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Diffstat (limited to '')
-rw-r--r-- | third_party/jpeg-xl/lib/jxl/base/span.h | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/third_party/jpeg-xl/lib/jxl/base/span.h b/third_party/jpeg-xl/lib/jxl/base/span.h new file mode 100644 index 0000000000..41c3623a4b --- /dev/null +++ b/third_party/jpeg-xl/lib/jxl/base/span.h @@ -0,0 +1,60 @@ +// Copyright (c) the JPEG XL Project Authors. All rights reserved. +// +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +#ifndef LIB_JXL_BASE_SPAN_H_ +#define LIB_JXL_BASE_SPAN_H_ + +// Span (array view) is a non-owning container that provides cheap "cut" +// operations and could be used as "ArrayLike" data source for PaddedBytes. + +#include <stddef.h> + +#include "lib/jxl/base/status.h" + +namespace jxl { + +template <typename T> +class Span { + public: + constexpr Span() noexcept : Span(nullptr, 0) {} + + constexpr Span(T* array, size_t length) noexcept + : ptr_(array), len_(length) {} + + template <size_t N> + explicit constexpr Span(T (&a)[N]) noexcept : Span(a, N) {} + + template <typename ArrayLike> + explicit constexpr Span(const ArrayLike& other) noexcept + : Span(reinterpret_cast<T*>(other.data()), other.size()) { + static_assert(sizeof(*other.data()) == sizeof(T), + "Incompatible type of source."); + } + + constexpr T* data() const noexcept { return ptr_; } + + constexpr size_t size() const noexcept { return len_; } + + constexpr bool empty() const noexcept { return len_ == 0; } + + constexpr T& operator[](size_t i) const noexcept { + // MSVC 2015 accepts this as constexpr, but not ptr_[i] + return *(data() + i); + } + + void remove_prefix(size_t n) noexcept { + JXL_ASSERT(size() >= n); + ptr_ += n; + len_ -= n; + } + + private: + T* ptr_; + size_t len_; +}; + +} // namespace jxl + +#endif // LIB_JXL_BASE_SPAN_H_ |