blob: e6b364f66711fee749b8671408377114094dacc8 [file] [log] [blame]
// Copyright 2020 The Dawn & Tint Authors
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef SRC_DAWN_COMMON_ITYP_SPAN_H_
#define SRC_DAWN_COMMON_ITYP_SPAN_H_
#include <type_traits>
#include "dawn/common/TypedInteger.h"
#include "dawn/common/UnderlyingType.h"
namespace dawn::ityp {
// ityp::span is a helper class that wraps an unowned packed array of type |Value|.
// It stores the size and pointer to first element. It has the restriction that
// indices must be a particular type |Index|. This provides a type-safe way to index
// raw pointers.
template <typename Index, typename Value>
class span {
using I = UnderlyingType<Index>;
public:
constexpr span() : mData(nullptr), mSize(0) {}
constexpr span(Value* data, Index size) : mData(data), mSize(size) {}
constexpr Value& operator[](Index i) const {
DAWN_ASSERT(i < mSize);
return mData[static_cast<I>(i)];
}
Value* data() noexcept { return mData; }
const Value* data() const noexcept { return mData; }
Value* begin() noexcept { return mData; }
const Value* begin() const noexcept { return mData; }
Value* end() noexcept { return mData + static_cast<I>(mSize); }
const Value* end() const noexcept { return mData + static_cast<I>(mSize); }
Value& front() {
DAWN_ASSERT(mData != nullptr);
DAWN_ASSERT(static_cast<I>(mSize) >= 0);
return *mData;
}
const Value& front() const {
DAWN_ASSERT(mData != nullptr);
DAWN_ASSERT(static_cast<I>(mSize) >= 0);
return *mData;
}
Value& back() {
DAWN_ASSERT(mData != nullptr);
DAWN_ASSERT(static_cast<I>(mSize) >= 0);
return *(mData + static_cast<I>(mSize) - 1);
}
const Value& back() const {
DAWN_ASSERT(mData != nullptr);
DAWN_ASSERT(static_cast<I>(mSize) >= 0);
return *(mData + static_cast<I>(mSize) - 1);
}
Index size() const { return mSize; }
private:
Value* mData;
Index mSize;
};
// ityp::SpanFromUntyped<Index>(myValues, myValueCount) creates a span<Index, Value> from a C-style
// span that's without a TypedInteger index. It is useful at the interface between code that doesn't
// use ityp and code that does.
template <typename Index, typename Value>
span<Index, Value> SpanFromUntyped(Value* data, size_t size) {
return {data, Index{static_cast<UnderlyingType<Index>>(size)}};
}
} // namespace dawn::ityp
#endif // SRC_DAWN_COMMON_ITYP_SPAN_H_