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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 14:29:10 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 14:29:10 +0000 |
commit | 2aa4a82499d4becd2284cdb482213d541b8804dd (patch) | |
tree | b80bf8bf13c3766139fbacc530efd0dd9d54394c /js/src/ds/FixedLengthVector.h | |
parent | Initial commit. (diff) | |
download | firefox-2aa4a82499d4becd2284cdb482213d541b8804dd.tar.xz firefox-2aa4a82499d4becd2284cdb482213d541b8804dd.zip |
Adding upstream version 86.0.1.upstream/86.0.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'js/src/ds/FixedLengthVector.h')
-rw-r--r-- | js/src/ds/FixedLengthVector.h | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/js/src/ds/FixedLengthVector.h b/js/src/ds/FixedLengthVector.h new file mode 100644 index 0000000000..fab8fb08aa --- /dev/null +++ b/js/src/ds/FixedLengthVector.h @@ -0,0 +1,112 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: set ts=8 sts=2 et sw=2 tw=80: + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef ds_FixedLengthVector_h +#define ds_FixedLengthVector_h + +#include "mozilla/Assertions.h" // MOZ_ASSERT +#include "mozilla/Attributes.h" // MOZ_MUST_USE +#include "mozilla/OperatorNewExtensions.h" // mozilla::KnownNotNull + +#include <stddef.h> // size_t + +#include "js/Utility.h" // js_free +#include "vm/JSContext.h" // JSContext + +namespace js { + +// A dynamically-allocated fixed-length vector with bounds checking assertions. +template <typename T> +class FixedLengthVector { + // The pointer to the storage. + T* data_ = nullptr; + + // The size of the storage. + size_t length_ = 0; + + public: + FixedLengthVector() = default; + + FixedLengthVector(FixedLengthVector&) = delete; + FixedLengthVector(FixedLengthVector&&) = default; + + ~FixedLengthVector() { + if (initialized()) { + js_free(data_); + } + } + + size_t length() const { return length_; } + + bool initialized() const { return !!data_; } + + // Allocate the storage with the given size, wihtout calling constructor. + // + // If the allocation fails, this returns false and sets the + // pending exception on the given context. + MOZ_MUST_USE bool allocateUninitialized(JSContext* cx, size_t length) { + MOZ_ASSERT(!initialized()); + + length_ = length; + data_ = cx->pod_malloc<T>(length); + if (MOZ_UNLIKELY(!data_)) { + return false; + } + + return true; + } + + // Allocate the storage with the given size and call default constructor. + // + // If the allocation fails, this returns false and sets the + // pending exception on the given context. + MOZ_MUST_USE bool allocate(JSContext* cx, size_t length) { + if (!allocateUninitialized(cx, length)) { + return false; + } + + for (size_t i = 0; i < length; i++) { + new (mozilla::KnownNotNull, &data_[i]) T(); + } + return true; + } + + T* begin() { + MOZ_ASSERT(initialized()); + return data_; + } + + const T* begin() const { + MOZ_ASSERT(initialized()); + return data_; + } + + T* end() { + MOZ_ASSERT(initialized()); + return data_ + length_; + } + + const T* end() const { + MOZ_ASSERT(initialized()); + return data_ + length_; + } + + T& operator[](size_t index) { + MOZ_ASSERT(initialized()); + MOZ_ASSERT(index < length_); + return begin()[index]; + } + + const T& operator[](size_t index) const { + MOZ_ASSERT(initialized()); + MOZ_ASSERT(index < length_); + return begin()[index]; + } +}; + +} // namespace js + +#endif // ds_FixedLengthVector_h |