                 : CordBuffer::CreateWithDefaultLimit(n);
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  //       absl::Span<char> data = buffer.available_up_to(n);
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  //       FillRandomValues(data.data(), data.size());
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  //       buffer.IncreaseLengthBy(data.size());
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  //       cord.Append(std::move(buffer));
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  //       n -= data.size();
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  //       first = false;
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  //     }
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  //   }
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  CordBuffer GetAppendBuffer(size_t capacity, size_t min_capacity = 16);
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  // Returns a CordBuffer, re-using potential existing capacity in this cord.
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  //
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  // This function is identical to `GetAppendBuffer`, except that in the case
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  // where a new `CordBuffer` is allocated, it is allocated using the provided
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  // custom limit instead of the default limit. `GetAppendBuffer` will default
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  // to `CordBuffer::CreateWithDefaultLimit(capacity)` whereas this method
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  // will default to `CordBuffer::CreateWithCustomLimit(block_size, capacity)`.
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  // This method is equivalent to `GetAppendBuffer` if `block_size` is zero.
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  // See the documentation for `CreateWithCustomLimit` for more details on the
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  // restrictions and legal values for `block_size`.
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  CordBuffer GetCustomAppendBuffer(size_t block_size, size_t capacity,
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                                   size_t min_capacity = 16);
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  // Cord::Prepend()
325
  //
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  // Prepends data to the Cord, which may come from another Cord or other string
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  // data.
328
  void Prepend(const Cord& src);
329
  void Prepend(absl::string_view src);
330
  template <typename T, EnableIfString<T> = 0>
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  void Prepend(T&& src);
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  // Prepends `buffer` to this cord, unless `buffer` has a zero length in which
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  // case this method has no effect on this cord instance.
335
  // This method is guaranteed to consume `buffer`.
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  void Prepend(CordBuffer buffer);
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  // Cord::RemovePrefix()
339
  //
340
  // Removes the first `n` bytes of a Cord.
341
  void RemovePrefix(size_t n);
342
  void RemoveSuffix(size_t n);
343
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  // Cord::Subcord()
345
  //
346
  // Returns a new Cord representing the subrange [pos, pos + new_size) of
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  // *this. If pos >= size(), the result is empty(). If
348
  // (pos + new_size) >= size(), the result is the subrange [pos, size()).
349
  Cord Subcord(size_t pos, size_t new_size) const;
350
351
  // Cord::swap()
352
  //
353
  // Swaps the contents of the Cord with `other`.
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  void swap(Cord& other) noexcept;
355
356
  // swap()
357
  //
358
  // Swaps the contents of two Cords.
359
0
  friend void swap(Cord& x, Cord& y) noexcept { x.swap(y); }
360
361
  // Cord::size()
362
  //
363
  // Returns the size of the Cord.
364
  size_t size() const;
365
366
  // Cord::empty()
367
  //
368
  // Determines whether the given Cord is empty, returning `true` if so.
369
  bool empty() const;
370
371
  // Cord::EstimatedMemoryUsage()
372
  //
373
  // Returns the *approximate* number of bytes held by this cord.
374
  // See CordMemoryAccounting for more information on the accounting method.
375
  size_t EstimatedMemoryUsage(CordMemoryAccounting accounting_method =
376
                                  CordMemoryAccounting::kTotal) const;
377
378
  // Cord::Compare()
379
  //
380
  // Compares 'this' Cord with rhs. This function and its relatives treat Cords
381
  // as sequences of unsigned bytes. The comparison is a straightforward
382
  // lexicographic comparison. `Cord::Compare()` returns values as follows:
383
  //
384
  //   -1  'this' Cord is smaller
385
  //    0  two Cords are equal
386
  //    1  'this' Cord is larger
387
  int Compare(absl::string_view rhs) const;
388
  int Compare(const Cord& rhs) const;
389
390
  // Cord::StartsWith()
391
  //
392
  // Determines whether the Cord starts with the passed string data `rhs`.
393
  bool StartsWith(const Cord& rhs) const;
394
  bool StartsWith(absl::string_view rhs) const;
395
396
  // Cord::EndsWith()
397
  //
398
  // Determines whether the Cord ends with the passed string data `rhs`.
399
  bool EndsWith(absl::string_view rhs) const;
400
  bool EndsWith(const Cord& rhs) const;
401
402
  // Cord::Contains()
403
  //
404
  // Determines whether the Cord contains the passed string data `rhs`.
405
  bool Contains(absl::string_view rhs) const;
406
  bool Contains(const Cord& rhs) const;
407
408
  // Cord::operator std::string()
409
  //
410
  // Converts a Cord into a `std::string()`. This operator is marked explicit to
411
  // prevent unintended Cord usage in functions that take a string.
412
  explicit operator std::string() const;
413
414
  // CopyCordToString()
415
  //
416
  // Copies the contents of a `src` Cord into a `*dst` string.
417
  //
418
  // This function optimizes the case of reusing the destination string since it
419
  // can reuse previously allocated capacity. However, this function does not
420
  // guarantee that pointers previously returned by `dst->data()` remain valid
421
  // even if `*dst` had enough capacity to hold `src`. If `*dst` is a new
422
  // object, prefer to simply use the conversion operator to `std::string`.
423
  friend void CopyCordToString(const Cord& src,
424
                               absl::Nonnull<std::string*> dst);
425
426
  // AppendCordToString()
427
  //
428
  // Appends the contents of a `src` Cord to a `*dst` string.
429
  //
430
  // This function optimizes the case of appending to a non-empty destination
431
  // string. If `*dst` already has capacity to store the contents of the cord,
432
  // this function does not invalidate pointers previously returned by
433
  // `dst->data()`. If `*dst` is a new object, prefer to simply use the
434
  // conversion operator to `std::string`.
435
  friend void AppendCordToString(const Cord& src,
436
                                 absl::Nonnull<std::string*> dst);
437
438
  class CharIterator;
439
440
  //----------------------------------------------------------------------------
441
  // Cord::ChunkIterator
442
  //----------------------------------------------------------------------------
443
  //
444
  // A `Cord::ChunkIterator` allows iteration over the constituent chunks of its
445
  // Cord. Such iteration allows you to perform non-const operations on the data
446
  // of a Cord without modifying it.
447
  //
448
  // Generally, you do not instantiate a `Cord::ChunkIterator` directly;
449
  // instead, you create one implicitly through use of the `Cord::Chunks()`
450
  // member function.
451
  //
452
  // The `Cord::ChunkIterator` has the following properties:
453
  //
454
  //   * The iterator is invalidated after any non-const operation on the
455
  //     Cord object over which it iterates.
456
  //   * The `string_view` returned by dereferencing a valid, non-`end()`
457
  //     iterator is guaranteed to be non-empty.
458
  //   * Two `ChunkIterator` objects can be compared equal if and only if they
459
  //     remain valid and iterate over the same Cord.
460
  //   * The iterator in this case is a proxy iterator; the `string_view`
461
  //     returned by the iterator does not live inside the Cord, and its
462
  //     lifetime is limited to the lifetime of the iterator itself. To help
463
  //     prevent lifetime issues, `ChunkIterator::reference` is not a true
464
  //     reference type and is equivalent to `value_type`.
465
  //   * The iterator keeps state that can grow for Cords that contain many
466
  //     nodes and are imbalanced due to sharing. Prefer to pass this type by
467
  //     const reference instead of by value.
468
  class ChunkIterator {
469
   public:
470
    using iterator_category = std::input_iterator_tag;
471
    using value_type = absl::string_view;
472
    using difference_type = ptrdiff_t;
473
    using pointer = absl::Nonnull<const value_type*>;
474
    using reference = value_type;
475
476
    ChunkIterator() = default;
477
478
    ChunkIterator& operator++();
479
    ChunkIterator operator++(int);
480
    bool operator==(const ChunkIterator& other) const;
481
    bool operator!=(const ChunkIterator& other) const;
482
    reference operator*() const;
483
    pointer operator->() const;
484
485
    friend class Cord;
486
    friend class CharIterator;
487
488
   private:
489
    using CordRep = absl::cord_internal::CordRep;
490
    using CordRepBtree = absl::cord_internal::CordRepBtree;
491
    using CordRepBtreeReader = absl::cord_internal::CordRepBtreeReader;
492
493
    // Constructs a `begin()` iterator from `tree`.
494
    explicit ChunkIterator(absl::Nonnull<cord_internal::CordRep*> tree);
495
496
    // Constructs a `begin()` iterator from `cord`.
497
    explicit ChunkIterator(absl::Nonnull<const Cord*> cord);
498
499
    // Initializes this instance from a tree. Invoked by constructors.
500
    void InitTree(absl::Nonnull<cord_internal::CordRep*> tree);
501
502
    // Removes `n` bytes from `current_chunk_`. Expects `n` to be smaller than
503
    // `current_chunk_.size()`.
504
    void RemoveChunkPrefix(size_t n);
505
    Cord AdvanceAndReadBytes(size_t n);
506
    void AdvanceBytes(size_t n);
507
508
    // Btree specific operator++
509
    ChunkIterator& AdvanceBtree();
510
    void AdvanceBytesBtree(size_t n);
511
512
    // A view into bytes of the current `CordRep`. It may only be a view to a
513
    // suffix of bytes if this is being used by `CharIterator`.
514
    absl::string_view current_chunk_;
515
    // The current leaf, or `nullptr` if the iterator points to short data.
516
    // If the current chunk is a substring node, current_leaf_ points to the
517
    // underlying flat or external node.
518
    absl::Nullable<absl::cord_internal::CordRep*> current_leaf_ = nullptr;
519
    // The number of bytes left in the `Cord` over which we are iterating.
520
    size_t bytes_remaining_ = 0;
521
522
    // Cord reader for cord btrees. Empty if not traversing a btree.
523
    CordRepBtreeReader btree_reader_;
524
  };
525
526
  // Cord::chunk_begin()
527
  //
528
  // Returns an iterator to the first chunk of the `Cord`.
529
  //
530
  // Generally, prefer using `Cord::Chunks()` within a range-based for loop for
531
  // iterating over the chunks of a Cord. This method may be useful for getting
532
  // a `ChunkIterator` where range-based for-loops are not useful.
533
  //
534
  // Example:
535
  //
536
  //   absl::Cord::ChunkIterator FindAsChunk(const absl::Cord& c,
537
  //                                         absl::string_view s) {
538
  //     return std::find(c.chunk_begin(), c.chunk_end(), s);
539
  //   }
540
  ChunkIterator chunk_begin() const ABSL_ATTRIBUTE_LIFETIME_BOUND;
541
542
  // Cord::chunk_end()
543
  //
544
  // Returns an iterator one increment past the last chunk of the `Cord`.
545
  //
546
  // Generally, prefer using `Cord::Chunks()` within a range-based for loop for
547
  // iterating over the chunks of a Cord. This method may be useful for getting
548
  // a `ChunkIterator` where range-based for-loops may not be available.
549
  ChunkIterator chunk_end() const ABSL_ATTRIBUTE_LIFETIME_BOUND;
550
551
  //----------------------------------------------------------------------------
552
  // Cord::ChunkRange
553
  //----------------------------------------------------------------------------
554
  //
555
  // `ChunkRange` is a helper class for iterating over the chunks of the `Cord`,
556
  // producing an iterator which can be used within a range-based for loop.
557
  // Construction of a `ChunkRange` will return an iterator pointing to the
558
  // first chunk of the Cord. Generally, do not construct a `ChunkRange`
559
  // directly; instead, prefer to use the `Cord::Chunks()` method.
560
  //
561
  // Implementation note: `ChunkRange` is simply a convenience wrapper over
562
  // `Cord::chunk_begin()` and `Cord::chunk_end()`.
563
  class ChunkRange {
564
   public:
565
    // Fulfill minimum c++ container requirements [container.requirements]
566
    // These (partial) container type definitions allow ChunkRange to be used
567
    // in various utilities expecting a subset of [container.requirements].
568
    // For example, the below enables using `::testing::ElementsAre(...)`
569
    using value_type = absl::string_view;
570
    using reference = value_type&;
571
    using const_reference = const value_type&;
572
    using iterator = ChunkIterator;
573
    using const_iterator = ChunkIterator;
574
575
0
    explicit ChunkRange(absl::Nonnull<const Cord*> cord) : cord_(cord) {}
576
577
    ChunkIterator begin() const;
578
    ChunkIterator end() const;
579
580
   private:
581
    absl::Nonnull<const Cord*> cord_;
582
  };
583
584
  // Cord::Chunks()
585
  //
586
  // Returns a `Cord::ChunkRange` for iterating over the chunks of a `Cord` with
587
  // a range-based for-loop. For most iteration tasks on a Cord, use
588
  // `Cord::Chunks()` to retrieve this iterator.
589
  //
590
  // Example:
591
  //
592
  //   void ProcessChunks(const Cord& cord) {
593
  //     for (absl::string_view chunk : cord.Chunks()) { ... }
594
  //   }
595
  //
596
  // Note that the ordinary caveats of temporary lifetime extension apply:
597
  //
598
  //   void Process() {
599
  //     for (absl::string_view chunk : CordFactory().Chunks()) {
600
  //       // The temporary Cord returned by CordFactory has been destroyed!
601
  //     }
602
  //   }
603
  ChunkRange Chunks() const ABSL_ATTRIBUTE_LIFETIME_BOUND;
604
605
  //----------------------------------------------------------------------------
606
  // Cord::CharIterator
607
  //----------------------------------------------------------------------------
608
  //
609
  // A `Cord::CharIterator` allows iteration over the constituent characters of
610
  // a `Cord`.
611
  //
612
  // Generally, you do not instantiate a `Cord::CharIterator` directly; instead,
613
  // you create one implicitly through use of the `Cord::Chars()` member
614
  // function.
615
  //
616
  // A `Cord::CharIterator` has the following properties:
617
  //
618
  //   * The iterator is invalidated after any non-const operation on the
619
  //     Cord object over which it iterates.
620
  //   * Two `CharIterator` objects can be compared equal if and only if they
621
  //     remain valid and iterate over the same Cord.
622
  //   * The iterator keeps state that can grow for Cords that contain many
623
  //     nodes and are imbalanced due to sharing. Prefer to pass this type by
624
  //     const reference instead of by value.
625
  //   * This type cannot act as a forward iterator because a `Cord` can reuse
626
  //     sections of memory. This fact violates the requirement for forward
627
  //     iterators to compare equal if dereferencing them returns the same
628
  //     object.
629
  class CharIterator {
630
   public:
631
    using iterator_category = std::input_iterator_tag;
632
    using value_type = char;
633
    using difference_type = ptrdiff_t;
634
    using pointer = absl::Nonnull<const char*>;
635
    using reference = const char&;
636
637
    CharIterator() = default;
638
639
    CharIterator& operator++();
640
    CharIterator operator++(int);
641
    bool operator==(const CharIterator& other) const;
642
    bool operator!=(const CharIterator& other) const;
643
    reference operator*() const;
644
645
    friend Cord;
646
647
   private:
648
    explicit CharIterator(absl::Nonnull<const Cord*> cord)
649
0
        : chunk_iterator_(cord) {}
650
651
    ChunkIterator chunk_iterator_;
652
  };
653
654
  // Cord::AdvanceAndRead()
655
  //
656
  // Advances the `Cord::CharIterator` by `n_bytes` and returns the bytes
657
  // advanced as a separate `Cord`. `n_bytes` must be less than or equal to the
658
  // number of bytes within the Cord; otherwise, behavior is undefined. It is
659
  // valid to pass `char_end()` and `0`.
660
  static Cord AdvanceAndRead(absl::Nonnull<CharIterator*> it, size_t n_bytes);
661
662
  // Cord::Advance()
663
  //
664
  // Advances the `Cord::CharIterator` by `n_bytes`. `n_bytes` must be less than
665
  // or equal to the number of bytes remaining within the Cord; otherwise,
666
  // behavior is undefined. It is valid to pass `char_end()` and `0`.
667
  static void Advance(absl::Nonnull<CharIterator*> it, size_t n_bytes);
668
669
  // Cord::ChunkRemaining()
670
  //
671
  // Returns the longest contiguous view starting at the iterator's position.
672
  //
673
  // `it` must be dereferenceable.
674
  static absl::string_view ChunkRemaining(const CharIterator& it);
675
676
  // Cord::char_begin()
677
  //
678
  // Returns an iterator to the first character of the `Cord`.
679
  //
680
  // Generally, prefer using `Cord::Chars()` within a range-based for loop for
681
  // iterating over the chunks of a Cord. This method may be useful for getting
682
  // a `CharIterator` where range-based for-loops may not be available.
683
  CharIterator char_begin() const ABSL_ATTRIBUTE_LIFETIME_BOUND;
684
685
  // Cord::char_end()
686
  //
687
  // Returns an iterator to one past the last character of the `Cord`.
688
  //
689
  // Generally, prefer using `Cord::Chars()` within a range-based for loop for
690
  // iterating over the chunks of a Cord. This method may be useful for getting
691
  // a `CharIterator` where range-based for-loops are not useful.
692
  CharIterator char_end() const ABSL_ATTRIBUTE_LIFETIME_BOUND;
693
694
  // Cord::CharRange
695
  //
696
  // `CharRange` is a helper class for iterating over the characters of a
697
  // producing an iterator which can be used within a range-based for loop.
698
  // Construction of a `CharRange` will return an iterator pointing to the first
699
  // character of the Cord. Generally, do not construct a `CharRange` directly;
700
  // instead, prefer to use the `Cord::Chars()` method shown below.
701
  //
702
  // Implementation note: `CharRange` is simply a convenience wrapper over
703
  // `Cord::char_begin()` and `Cord::char_end()`.
704
  class CharRange {
705
   public:
706
    // Fulfill minimum c++ container requirements [container.requirements]
707
    // These (partial) container type definitions allow CharRange to be used
708
    // in various utilities expecting a subset of [container.requirements].
709
    // For example, the below enables using `::testing::ElementsAre(...)`
710
    using value_type = char;
711
    using reference = value_type&;
712
    using const_reference = const value_type&;
713
    using iterator = CharIterator;
714
    using const_iterator = CharIterator;
715
716
0
    explicit CharRange(absl::Nonnull<const Cord*> cord) : cord_(cord) {}
717
718
    CharIterator begin() const;
719
    CharIterator end() const;
720
721
   private:
722
    absl::Nonnull<const Cord*> cord_;
723
  };
724
725
  // Cord::Chars()
726
  //
727
  // Returns a `Cord::CharRange` for iterating over the characters of a `Cord`
728
  // with a range-based for-loop. For most character-based iteration tasks on a
729
  // Cord, use `Cord::Chars()` to retrieve this iterator.
730
  //
731
  // Example:
732
  //
733
  //   void ProcessCord(const Cord& cord) {
734
  //     for (char c : cord.Chars()) { ... }
735
  //   }
736
  //
737
  // Note that the ordinary caveats of temporary lifetime extension apply:
738
  //
739
  //   void Process() {
740
  //     for (char c : CordFactory().Chars()) {
741
  //       // The temporary Cord returned by CordFactory has been destroyed!
742
  //     }
743
  //   }
744
  CharRange Chars() const ABSL_ATTRIBUTE_LIFETIME_BOUND;
745
746
  // Cord::operator[]
747
  //
748
  // Gets the "i"th character of the Cord and returns it, provided that
749
  // 0 <= i < Cord.size().
750
  //
751
  // NOTE: This routine is reasonably efficient. It is roughly
752
  // logarithmic based on the number of chunks that make up the cord. Still,
753
  // if you need to iterate over the contents of a cord, you should
754
  // use a CharIterator/ChunkIterator rather than call operator[] or Get()
755
  // repeatedly in a loop.
756
  char operator[](size_t i) const;
757
758
  // Cord::TryFlat()
759
  //
760
  // If this cord's representation is a single flat array, returns a
761
  // string_view referencing that array.  Otherwise returns nullopt.
762
  absl::optional<absl::string_view> TryFlat() const
763
      ABSL_ATTRIBUTE_LIFETIME_BOUND;
764
765
  // Cord::Flatten()
766
  //
767
  // Flattens the cord into a single array and returns a view of the data.
768
  //
769
  // If the cord was already flat, the contents are not modified.
770
  absl::string_view Flatten() ABSL_ATTRIBUTE_LIFETIME_BOUND;
771
772
  // Cord::Find()
773
  //
774
  // Returns an iterator to the first occurrence of the substring `needle`.
775
  //
776
  // If the substring `needle` does not occur, `Cord::char_end()` is returned.
777
  CharIterator Find(absl::string_view needle) const;
778
  CharIterator Find(const absl::Cord& needle) const;
779
780
  // Supports absl::Cord as a sink object for absl::Format().
781
  friend void AbslFormatFlush(absl::Nonnull<absl::Cord*> cord,
782
0
                              absl::string_view part) {
783
0
    cord->Append(part);
784
0
  }
785
786
  // Support automatic stringification with absl::StrCat and absl::StrFormat.
787
  template <typename Sink>
788
  friend void AbslStringify(Sink& sink, const absl::Cord& cord) {
789
    for (absl::string_view chunk : cord.Chunks()) {
790
      sink.Append(chunk);
791
    }
792
  }
793
794
  // Cord::SetExpectedChecksum()
795
  //
796
  // Stores a checksum value with this non-empty cord instance, for later
797
  // retrieval.
798
  //
799
  // The expected checksum is a number stored out-of-band, alongside the data.
800
  // It is preserved across copies and assignments, but any mutations to a cord
801
  // will cause it to lose its expected checksum.
802
  //
803
  // The expected checksum is not part of a Cord's value, and does not affect
804
  // operations such as equality or hashing.
805
  //
806
  // This field is intended to store a CRC32C checksum for later validation, to
807
  // help support end-to-end checksum workflows.  However, the Cord API itself
808
  // does no CRC validation, and assigns no meaning to this number.
809
  //
810
  // This call has no effect if this cord is empty.
811
  void SetExpectedChecksum(uint32_t crc);
812
813
  // Returns this cord's expected checksum, if it has one.  Otherwise, returns
814
  // nullopt.
815
  absl::optional<uint32_t> ExpectedChecksum() const;
816
817
  template <typename H>
818
0
  friend H AbslHashValue(H hash_state, const absl::Cord& c) {
819
0
    absl::optional<absl::string_view> maybe_flat = c.TryFlat();
820
0
    if (maybe_flat.has_value()) {
821
0
      return H::combine(std::move(hash_state), *maybe_flat);
822
0
    }
823
0
    return c.HashFragmented(std::move(hash_state));
824
0
  }
825
826
  // Create a Cord with the contents of StringConstant<T>::value.
827
  // No allocations will be done and no data will be copied.
828
  // This is an INTERNAL API and subject to change or removal. This API can only
829
  // be used by spelling absl::strings_internal::MakeStringConstant, which is
830
  // also an internal API.
831
  template <typename T>
832
  // NOLINTNEXTLINE(google-explicit-constructor)
833
  constexpr Cord(strings_internal::StringConstant<T>);
834
835
 private:
836
  using CordRep = absl::cord_internal::CordRep;
837
  using CordRepFlat = absl::cord_internal::CordRepFlat;
838
  using CordzInfo = cord_internal::CordzInfo;
839
  using CordzUpdateScope = cord_internal::CordzUpdateScope;
840
  using CordzUpdateTracker = cord_internal::CordzUpdateTracker;
841
  using InlineData = cord_internal::InlineData;
842
  using MethodIdentifier = CordzUpdateTracker::MethodIdentifier;
843
844
  // Creates a cord instance with `method` representing the originating
845
  // public API call causing the cord to be created.
846
  explicit Cord(absl::string_view src, MethodIdentifier method);
847
848
  friend class CordTestPeer;
849
  friend bool operator==(const Cord& lhs, const Cord& rhs);
850
  friend bool operator==(const Cord& lhs, absl::string_view rhs);
851
852
#ifdef __cpp_impl_three_way_comparison
853
854
  // Cords support comparison with other Cords and string_views via operator<
855
  // and others; here we provide a wrapper for the C++20 three-way comparison
856
  // <=> operator.
857
858
  static inline std::strong_ordering ConvertCompareResultToStrongOrdering(
859
      int c) {
860
    if (c == 0) {
861
      return std::strong_ordering::equal;
862
    } else if (c < 0) {
863
      return std::strong_ordering::less;
864
    } else {
865
      return std::strong_ordering::greater;
866
    }
867
  }
868
869
  friend inline std::strong_ordering operator<=>(const Cord& x, const Cord& y) {
870
    return ConvertCompareResultToStrongOrdering(x.Compare(y));
871
  }
872
873
  friend inline std::strong_ordering operator<=>(const Cord& lhs,
874
                                                 absl::string_view rhs) {
875
    return ConvertCompareResultToStrongOrdering(lhs.Compare(rhs));
876
  }
877
878
  friend inline std::strong_ordering operator<=>(absl::string_view lhs,
879
                                                 const Cord& rhs) {
880
    return ConvertCompareResultToStrongOrdering(-rhs.Compare(lhs));
881
  }
882
#endif
883
884
  friend absl::Nullable<const CordzInfo*> GetCordzInfoForTesting(
885
      const Cord& cord);
886
887
  // Calls the provided function once for each cord chunk, in order.  Unlike
888
  // Chunks(), this API will not allocate memory.
889
  void ForEachChunk(absl::FunctionRef<void(absl::string_view)>) const;
890
891
  // Allocates new contiguous storage for the contents of the cord. This is
892
  // called by Flatten() when the cord was not already flat.
893
  absl::string_view FlattenSlowPath();
894
895
  // Actual cord contents are hidden inside the following simple
896
  // class so that we can isolate the bulk of cord.cc from changes
897
  // to the representation.
898
  //
899
  // InlineRep holds either a tree pointer, or an array of kMaxInline bytes.
900
  class InlineRep {
901
   public:
902
    static constexpr unsigned char kMaxInline = cord_internal::kMaxInline;
903
    static_assert(kMaxInline >= sizeof(absl::cord_internal::CordRep*), "");
904
905
0
    constexpr InlineRep() : data_() {}
906
0
    explicit InlineRep(InlineData::DefaultInitType init) : data_(init) {}
907
    InlineRep(const InlineRep& src);
908
    InlineRep(InlineRep&& src);
909
    InlineRep& operator=(const InlineRep& src);
910
    InlineRep& operator=(InlineRep&& src) noexcept;
911
912
    explicit constexpr InlineRep(absl::string_view sv,
913
                                 absl::Nullable<CordRep*> rep);
914
915
    void Swap(absl::Nonnull<InlineRep*> rhs);
916
    size_t size() const;
917
    // Returns nullptr if holding pointer
918
    absl::Nullable<const char*> data() const;
919
    // Discards pointer, if any
920
    void set_data(absl::Nonnull<const char*> data, size_t n);
921
    absl::Nonnull<char*> set_data(size_t n);  // Write data to the result
922
    // Returns nullptr if holding bytes
923
    absl::Nullable<absl::cord_internal::CordRep*> tree() const;
924
    absl::Nonnull<absl::cord_internal::CordRep*> as_tree() const;
925
    absl::Nonnull<const char*> as_chars() const;
926
    // Returns non-null iff was holding a pointer
927
    absl::Nullable<absl::cord_internal::CordRep*> clear();
928
    // Converts to pointer if necessary.
929
    void reduce_size(size_t n);    // REQUIRES: holding data
930
    void remove_prefix(size_t n);  // REQUIRES: holding data
931
    void AppendArray(absl::string_view src, MethodIdentifier method);
932
    absl::string_view FindFlatStartPiece() const;
933
934
    // Creates a CordRepFlat instance from the current inlined data with `extra'
935
    // bytes of desired additional capacity.
936
    absl::Nonnull<CordRepFlat*> MakeFlatWithExtraCapacity(size_t extra);
937
938
    // Sets the tree value for this instance. `rep` must not be null.
939
    // Requires the current instance to hold a tree, and a lock to be held on
940
    // any CordzInfo referenced by this instance. The latter is enforced through
941
    // the CordzUpdateScope argument. If the current instance is sampled, then
942
    // the CordzInfo instance is updated to reference the new `rep` value.
943
    void SetTree(absl::Nonnull<CordRep*> rep, const CordzUpdateScope& scope);
944
945
    // Identical to SetTree(), except that `rep` is allowed to be null, in
946
    // which case the current instance is reset to an empty value.
947
    void SetTreeOrEmpty(absl::Nullable<CordRep*> rep,
948
                        const CordzUpdateScope& scope);
949
950
    // Sets the tree value for this instance, and randomly samples this cord.
951
    // This function disregards existing contents in `data_`, and should be
952
    // called when a Cord is 'promoted' from an 'uninitialized' or 'inlined'
953
    // value to a non-inlined (tree / ring) value.
954
    void EmplaceTree(absl::Nonnull<CordRep*> rep, MethodIdentifier method);
955
956
    // Identical to EmplaceTree, except that it copies the parent stack from
957
    // the provided `parent` data if the parent is sampled.
958
    void EmplaceTree(absl::Nonnull<CordRep*> rep, const InlineData& parent,
959
                     MethodIdentifier method);
960
961
    // Commits the change of a newly created, or updated `rep` root value into
962
    // this cord. `old_rep` indicates the old (inlined or tree) value of the
963
    // cord, and determines if the commit invokes SetTree() or EmplaceTree().
964
    void CommitTree(absl::Nullable<const CordRep*> old_rep,
965
                    absl::Nonnull<CordRep*> rep, const CordzUpdateScope& scope,
966
                    MethodIdentifier method);
967
968
    void AppendTreeToInlined(absl::Nonnull<CordRep*> tree,
969
                             MethodIdentifier method);
970
    void AppendTreeToTree(absl::Nonnull<CordRep*> tree,
971
                          MethodIdentifier method);
972
    void AppendTree(absl::Nonnull<CordRep*> tree, MethodIdentifier method);
973
    void PrependTreeToInlined(absl::Nonnull<CordRep*> tree,
974
                              MethodIdentifier method);
975
    void PrependTreeToTree(absl::Nonnull<CordRep*> tree,
976
                           MethodIdentifier method);
977
    void PrependTree(absl::Nonnull<CordRep*> tree, MethodIdentifier method);
978
979
0
    bool IsSame(const InlineRep& other) const { return data_ == other.data_; }
980
981
0
    void CopyTo(absl::Nonnull<std::string*> dst) const {
982
0
      // memcpy is much faster when operating on a known size. On most supported
983
0
      // platforms, the small string optimization is large enough that resizing
984
0
      // to 15 bytes does not cause a memory allocation.
985
0
      absl::strings_internal::STLStringResizeUninitialized(dst, kMaxInline);
986
0
      data_.copy_max_inline_to(&(*dst)[0]);
987
0
      // erase is faster than resize because the logic for memory allocation is
988
0
      // not needed.
989
0
      dst->erase(inline_size());
990
0
    }
991
992
    // Copies the inline contents into `dst`. Assumes the cord is not empty.
993
    void CopyToArray(absl::Nonnull<char*> dst) const;
994
995
0
    bool is_tree() const { return data_.is_tree(); }
996
997
    // Returns true if the Cord is being profiled by cordz.
998
0
    bool is_profiled() const { return data_.is_tree() && data_.is_profiled(); }
999
1000
    // Returns the available inlined capacity, or 0 if is_tree() == true.
1001
0
    size_t remaining_inline_capacity() const {
1002
0
      return data_.is_tree() ? 0 : kMaxInline - data_.inline_size();
1003
0
    }
1004
1005
    // Returns the profiled CordzInfo, or nullptr if not sampled.
1006
0
    absl::Nullable<absl::cord_internal::CordzInfo*> cordz_info() const {
1007
0
      return data_.cordz_info();
1008
0
    }
1009
1010
    // Sets the profiled CordzInfo.
1011
0
    void set_cordz_info(absl::Nonnull<cord_internal::CordzInfo*> cordz_info) {
1012
0
      assert(cordz_info != nullptr);
1013
0
      data_.set_cordz_info(cordz_info);
1014
0
    }
1015
1016
    // Resets the current cordz_info to null / empty.
1017
0
    void clear_cordz_info() { data_.clear_cordz_info(); }
1018
1019
   private:
1020
    friend class Cord;
1021
1022
    void AssignSlow(const InlineRep& src);
1023
    // Unrefs the tree and stops profiling.
1024
    void UnrefTree();
1025
1026
0
    void ResetToEmpty() { data_ = {}; }
1027
1028
0
    void set_inline_size(size_t size) { data_.set_inline_size(size); }
1029
0
    size_t inline_size() const { return data_.inline_size(); }
1030
1031
    // Empty cords that carry a checksum have a CordRepCrc node with a null
1032
    // child node. The code can avoid lots of special cases where it would
1033
    // otherwise transition from tree to inline storage if we just remove the
1034
    // CordRepCrc node before mutations. Must never be called inside a
1035
    // CordzUpdateScope since it untracks the cordz info.
1036
    void MaybeRemoveEmptyCrcNode();
1037
1038
    cord_internal::InlineData data_;
1039
  };
1040
  InlineRep contents_;
1041
1042
  // Helper for GetFlat() and TryFlat().
1043
  static bool GetFlatAux(absl::Nonnull<absl::cord_internal::CordRep*> rep,
1044
                         absl::Nonnull<absl::string_view*> fragment);
1045
1046
  // Helper for ForEachChunk().
1047
  static void ForEachChunkAux(
1048
      absl::Nonnull<absl::cord_internal::CordRep*> rep,
1049
      absl::FunctionRef<void(absl::string_view)> callback);
1050
1051
  // The destructor for non-empty Cords.
1052
  void DestroyCordSlow();
1053
1054
  // Out-of-line implementation of slower parts of logic.
1055
  void CopyToArraySlowPath(absl::Nonnull<char*> dst) const;
1056
  int CompareSlowPath(absl::string_view rhs, size_t compared_size,
1057
                      size_t size_to_compare) const;
1058
  int CompareSlowPath(const Cord& rhs, size_t compared_size,
1059
                      size_t size_to_compare) const;
1060
  bool EqualsImpl(absl::string_view rhs, size_t size_to_compare) const;
1061
  bool EqualsImpl(const Cord& rhs, size_t size_to_compare) const;
1062
  int CompareImpl(const Cord& rhs) const;
1063
1064
  template <typename ResultType, typename RHS>
1065
  friend ResultType GenericCompare(const Cord& lhs, const RHS& rhs,
1066
                                   size_t size_to_compare);
1067
  static absl::string_view GetFirstChunk(const Cord& c);
1068
  static absl::string_view GetFirstChunk(absl::string_view sv);
1069
1070
  // Returns a new reference to contents_.tree(), or steals an existing
1071
  // reference if called on an rvalue.
1072
  absl::Nonnull<absl::cord_internal::CordRep*> TakeRep() const&;
1073
  absl::Nonnull<absl::cord_internal::CordRep*> TakeRep() &&;
1074
1075
  // Helper for Append().
1076
  template <typename C>
1077
  void AppendImpl(C&& src);
1078
1079
  // Appends / Prepends `src` to this instance, using precise sizing.
1080
  // This method does explicitly not attempt to use any spare capacity
1081
  // in any pending last added private owned flat.
1082
  // Requires `src` to be <= kMaxFlatLength.
1083
  void AppendPrecise(absl::string_view src, MethodIdentifier method);
1084
  void PrependPrecise(absl::string_view src, MethodIdentifier method);
1085
1086
  CordBuffer GetAppendBufferSlowPath(size_t block_size, size_t capacity,
1087
                                     size_t min_capacity);
1088
1089
  // Prepends the provided data to this instance. `method` contains the public
1090
  // API method for this action which is tracked for Cordz sampling purposes.
1091
  void PrependArray(absl::string_view src, MethodIdentifier method);
1092
1093
  // Assigns the value in 'src' to this instance, 'stealing' its contents.
1094
  // Requires src.length() > kMaxBytesToCopy.
1095
  Cord& AssignLargeString(std::string&& src);
1096
1097
  // Helper for AbslHashValue().
1098
  template <typename H>
1099
0
  H HashFragmented(H hash_state) const {
1100
0
    typename H::AbslInternalPiecewiseCombiner combiner;
1101
0
    ForEachChunk([&combiner, &hash_state](absl::string_view chunk) {
1102
0
      hash_state = combiner.add_buffer(std::move(hash_state), chunk.data(),
1103
0
                                       chunk.size());
1104
0
    });
1105
0
    return H::combine(combiner.finalize(std::move(hash_state)), size());
1106
0
  }
1107
1108
  friend class CrcCord;
1109
  void SetCrcCordState(crc_internal::CrcCordState state);
1110
  absl::Nullable<const crc_internal::CrcCordState*> MaybeGetCrcCordState()
1111
      const;
1112
1113
  CharIterator FindImpl(CharIterator it, absl::string_view needle) const;
1114
1115
  void CopyToArrayImpl(absl::Nonnull<char*> dst) const;
1116
};
1117
1118
ABSL_NAMESPACE_END
1119
}  // namespace absl
1120
1121
namespace absl {
1122
ABSL_NAMESPACE_BEGIN
1123
1124
// allow a Cord to be logged
1125
extern std::ostream& operator<<(std::ostream& out, const Cord& cord);
1126
1127
// ------------------------------------------------------------------
1128
// Internal details follow.  Clients should ignore.
1129
1130
namespace cord_internal {
1131
1132
// Does non-template-specific `CordRepExternal` initialization.
1133
// Requires `data` to be non-empty.
1134
void InitializeCordRepExternal(absl::string_view data,
1135
                               absl::Nonnull<CordRepExternal*> rep);
1136
1137
// Creates a new `CordRep` that owns `data` and `releaser` and returns a pointer
1138
// to it. Requires `data` to be non-empty.
1139
template <typename Releaser>
1140
// NOLINTNEXTLINE - suppress clang-tidy raw pointer return.
1141
absl::Nonnull<CordRep*> NewExternalRep(absl::string_view data,
1142
0
                                       Releaser&& releaser) {
1143
0
  assert(!data.empty());
1144
0
  using ReleaserType = absl::decay_t<Releaser>;
1145
0
  CordRepExternal* rep = new CordRepExternalImpl<ReleaserType>(
1146
0
      std::forward<Releaser>(releaser), 0);
1147
0
  InitializeCordRepExternal(data, rep);
1148
0
  return rep;
1149
0
}
1150
1151
// Overload for function reference types that dispatches using a function
1152
// pointer because there are no `alignof()` or `sizeof()` a function reference.
1153
// NOLINTNEXTLINE - suppress clang-tidy raw pointer return.
1154
inline absl::Nonnull<CordRep*> NewExternalRep(
1155
0
    absl::string_view data, void (&releaser)(absl::string_view)) {
1156
0
  return NewExternalRep(data, &releaser);
1157
0
}
1158
1159
}  // namespace cord_internal
1160
1161
template <typename Releaser>
1162
Cord MakeCordFromExternal(absl::string_view data, Releaser&& releaser) {
1163
  Cord cord;
1164
  if (ABSL_PREDICT_TRUE(!data.empty())) {
1165
    cord.contents_.EmplaceTree(::absl::cord_internal::NewExternalRep(
1166
                                   data, std::forward<Releaser>(releaser)),
1167
                               Cord::MethodIdentifier::kMakeCordFromExternal);
1168
  } else {
1169
    using ReleaserType = absl::decay_t<Releaser>;
1170
    cord_internal::InvokeReleaser(
1171
        cord_internal::Rank1{}, ReleaserType(std::forward<Releaser>(releaser)),
1172
        data);
1173
  }
1174
  return cord;
1175
}
1176
1177
constexpr Cord::InlineRep::InlineRep(absl::string_view sv,
1178
                                     absl::Nullable<CordRep*> rep)
1179
    : data_(sv, rep) {}
1180
1181
inline Cord::InlineRep::InlineRep(const Cord::InlineRep& src)
1182
    : data_(InlineData::kDefaultInit) {
1183
  if (CordRep* tree = src.tree()) {
1184
    EmplaceTree(CordRep::Ref(tree), src.data_,
1185
                CordzUpdateTracker::kConstructorCord);
1186
  } else {
1187
    data_ = src.data_;
1188
  }
1189
}
1190
1191
inline Cord::InlineRep::InlineRep(Cord::InlineRep&& src) : data_(src.data_) {
1192
  src.ResetToEmpty();
1193
}
1194
1195
0
inline Cord::InlineRep& Cord::InlineRep::operator=(const Cord::InlineRep& src) {
1196
0
  if (this == &src) {
1197
0
    return *this;
1198
0
  }
1199
0
  if (!is_tree() && !src.is_tree()) {
1200
0
    data_ = src.data_;
1201
0
    return *this;
1202
0
  }
1203
0
  AssignSlow(src);
1204
0
  return *this;
1205
0
}
1206
1207
inline Cord::InlineRep& Cord::InlineRep::operator=(
1208
0
    Cord::InlineRep&& src) noexcept {
1209
0
  if (is_tree()) {
1210
0
    UnrefTree();
1211
0
  }
1212
0
  data_ = src.data_;
1213
0
  src.ResetToEmpty();
1214
0
  return *this;
1215
0
}
1216
1217
0
inline void Cord::InlineRep::Swap(absl::Nonnull<Cord::InlineRep*> rhs) {
1218
0
  if (rhs == this) {
1219
0
    return;
1220
0
  }
1221
0
  using std::swap;
1222
0
  swap(data_, rhs->data_);
1223
0
}
1224
1225
0
inline absl::Nullable<const char*> Cord::InlineRep::data() const {
1226
0
  return is_tree() ? nullptr : data_.as_chars();
1227
0
}
1228
1229
0
inline absl::Nonnull<const char*> Cord::InlineRep::as_chars() const {
1230
0
  assert(!data_.is_tree());
1231
0
  return data_.as_chars();
1232
0
}
1233
1234
inline absl::Nonnull<absl::cord_internal::CordRep*> Cord::InlineRep::as_tree()
1235
0
    const {
1236
0
  assert(data_.is_tree());
1237
0
  return data_.as_tree();
1238
0
}
1239
1240
inline absl::Nullable<absl::cord_internal::CordRep*> Cord::InlineRep::tree()
1241
0
    const {
1242
0
  if (is_tree()) {
1243
0
    return as_tree();
1244
0
  } else {
1245
0
    return nullptr;
1246
0
  }
1247
0
}
1248
1249
0
inline size_t Cord::InlineRep::size() const {
1250
0
  return is_tree() ? as_tree()->length : inline_size();
1251
0
}
1252
1253
inline absl::Nonnull<cord_internal::CordRepFlat*>
1254
0
Cord::InlineRep::MakeFlatWithExtraCapacity(size_t extra) {
1255
0
  static_assert(cord_internal::kMinFlatLength >= sizeof(data_), "");
1256
0
  size_t len = data_.inline_size();
1257
0
  auto* result = CordRepFlat::New(len + extra);
1258
0
  result->length = len;
1259
0
  data_.copy_max_inline_to(result->Data());
1260
0
  return result;
1261
0
}
1262
1263
inline void Cord::InlineRep::EmplaceTree(absl::Nonnull<CordRep*> rep,
1264
0
                                         MethodIdentifier method) {
1265
0
  assert(rep);
1266
0
  data_.make_tree(rep);
1267
0
  CordzInfo::MaybeTrackCord(data_, method);
1268
0
}
1269
1270
inline void Cord::InlineRep::EmplaceTree(absl::Nonnull<CordRep*> rep,
1271
                                         const InlineData& parent,
1272
0
                                         MethodIdentifier method) {
1273
0
  data_.make_tree(rep);
1274
0
  CordzInfo::MaybeTrackCord(data_, parent, method);
1275
0
}
1276
1277
inline void Cord::InlineRep::SetTree(absl::Nonnull<CordRep*> rep,
1278
0
                                     const CordzUpdateScope& scope) {
1279
0
  assert(rep);
1280
0
  assert(data_.is_tree());
1281
0
  data_.set_tree(rep);
1282
0
  scope.SetCordRep(rep);
1283
0
}
1284
1285
inline void Cord::InlineRep::SetTreeOrEmpty(absl::Nullable<CordRep*> rep,
1286
0
                                            const CordzUpdateScope& scope) {
1287
0
  assert(data_.is_tree());
1288
0
  if (rep) {
1289
0
    data_.set_tree(rep);
1290
0
  } else {
1291
0
    data_ = {};
1292
0
  }
1293
0
  scope.SetCordRep(rep);
1294
0
}
1295
1296
inline void Cord::InlineRep::CommitTree(absl::Nullable<const CordRep*> old_rep,
1297
                                        absl::Nonnull<CordRep*> rep,
1298
                                        const CordzUpdateScope& scope,
1299
0
                                        MethodIdentifier method) {
1300
0
  if (old_rep) {
1301
0
    SetTree(rep, scope);
1302
0
  } else {
1303
0
    EmplaceTree(rep, method);
1304
0
  }
1305
0
}
1306
1307
0
inline absl::Nullable<absl::cord_internal::CordRep*> Cord::InlineRep::clear() {
1308
0
  if (is_tree()) {
1309
0
    CordzInfo::MaybeUntrackCord(cordz_info());
1310
0
  }
1311
0
  absl::cord_internal::CordRep* result = tree();
1312
0
  ResetToEmpty();
1313
0
  return result;
1314
0
}
1315
1316
0
inline void Cord::InlineRep::CopyToArray(absl::Nonnull<char*> dst) const {
1317
0
  assert(!is_tree());
1318
0
  size_t n = inline_size();
1319
0
  assert(n != 0);
1320
0
  cord_internal::SmallMemmove(dst, data_.as_chars(), n);
1321
0
}
1322
1323
0
inline void Cord::InlineRep::MaybeRemoveEmptyCrcNode() {
1324
0
  CordRep* rep = tree();
1325
0
  if (rep == nullptr || ABSL_PREDICT_TRUE(rep->length > 0)) {
1326
0
    return;
1327
0
  }
1328
0
  assert(rep->IsCrc());
1329
0
  assert(rep->crc()->child == nullptr);
1330
0
  CordzInfo::MaybeUntrackCord(cordz_info());
1331
0
  CordRep::Unref(rep);
1332
0
  ResetToEmpty();
1333
0
}
1334
1335
constexpr inline Cord::Cord() noexcept {}
1336
1337
inline Cord::Cord(absl::string_view src)
1338
    : Cord(src, CordzUpdateTracker::kConstructorString) {}
1339
1340
template <typename T>
1341
constexpr Cord::Cord(strings_internal::StringConstant<T>)
1342
    : contents_(strings_internal::StringConstant<T>::value,
1343
                strings_internal::StringConstant<T>::value.size() <=
1344
                        cord_internal::kMaxInline
1345
                    ? nullptr
1346
                    : &cord_internal::ConstInitExternalStorage<
1347
                          strings_internal::StringConstant<T>>::value) {}
1348
1349
0
inline Cord& Cord::operator=(const Cord& x) {
1350
0
  contents_ = x.contents_;
1351
0
  return *this;
1352
0
}
1353
1354
template <typename T, Cord::EnableIfString<T>>
1355
Cord& Cord::operator=(T&& src) {
1356
  if (src.size() <= cord_internal::kMaxBytesToCopy) {
1357
    return operator=(absl::string_view(src));
1358
  } else {
1359
    return AssignLargeString(std::forward<T>(src));
1360
  }
1361
}
1362
1363
inline Cord::Cord(const Cord& src) : contents_(src.contents_) {}
1364
1365
inline Cord::Cord(Cord&& src) noexcept : contents_(std::move(src.contents_)) {}
1366
1367
0
inline void Cord::swap(Cord& other) noexcept {
1368
0
  contents_.Swap(&other.contents_);
1369
0
}
1370
1371
0
inline Cord& Cord::operator=(Cord&& x) noexcept {
1372
0
  contents_ = std::move(x.contents_);
1373
0
  return *this;
1374
0
}
1375
1376
extern template Cord::Cord(std::string&& src);
1377
1378
0
inline size_t Cord::size() const {
1379
0
  // Length is 1st field in str.rep_
1380
0
  return contents_.size();
1381
0
}
1382
1383
0
inline bool Cord::empty() const { return size() == 0; }
1384
1385
inline size_t Cord::EstimatedMemoryUsage(
1386
0
    CordMemoryAccounting accounting_method) const {
1387
0
  size_t result = sizeof(Cord);
1388
0
  if (const absl::cord_internal::CordRep* rep = contents_.tree()) {
1389
0
    switch (accounting_method) {
1390
0
      case CordMemoryAccounting::kFairShare:
1391
0
        result += cord_internal::GetEstimatedFairShareMemoryUsage(rep);
1392
0
        break;
1393
0
      case CordMemoryAccounting::kTotalMorePrecise:
1394
0
        result += cord_internal::GetMorePreciseMemoryUsage(rep);
1395
0
        break;
1396
0
      case CordMemoryAccounting::kTotal:
1397
0
        result += cord_internal::GetEstimatedMemoryUsage(rep);
1398
0
        break;
1399
0
    }
1400
0
  }
1401
0
  return result;
1402
0
}
1403
1404
inline absl::optional<absl::string_view> Cord::TryFlat() const
1405
0
    ABSL_ATTRIBUTE_LIFETIME_BOUND {
1406
0
  absl::cord_internal::CordRep* rep = contents_.tree();
1407
0
  if (rep == nullptr) {
1408
0
    return absl::string_view(contents_.data(), contents_.size());
1409
0
  }
1410
0
  absl::string_view fragment;
1411
0
  if (GetFlatAux(rep, &fragment)) {
1412
0
    return fragment;
1413
0
  }
1414
0
  return absl::nullopt;
1415
0
}
1416
1417
0
inline absl::string_view Cord::Flatten() ABSL_ATTRIBUTE_LIFETIME_BOUND {
1418
0
  absl::cord_internal::CordRep* rep = contents_.tree();
1419
0
  if (rep == nullptr) {
1420
0
    return absl::string_view(contents_.data(), contents_.size());
1421
0
  } else {
1422
0
    absl::string_view already_flat_contents;
1423
0
    if (GetFlatAux(rep, &already_flat_contents)) {
1424
0
      return already_flat_contents;
1425
0
    }
1426
0
  }
1427
0
  return FlattenSlowPath();
1428
0
}
1429
1430
0
inline void Cord::Append(absl::string_view src) {
1431
0
  contents_.AppendArray(src, CordzUpdateTracker::kAppendString);
1432
0
}
1433
1434
0
inline void Cord::Prepend(absl::string_view src) {
1435
0
  PrependArray(src, CordzUpdateTracker::kPrependString);
1436
0
}
1437
1438
0
inline void Cord::Append(CordBuffer buffer) {
1439
0
  if (ABSL_PREDICT_FALSE(buffer.length() == 0)) return;
1440
0
  contents_.MaybeRemoveEmptyCrcNode();
1441
0
  absl::string_view short_value;
1442
0
  if (CordRep* rep = buffer.ConsumeValue(short_value)) {
1443
0
    contents_.AppendTree(rep, CordzUpdateTracker::kAppendCordBuffer);
1444
0
  } else {
1445
0
    AppendPrecise(short_value, CordzUpdateTracker::kAppendCordBuffer);
1446
0
  }
1447
0
}
1448
1449
0
inline void Cord::Prepend(CordBuffer buffer) {
1450
0
  if (ABSL_PREDICT_FALSE(buffer.length() == 0)) return;
1451
0
  contents_.MaybeRemoveEmptyCrcNode();
1452
0
  absl::string_view short_value;
1453
0
  if (CordRep* rep = buffer.ConsumeValue(short_value)) {
1454
0
    contents_.PrependTree(rep, CordzUpdateTracker::kPrependCordBuffer);
1455
0
  } else {
1456
0
    PrependPrecise(short_value, CordzUpdateTracker::kPrependCordBuffer);
1457
0
  }
1458
0
}
1459
1460
0
inline CordBuffer Cord::GetAppendBuffer(size_t capacity, size_t min_capacity) {
1461
0
  if (empty()) return CordBuffer::CreateWithDefaultLimit(capacity);
1462
0
  return GetAppendBufferSlowPath(0, capacity, min_capacity);
1463
0
}
1464
1465
inline CordBuffer Cord::GetCustomAppendBuffer(size_t block_size,
1466
                                              size_t capacity,
1467
0
                                              size_t min_capacity) {
1468
0
  if (empty()) {
1469
0
    return block_size ? CordBuffer::CreateWithCustomLimit(block_size, capacity)
1470
0
                      : CordBuffer::CreateWithDefaultLimit(capacity);
1471
0
  }
1472
0
  return GetAppendBufferSlowPath(block_size, capacity, min_capacity);
1473
0
}
1474
1475
extern template void Cord::Append(std::string&& src);
1476
extern template void Cord::Prepend(std::string&& src);
1477
1478
0
inline int Cord::Compare(const Cord& rhs) const {
1479
0
  if (!contents_.is_tree() && !rhs.contents_.is_tree()) {
1480
0
    return contents_.data_.Compare(rhs.contents_.data_);
1481
0
  }
1482
0
1483
0
  return CompareImpl(rhs);
1484
0
}
1485
1486
// Does 'this' cord start/end with rhs
1487
0
inline bool Cord::StartsWith(const Cord& rhs) const {
1488
0
  if (contents_.IsSame(rhs.contents_)) return true;
1489
0
  size_t rhs_size = rhs.size();
1490
0
  if (size() < rhs_size) return false;
1491
0
  return EqualsImpl(rhs, rhs_size);
1492
0
}
1493
1494
0
inline bool Cord::StartsWith(absl::string_view rhs) const {
1495
0
  size_t rhs_size = rhs.size();
1496
0
  if (size() < rhs_size) return false;
1497
0
  return EqualsImpl(rhs, rhs_size);
1498
0
}
1499
1500
0
inline void Cord::CopyToArrayImpl(absl::Nonnull<char*> dst) const {
1501
0
  if (!contents_.is_tree()) {
1502
0
    if (!empty()) contents_.CopyToArray(dst);
1503
0
  } else {
1504
0
    CopyToArraySlowPath(dst);
1505
0
  }
1506
0
}
1507
1508
inline void Cord::ChunkIterator::InitTree(
1509
0
    absl::Nonnull<cord_internal::CordRep*> tree) {
1510
0
  tree = cord_internal::SkipCrcNode(tree);
1511
0
  if (tree->tag == cord_internal::BTREE) {
1512
0
    current_chunk_ = btree_reader_.Init(tree->btree());
1513
0
  } else {
1514
0
    current_leaf_ = tree;
1515
0
    current_chunk_ = cord_internal::EdgeData(tree);
1516
0
  }
1517
0
}
1518
1519
inline Cord::ChunkIterator::ChunkIterator(
1520
    absl::Nonnull<cord_internal::CordRep*> tree) {
1521
  bytes_remaining_ = tree->length;
1522
  InitTree(tree);
1523
}
1524
1525
inline Cord::ChunkIterator::ChunkIterator(absl::Nonnull<const Cord*> cord) {
1526
  if (CordRep* tree = cord->contents_.tree()) {
1527
    bytes_remaining_ = tree->length;
1528
    if (ABSL_PREDICT_TRUE(bytes_remaining_ != 0)) {
1529
      InitTree(tree);
1530
    } else {
1531
      current_chunk_ = {};
1532
    }
1533
  } else {
1534
    bytes_remaining_ = cord->contents_.inline_size();
1535
    current_chunk_ = {cord->contents_.data(), bytes_remaining_};
1536
  }
1537
}
1538
1539
0
inline Cord::ChunkIterator& Cord::ChunkIterator::AdvanceBtree() {
1540
0
  current_chunk_ = btree_reader_.Next();
1541
0
  return *this;
1542
0
}
1543
1544
0
inline void Cord::ChunkIterator::AdvanceBytesBtree(size_t n) {
1545
0
  assert(n >= current_chunk_.size());
1546
0
  bytes_remaining_ -= n;
1547
0
  if (bytes_remaining_) {
1548
0
    if (n == current_chunk_.size()) {
1549
0
      current_chunk_ = btree_reader_.Next();
1550
0
    } else {
1551
0
      size_t offset = btree_reader_.length() - bytes_remaining_;
1552
0
      current_chunk_ = btree_reader_.Seek(offset);
1553
0
    }
1554
0
  } else {
1555
0
    current_chunk_ = {};
1556
0
  }
1557
0
}
1558
1559
0
inline Cord::ChunkIterator& Cord::ChunkIterator::operator++() {
1560
0
  ABSL_HARDENING_ASSERT(bytes_remaining_ > 0 &&
1561
0
                        "Attempted to iterate past `end()`");
1562
0
  assert(bytes_remaining_ >= current_chunk_.size());
1563
0
  bytes_remaining_ -= current_chunk_.size();
1564
0
  if (bytes_remaining_ > 0) {
1565
0
    if (btree_reader_) {
1566
0
      return AdvanceBtree();
1567
0
    } else {
1568
0
      assert(!current_chunk_.empty());  // Called on invalid iterator.
1569
0
    }
1570
0
    current_chunk_ = {};
1571
0
  }
1572
0
  return *this;
1573
0
}
1574
1575
0
inline Cord::ChunkIterator Cord::ChunkIterator::operator++(int) {
1576
0
  ChunkIterator tmp(*this);
1577
0
  operator++();
1578
0
  return tmp;
1579
0
}
1580
1581
0
inline bool Cord::ChunkIterator::operator==(const ChunkIterator& other) const {
1582
0
  return bytes_remaining_ == other.bytes_remaining_;
1583
0
}
1584
1585
0
inline bool Cord::ChunkIterator::operator!=(const ChunkIterator& other) const {
1586
0
  return !(*this == other);
1587
0
}
1588
1589
0
inline Cord::ChunkIterator::reference Cord::ChunkIterator::operator*() const {
1590
0
  ABSL_HARDENING_ASSERT(bytes_remaining_ != 0);
1591
0
  return current_chunk_;
1592
0
}
1593
1594
0
inline Cord::ChunkIterator::pointer Cord::ChunkIterator::operator->() const {
1595
0
  ABSL_HARDENING_ASSERT(bytes_remaining_ != 0);
1596
0
  return &current_chunk_;
1597
0
}
1598
1599
0
inline void Cord::ChunkIterator::RemoveChunkPrefix(size_t n) {
1600
0
  assert(n < current_chunk_.size());
1601
0
  current_chunk_.remove_prefix(n);
1602
0
  bytes_remaining_ -= n;
1603
0
}
1604
1605
0
inline void Cord::ChunkIterator::AdvanceBytes(size_t n) {
1606
0
  assert(bytes_remaining_ >= n);
1607
0
  if (ABSL_PREDICT_TRUE(n < current_chunk_.size())) {
1608
0
    RemoveChunkPrefix(n);
1609
0
  } else if (n != 0) {
1610
0
    if (btree_reader_) {
1611
0
      AdvanceBytesBtree(n);
1612
0
    } else {
1613
0
      bytes_remaining_ = 0;
1614
0
    }
1615
0
  }
1616
0
}
1617
1618
0
inline Cord::ChunkIterator Cord::chunk_begin() const {
1619
0
  return ChunkIterator(this);
1620
0
}
1621
1622
0
inline Cord::ChunkIterator Cord::chunk_end() const { return ChunkIterator(); }
1623
1624
0
inline Cord::ChunkIterator Cord::ChunkRange::begin() const {
1625
0
  return cord_->chunk_begin();
1626
0
}
1627
1628
0
inline Cord::ChunkIterator Cord::ChunkRange::end() const {
1629
0
  return cord_->chunk_end();
1630
0
}
1631
1632
0
inline Cord::ChunkRange Cord::Chunks() const { return ChunkRange(this); }
1633
1634
0
inline Cord::CharIterator& Cord::CharIterator::operator++() {
1635
0
  if (ABSL_PREDICT_TRUE(chunk_iterator_->size() > 1)) {
1636
0
    chunk_iterator_.RemoveChunkPrefix(1);
1637
0
  } else {
1638
0
    ++chunk_iterator_;
1639
0
  }
1640
0
  return *this;
1641
0
}
1642
1643
0
inline Cord::CharIterator Cord::CharIterator::operator++(int) {
1644
0
  CharIterator tmp(*this);
1645
0
  operator++();
1646
0
  return tmp;
1647
0
}
1648
1649
0
inline bool Cord::CharIterator::operator==(const CharIterator& other) const {
1650
0
  return chunk_iterator_ == other.chunk_iterator_;
1651
0
}
1652
1653
0
inline bool Cord::CharIterator::operator!=(const CharIterator& other) const {
1654
0
  return !(*this == other);
1655
0
}
1656
1657
0
inline Cord::CharIterator::reference Cord::CharIterator::operator*() const {
1658
0
  return *chunk_iterator_->data();
1659
0
}
1660
1661
inline Cord Cord::AdvanceAndRead(absl::Nonnull<CharIterator*> it,
1662
0
                                 size_t n_bytes) {
1663
0
  assert(it != nullptr);
1664
0
  return it->chunk_iterator_.AdvanceAndReadBytes(n_bytes);
1665
0
}
1666
1667
0
inline void Cord::Advance(absl::Nonnull<CharIterator*> it, size_t n_bytes) {
1668
0
  assert(it != nullptr);
1669
0
  it->chunk_iterator_.AdvanceBytes(n_bytes);
1670
0
}
1671
1672
0
inline absl::string_view Cord::ChunkRemaining(const CharIterator& it) {
1673
0
  return *it.chunk_iterator_;
1674
0
}
1675
1676
0
inline Cord::CharIterator Cord::char_begin() const {
1677
0
  return CharIterator(this);
1678
0
}
1679
1680
0
inline Cord::CharIterator Cord::char_end() const { return CharIterator(); }
1681
1682
0
inline Cord::CharIterator Cord::CharRange::begin() const {
1683
0
  return cord_->char_begin();
1684
0
}
1685
1686
0
inline Cord::CharIterator Cord::CharRange::end() const {
1687
0
  return cord_->char_end();
1688
0
}
1689
1690
0
inline Cord::CharRange Cord::Chars() const { return CharRange(this); }
1691
1692
inline void Cord::ForEachChunk(
1693
0
    absl::FunctionRef<void(absl::string_view)> callback) const {
1694
0
  absl::cord_internal::CordRep* rep = contents_.tree();
1695
0
  if (rep == nullptr) {
1696
0
    callback(absl::string_view(contents_.data(), contents_.size()));
1697
0
  } else {
1698
0
    ForEachChunkAux(rep, callback);
1699
0
  }
1700
0
}
1701
1702
// Nonmember Cord-to-Cord relational operators.
1703
0
inline bool operator==(const Cord& lhs, const Cord& rhs) {
1704
0
  if (lhs.contents_.IsSame(rhs.contents_)) return true;
1705
0
  size_t rhs_size = rhs.size();
1706
0
  if (lhs.size() != rhs_size) return false;
1707
0
  return lhs.EqualsImpl(rhs, rhs_size);
1708
0
}
1709
1710
0
inline bool operator!=(const Cord& x, const Cord& y) { return !(x == y); }
1711
0
inline bool operator<(const Cord& x, const Cord& y) { return x.Compare(y) < 0; }
1712
0
inline bool operator>(const Cord& x, const Cord& y) { return x.Compare(y) > 0; }
1713
0
inline bool operator<=(const Cord& x, const Cord& y) {
1714
0
  return x.Compare(y) <= 0;
1715
0
}
1716
0
inline bool operator>=(const Cord& x, const Cord& y) {
1717
0
  return x.Compare(y) >= 0;
1718
0
}
1719
1720
// Nonmember Cord-to-absl::string_view relational operators.
1721
//
1722
// Due to implicit conversions, these also enable comparisons of Cord with
1723
// std::string and const char*.
1724
0
inline bool operator==(const Cord& lhs, absl::string_view rhs) {
1725
0
  size_t lhs_size = lhs.size();
1726
0
  size_t rhs_size = rhs.size();
1727
0
  if (lhs_size != rhs_size) return false;
1728
0
  return lhs.EqualsImpl(rhs, rhs_size);
1729
0
}
1730
1731
0
inline bool operator==(absl::string_view x, const Cord& y) { return y == x; }
1732
0
inline bool operator!=(const Cord& x, absl::string_view y) { return !(x == y); }
1733
0
inline bool operator!=(absl::string_view x, const Cord& y) { return !(x == y); }
1734
0
inline bool operator<(const Cord& x, absl::string_view y) {
1735
0
  return x.Compare(y) < 0;
1736
0
}
1737
0
inline bool operator<(absl::string_view x, const Cord& y) {
1738
0
  return y.Compare(x) > 0;
1739
0
}
1740
0
inline bool operator>(const Cord& x, absl::string_view y) { return y < x; }
1741
0
inline bool operator>(absl::string_view x, const Cord& y) { return y < x; }
1742
0
inline bool operator<=(const Cord& x, absl::string_view y) { return !(y < x); }
1743
0
inline bool operator<=(absl::string_view x, const Cord& y) { return !(y < x); }
1744
0
inline bool operator>=(const Cord& x, absl::string_view y) { return !(x < y); }
1745
0
inline bool operator>=(absl::string_view x, const Cord& y) { return !(x < y); }
1746
1747
// Some internals exposed to test code.
1748
namespace strings_internal {
1749
class CordTestAccess {
1750
 public:
1751
  static size_t FlatOverhead();
1752
  static size_t MaxFlatLength();
1753
  static size_t SizeofCordRepExternal();
1754
  static size_t SizeofCordRepSubstring();
1755
  static size_t FlatTagToLength(uint8_t tag);
1756
  static uint8_t LengthToTag(size_t s);
1757
};
1758
}  // namespace strings_internal
1759
ABSL_NAMESPACE_END
1760
}  // namespace absl
1761
1762
#endif  // ABSL_STRINGS_CORD_H_