/src/spirv-cross/spirv_cross_containers.hpp

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/*
 * Copyright 2019-2021 Hans-Kristian Arntzen
 * SPDX-License-Identifier: Apache-2.0 OR MIT
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * At your option, you may choose to accept this material under either:
 *  1. The Apache License, Version 2.0, found at <http://www.apache.org/licenses/LICENSE-2.0>, or
 *  2. The MIT License, found at <http://opensource.org/licenses/MIT>.
 */

#ifndef SPIRV_CROSS_CONTAINERS_HPP
#define SPIRV_CROSS_CONTAINERS_HPP

#include "spirv_cross_error_handling.hpp"
#include <algorithm>
#include <exception>
#include <functional>
#include <iterator>
#include <limits>
#include <memory>
#include <stack>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

#ifdef SPIRV_CROSS_NAMESPACE_OVERRIDE
#define SPIRV_CROSS_NAMESPACE SPIRV_CROSS_NAMESPACE_OVERRIDE
#else
#define SPIRV_CROSS_NAMESPACE spirv_cross
#endif

namespace SPIRV_CROSS_NAMESPACE
{
#ifndef SPIRV_CROSS_FORCE_STL_TYPES
// std::aligned_storage does not support size == 0, so roll our own.
template <typename T, size_t N>
class AlignedBuffer
{
public:
  T *data()
  {
#if defined(_MSC_VER) && _MSC_VER < 1900
    // MSVC 2013 workarounds, sigh ...
    // Only use this workaround on MSVC 2013 due to some confusion around default initialized unions.
    // Spec seems to suggest the memory will be zero-initialized, which is *not* what we want.
    return reinterpret_cast<T *>(u.aligned_char);
#else
    return reinterpret_cast<T *>(aligned_char);
#endif
  }

private:
#if defined(_MSC_VER) && _MSC_VER < 1900
  // MSVC 2013 workarounds, sigh ...
  union
  {
    char aligned_char[sizeof(T) * N];
    double dummy_aligner;
  } u;
#else
  alignas(T) char aligned_char[sizeof(T) * N];
#endif
};

template <typename T>
class AlignedBuffer<T, 0>
{
public:
  T *data()
  {
    return nullptr;
  }
};

// An immutable version of SmallVector which erases type information about storage.
template <typename T>
class VectorView
{
public:
  T &operator[](size_t i) SPIRV_CROSS_NOEXCEPT
  {
    return ptr[i];
  }

  const T &operator[](size_t i) const SPIRV_CROSS_NOEXCEPT
  {
    return ptr[i];
  }

  bool empty() const SPIRV_CROSS_NOEXCEPT
  {
    return buffer_size == 0;
  }

  size_t size() const SPIRV_CROSS_NOEXCEPT
  {
    return buffer_size;
  }

  T *data() SPIRV_CROSS_NOEXCEPT
  {
    return ptr;
  }

  const T *data() const SPIRV_CROSS_NOEXCEPT
  {
    return ptr;
  }

  T *begin() SPIRV_CROSS_NOEXCEPT
  {
    return ptr;
  }

  T *end() SPIRV_CROSS_NOEXCEPT
  {
    return ptr + buffer_size;
  }

  const T *begin() const SPIRV_CROSS_NOEXCEPT
  {
    return ptr;
  }

  const T *end() const SPIRV_CROSS_NOEXCEPT
  {
    return ptr + buffer_size;
  }

  T &front() SPIRV_CROSS_NOEXCEPT
  {
    return ptr[0];
  }

  const T &front() const SPIRV_CROSS_NOEXCEPT
  {
    return ptr[0];
  }

  T &back() SPIRV_CROSS_NOEXCEPT
  {
    return ptr[buffer_size - 1];
  }

  const T &back() const SPIRV_CROSS_NOEXCEPT
  {
    return ptr[buffer_size - 1];
  }

  // Makes it easier to consume SmallVector.
#if defined(_MSC_VER) && _MSC_VER < 1900
  explicit operator std::vector<T>() const
  {
    // Another MSVC 2013 workaround. It does not understand lvalue/rvalue qualified operations.
    return std::vector<T>(ptr, ptr + buffer_size);
  }
#else
  // Makes it easier to consume SmallVector.
  explicit operator std::vector<T>() const &
  {
    return std::vector<T>(ptr, ptr + buffer_size);
  }

  // If we are converting as an r-value, we can pilfer our elements.
  explicit operator std::vector<T>() &&
  {
    return std::vector<T>(std::make_move_iterator(ptr), std::make_move_iterator(ptr + buffer_size));
  }
#endif

  // Avoid sliced copies. Base class should only be read as a reference.
  VectorView(const VectorView &) = delete;
  void operator=(const VectorView &) = delete;

protected:
  VectorView() = default;
  T *ptr = nullptr;
  size_t buffer_size = 0;
};

// Simple vector which supports up to N elements inline, without malloc/free.
// We use a lot of throwaway vectors all over the place which triggers allocations.
// This class only implements the subset of std::vector we need in SPIRV-Cross.
// It is *NOT* a drop-in replacement in general projects.
template <typename T, size_t N = 8>
class SmallVector : public VectorView<T>
{
public:
  SmallVector() SPIRV_CROSS_NOEXCEPT
  {
    this->ptr = stack_storage.data();
    buffer_capacity = N;
  }

  template <typename U>
  SmallVector(const U *arg_list_begin, const U *arg_list_end) SPIRV_CROSS_NOEXCEPT : SmallVector()
  {
    auto count = size_t(arg_list_end - arg_list_begin);
    reserve(count);
    for (size_t i = 0; i < count; i++, arg_list_begin++)
      new (&this->ptr[i]) T(*arg_list_begin);
    this->buffer_size = count;
  }

  template <typename U>
  SmallVector(std::initializer_list<U> init) SPIRV_CROSS_NOEXCEPT : SmallVector(init.begin(), init.end())
  {
  }

  template <typename U, size_t M>
  explicit SmallVector(const U (&init)[M]) SPIRV_CROSS_NOEXCEPT : SmallVector(init, init + M)
  {
  }

  SmallVector(SmallVector &&other) SPIRV_CROSS_NOEXCEPT : SmallVector()
  {
    *this = std::move(other);
  }

  SmallVector &operator=(SmallVector &&other) SPIRV_CROSS_NOEXCEPT
  {
    clear();
    if (other.ptr != other.stack_storage.data())
    {
      // Pilfer allocated pointer.
      if (this->ptr != stack_storage.data())
        free(this->ptr);
      this->ptr = other.ptr;
      this->buffer_size = other.buffer_size;
      buffer_capacity = other.buffer_capacity;
      other.ptr = nullptr;
      other.buffer_size = 0;
      other.buffer_capacity = 0;
    }
    else
    {
      // Need to move the stack contents individually.
      reserve(other.buffer_size);
      for (size_t i = 0; i < other.buffer_size; i++)
      {
        new (&this->ptr[i]) T(std::move(other.ptr[i]));
        other.ptr[i].~T();
      }
      this->buffer_size = other.buffer_size;
      other.buffer_size = 0;
    }
    return *this;
  }

  SmallVector(const SmallVector &other) SPIRV_CROSS_NOEXCEPT : SmallVector()
  {
    *this = other;
  }

  SmallVector &operator=(const SmallVector &other) SPIRV_CROSS_NOEXCEPT
  {
    if (this == &other)
      return *this;

    clear();
    reserve(other.buffer_size);
    for (size_t i = 0; i < other.buffer_size; i++)
      new (&this->ptr[i]) T(other.ptr[i]);
    this->buffer_size = other.buffer_size;
    return *this;
  }

  explicit SmallVector(size_t count) SPIRV_CROSS_NOEXCEPT : SmallVector()
  {
    resize(count);
  }

  ~SmallVector()
  {
    clear();
    if (this->ptr != stack_storage.data())
      free(this->ptr);
  }

  void clear() SPIRV_CROSS_NOEXCEPT
  {
    for (size_t i = 0; i < this->buffer_size; i++)
      this->ptr[i].~T();
    this->buffer_size = 0;
  }

  void push_back(const T &t) SPIRV_CROSS_NOEXCEPT
  {
    reserve(this->buffer_size + 1);
    new (&this->ptr[this->buffer_size]) T(t);
    this->buffer_size++;
  }

  void push_back(T &&t) SPIRV_CROSS_NOEXCEPT
  {
    reserve(this->buffer_size + 1);
    new (&this->ptr[this->buffer_size]) T(std::move(t));
    this->buffer_size++;
  }

  void pop_back() SPIRV_CROSS_NOEXCEPT
  {
    // Work around false positive warning on GCC 8.3.
    // Calling pop_back on empty vector is undefined.
    if (!this->empty())
      resize(this->buffer_size - 1);
  }

  template <typename... Ts>
  void emplace_back(Ts &&... ts) SPIRV_CROSS_NOEXCEPT
  {
    reserve(this->buffer_size + 1);
    new (&this->ptr[this->buffer_size]) T(std::forward<Ts>(ts)...);
    this->buffer_size++;
  }

  void reserve(size_t count) SPIRV_CROSS_NOEXCEPT
  {
    if ((count > (std::numeric_limits<size_t>::max)() / sizeof(T)) ||
        (count > (std::numeric_limits<size_t>::max)() / 2))
    {
      // Only way this should ever happen is with garbage input, terminate.
      std::terminate();
    }

    if (count > buffer_capacity)
    {
      size_t target_capacity = buffer_capacity;
      if (target_capacity == 0)
        target_capacity = 1;

      // Weird parens works around macro issues on Windows if NOMINMAX is not used.
      target_capacity = (std::max)(target_capacity, N);

      // Need to ensure there is a POT value of target capacity which is larger than count,
      // otherwise this will overflow.
      while (target_capacity < count)
        target_capacity <<= 1u;

      T *new_buffer =
          target_capacity > N ? static_cast<T *>(malloc(target_capacity * sizeof(T))) : stack_storage.data();

      // If we actually fail this malloc, we are hosed anyways, there is no reason to attempt recovery.
      if (!new_buffer)
        std::terminate();

      // In case for some reason two allocations both come from same stack.
      if (new_buffer != this->ptr)
      {
        // We don't deal with types which can throw in move constructor.
        for (size_t i = 0; i < this->buffer_size; i++)
        {
          new (&new_buffer[i]) T(std::move(this->ptr[i]));
          this->ptr[i].~T();
        }
      }

      if (this->ptr != stack_storage.data())
        free(this->ptr);
      this->ptr = new_buffer;
      buffer_capacity = target_capacity;
    }
  }

  void insert(T *itr, const T *insert_begin, const T *insert_end) SPIRV_CROSS_NOEXCEPT
  {
    auto count = size_t(insert_end - insert_begin);
    if (itr == this->end())
    {
      reserve(this->buffer_size + count);
      for (size_t i = 0; i < count; i++, insert_begin++)
        new (&this->ptr[this->buffer_size + i]) T(*insert_begin);
      this->buffer_size += count;
    }
    else
    {
      if (this->buffer_size + count > buffer_capacity)
      {
        auto target_capacity = this->buffer_size + count;
        if (target_capacity == 0)
          target_capacity = 1;
        if (target_capacity < N)
          target_capacity = N;

        while (target_capacity < count)
          target_capacity <<= 1u;

        // Need to allocate new buffer. Move everything to a new buffer.
        T *new_buffer =
            target_capacity > N ? static_cast<T *>(malloc(target_capacity * sizeof(T))) : stack_storage.data();

        // If we actually fail this malloc, we are hosed anyways, there is no reason to attempt recovery.
        if (!new_buffer)
          std::terminate();

        // First, move elements from source buffer to new buffer.
        // We don't deal with types which can throw in move constructor.
        auto *target_itr = new_buffer;
        auto *original_source_itr = this->begin();

        if (new_buffer != this->ptr)
        {
          while (original_source_itr != itr)
          {
            new (target_itr) T(std::move(*original_source_itr));
            original_source_itr->~T();
            ++original_source_itr;
            ++target_itr;
          }
        }

        // Copy-construct new elements.
        for (auto *source_itr = insert_begin; source_itr != insert_end; ++source_itr, ++target_itr)
          new (target_itr) T(*source_itr);

        // Move over the other half.
        if (new_buffer != this->ptr || insert_begin != insert_end)
        {
          while (original_source_itr != this->end())
          {
            new (target_itr) T(std::move(*original_source_itr));
            original_source_itr->~T();
            ++original_source_itr;
            ++target_itr;
          }
        }

        if (this->ptr != stack_storage.data())
          free(this->ptr);
        this->ptr = new_buffer;
        buffer_capacity = target_capacity;
      }
      else
      {
        // Move in place, need to be a bit careful about which elements are constructed and which are not.
        // Move the end and construct the new elements.
        auto *target_itr = this->end() + count;
        auto *source_itr = this->end();
        while (target_itr != this->end() && source_itr != itr)
        {
          --target_itr;
          --source_itr;
          new (target_itr) T(std::move(*source_itr));
        }

        // For already constructed elements we can move-assign.
        std::move_backward(itr, source_itr, target_itr);

        // For the inserts which go to already constructed elements, we can do a plain copy.
        while (itr != this->end() && insert_begin != insert_end)
          *itr++ = *insert_begin++;

        // For inserts into newly allocated memory, we must copy-construct instead.
        while (insert_begin != insert_end)
        {
          new (itr) T(*insert_begin);
          ++itr;
          ++insert_begin;
        }
      }

      this->buffer_size += count;
    }
  }

  void insert(T *itr, const T &value) SPIRV_CROSS_NOEXCEPT
  {
    insert(itr, &value, &value + 1);
  }

  T *erase(T *itr) SPIRV_CROSS_NOEXCEPT
  {
    std::move(itr + 1, this->end(), itr);
    this->ptr[--this->buffer_size].~T();
    return itr;
  }

  void erase(T *start_erase, T *end_erase) SPIRV_CROSS_NOEXCEPT
  {
    if (end_erase == this->end())
    {
      resize(size_t(start_erase - this->begin()));
    }
    else
    {
      auto new_size = this->buffer_size - (end_erase - start_erase);
      std::move(end_erase, this->end(), start_erase);
      resize(new_size);
    }
  }

  void resize(size_t new_size) SPIRV_CROSS_NOEXCEPT
  {
    if (new_size < this->buffer_size)
    {
      for (size_t i = new_size; i < this->buffer_size; i++)
        this->ptr[i].~T();
    }
    else if (new_size > this->buffer_size)
    {
      reserve(new_size);
      for (size_t i = this->buffer_size; i < new_size; i++)
        new (&this->ptr[i]) T();
    }

    this->buffer_size = new_size;
  }

private:
  size_t buffer_capacity = 0;
  AlignedBuffer<T, N> stack_storage;
};

// A vector without stack storage.
// Could also be a typedef-ed to std::vector,
// but might as well use the one we have.
template <typename T>
using Vector = SmallVector<T, 0>;

#else // SPIRV_CROSS_FORCE_STL_TYPES

template <typename T, size_t N = 8>
using SmallVector = std::vector<T>;
template <typename T>
using Vector = std::vector<T>;
template <typename T>
using VectorView = std::vector<T>;

#endif // SPIRV_CROSS_FORCE_STL_TYPES

// An object pool which we use for allocating IVariant-derived objects.
// We know we are going to allocate a bunch of objects of each type,
// so amortize the mallocs.
class ObjectPoolBase
{
public:
  virtual ~ObjectPoolBase() = default;
  virtual void deallocate_opaque(void *ptr) = 0;
};

template <typename T>
class ObjectPool : public ObjectPoolBase
{
public:
  explicit ObjectPool(unsigned start_object_count_ = 16)
      : start_object_count(start_object_count_)
  {
  }

  template <typename... P>
  T *allocate(P &&... p)
  {
    if (vacants.empty())
    {
      unsigned num_objects = start_object_count << memory.size();
      T *ptr = static_cast<T *>(malloc(num_objects * sizeof(T)));
      if (!ptr)
        return nullptr;

      vacants.reserve(num_objects);
      for (unsigned i = 0; i < num_objects; i++)
        vacants.push_back(&ptr[i]);

      memory.emplace_back(ptr);
    }

    T *ptr = vacants.back();
    vacants.pop_back();
    new (ptr) T(std::forward<P>(p)...);
    return ptr;
  }

  void deallocate(T *ptr)
  {
    ptr->~T();
    vacants.push_back(ptr);
  }

  void deallocate_opaque(void *ptr) override
  {
    deallocate(static_cast<T *>(ptr));
  }

  void clear()
  {
    vacants.clear();
    memory.clear();
  }

protected:
  Vector<T *> vacants;

  struct MallocDeleter
  {
    void operator()(T *ptr)
    {
      ::free(ptr);
    }
  };

  SmallVector<std::unique_ptr<T, MallocDeleter>> memory;
  unsigned start_object_count;
};

template <size_t StackSize = 4096, size_t BlockSize = 4096>
class StringStream
{
public:
  StringStream()
  {
    reset();
  }

  ~StringStream()
  {
    reset();
  }

  // Disable copies and moves. Makes it easier to implement, and we don't need it.
  StringStream(const StringStream &) = delete;
  void operator=(const StringStream &) = delete;

  template <typename T, typename std::enable_if<!std::is_floating_point<T>::value, int>::type = 0>
  StringStream &operator<<(const T &t)
  {
    auto s = std::to_string(t);
    append(s.data(), s.size());
    return *this;
  }

  // Only overload this to make float/double conversions ambiguous.
  StringStream &operator<<(uint32_t v)
  {
    auto s = std::to_string(v);
    append(s.data(), s.size());
    return *this;
  }

  StringStream &operator<<(char c)
  {
    append(&c, 1);
    return *this;
  }

  StringStream &operator<<(const std::string &s)
  {
    append(s.data(), s.size());
    return *this;
  }

  StringStream &operator<<(const char *s)
  {
    append(s, strlen(s));
    return *this;
  }

  template <size_t N>
  StringStream &operator<<(const char (&s)[N])
  {
    append(s, strlen(s));
    return *this;
  }

  std::string str() const
  {
    std::string ret;
    size_t target_size = 0;
    for (auto &saved : saved_buffers)
      target_size += saved.offset;
    target_size += current_buffer.offset;
    ret.reserve(target_size);

    for (auto &saved : saved_buffers)
      ret.insert(ret.end(), saved.buffer, saved.buffer + saved.offset);
    ret.insert(ret.end(), current_buffer.buffer, current_buffer.buffer + current_buffer.offset);
    return ret;
  }

  void reset()
  {
    for (auto &saved : saved_buffers)
      if (saved.buffer != stack_buffer)
        free(saved.buffer);
    if (current_buffer.buffer != stack_buffer)
      free(current_buffer.buffer);

    saved_buffers.clear();
    current_buffer.buffer = stack_buffer;
    current_buffer.offset = 0;
    current_buffer.size = sizeof(stack_buffer);
  }

private:
  struct Buffer
  {
    char *buffer = nullptr;
    size_t offset = 0;
    size_t size = 0;
  };
  Buffer current_buffer;
  char stack_buffer[StackSize];
  SmallVector<Buffer> saved_buffers;

  void append(const char *s, size_t len)
  {
    size_t avail = current_buffer.size - current_buffer.offset;
    if (avail < len)
    {
      if (avail > 0)
      {
        memcpy(current_buffer.buffer + current_buffer.offset, s, avail);
        s += avail;
        len -= avail;
        current_buffer.offset += avail;
      }

      saved_buffers.push_back(current_buffer);
      size_t target_size = len > BlockSize ? len : BlockSize;
      current_buffer.buffer = static_cast<char *>(malloc(target_size));
      if (!current_buffer.buffer)
        SPIRV_CROSS_THROW("Out of memory.");

      memcpy(current_buffer.buffer, s, len);
      current_buffer.offset = len;
      current_buffer.size = target_size;
    }
    else
    {
      memcpy(current_buffer.buffer + current_buffer.offset, s, len);
      current_buffer.offset += len;
    }
  }
};

} // namespace SPIRV_CROSS_NAMESPACE

#endif

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Created: 2025-06-13 06:55