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2020 lines
63 KiB
2020 lines
63 KiB
// 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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#include "absl/strings/cord.h"
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#include <algorithm>
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#include <cstddef>
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#include <cstdio>
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#include <cstdlib>
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#include <iomanip>
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#include <limits>
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#include <ostream>
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#include <sstream>
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#include <type_traits>
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#include <unordered_set>
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#include <vector>
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#include "absl/base/casts.h"
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#include "absl/base/internal/raw_logging.h"
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#include "absl/base/port.h"
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#include "absl/container/fixed_array.h"
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#include "absl/container/inlined_vector.h"
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#include "absl/strings/escaping.h"
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#include "absl/strings/internal/cord_internal.h"
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#include "absl/strings/internal/resize_uninitialized.h"
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#include "absl/strings/str_cat.h"
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#include "absl/strings/str_format.h"
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#include "absl/strings/str_join.h"
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#include "absl/strings/string_view.h"
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namespace absl {
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ABSL_NAMESPACE_BEGIN
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using ::absl::cord_internal::CordRep;
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using ::absl::cord_internal::CordRepConcat;
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using ::absl::cord_internal::CordRepExternal;
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using ::absl::cord_internal::CordRepSubstring;
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// Various representations that we allow
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enum CordRepKind {
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CONCAT = 0,
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EXTERNAL = 1,
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SUBSTRING = 2,
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// We have different tags for different sized flat arrays,
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// starting with FLAT
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FLAT = 3,
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};
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namespace {
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// Type used with std::allocator for allocating and deallocating
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// `CordRepExternal`. std::allocator is used because it opaquely handles the
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// different new / delete overloads available on a given platform.
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struct alignas(absl::cord_internal::ExternalRepAlignment()) ExternalAllocType {
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unsigned char value[absl::cord_internal::ExternalRepAlignment()];
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};
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// Returns the number of objects to pass in to std::allocator<ExternalAllocType>
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// allocate() and deallocate() to create enough room for `CordRepExternal` with
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// `releaser_size` bytes on the end.
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constexpr size_t GetExternalAllocNumObjects(size_t releaser_size) {
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// Be sure to round up since `releaser_size` could be smaller than
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// `sizeof(ExternalAllocType)`.
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return (sizeof(CordRepExternal) + releaser_size + sizeof(ExternalAllocType) -
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1) /
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sizeof(ExternalAllocType);
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}
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// Allocates enough memory for `CordRepExternal` and a releaser with size
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// `releaser_size` bytes.
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void* AllocateExternal(size_t releaser_size) {
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return std::allocator<ExternalAllocType>().allocate(
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GetExternalAllocNumObjects(releaser_size));
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}
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// Deallocates the memory for a `CordRepExternal` assuming it was allocated with
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// a releaser of given size and alignment.
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void DeallocateExternal(CordRepExternal* p, size_t releaser_size) {
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std::allocator<ExternalAllocType>().deallocate(
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reinterpret_cast<ExternalAllocType*>(p),
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GetExternalAllocNumObjects(releaser_size));
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}
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// Returns a pointer to the type erased releaser for the given CordRepExternal.
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void* GetExternalReleaser(CordRepExternal* rep) {
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return rep + 1;
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}
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} // namespace
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namespace cord_internal {
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inline CordRepConcat* CordRep::concat() {
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assert(tag == CONCAT);
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return static_cast<CordRepConcat*>(this);
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}
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inline const CordRepConcat* CordRep::concat() const {
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assert(tag == CONCAT);
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return static_cast<const CordRepConcat*>(this);
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}
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inline CordRepSubstring* CordRep::substring() {
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assert(tag == SUBSTRING);
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return static_cast<CordRepSubstring*>(this);
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}
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inline const CordRepSubstring* CordRep::substring() const {
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assert(tag == SUBSTRING);
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return static_cast<const CordRepSubstring*>(this);
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}
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inline CordRepExternal* CordRep::external() {
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assert(tag == EXTERNAL);
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return static_cast<CordRepExternal*>(this);
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}
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inline const CordRepExternal* CordRep::external() const {
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assert(tag == EXTERNAL);
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return static_cast<const CordRepExternal*>(this);
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}
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} // namespace cord_internal
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static const size_t kFlatOverhead = offsetof(CordRep, data);
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static_assert(kFlatOverhead == 13, "Unittests assume kFlatOverhead == 13");
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// Largest and smallest flat node lengths we are willing to allocate
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// Flat allocation size is stored in tag, which currently can encode sizes up
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// to 4K, encoded as multiple of either 8 or 32 bytes.
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// If we allow for larger sizes, we need to change this to 8/64, 16/128, etc.
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static constexpr size_t kMaxFlatSize = 4096;
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static constexpr size_t kMaxFlatLength = kMaxFlatSize - kFlatOverhead;
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static constexpr size_t kMinFlatLength = 32 - kFlatOverhead;
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// Prefer copying blocks of at most this size, otherwise reference count.
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static const size_t kMaxBytesToCopy = 511;
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// Helper functions for rounded div, and rounding to exact sizes.
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static size_t DivUp(size_t n, size_t m) { return (n + m - 1) / m; }
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static size_t RoundUp(size_t n, size_t m) { return DivUp(n, m) * m; }
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// Returns the size to the nearest equal or larger value that can be
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// expressed exactly as a tag value.
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static size_t RoundUpForTag(size_t size) {
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return RoundUp(size, (size <= 1024) ? 8 : 32);
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}
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// Converts the allocated size to a tag, rounding down if the size
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// does not exactly match a 'tag expressible' size value. The result is
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// undefined if the size exceeds the maximum size that can be encoded in
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// a tag, i.e., if size is larger than TagToAllocatedSize(<max tag>).
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static uint8_t AllocatedSizeToTag(size_t size) {
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const size_t tag = (size <= 1024) ? size / 8 : 128 + size / 32 - 1024 / 32;
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assert(tag <= std::numeric_limits<uint8_t>::max());
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return tag;
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}
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// Converts the provided tag to the corresponding allocated size
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static constexpr size_t TagToAllocatedSize(uint8_t tag) {
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return (tag <= 128) ? (tag * 8) : (1024 + (tag - 128) * 32);
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}
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// Converts the provided tag to the corresponding available data length
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static constexpr size_t TagToLength(uint8_t tag) {
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return TagToAllocatedSize(tag) - kFlatOverhead;
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}
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// Enforce that kMaxFlatSize maps to a well-known exact tag value.
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static_assert(TagToAllocatedSize(224) == kMaxFlatSize, "Bad tag logic");
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constexpr uint64_t Fibonacci(unsigned char n, uint64_t a = 0, uint64_t b = 1) {
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return n == 0 ? a : Fibonacci(n - 1, b, a + b);
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}
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static_assert(Fibonacci(63) == 6557470319842,
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"Fibonacci values computed incorrectly");
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// Minimum length required for a given depth tree -- a tree is considered
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// balanced if
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// length(t) >= min_length[depth(t)]
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// The root node depth is allowed to become twice as large to reduce rebalancing
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// for larger strings (see IsRootBalanced).
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static constexpr uint64_t min_length[] = {
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Fibonacci(2),
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Fibonacci(3),
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Fibonacci(4),
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Fibonacci(5),
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Fibonacci(6),
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Fibonacci(7),
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Fibonacci(8),
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Fibonacci(9),
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Fibonacci(10),
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Fibonacci(11),
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Fibonacci(12),
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Fibonacci(13),
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Fibonacci(14),
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Fibonacci(15),
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Fibonacci(16),
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Fibonacci(17),
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Fibonacci(18),
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Fibonacci(19),
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Fibonacci(20),
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Fibonacci(21),
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Fibonacci(22),
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Fibonacci(23),
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Fibonacci(24),
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Fibonacci(25),
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Fibonacci(26),
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Fibonacci(27),
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Fibonacci(28),
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Fibonacci(29),
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Fibonacci(30),
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Fibonacci(31),
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Fibonacci(32),
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Fibonacci(33),
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Fibonacci(34),
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Fibonacci(35),
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Fibonacci(36),
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Fibonacci(37),
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Fibonacci(38),
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Fibonacci(39),
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Fibonacci(40),
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Fibonacci(41),
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Fibonacci(42),
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Fibonacci(43),
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Fibonacci(44),
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Fibonacci(45),
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Fibonacci(46),
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Fibonacci(47),
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0xffffffffffffffffull, // Avoid overflow
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};
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static const int kMinLengthSize = ABSL_ARRAYSIZE(min_length);
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// The inlined size to use with absl::InlinedVector.
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//
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// Note: The InlinedVectors in this file (and in cord.h) do not need to use
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// the same value for their inlined size. The fact that they do is historical.
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// It may be desirable for each to use a different inlined size optimized for
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// that InlinedVector's usage.
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//
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// TODO(jgm): Benchmark to see if there's a more optimal value than 47 for
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// the inlined vector size (47 exists for backward compatibility).
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static const int kInlinedVectorSize = 47;
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static inline bool IsRootBalanced(CordRep* node) {
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if (node->tag != CONCAT) {
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return true;
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} else if (node->concat()->depth() <= 15) {
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return true;
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} else if (node->concat()->depth() > kMinLengthSize) {
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return false;
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} else {
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// Allow depth to become twice as large as implied by fibonacci rule to
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// reduce rebalancing for larger strings.
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return (node->length >= min_length[node->concat()->depth() / 2]);
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}
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}
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static CordRep* Rebalance(CordRep* node);
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static void DumpNode(CordRep* rep, bool include_data, std::ostream* os);
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static bool VerifyNode(CordRep* root, CordRep* start_node,
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bool full_validation);
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static inline CordRep* VerifyTree(CordRep* node) {
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// Verification is expensive, so only do it in debug mode.
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// Even in debug mode we normally do only light validation.
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// If you are debugging Cord itself, you should define the
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// macro EXTRA_CORD_VALIDATION, e.g. by adding
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// --copt=-DEXTRA_CORD_VALIDATION to the blaze line.
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#ifdef EXTRA_CORD_VALIDATION
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assert(node == nullptr || VerifyNode(node, node, /*full_validation=*/true));
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#else // EXTRA_CORD_VALIDATION
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assert(node == nullptr || VerifyNode(node, node, /*full_validation=*/false));
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#endif // EXTRA_CORD_VALIDATION
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static_cast<void>(&VerifyNode);
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return node;
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}
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// --------------------------------------------------------------------
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// Memory management
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inline CordRep* Ref(CordRep* rep) {
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if (rep != nullptr) {
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rep->refcount.Increment();
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}
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return rep;
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}
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// This internal routine is called from the cold path of Unref below. Keeping it
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// in a separate routine allows good inlining of Unref into many profitable call
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// sites. However, the call to this function can be highly disruptive to the
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// register pressure in those callers. To minimize the cost to callers, we use
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// a special LLVM calling convention that preserves most registers. This allows
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// the call to this routine in cold paths to not disrupt the caller's register
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// pressure. This calling convention is not available on all platforms; we
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// intentionally allow LLVM to ignore the attribute rather than attempting to
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// hardcode the list of supported platforms.
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#if defined(__clang__) && !defined(__i386__)
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#pragma clang diagnostic push
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#pragma clang diagnostic ignored "-Wattributes"
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__attribute__((preserve_most))
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#pragma clang diagnostic pop
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#endif
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static void UnrefInternal(CordRep* rep) {
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assert(rep != nullptr);
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absl::InlinedVector<CordRep*, kInlinedVectorSize> pending;
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while (true) {
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if (rep->tag == CONCAT) {
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CordRepConcat* rep_concat = rep->concat();
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CordRep* right = rep_concat->right;
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if (!right->refcount.Decrement()) {
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pending.push_back(right);
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}
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CordRep* left = rep_concat->left;
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delete rep_concat;
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rep = nullptr;
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if (!left->refcount.Decrement()) {
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rep = left;
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continue;
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}
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} else if (rep->tag == EXTERNAL) {
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CordRepExternal* rep_external = rep->external();
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absl::string_view data(rep_external->base, rep->length);
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void* releaser = GetExternalReleaser(rep_external);
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size_t releaser_size = rep_external->releaser_invoker(releaser, data);
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rep_external->~CordRepExternal();
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DeallocateExternal(rep_external, releaser_size);
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rep = nullptr;
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} else if (rep->tag == SUBSTRING) {
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CordRepSubstring* rep_substring = rep->substring();
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CordRep* child = rep_substring->child;
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delete rep_substring;
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rep = nullptr;
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if (!child->refcount.Decrement()) {
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rep = child;
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continue;
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}
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} else {
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// Flat CordReps are allocated and constructed with raw ::operator new
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// and placement new, and must be destructed and deallocated
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// accordingly.
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#if defined(__cpp_sized_deallocation)
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size_t size = TagToAllocatedSize(rep->tag);
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rep->~CordRep();
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::operator delete(rep, size);
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#else
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rep->~CordRep();
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::operator delete(rep);
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#endif
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rep = nullptr;
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}
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if (!pending.empty()) {
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rep = pending.back();
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pending.pop_back();
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} else {
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break;
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}
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}
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}
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inline void Unref(CordRep* rep) {
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// Fast-path for two common, hot cases: a null rep and a shared root.
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if (ABSL_PREDICT_TRUE(rep == nullptr ||
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rep->refcount.DecrementExpectHighRefcount())) {
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return;
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}
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UnrefInternal(rep);
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}
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// Return the depth of a node
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static int Depth(const CordRep* rep) {
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if (rep->tag == CONCAT) {
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return rep->concat()->depth();
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} else {
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return 0;
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}
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}
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static void SetConcatChildren(CordRepConcat* concat, CordRep* left,
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CordRep* right) {
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concat->left = left;
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concat->right = right;
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concat->length = left->length + right->length;
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concat->set_depth(1 + std::max(Depth(left), Depth(right)));
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}
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// Create a concatenation of the specified nodes.
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// Does not change the refcounts of "left" and "right".
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// The returned node has a refcount of 1.
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static CordRep* RawConcat(CordRep* left, CordRep* right) {
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// Avoid making degenerate concat nodes (one child is empty)
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if (left == nullptr || left->length == 0) {
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Unref(left);
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return right;
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}
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if (right == nullptr || right->length == 0) {
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Unref(right);
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return left;
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}
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CordRepConcat* rep = new CordRepConcat();
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rep->tag = CONCAT;
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SetConcatChildren(rep, left, right);
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return rep;
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}
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static CordRep* Concat(CordRep* left, CordRep* right) {
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CordRep* rep = RawConcat(left, right);
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if (rep != nullptr && !IsRootBalanced(rep)) {
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rep = Rebalance(rep);
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}
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return VerifyTree(rep);
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}
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// Make a balanced tree out of an array of leaf nodes.
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static CordRep* MakeBalancedTree(CordRep** reps, size_t n) {
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// Make repeated passes over the array, merging adjacent pairs
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// until we are left with just a single node.
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while (n > 1) {
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size_t dst = 0;
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for (size_t src = 0; src < n; src += 2) {
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if (src + 1 < n) {
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reps[dst] = Concat(reps[src], reps[src + 1]);
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} else {
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reps[dst] = reps[src];
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}
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dst++;
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}
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n = dst;
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}
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return reps[0];
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}
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// Create a new flat node.
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static CordRep* NewFlat(size_t length_hint) {
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if (length_hint <= kMinFlatLength) {
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length_hint = kMinFlatLength;
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} else if (length_hint > kMaxFlatLength) {
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length_hint = kMaxFlatLength;
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}
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// Round size up so it matches a size we can exactly express in a tag.
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const size_t size = RoundUpForTag(length_hint + kFlatOverhead);
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void* const raw_rep = ::operator new(size);
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CordRep* rep = new (raw_rep) CordRep();
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rep->tag = AllocatedSizeToTag(size);
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return VerifyTree(rep);
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}
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// Create a new tree out of the specified array.
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// The returned node has a refcount of 1.
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static CordRep* NewTree(const char* data,
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size_t length,
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size_t alloc_hint) {
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if (length == 0) return nullptr;
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absl::FixedArray<CordRep*> reps((length - 1) / kMaxFlatLength + 1);
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size_t n = 0;
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do {
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const size_t len = std::min(length, kMaxFlatLength);
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CordRep* rep = NewFlat(len + alloc_hint);
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rep->length = len;
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memcpy(rep->data, data, len);
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reps[n++] = VerifyTree(rep);
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data += len;
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length -= len;
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} while (length != 0);
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return MakeBalancedTree(reps.data(), n);
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}
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namespace cord_internal {
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ExternalRepReleaserPair NewExternalWithUninitializedReleaser(
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absl::string_view data, ExternalReleaserInvoker invoker,
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size_t releaser_size) {
|
|
assert(!data.empty());
|
|
|
|
void* raw_rep = AllocateExternal(releaser_size);
|
|
auto* rep = new (raw_rep) CordRepExternal();
|
|
rep->length = data.size();
|
|
rep->tag = EXTERNAL;
|
|
rep->base = data.data();
|
|
rep->releaser_invoker = invoker;
|
|
return {VerifyTree(rep), GetExternalReleaser(rep)};
|
|
}
|
|
|
|
} // namespace cord_internal
|
|
|
|
static CordRep* NewSubstring(CordRep* child, size_t offset, size_t length) {
|
|
// Never create empty substring nodes
|
|
if (length == 0) {
|
|
Unref(child);
|
|
return nullptr;
|
|
} else {
|
|
CordRepSubstring* rep = new CordRepSubstring();
|
|
assert((offset + length) <= child->length);
|
|
rep->length = length;
|
|
rep->tag = SUBSTRING;
|
|
rep->start = offset;
|
|
rep->child = child;
|
|
return VerifyTree(rep);
|
|
}
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
// Cord::InlineRep functions
|
|
|
|
// This will trigger LNK2005 in MSVC.
|
|
#ifndef COMPILER_MSVC
|
|
const unsigned char Cord::InlineRep::kMaxInline;
|
|
#endif // COMPILER_MSVC
|
|
|
|
inline void Cord::InlineRep::set_data(const char* data, size_t n,
|
|
bool nullify_tail) {
|
|
static_assert(kMaxInline == 15, "set_data is hard-coded for a length of 15");
|
|
|
|
cord_internal::SmallMemmove(data_, data, n, nullify_tail);
|
|
data_[kMaxInline] = static_cast<char>(n);
|
|
}
|
|
|
|
inline char* Cord::InlineRep::set_data(size_t n) {
|
|
assert(n <= kMaxInline);
|
|
memset(data_, 0, sizeof(data_));
|
|
data_[kMaxInline] = static_cast<char>(n);
|
|
return data_;
|
|
}
|
|
|
|
inline CordRep* Cord::InlineRep::force_tree(size_t extra_hint) {
|
|
size_t len = data_[kMaxInline];
|
|
CordRep* result;
|
|
if (len > kMaxInline) {
|
|
memcpy(&result, data_, sizeof(result));
|
|
} else {
|
|
result = NewFlat(len + extra_hint);
|
|
result->length = len;
|
|
memcpy(result->data, data_, len);
|
|
set_tree(result);
|
|
}
|
|
return result;
|
|
}
|
|
|
|
inline void Cord::InlineRep::reduce_size(size_t n) {
|
|
size_t tag = data_[kMaxInline];
|
|
assert(tag <= kMaxInline);
|
|
assert(tag >= n);
|
|
tag -= n;
|
|
memset(data_ + tag, 0, n);
|
|
data_[kMaxInline] = static_cast<char>(tag);
|
|
}
|
|
|
|
inline void Cord::InlineRep::remove_prefix(size_t n) {
|
|
cord_internal::SmallMemmove(data_, data_ + n, data_[kMaxInline] - n);
|
|
reduce_size(n);
|
|
}
|
|
|
|
void Cord::InlineRep::AppendTree(CordRep* tree) {
|
|
if (tree == nullptr) return;
|
|
size_t len = data_[kMaxInline];
|
|
if (len == 0) {
|
|
set_tree(tree);
|
|
} else {
|
|
set_tree(Concat(force_tree(0), tree));
|
|
}
|
|
}
|
|
|
|
void Cord::InlineRep::PrependTree(CordRep* tree) {
|
|
if (tree == nullptr) return;
|
|
size_t len = data_[kMaxInline];
|
|
if (len == 0) {
|
|
set_tree(tree);
|
|
} else {
|
|
set_tree(Concat(tree, force_tree(0)));
|
|
}
|
|
}
|
|
|
|
// Searches for a non-full flat node at the rightmost leaf of the tree. If a
|
|
// suitable leaf is found, the function will update the length field for all
|
|
// nodes to account for the size increase. The append region address will be
|
|
// written to region and the actual size increase will be written to size.
|
|
static inline bool PrepareAppendRegion(CordRep* root, char** region,
|
|
size_t* size, size_t max_length) {
|
|
// Search down the right-hand path for a non-full FLAT node.
|
|
CordRep* dst = root;
|
|
while (dst->tag == CONCAT && dst->refcount.IsOne()) {
|
|
dst = dst->concat()->right;
|
|
}
|
|
|
|
if (dst->tag < FLAT || !dst->refcount.IsOne()) {
|
|
*region = nullptr;
|
|
*size = 0;
|
|
return false;
|
|
}
|
|
|
|
const size_t in_use = dst->length;
|
|
const size_t capacity = TagToLength(dst->tag);
|
|
if (in_use == capacity) {
|
|
*region = nullptr;
|
|
*size = 0;
|
|
return false;
|
|
}
|
|
|
|
size_t size_increase = std::min(capacity - in_use, max_length);
|
|
|
|
// We need to update the length fields for all nodes, including the leaf node.
|
|
for (CordRep* rep = root; rep != dst; rep = rep->concat()->right) {
|
|
rep->length += size_increase;
|
|
}
|
|
dst->length += size_increase;
|
|
|
|
*region = dst->data + in_use;
|
|
*size = size_increase;
|
|
return true;
|
|
}
|
|
|
|
void Cord::InlineRep::GetAppendRegion(char** region, size_t* size,
|
|
size_t max_length) {
|
|
if (max_length == 0) {
|
|
*region = nullptr;
|
|
*size = 0;
|
|
return;
|
|
}
|
|
|
|
// Try to fit in the inline buffer if possible.
|
|
size_t inline_length = data_[kMaxInline];
|
|
if (inline_length < kMaxInline && max_length <= kMaxInline - inline_length) {
|
|
*region = data_ + inline_length;
|
|
*size = max_length;
|
|
data_[kMaxInline] = static_cast<char>(inline_length + max_length);
|
|
return;
|
|
}
|
|
|
|
CordRep* root = force_tree(max_length);
|
|
|
|
if (PrepareAppendRegion(root, region, size, max_length)) {
|
|
return;
|
|
}
|
|
|
|
// Allocate new node.
|
|
CordRep* new_node =
|
|
NewFlat(std::max(static_cast<size_t>(root->length), max_length));
|
|
new_node->length =
|
|
std::min(static_cast<size_t>(TagToLength(new_node->tag)), max_length);
|
|
*region = new_node->data;
|
|
*size = new_node->length;
|
|
replace_tree(Concat(root, new_node));
|
|
}
|
|
|
|
void Cord::InlineRep::GetAppendRegion(char** region, size_t* size) {
|
|
const size_t max_length = std::numeric_limits<size_t>::max();
|
|
|
|
// Try to fit in the inline buffer if possible.
|
|
size_t inline_length = data_[kMaxInline];
|
|
if (inline_length < kMaxInline) {
|
|
*region = data_ + inline_length;
|
|
*size = kMaxInline - inline_length;
|
|
data_[kMaxInline] = kMaxInline;
|
|
return;
|
|
}
|
|
|
|
CordRep* root = force_tree(max_length);
|
|
|
|
if (PrepareAppendRegion(root, region, size, max_length)) {
|
|
return;
|
|
}
|
|
|
|
// Allocate new node.
|
|
CordRep* new_node = NewFlat(root->length);
|
|
new_node->length = TagToLength(new_node->tag);
|
|
*region = new_node->data;
|
|
*size = new_node->length;
|
|
replace_tree(Concat(root, new_node));
|
|
}
|
|
|
|
// If the rep is a leaf, this will increment the value at total_mem_usage and
|
|
// will return true.
|
|
static bool RepMemoryUsageLeaf(const CordRep* rep, size_t* total_mem_usage) {
|
|
if (rep->tag >= FLAT) {
|
|
*total_mem_usage += TagToAllocatedSize(rep->tag);
|
|
return true;
|
|
}
|
|
if (rep->tag == EXTERNAL) {
|
|
*total_mem_usage += sizeof(CordRepConcat) + rep->length;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
void Cord::InlineRep::AssignSlow(const Cord::InlineRep& src) {
|
|
ClearSlow();
|
|
|
|
memcpy(data_, src.data_, sizeof(data_));
|
|
if (is_tree()) {
|
|
Ref(tree());
|
|
}
|
|
}
|
|
|
|
void Cord::InlineRep::ClearSlow() {
|
|
if (is_tree()) {
|
|
Unref(tree());
|
|
}
|
|
memset(data_, 0, sizeof(data_));
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
// Constructors and destructors
|
|
|
|
Cord::Cord(const Cord& src) : contents_(src.contents_) {
|
|
Ref(contents_.tree()); // Does nothing if contents_ has embedded data
|
|
}
|
|
|
|
Cord::Cord(absl::string_view src) {
|
|
const size_t n = src.size();
|
|
if (n <= InlineRep::kMaxInline) {
|
|
contents_.set_data(src.data(), n, false);
|
|
} else {
|
|
contents_.set_tree(NewTree(src.data(), n, 0));
|
|
}
|
|
}
|
|
|
|
// The destruction code is separate so that the compiler can determine
|
|
// that it does not need to call the destructor on a moved-from Cord.
|
|
void Cord::DestroyCordSlow() {
|
|
Unref(VerifyTree(contents_.tree()));
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
// Mutators
|
|
|
|
void Cord::Clear() {
|
|
Unref(contents_.clear());
|
|
}
|
|
|
|
Cord& Cord::operator=(absl::string_view src) {
|
|
|
|
const char* data = src.data();
|
|
size_t length = src.size();
|
|
CordRep* tree = contents_.tree();
|
|
if (length <= InlineRep::kMaxInline) {
|
|
// Embed into this->contents_
|
|
contents_.set_data(data, length, true);
|
|
Unref(tree);
|
|
return *this;
|
|
}
|
|
if (tree != nullptr && tree->tag >= FLAT &&
|
|
TagToLength(tree->tag) >= length && tree->refcount.IsOne()) {
|
|
// Copy in place if the existing FLAT node is reusable.
|
|
memmove(tree->data, data, length);
|
|
tree->length = length;
|
|
VerifyTree(tree);
|
|
return *this;
|
|
}
|
|
contents_.set_tree(NewTree(data, length, 0));
|
|
Unref(tree);
|
|
return *this;
|
|
}
|
|
|
|
// TODO(sanjay): Move to Cord::InlineRep section of file. For now,
|
|
// we keep it here to make diffs easier.
|
|
void Cord::InlineRep::AppendArray(const char* src_data, size_t src_size) {
|
|
if (src_size == 0) return; // memcpy(_, nullptr, 0) is undefined.
|
|
// Try to fit in the inline buffer if possible.
|
|
size_t inline_length = data_[kMaxInline];
|
|
if (inline_length < kMaxInline && src_size <= kMaxInline - inline_length) {
|
|
// Append new data to embedded array
|
|
data_[kMaxInline] = static_cast<char>(inline_length + src_size);
|
|
memcpy(data_ + inline_length, src_data, src_size);
|
|
return;
|
|
}
|
|
|
|
CordRep* root = tree();
|
|
|
|
size_t appended = 0;
|
|
if (root) {
|
|
char* region;
|
|
if (PrepareAppendRegion(root, ®ion, &appended, src_size)) {
|
|
memcpy(region, src_data, appended);
|
|
}
|
|
} else {
|
|
// It is possible that src_data == data_, but when we transition from an
|
|
// InlineRep to a tree we need to assign data_ = root via set_tree. To
|
|
// avoid corrupting the source data before we copy it, delay calling
|
|
// set_tree until after we've copied data.
|
|
// We are going from an inline size to beyond inline size. Make the new size
|
|
// either double the inlined size, or the added size + 10%.
|
|
const size_t size1 = inline_length * 2 + src_size;
|
|
const size_t size2 = inline_length + src_size / 10;
|
|
root = NewFlat(std::max<size_t>(size1, size2));
|
|
appended = std::min(src_size, TagToLength(root->tag) - inline_length);
|
|
memcpy(root->data, data_, inline_length);
|
|
memcpy(root->data + inline_length, src_data, appended);
|
|
root->length = inline_length + appended;
|
|
set_tree(root);
|
|
}
|
|
|
|
src_data += appended;
|
|
src_size -= appended;
|
|
if (src_size == 0) {
|
|
return;
|
|
}
|
|
|
|
// Use new block(s) for any remaining bytes that were not handled above.
|
|
// Alloc extra memory only if the right child of the root of the new tree is
|
|
// going to be a FLAT node, which will permit further inplace appends.
|
|
size_t length = src_size;
|
|
if (src_size < kMaxFlatLength) {
|
|
// The new length is either
|
|
// - old size + 10%
|
|
// - old_size + src_size
|
|
// This will cause a reasonable conservative step-up in size that is still
|
|
// large enough to avoid excessive amounts of small fragments being added.
|
|
length = std::max<size_t>(root->length / 10, src_size);
|
|
}
|
|
set_tree(Concat(root, NewTree(src_data, src_size, length - src_size)));
|
|
}
|
|
|
|
inline CordRep* Cord::TakeRep() const& {
|
|
return Ref(contents_.tree());
|
|
}
|
|
|
|
inline CordRep* Cord::TakeRep() && {
|
|
CordRep* rep = contents_.tree();
|
|
contents_.clear();
|
|
return rep;
|
|
}
|
|
|
|
template <typename C>
|
|
inline void Cord::AppendImpl(C&& src) {
|
|
if (empty()) {
|
|
// In case of an empty destination avoid allocating a new node, do not copy
|
|
// data.
|
|
*this = std::forward<C>(src);
|
|
return;
|
|
}
|
|
|
|
// For short cords, it is faster to copy data if there is room in dst.
|
|
const size_t src_size = src.contents_.size();
|
|
if (src_size <= kMaxBytesToCopy) {
|
|
CordRep* src_tree = src.contents_.tree();
|
|
if (src_tree == nullptr) {
|
|
// src has embedded data.
|
|
contents_.AppendArray(src.contents_.data(), src_size);
|
|
return;
|
|
}
|
|
if (src_tree->tag >= FLAT) {
|
|
// src tree just has one flat node.
|
|
contents_.AppendArray(src_tree->data, src_size);
|
|
return;
|
|
}
|
|
if (&src == this) {
|
|
// ChunkIterator below assumes that src is not modified during traversal.
|
|
Append(Cord(src));
|
|
return;
|
|
}
|
|
// TODO(mec): Should we only do this if "dst" has space?
|
|
for (absl::string_view chunk : src.Chunks()) {
|
|
Append(chunk);
|
|
}
|
|
return;
|
|
}
|
|
|
|
contents_.AppendTree(std::forward<C>(src).TakeRep());
|
|
}
|
|
|
|
void Cord::Append(const Cord& src) { AppendImpl(src); }
|
|
|
|
void Cord::Append(Cord&& src) { AppendImpl(std::move(src)); }
|
|
|
|
void Cord::Prepend(const Cord& src) {
|
|
CordRep* src_tree = src.contents_.tree();
|
|
if (src_tree != nullptr) {
|
|
Ref(src_tree);
|
|
contents_.PrependTree(src_tree);
|
|
return;
|
|
}
|
|
|
|
// `src` cord is inlined.
|
|
absl::string_view src_contents(src.contents_.data(), src.contents_.size());
|
|
return Prepend(src_contents);
|
|
}
|
|
|
|
void Cord::Prepend(absl::string_view src) {
|
|
if (src.empty()) return; // memcpy(_, nullptr, 0) is undefined.
|
|
size_t cur_size = contents_.size();
|
|
if (!contents_.is_tree() && cur_size + src.size() <= InlineRep::kMaxInline) {
|
|
// Use embedded storage.
|
|
char data[InlineRep::kMaxInline + 1] = {0};
|
|
data[InlineRep::kMaxInline] = cur_size + src.size(); // set size
|
|
memcpy(data, src.data(), src.size());
|
|
memcpy(data + src.size(), contents_.data(), cur_size);
|
|
memcpy(reinterpret_cast<void*>(&contents_), data,
|
|
InlineRep::kMaxInline + 1);
|
|
} else {
|
|
contents_.PrependTree(NewTree(src.data(), src.size(), 0));
|
|
}
|
|
}
|
|
|
|
static CordRep* RemovePrefixFrom(CordRep* node, size_t n) {
|
|
if (n >= node->length) return nullptr;
|
|
if (n == 0) return Ref(node);
|
|
absl::InlinedVector<CordRep*, kInlinedVectorSize> rhs_stack;
|
|
|
|
while (node->tag == CONCAT) {
|
|
assert(n <= node->length);
|
|
if (n < node->concat()->left->length) {
|
|
// Push right to stack, descend left.
|
|
rhs_stack.push_back(node->concat()->right);
|
|
node = node->concat()->left;
|
|
} else {
|
|
// Drop left, descend right.
|
|
n -= node->concat()->left->length;
|
|
node = node->concat()->right;
|
|
}
|
|
}
|
|
assert(n <= node->length);
|
|
|
|
if (n == 0) {
|
|
Ref(node);
|
|
} else {
|
|
size_t start = n;
|
|
size_t len = node->length - n;
|
|
if (node->tag == SUBSTRING) {
|
|
// Consider in-place update of node, similar to in RemoveSuffixFrom().
|
|
start += node->substring()->start;
|
|
node = node->substring()->child;
|
|
}
|
|
node = NewSubstring(Ref(node), start, len);
|
|
}
|
|
while (!rhs_stack.empty()) {
|
|
node = Concat(node, Ref(rhs_stack.back()));
|
|
rhs_stack.pop_back();
|
|
}
|
|
return node;
|
|
}
|
|
|
|
// RemoveSuffixFrom() is very similar to RemovePrefixFrom(), with the
|
|
// exception that removing a suffix has an optimization where a node may be
|
|
// edited in place iff that node and all its ancestors have a refcount of 1.
|
|
static CordRep* RemoveSuffixFrom(CordRep* node, size_t n) {
|
|
if (n >= node->length) return nullptr;
|
|
if (n == 0) return Ref(node);
|
|
absl::InlinedVector<CordRep*, kInlinedVectorSize> lhs_stack;
|
|
bool inplace_ok = node->refcount.IsOne();
|
|
|
|
while (node->tag == CONCAT) {
|
|
assert(n <= node->length);
|
|
if (n < node->concat()->right->length) {
|
|
// Push left to stack, descend right.
|
|
lhs_stack.push_back(node->concat()->left);
|
|
node = node->concat()->right;
|
|
} else {
|
|
// Drop right, descend left.
|
|
n -= node->concat()->right->length;
|
|
node = node->concat()->left;
|
|
}
|
|
inplace_ok = inplace_ok && node->refcount.IsOne();
|
|
}
|
|
assert(n <= node->length);
|
|
|
|
if (n == 0) {
|
|
Ref(node);
|
|
} else if (inplace_ok && node->tag != EXTERNAL) {
|
|
// Consider making a new buffer if the current node capacity is much
|
|
// larger than the new length.
|
|
Ref(node);
|
|
node->length -= n;
|
|
} else {
|
|
size_t start = 0;
|
|
size_t len = node->length - n;
|
|
if (node->tag == SUBSTRING) {
|
|
start = node->substring()->start;
|
|
node = node->substring()->child;
|
|
}
|
|
node = NewSubstring(Ref(node), start, len);
|
|
}
|
|
while (!lhs_stack.empty()) {
|
|
node = Concat(Ref(lhs_stack.back()), node);
|
|
lhs_stack.pop_back();
|
|
}
|
|
return node;
|
|
}
|
|
|
|
void Cord::RemovePrefix(size_t n) {
|
|
ABSL_INTERNAL_CHECK(n <= size(),
|
|
absl::StrCat("Requested prefix size ", n,
|
|
" exceeds Cord's size ", size()));
|
|
CordRep* tree = contents_.tree();
|
|
if (tree == nullptr) {
|
|
contents_.remove_prefix(n);
|
|
} else {
|
|
CordRep* newrep = RemovePrefixFrom(tree, n);
|
|
Unref(tree);
|
|
contents_.replace_tree(VerifyTree(newrep));
|
|
}
|
|
}
|
|
|
|
void Cord::RemoveSuffix(size_t n) {
|
|
ABSL_INTERNAL_CHECK(n <= size(),
|
|
absl::StrCat("Requested suffix size ", n,
|
|
" exceeds Cord's size ", size()));
|
|
CordRep* tree = contents_.tree();
|
|
if (tree == nullptr) {
|
|
contents_.reduce_size(n);
|
|
} else {
|
|
CordRep* newrep = RemoveSuffixFrom(tree, n);
|
|
Unref(tree);
|
|
contents_.replace_tree(VerifyTree(newrep));
|
|
}
|
|
}
|
|
|
|
// Work item for NewSubRange().
|
|
struct SubRange {
|
|
SubRange(CordRep* a_node, size_t a_pos, size_t a_n)
|
|
: node(a_node), pos(a_pos), n(a_n) {}
|
|
CordRep* node; // nullptr means concat last 2 results.
|
|
size_t pos;
|
|
size_t n;
|
|
};
|
|
|
|
static CordRep* NewSubRange(CordRep* node, size_t pos, size_t n) {
|
|
absl::InlinedVector<CordRep*, kInlinedVectorSize> results;
|
|
absl::InlinedVector<SubRange, kInlinedVectorSize> todo;
|
|
todo.push_back(SubRange(node, pos, n));
|
|
do {
|
|
const SubRange& sr = todo.back();
|
|
node = sr.node;
|
|
pos = sr.pos;
|
|
n = sr.n;
|
|
todo.pop_back();
|
|
|
|
if (node == nullptr) {
|
|
assert(results.size() >= 2);
|
|
CordRep* right = results.back();
|
|
results.pop_back();
|
|
CordRep* left = results.back();
|
|
results.pop_back();
|
|
results.push_back(Concat(left, right));
|
|
} else if (pos == 0 && n == node->length) {
|
|
results.push_back(Ref(node));
|
|
} else if (node->tag != CONCAT) {
|
|
if (node->tag == SUBSTRING) {
|
|
pos += node->substring()->start;
|
|
node = node->substring()->child;
|
|
}
|
|
results.push_back(NewSubstring(Ref(node), pos, n));
|
|
} else if (pos + n <= node->concat()->left->length) {
|
|
todo.push_back(SubRange(node->concat()->left, pos, n));
|
|
} else if (pos >= node->concat()->left->length) {
|
|
pos -= node->concat()->left->length;
|
|
todo.push_back(SubRange(node->concat()->right, pos, n));
|
|
} else {
|
|
size_t left_n = node->concat()->left->length - pos;
|
|
todo.push_back(SubRange(nullptr, 0, 0)); // Concat()
|
|
todo.push_back(SubRange(node->concat()->right, 0, n - left_n));
|
|
todo.push_back(SubRange(node->concat()->left, pos, left_n));
|
|
}
|
|
} while (!todo.empty());
|
|
assert(results.size() == 1);
|
|
return results[0];
|
|
}
|
|
|
|
Cord Cord::Subcord(size_t pos, size_t new_size) const {
|
|
Cord sub_cord;
|
|
size_t length = size();
|
|
if (pos > length) pos = length;
|
|
if (new_size > length - pos) new_size = length - pos;
|
|
CordRep* tree = contents_.tree();
|
|
if (tree == nullptr) {
|
|
// sub_cord is newly constructed, no need to re-zero-out the tail of
|
|
// contents_ memory.
|
|
sub_cord.contents_.set_data(contents_.data() + pos, new_size, false);
|
|
} else if (new_size == 0) {
|
|
// We want to return empty subcord, so nothing to do.
|
|
} else if (new_size <= InlineRep::kMaxInline) {
|
|
Cord::ChunkIterator it = chunk_begin();
|
|
it.AdvanceBytes(pos);
|
|
char* dest = sub_cord.contents_.data_;
|
|
size_t remaining_size = new_size;
|
|
while (remaining_size > it->size()) {
|
|
cord_internal::SmallMemmove(dest, it->data(), it->size());
|
|
remaining_size -= it->size();
|
|
dest += it->size();
|
|
++it;
|
|
}
|
|
cord_internal::SmallMemmove(dest, it->data(), remaining_size);
|
|
sub_cord.contents_.data_[InlineRep::kMaxInline] = new_size;
|
|
} else {
|
|
sub_cord.contents_.set_tree(NewSubRange(tree, pos, new_size));
|
|
}
|
|
return sub_cord;
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
// Balancing
|
|
|
|
class CordForest {
|
|
public:
|
|
explicit CordForest(size_t length)
|
|
: root_length_(length), trees_(kMinLengthSize, nullptr) {}
|
|
|
|
void Build(CordRep* cord_root) {
|
|
std::vector<CordRep*> pending = {cord_root};
|
|
|
|
while (!pending.empty()) {
|
|
CordRep* node = pending.back();
|
|
pending.pop_back();
|
|
CheckNode(node);
|
|
if (ABSL_PREDICT_FALSE(node->tag != CONCAT)) {
|
|
AddNode(node);
|
|
continue;
|
|
}
|
|
|
|
CordRepConcat* concat_node = node->concat();
|
|
if (concat_node->depth() >= kMinLengthSize ||
|
|
concat_node->length < min_length[concat_node->depth()]) {
|
|
pending.push_back(concat_node->right);
|
|
pending.push_back(concat_node->left);
|
|
|
|
if (concat_node->refcount.IsOne()) {
|
|
concat_node->left = concat_freelist_;
|
|
concat_freelist_ = concat_node;
|
|
} else {
|
|
Ref(concat_node->right);
|
|
Ref(concat_node->left);
|
|
Unref(concat_node);
|
|
}
|
|
} else {
|
|
AddNode(node);
|
|
}
|
|
}
|
|
}
|
|
|
|
CordRep* ConcatNodes() {
|
|
CordRep* sum = nullptr;
|
|
for (auto* node : trees_) {
|
|
if (node == nullptr) continue;
|
|
|
|
sum = PrependNode(node, sum);
|
|
root_length_ -= node->length;
|
|
if (root_length_ == 0) break;
|
|
}
|
|
ABSL_INTERNAL_CHECK(sum != nullptr, "Failed to locate sum node");
|
|
return VerifyTree(sum);
|
|
}
|
|
|
|
private:
|
|
CordRep* AppendNode(CordRep* node, CordRep* sum) {
|
|
return (sum == nullptr) ? node : MakeConcat(sum, node);
|
|
}
|
|
|
|
CordRep* PrependNode(CordRep* node, CordRep* sum) {
|
|
return (sum == nullptr) ? node : MakeConcat(node, sum);
|
|
}
|
|
|
|
void AddNode(CordRep* node) {
|
|
CordRep* sum = nullptr;
|
|
|
|
// Collect together everything with which we will merge node
|
|
int i = 0;
|
|
for (; node->length > min_length[i + 1]; ++i) {
|
|
auto& tree_at_i = trees_[i];
|
|
|
|
if (tree_at_i == nullptr) continue;
|
|
sum = PrependNode(tree_at_i, sum);
|
|
tree_at_i = nullptr;
|
|
}
|
|
|
|
sum = AppendNode(node, sum);
|
|
|
|
// Insert sum into appropriate place in the forest
|
|
for (; sum->length >= min_length[i]; ++i) {
|
|
auto& tree_at_i = trees_[i];
|
|
if (tree_at_i == nullptr) continue;
|
|
|
|
sum = MakeConcat(tree_at_i, sum);
|
|
tree_at_i = nullptr;
|
|
}
|
|
|
|
// min_length[0] == 1, which means sum->length >= min_length[0]
|
|
assert(i > 0);
|
|
trees_[i - 1] = sum;
|
|
}
|
|
|
|
// Make concat node trying to resue existing CordRepConcat nodes we
|
|
// already collected in the concat_freelist_.
|
|
CordRep* MakeConcat(CordRep* left, CordRep* right) {
|
|
if (concat_freelist_ == nullptr) return RawConcat(left, right);
|
|
|
|
CordRepConcat* rep = concat_freelist_;
|
|
if (concat_freelist_->left == nullptr) {
|
|
concat_freelist_ = nullptr;
|
|
} else {
|
|
concat_freelist_ = concat_freelist_->left->concat();
|
|
}
|
|
SetConcatChildren(rep, left, right);
|
|
|
|
return rep;
|
|
}
|
|
|
|
static void CheckNode(CordRep* node) {
|
|
ABSL_INTERNAL_CHECK(node->length != 0u, "");
|
|
if (node->tag == CONCAT) {
|
|
ABSL_INTERNAL_CHECK(node->concat()->left != nullptr, "");
|
|
ABSL_INTERNAL_CHECK(node->concat()->right != nullptr, "");
|
|
ABSL_INTERNAL_CHECK(node->length == (node->concat()->left->length +
|
|
node->concat()->right->length),
|
|
"");
|
|
}
|
|
}
|
|
|
|
size_t root_length_;
|
|
|
|
// use an inlined vector instead of a flat array to get bounds checking
|
|
absl::InlinedVector<CordRep*, kInlinedVectorSize> trees_;
|
|
|
|
// List of concat nodes we can re-use for Cord balancing.
|
|
CordRepConcat* concat_freelist_ = nullptr;
|
|
};
|
|
|
|
static CordRep* Rebalance(CordRep* node) {
|
|
VerifyTree(node);
|
|
assert(node->tag == CONCAT);
|
|
|
|
if (node->length == 0) {
|
|
return nullptr;
|
|
}
|
|
|
|
CordForest forest(node->length);
|
|
forest.Build(node);
|
|
return forest.ConcatNodes();
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
// Comparators
|
|
|
|
namespace {
|
|
|
|
int ClampResult(int memcmp_res) {
|
|
return static_cast<int>(memcmp_res > 0) - static_cast<int>(memcmp_res < 0);
|
|
}
|
|
|
|
int CompareChunks(absl::string_view* lhs, absl::string_view* rhs,
|
|
size_t* size_to_compare) {
|
|
size_t compared_size = std::min(lhs->size(), rhs->size());
|
|
assert(*size_to_compare >= compared_size);
|
|
*size_to_compare -= compared_size;
|
|
|
|
int memcmp_res = ::memcmp(lhs->data(), rhs->data(), compared_size);
|
|
if (memcmp_res != 0) return memcmp_res;
|
|
|
|
lhs->remove_prefix(compared_size);
|
|
rhs->remove_prefix(compared_size);
|
|
|
|
return 0;
|
|
}
|
|
|
|
// This overload set computes comparison results from memcmp result. This
|
|
// interface is used inside GenericCompare below. Differet implementations
|
|
// are specialized for int and bool. For int we clamp result to {-1, 0, 1}
|
|
// set. For bool we just interested in "value == 0".
|
|
template <typename ResultType>
|
|
ResultType ComputeCompareResult(int memcmp_res) {
|
|
return ClampResult(memcmp_res);
|
|
}
|
|
template <>
|
|
bool ComputeCompareResult<bool>(int memcmp_res) {
|
|
return memcmp_res == 0;
|
|
}
|
|
|
|
} // namespace
|
|
|
|
// Helper routine. Locates the first flat chunk of the Cord without
|
|
// initializing the iterator.
|
|
inline absl::string_view Cord::InlineRep::FindFlatStartPiece() const {
|
|
size_t n = data_[kMaxInline];
|
|
if (n <= kMaxInline) {
|
|
return absl::string_view(data_, n);
|
|
}
|
|
|
|
CordRep* node = tree();
|
|
if (node->tag >= FLAT) {
|
|
return absl::string_view(node->data, node->length);
|
|
}
|
|
|
|
if (node->tag == EXTERNAL) {
|
|
return absl::string_view(node->external()->base, node->length);
|
|
}
|
|
|
|
// Walk down the left branches until we hit a non-CONCAT node.
|
|
while (node->tag == CONCAT) {
|
|
node = node->concat()->left;
|
|
}
|
|
|
|
// Get the child node if we encounter a SUBSTRING.
|
|
size_t offset = 0;
|
|
size_t length = node->length;
|
|
assert(length != 0);
|
|
|
|
if (node->tag == SUBSTRING) {
|
|
offset = node->substring()->start;
|
|
node = node->substring()->child;
|
|
}
|
|
|
|
if (node->tag >= FLAT) {
|
|
return absl::string_view(node->data + offset, length);
|
|
}
|
|
|
|
assert((node->tag == EXTERNAL) && "Expect FLAT or EXTERNAL node here");
|
|
|
|
return absl::string_view(node->external()->base + offset, length);
|
|
}
|
|
|
|
inline int Cord::CompareSlowPath(absl::string_view rhs, size_t compared_size,
|
|
size_t size_to_compare) const {
|
|
auto advance = [](Cord::ChunkIterator* it, absl::string_view* chunk) {
|
|
if (!chunk->empty()) return true;
|
|
++*it;
|
|
if (it->bytes_remaining_ == 0) return false;
|
|
*chunk = **it;
|
|
return true;
|
|
};
|
|
|
|
Cord::ChunkIterator lhs_it = chunk_begin();
|
|
|
|
// compared_size is inside first chunk.
|
|
absl::string_view lhs_chunk =
|
|
(lhs_it.bytes_remaining_ != 0) ? *lhs_it : absl::string_view();
|
|
assert(compared_size <= lhs_chunk.size());
|
|
assert(compared_size <= rhs.size());
|
|
lhs_chunk.remove_prefix(compared_size);
|
|
rhs.remove_prefix(compared_size);
|
|
size_to_compare -= compared_size; // skip already compared size.
|
|
|
|
while (advance(&lhs_it, &lhs_chunk) && !rhs.empty()) {
|
|
int comparison_result = CompareChunks(&lhs_chunk, &rhs, &size_to_compare);
|
|
if (comparison_result != 0) return comparison_result;
|
|
if (size_to_compare == 0) return 0;
|
|
}
|
|
|
|
return static_cast<int>(rhs.empty()) - static_cast<int>(lhs_chunk.empty());
|
|
}
|
|
|
|
inline int Cord::CompareSlowPath(const Cord& rhs, size_t compared_size,
|
|
size_t size_to_compare) const {
|
|
auto advance = [](Cord::ChunkIterator* it, absl::string_view* chunk) {
|
|
if (!chunk->empty()) return true;
|
|
++*it;
|
|
if (it->bytes_remaining_ == 0) return false;
|
|
*chunk = **it;
|
|
return true;
|
|
};
|
|
|
|
Cord::ChunkIterator lhs_it = chunk_begin();
|
|
Cord::ChunkIterator rhs_it = rhs.chunk_begin();
|
|
|
|
// compared_size is inside both first chunks.
|
|
absl::string_view lhs_chunk =
|
|
(lhs_it.bytes_remaining_ != 0) ? *lhs_it : absl::string_view();
|
|
absl::string_view rhs_chunk =
|
|
(rhs_it.bytes_remaining_ != 0) ? *rhs_it : absl::string_view();
|
|
assert(compared_size <= lhs_chunk.size());
|
|
assert(compared_size <= rhs_chunk.size());
|
|
lhs_chunk.remove_prefix(compared_size);
|
|
rhs_chunk.remove_prefix(compared_size);
|
|
size_to_compare -= compared_size; // skip already compared size.
|
|
|
|
while (advance(&lhs_it, &lhs_chunk) && advance(&rhs_it, &rhs_chunk)) {
|
|
int memcmp_res = CompareChunks(&lhs_chunk, &rhs_chunk, &size_to_compare);
|
|
if (memcmp_res != 0) return memcmp_res;
|
|
if (size_to_compare == 0) return 0;
|
|
}
|
|
|
|
return static_cast<int>(rhs_chunk.empty()) -
|
|
static_cast<int>(lhs_chunk.empty());
|
|
}
|
|
|
|
inline absl::string_view Cord::GetFirstChunk(const Cord& c) {
|
|
return c.contents_.FindFlatStartPiece();
|
|
}
|
|
inline absl::string_view Cord::GetFirstChunk(absl::string_view sv) {
|
|
return sv;
|
|
}
|
|
|
|
// Compares up to 'size_to_compare' bytes of 'lhs' with 'rhs'. It is assumed
|
|
// that 'size_to_compare' is greater that size of smallest of first chunks.
|
|
template <typename ResultType, typename RHS>
|
|
ResultType GenericCompare(const Cord& lhs, const RHS& rhs,
|
|
size_t size_to_compare) {
|
|
absl::string_view lhs_chunk = Cord::GetFirstChunk(lhs);
|
|
absl::string_view rhs_chunk = Cord::GetFirstChunk(rhs);
|
|
|
|
size_t compared_size = std::min(lhs_chunk.size(), rhs_chunk.size());
|
|
assert(size_to_compare >= compared_size);
|
|
int memcmp_res = ::memcmp(lhs_chunk.data(), rhs_chunk.data(), compared_size);
|
|
if (compared_size == size_to_compare || memcmp_res != 0) {
|
|
return ComputeCompareResult<ResultType>(memcmp_res);
|
|
}
|
|
|
|
return ComputeCompareResult<ResultType>(
|
|
lhs.CompareSlowPath(rhs, compared_size, size_to_compare));
|
|
}
|
|
|
|
bool Cord::EqualsImpl(absl::string_view rhs, size_t size_to_compare) const {
|
|
return GenericCompare<bool>(*this, rhs, size_to_compare);
|
|
}
|
|
|
|
bool Cord::EqualsImpl(const Cord& rhs, size_t size_to_compare) const {
|
|
return GenericCompare<bool>(*this, rhs, size_to_compare);
|
|
}
|
|
|
|
template <typename RHS>
|
|
inline int SharedCompareImpl(const Cord& lhs, const RHS& rhs) {
|
|
size_t lhs_size = lhs.size();
|
|
size_t rhs_size = rhs.size();
|
|
if (lhs_size == rhs_size) {
|
|
return GenericCompare<int>(lhs, rhs, lhs_size);
|
|
}
|
|
if (lhs_size < rhs_size) {
|
|
auto data_comp_res = GenericCompare<int>(lhs, rhs, lhs_size);
|
|
return data_comp_res == 0 ? -1 : data_comp_res;
|
|
}
|
|
|
|
auto data_comp_res = GenericCompare<int>(lhs, rhs, rhs_size);
|
|
return data_comp_res == 0 ? +1 : data_comp_res;
|
|
}
|
|
|
|
int Cord::Compare(absl::string_view rhs) const {
|
|
return SharedCompareImpl(*this, rhs);
|
|
}
|
|
|
|
int Cord::CompareImpl(const Cord& rhs) const {
|
|
return SharedCompareImpl(*this, rhs);
|
|
}
|
|
|
|
bool Cord::EndsWith(absl::string_view rhs) const {
|
|
size_t my_size = size();
|
|
size_t rhs_size = rhs.size();
|
|
|
|
if (my_size < rhs_size) return false;
|
|
|
|
Cord tmp(*this);
|
|
tmp.RemovePrefix(my_size - rhs_size);
|
|
return tmp.EqualsImpl(rhs, rhs_size);
|
|
}
|
|
|
|
bool Cord::EndsWith(const Cord& rhs) const {
|
|
size_t my_size = size();
|
|
size_t rhs_size = rhs.size();
|
|
|
|
if (my_size < rhs_size) return false;
|
|
|
|
Cord tmp(*this);
|
|
tmp.RemovePrefix(my_size - rhs_size);
|
|
return tmp.EqualsImpl(rhs, rhs_size);
|
|
}
|
|
|
|
// --------------------------------------------------------------------
|
|
// Misc.
|
|
|
|
Cord::operator std::string() const {
|
|
std::string s;
|
|
absl::CopyCordToString(*this, &s);
|
|
return s;
|
|
}
|
|
|
|
void CopyCordToString(const Cord& src, std::string* dst) {
|
|
if (!src.contents_.is_tree()) {
|
|
src.contents_.CopyTo(dst);
|
|
} else {
|
|
absl::strings_internal::STLStringResizeUninitialized(dst, src.size());
|
|
src.CopyToArraySlowPath(&(*dst)[0]);
|
|
}
|
|
}
|
|
|
|
void Cord::CopyToArraySlowPath(char* dst) const {
|
|
assert(contents_.is_tree());
|
|
absl::string_view fragment;
|
|
if (GetFlatAux(contents_.tree(), &fragment)) {
|
|
memcpy(dst, fragment.data(), fragment.size());
|
|
return;
|
|
}
|
|
for (absl::string_view chunk : Chunks()) {
|
|
memcpy(dst, chunk.data(), chunk.size());
|
|
dst += chunk.size();
|
|
}
|
|
}
|
|
|
|
Cord::ChunkIterator& Cord::ChunkIterator::operator++() {
|
|
assert(bytes_remaining_ > 0 && "Attempted to iterate past `end()`");
|
|
assert(bytes_remaining_ >= current_chunk_.size());
|
|
bytes_remaining_ -= current_chunk_.size();
|
|
|
|
if (stack_of_right_children_.empty()) {
|
|
assert(!current_chunk_.empty()); // Called on invalid iterator.
|
|
// We have reached the end of the Cord.
|
|
return *this;
|
|
}
|
|
|
|
// Process the next node on the stack.
|
|
CordRep* node = stack_of_right_children_.back();
|
|
stack_of_right_children_.pop_back();
|
|
|
|
// Walk down the left branches until we hit a non-CONCAT node. Save the
|
|
// right children to the stack for subsequent traversal.
|
|
while (node->tag == CONCAT) {
|
|
stack_of_right_children_.push_back(node->concat()->right);
|
|
node = node->concat()->left;
|
|
}
|
|
|
|
// Get the child node if we encounter a SUBSTRING.
|
|
size_t offset = 0;
|
|
size_t length = node->length;
|
|
if (node->tag == SUBSTRING) {
|
|
offset = node->substring()->start;
|
|
node = node->substring()->child;
|
|
}
|
|
|
|
assert(node->tag == EXTERNAL || node->tag >= FLAT);
|
|
assert(length != 0);
|
|
const char* data =
|
|
node->tag == EXTERNAL ? node->external()->base : node->data;
|
|
current_chunk_ = absl::string_view(data + offset, length);
|
|
current_leaf_ = node;
|
|
return *this;
|
|
}
|
|
|
|
Cord Cord::ChunkIterator::AdvanceAndReadBytes(size_t n) {
|
|
assert(bytes_remaining_ >= n && "Attempted to iterate past `end()`");
|
|
Cord subcord;
|
|
|
|
if (n <= InlineRep::kMaxInline) {
|
|
// Range to read fits in inline data. Flatten it.
|
|
char* data = subcord.contents_.set_data(n);
|
|
while (n > current_chunk_.size()) {
|
|
memcpy(data, current_chunk_.data(), current_chunk_.size());
|
|
data += current_chunk_.size();
|
|
n -= current_chunk_.size();
|
|
++*this;
|
|
}
|
|
memcpy(data, current_chunk_.data(), n);
|
|
if (n < current_chunk_.size()) {
|
|
RemoveChunkPrefix(n);
|
|
} else if (n > 0) {
|
|
++*this;
|
|
}
|
|
return subcord;
|
|
}
|
|
if (n < current_chunk_.size()) {
|
|
// Range to read is a proper subrange of the current chunk.
|
|
assert(current_leaf_ != nullptr);
|
|
CordRep* subnode = Ref(current_leaf_);
|
|
const char* data =
|
|
subnode->tag == EXTERNAL ? subnode->external()->base : subnode->data;
|
|
subnode = NewSubstring(subnode, current_chunk_.data() - data, n);
|
|
subcord.contents_.set_tree(VerifyTree(subnode));
|
|
RemoveChunkPrefix(n);
|
|
return subcord;
|
|
}
|
|
|
|
// Range to read begins with a proper subrange of the current chunk.
|
|
assert(!current_chunk_.empty());
|
|
assert(current_leaf_ != nullptr);
|
|
CordRep* subnode = Ref(current_leaf_);
|
|
if (current_chunk_.size() < subnode->length) {
|
|
const char* data =
|
|
subnode->tag == EXTERNAL ? subnode->external()->base : subnode->data;
|
|
subnode = NewSubstring(subnode, current_chunk_.data() - data,
|
|
current_chunk_.size());
|
|
}
|
|
n -= current_chunk_.size();
|
|
bytes_remaining_ -= current_chunk_.size();
|
|
|
|
// Process the next node(s) on the stack, reading whole subtrees depending on
|
|
// their length and how many bytes we are advancing.
|
|
CordRep* node = nullptr;
|
|
while (!stack_of_right_children_.empty()) {
|
|
node = stack_of_right_children_.back();
|
|
stack_of_right_children_.pop_back();
|
|
if (node->length > n) break;
|
|
// TODO(qrczak): This might unnecessarily recreate existing concat nodes.
|
|
// Avoiding that would need pretty complicated logic (instead of
|
|
// current_leaf_, keep current_subtree_ which points to the highest node
|
|
// such that the current leaf can be found on the path of left children
|
|
// starting from current_subtree_; delay creating subnode while node is
|
|
// below current_subtree_; find the proper node along the path of left
|
|
// children starting from current_subtree_ if this loop exits while staying
|
|
// below current_subtree_; etc.; alternatively, push parents instead of
|
|
// right children on the stack).
|
|
subnode = Concat(subnode, Ref(node));
|
|
n -= node->length;
|
|
bytes_remaining_ -= node->length;
|
|
node = nullptr;
|
|
}
|
|
|
|
if (node == nullptr) {
|
|
// We have reached the end of the Cord.
|
|
assert(bytes_remaining_ == 0);
|
|
subcord.contents_.set_tree(VerifyTree(subnode));
|
|
return subcord;
|
|
}
|
|
|
|
// Walk down the appropriate branches until we hit a non-CONCAT node. Save the
|
|
// right children to the stack for subsequent traversal.
|
|
while (node->tag == CONCAT) {
|
|
if (node->concat()->left->length > n) {
|
|
// Push right, descend left.
|
|
stack_of_right_children_.push_back(node->concat()->right);
|
|
node = node->concat()->left;
|
|
} else {
|
|
// Read left, descend right.
|
|
subnode = Concat(subnode, Ref(node->concat()->left));
|
|
n -= node->concat()->left->length;
|
|
bytes_remaining_ -= node->concat()->left->length;
|
|
node = node->concat()->right;
|
|
}
|
|
}
|
|
|
|
// Get the child node if we encounter a SUBSTRING.
|
|
size_t offset = 0;
|
|
size_t length = node->length;
|
|
if (node->tag == SUBSTRING) {
|
|
offset = node->substring()->start;
|
|
node = node->substring()->child;
|
|
}
|
|
|
|
// Range to read ends with a proper (possibly empty) subrange of the current
|
|
// chunk.
|
|
assert(node->tag == EXTERNAL || node->tag >= FLAT);
|
|
assert(length > n);
|
|
if (n > 0) subnode = Concat(subnode, NewSubstring(Ref(node), offset, n));
|
|
const char* data =
|
|
node->tag == EXTERNAL ? node->external()->base : node->data;
|
|
current_chunk_ = absl::string_view(data + offset + n, length - n);
|
|
current_leaf_ = node;
|
|
bytes_remaining_ -= n;
|
|
subcord.contents_.set_tree(VerifyTree(subnode));
|
|
return subcord;
|
|
}
|
|
|
|
void Cord::ChunkIterator::AdvanceBytesSlowPath(size_t n) {
|
|
assert(bytes_remaining_ >= n && "Attempted to iterate past `end()`");
|
|
assert(n >= current_chunk_.size()); // This should only be called when
|
|
// iterating to a new node.
|
|
|
|
n -= current_chunk_.size();
|
|
bytes_remaining_ -= current_chunk_.size();
|
|
|
|
// Process the next node(s) on the stack, skipping whole subtrees depending on
|
|
// their length and how many bytes we are advancing.
|
|
CordRep* node = nullptr;
|
|
while (!stack_of_right_children_.empty()) {
|
|
node = stack_of_right_children_.back();
|
|
stack_of_right_children_.pop_back();
|
|
if (node->length > n) break;
|
|
n -= node->length;
|
|
bytes_remaining_ -= node->length;
|
|
node = nullptr;
|
|
}
|
|
|
|
if (node == nullptr) {
|
|
// We have reached the end of the Cord.
|
|
assert(bytes_remaining_ == 0);
|
|
return;
|
|
}
|
|
|
|
// Walk down the appropriate branches until we hit a non-CONCAT node. Save the
|
|
// right children to the stack for subsequent traversal.
|
|
while (node->tag == CONCAT) {
|
|
if (node->concat()->left->length > n) {
|
|
// Push right, descend left.
|
|
stack_of_right_children_.push_back(node->concat()->right);
|
|
node = node->concat()->left;
|
|
} else {
|
|
// Skip left, descend right.
|
|
n -= node->concat()->left->length;
|
|
bytes_remaining_ -= node->concat()->left->length;
|
|
node = node->concat()->right;
|
|
}
|
|
}
|
|
|
|
// Get the child node if we encounter a SUBSTRING.
|
|
size_t offset = 0;
|
|
size_t length = node->length;
|
|
if (node->tag == SUBSTRING) {
|
|
offset = node->substring()->start;
|
|
node = node->substring()->child;
|
|
}
|
|
|
|
assert(node->tag == EXTERNAL || node->tag >= FLAT);
|
|
assert(length > n);
|
|
const char* data =
|
|
node->tag == EXTERNAL ? node->external()->base : node->data;
|
|
current_chunk_ = absl::string_view(data + offset + n, length - n);
|
|
current_leaf_ = node;
|
|
bytes_remaining_ -= n;
|
|
}
|
|
|
|
char Cord::operator[](size_t i) const {
|
|
assert(i < size());
|
|
size_t offset = i;
|
|
const CordRep* rep = contents_.tree();
|
|
if (rep == nullptr) {
|
|
return contents_.data()[i];
|
|
}
|
|
while (true) {
|
|
assert(rep != nullptr);
|
|
assert(offset < rep->length);
|
|
if (rep->tag >= FLAT) {
|
|
// Get the "i"th character directly from the flat array.
|
|
return rep->data[offset];
|
|
} else if (rep->tag == EXTERNAL) {
|
|
// Get the "i"th character from the external array.
|
|
return rep->external()->base[offset];
|
|
} else if (rep->tag == CONCAT) {
|
|
// Recursively branch to the side of the concatenation that the "i"th
|
|
// character is on.
|
|
size_t left_length = rep->concat()->left->length;
|
|
if (offset < left_length) {
|
|
rep = rep->concat()->left;
|
|
} else {
|
|
offset -= left_length;
|
|
rep = rep->concat()->right;
|
|
}
|
|
} else {
|
|
// This must be a substring a node, so bypass it to get to the child.
|
|
assert(rep->tag == SUBSTRING);
|
|
offset += rep->substring()->start;
|
|
rep = rep->substring()->child;
|
|
}
|
|
}
|
|
}
|
|
|
|
absl::string_view Cord::FlattenSlowPath() {
|
|
size_t total_size = size();
|
|
CordRep* new_rep;
|
|
char* new_buffer;
|
|
|
|
// Try to put the contents into a new flat rep. If they won't fit in the
|
|
// biggest possible flat node, use an external rep instead.
|
|
if (total_size <= kMaxFlatLength) {
|
|
new_rep = NewFlat(total_size);
|
|
new_rep->length = total_size;
|
|
new_buffer = new_rep->data;
|
|
CopyToArraySlowPath(new_buffer);
|
|
} else {
|
|
new_buffer = std::allocator<char>().allocate(total_size);
|
|
CopyToArraySlowPath(new_buffer);
|
|
new_rep = absl::cord_internal::NewExternalRep(
|
|
absl::string_view(new_buffer, total_size), [](absl::string_view s) {
|
|
std::allocator<char>().deallocate(const_cast<char*>(s.data()),
|
|
s.size());
|
|
});
|
|
}
|
|
Unref(contents_.tree());
|
|
contents_.set_tree(new_rep);
|
|
return absl::string_view(new_buffer, total_size);
|
|
}
|
|
|
|
/* static */ bool Cord::GetFlatAux(CordRep* rep, absl::string_view* fragment) {
|
|
assert(rep != nullptr);
|
|
if (rep->tag >= FLAT) {
|
|
*fragment = absl::string_view(rep->data, rep->length);
|
|
return true;
|
|
} else if (rep->tag == EXTERNAL) {
|
|
*fragment = absl::string_view(rep->external()->base, rep->length);
|
|
return true;
|
|
} else if (rep->tag == SUBSTRING) {
|
|
CordRep* child = rep->substring()->child;
|
|
if (child->tag >= FLAT) {
|
|
*fragment =
|
|
absl::string_view(child->data + rep->substring()->start, rep->length);
|
|
return true;
|
|
} else if (child->tag == EXTERNAL) {
|
|
*fragment = absl::string_view(
|
|
child->external()->base + rep->substring()->start, rep->length);
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/* static */ void Cord::ForEachChunkAux(
|
|
absl::cord_internal::CordRep* rep,
|
|
absl::FunctionRef<void(absl::string_view)> callback) {
|
|
assert(rep != nullptr);
|
|
int stack_pos = 0;
|
|
constexpr int stack_max = 128;
|
|
// Stack of right branches for tree traversal
|
|
absl::cord_internal::CordRep* stack[stack_max];
|
|
absl::cord_internal::CordRep* current_node = rep;
|
|
while (true) {
|
|
if (current_node->tag == CONCAT) {
|
|
if (stack_pos == stack_max) {
|
|
// There's no more room on our stack array to add another right branch,
|
|
// and the idea is to avoid allocations, so call this function
|
|
// recursively to navigate this subtree further. (This is not something
|
|
// we expect to happen in practice).
|
|
ForEachChunkAux(current_node, callback);
|
|
|
|
// Pop the next right branch and iterate.
|
|
current_node = stack[--stack_pos];
|
|
continue;
|
|
} else {
|
|
// Save the right branch for later traversal and continue down the left
|
|
// branch.
|
|
stack[stack_pos++] = current_node->concat()->right;
|
|
current_node = current_node->concat()->left;
|
|
continue;
|
|
}
|
|
}
|
|
// This is a leaf node, so invoke our callback.
|
|
absl::string_view chunk;
|
|
bool success = GetFlatAux(current_node, &chunk);
|
|
assert(success);
|
|
if (success) {
|
|
callback(chunk);
|
|
}
|
|
if (stack_pos == 0) {
|
|
// end of traversal
|
|
return;
|
|
}
|
|
current_node = stack[--stack_pos];
|
|
}
|
|
}
|
|
|
|
static void DumpNode(CordRep* rep, bool include_data, std::ostream* os) {
|
|
const int kIndentStep = 1;
|
|
int indent = 0;
|
|
absl::InlinedVector<CordRep*, kInlinedVectorSize> stack;
|
|
absl::InlinedVector<int, kInlinedVectorSize> indents;
|
|
for (;;) {
|
|
*os << std::setw(3) << rep->refcount.Get();
|
|
*os << " " << std::setw(7) << rep->length;
|
|
*os << " [";
|
|
if (include_data) *os << static_cast<void*>(rep);
|
|
*os << "]";
|
|
*os << " " << (IsRootBalanced(rep) ? 'b' : 'u');
|
|
*os << " " << std::setw(indent) << "";
|
|
if (rep->tag == CONCAT) {
|
|
*os << "CONCAT depth=" << Depth(rep) << "\n";
|
|
indent += kIndentStep;
|
|
indents.push_back(indent);
|
|
stack.push_back(rep->concat()->right);
|
|
rep = rep->concat()->left;
|
|
} else if (rep->tag == SUBSTRING) {
|
|
*os << "SUBSTRING @ " << rep->substring()->start << "\n";
|
|
indent += kIndentStep;
|
|
rep = rep->substring()->child;
|
|
} else { // Leaf
|
|
if (rep->tag == EXTERNAL) {
|
|
*os << "EXTERNAL [";
|
|
if (include_data)
|
|
*os << absl::CEscape(std::string(rep->external()->base, rep->length));
|
|
*os << "]\n";
|
|
} else {
|
|
*os << "FLAT cap=" << TagToLength(rep->tag) << " [";
|
|
if (include_data)
|
|
*os << absl::CEscape(std::string(rep->data, rep->length));
|
|
*os << "]\n";
|
|
}
|
|
if (stack.empty()) break;
|
|
rep = stack.back();
|
|
stack.pop_back();
|
|
indent = indents.back();
|
|
indents.pop_back();
|
|
}
|
|
}
|
|
ABSL_INTERNAL_CHECK(indents.empty(), "");
|
|
}
|
|
|
|
static std::string ReportError(CordRep* root, CordRep* node) {
|
|
std::ostringstream buf;
|
|
buf << "Error at node " << node << " in:";
|
|
DumpNode(root, true, &buf);
|
|
return buf.str();
|
|
}
|
|
|
|
static bool VerifyNode(CordRep* root, CordRep* start_node,
|
|
bool full_validation) {
|
|
absl::InlinedVector<CordRep*, 2> worklist;
|
|
worklist.push_back(start_node);
|
|
do {
|
|
CordRep* node = worklist.back();
|
|
worklist.pop_back();
|
|
|
|
ABSL_INTERNAL_CHECK(node != nullptr, ReportError(root, node));
|
|
if (node != root) {
|
|
ABSL_INTERNAL_CHECK(node->length != 0, ReportError(root, node));
|
|
}
|
|
|
|
if (node->tag == CONCAT) {
|
|
ABSL_INTERNAL_CHECK(node->concat()->left != nullptr,
|
|
ReportError(root, node));
|
|
ABSL_INTERNAL_CHECK(node->concat()->right != nullptr,
|
|
ReportError(root, node));
|
|
ABSL_INTERNAL_CHECK((node->length == node->concat()->left->length +
|
|
node->concat()->right->length),
|
|
ReportError(root, node));
|
|
if (full_validation) {
|
|
worklist.push_back(node->concat()->right);
|
|
worklist.push_back(node->concat()->left);
|
|
}
|
|
} else if (node->tag >= FLAT) {
|
|
ABSL_INTERNAL_CHECK(node->length <= TagToLength(node->tag),
|
|
ReportError(root, node));
|
|
} else if (node->tag == EXTERNAL) {
|
|
ABSL_INTERNAL_CHECK(node->external()->base != nullptr,
|
|
ReportError(root, node));
|
|
} else if (node->tag == SUBSTRING) {
|
|
ABSL_INTERNAL_CHECK(
|
|
node->substring()->start < node->substring()->child->length,
|
|
ReportError(root, node));
|
|
ABSL_INTERNAL_CHECK(node->substring()->start + node->length <=
|
|
node->substring()->child->length,
|
|
ReportError(root, node));
|
|
}
|
|
} while (!worklist.empty());
|
|
return true;
|
|
}
|
|
|
|
// Traverses the tree and computes the total memory allocated.
|
|
/* static */ size_t Cord::MemoryUsageAux(const CordRep* rep) {
|
|
size_t total_mem_usage = 0;
|
|
|
|
// Allow a quick exit for the common case that the root is a leaf.
|
|
if (RepMemoryUsageLeaf(rep, &total_mem_usage)) {
|
|
return total_mem_usage;
|
|
}
|
|
|
|
// Iterate over the tree. cur_node is never a leaf node and leaf nodes will
|
|
// never be appended to tree_stack. This reduces overhead from manipulating
|
|
// tree_stack.
|
|
absl::InlinedVector<const CordRep*, kInlinedVectorSize> tree_stack;
|
|
const CordRep* cur_node = rep;
|
|
while (true) {
|
|
const CordRep* next_node = nullptr;
|
|
|
|
if (cur_node->tag == CONCAT) {
|
|
total_mem_usage += sizeof(CordRepConcat);
|
|
const CordRep* left = cur_node->concat()->left;
|
|
if (!RepMemoryUsageLeaf(left, &total_mem_usage)) {
|
|
next_node = left;
|
|
}
|
|
|
|
const CordRep* right = cur_node->concat()->right;
|
|
if (!RepMemoryUsageLeaf(right, &total_mem_usage)) {
|
|
if (next_node) {
|
|
tree_stack.push_back(next_node);
|
|
}
|
|
next_node = right;
|
|
}
|
|
} else {
|
|
// Since cur_node is not a leaf or a concat node it must be a substring.
|
|
assert(cur_node->tag == SUBSTRING);
|
|
total_mem_usage += sizeof(CordRepSubstring);
|
|
next_node = cur_node->substring()->child;
|
|
if (RepMemoryUsageLeaf(next_node, &total_mem_usage)) {
|
|
next_node = nullptr;
|
|
}
|
|
}
|
|
|
|
if (!next_node) {
|
|
if (tree_stack.empty()) {
|
|
return total_mem_usage;
|
|
}
|
|
next_node = tree_stack.back();
|
|
tree_stack.pop_back();
|
|
}
|
|
cur_node = next_node;
|
|
}
|
|
}
|
|
|
|
std::ostream& operator<<(std::ostream& out, const Cord& cord) {
|
|
for (absl::string_view chunk : cord.Chunks()) {
|
|
out.write(chunk.data(), chunk.size());
|
|
}
|
|
return out;
|
|
}
|
|
|
|
namespace strings_internal {
|
|
size_t CordTestAccess::FlatOverhead() { return kFlatOverhead; }
|
|
size_t CordTestAccess::MaxFlatLength() { return kMaxFlatLength; }
|
|
size_t CordTestAccess::FlatTagToLength(uint8_t tag) {
|
|
return TagToLength(tag);
|
|
}
|
|
uint8_t CordTestAccess::LengthToTag(size_t s) {
|
|
ABSL_INTERNAL_CHECK(s <= kMaxFlatLength, absl::StrCat("Invalid length ", s));
|
|
return AllocatedSizeToTag(s + kFlatOverhead);
|
|
}
|
|
size_t CordTestAccess::SizeofCordRepConcat() { return sizeof(CordRepConcat); }
|
|
size_t CordTestAccess::SizeofCordRepExternal() {
|
|
return sizeof(CordRepExternal);
|
|
}
|
|
size_t CordTestAccess::SizeofCordRepSubstring() {
|
|
return sizeof(CordRepSubstring);
|
|
}
|
|
} // namespace strings_internal
|
|
ABSL_NAMESPACE_END
|
|
} // namespace absl
|