span.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef COMMON_SPAN_H
#define COMMON_SPAN_H

#include "common/file.h"
#include "common/memstream.h"
#include "common/safe-bool.h"
#include "common/scummsys.h"
#include "common/type_traits.h"

namespace Common {

#define COMMON_SPAN_TYPEDEFS \
    typedef typename super_type::value_type value_type; \
    typedef typename super_type::difference_type difference_type; \
    typedef typename super_type::index_type index_type; \
    typedef typename super_type::size_type size_type; \
    typedef typename super_type::const_iterator const_iterator; \
    typedef typename super_type::iterator iterator; \
    typedef typename super_type::pointer pointer; \
    typedef typename super_type::const_pointer const_pointer; \
    typedef typename super_type::reference reference; \
    typedef typename super_type::const_reference const_reference

enum : uint {
    kSpanMaxSize = 0xFFFFFFFF,
    kSpanKeepOffset = 0xFFFFFFFF
};

#pragma mark -
#pragma mark SpanValidationMode

enum SpanValidationMode {
    kValidateRead,
    kValidateWrite,
    kValidateSeek
};

namespace SpanInternal {
#pragma mark -
#pragma mark SpanIterator

    template <typename Span, bool IsConst>
    class SpanIterator {
        typedef typename Span::value_type span_value_type;
        typedef typename conditional<IsConst, const Span, Span>::type span_type;

    public:
        typedef typename Span::difference_type difference_type;
        typedef typename remove_const<span_value_type>::type value_type;
        typedef typename conditional<IsConst, const span_value_type, span_value_type>::type *pointer;
        typedef typename conditional<IsConst, const span_value_type, span_value_type>::type &reference;

        inline SpanIterator() : _span(nullptr), _index(0) {}

        inline SpanIterator(span_type *const span, const difference_type index) :
            _span(span),
            _index(index) {
            if (span != nullptr) {
                span->validate(index, 0, kValidateSeek);
            }
        }

        inline SpanIterator(const SpanIterator &other) :
            _span(other._span),
            _index(other._index) {}

        inline SpanIterator &operator=(const SpanIterator &other) {
            _span = other._span;
            _index = other._index;
            return *this;
        }

#pragma mark -
#pragma mark SpanIterator - Dereferencing operations

    public:
        inline reference operator*() const {
            // validation is in Span::operator[]
            return (*_span)[_index];
        }

        inline pointer operator->() const {
            return &operator*();
        }

        inline reference operator[](const difference_type index) const {
            // validation is in SpanIterator::operator+=
            return *(*this + index);
        }

#pragma mark -
#pragma mark SpanIterator - Arithmetic operations

    public:
        inline SpanIterator &operator+=(const difference_type delta) {
            assert(_span != nullptr);
            _span->validate(_index, delta, kValidateSeek);
            _index += delta;
            return *this;
        }

        inline SpanIterator &operator-=(const difference_type delta) {
            return operator+=(-delta);
        }

        inline SpanIterator &operator++() {
            return operator+=(1);
        }

        inline SpanIterator operator++(int) {
            SpanIterator old(*this);
            operator+=(1);
            return old;
        }

        inline SpanIterator &operator--() {
            return operator+=(-1);
        }

        inline SpanIterator operator--(int) {
            SpanIterator old(*this);
            operator+=(-1);
            return old;
        }

        inline SpanIterator operator+(const difference_type delta) const {
            SpanIterator it(*this);
            return it += delta;
        }

        inline SpanIterator operator-(const difference_type delta) const {
            return operator+(-delta);
        }

        inline difference_type operator-(const SpanIterator &other) const {
            assert(_span == other._span);
            return _index - other._index;
        }

#pragma mark -
#pragma mark SpanIterator - Comparison operations

    public:
        inline bool operator==(const SpanIterator& other) const {
            return _span == other._span && _index == other._index;
        }

        inline bool operator!=(const SpanIterator& other) const {
            return !operator==(other);
        }

        inline bool operator<(const SpanIterator& other) const {
            assert(_span == other._span);
            return _index < other._index;
        }

        inline bool operator<=(const SpanIterator& other) const {
            return !other.operator<(*this);
        }

        inline bool operator>(const SpanIterator& other) const {
            return other.operator<(*this);
        }

        inline bool operator>=(const SpanIterator& other) const {
            return !operator<(other);
        }

#pragma mark -
#pragma mark SpanIterator - Data access convenience functions

    public:
        inline int8 getInt8() const {
            return _span->getInt8At(_index);
        }

        inline uint8 getUint8() const {
            return _span->getUint8At(_index);
        }

        inline int16 getInt16BE() const {
            return _span->getInt16BEAt(_index);
        }

        inline int16 getInt16LE() const {
            return _span->getInt16LEAt(_index);
        }

        inline uint16 getUint16BE() const {
            return _span->getUint16BEAt(_index);
        }

        inline uint16 getUint16LE() const {
            return _span->getUint16LEAt(_index);
        }

        inline uint32 getUint24LE() const {
            return _span->getUint24LEAt(_index);
        }

        inline uint32 getUint32() const {
            return _span->getUint32At(_index);
        }

        inline int32 getInt32BE() const {
            return _span->getInt32BEAt(_index);
        }

        inline int32 getInt32LE() const {
            return _span->getInt32LEAt(_index);
        }

        inline uint32 getUint32BE() const {
            return _span->getUint32BEAt(_index);
        }

        inline uint32 getUint32LE() const {
            return _span->getUint32LEAt(_index);
        }

    protected:
        span_type *_span;
        difference_type _index;
    };
} // End of namespace SpanInternal

#pragma mark -
#pragma mark SpanBase

template <typename ValueType, template <typename> class Derived>
class SpanBase : public SafeBool<Derived<ValueType> > {
    typedef Derived<ValueType> derived_type;
    typedef typename add_const<derived_type>::type const_derived_type;
    typedef typename remove_const<derived_type>::type mutable_derived_type;

    template <typename T, bool U> friend class SpanInternal::SpanIterator;
    template <typename T, template <typename> class U> friend class SpanBase;
    template <typename T, typename U> friend struct SafeBool;
#ifdef CXXTEST_RUNNING
    friend class ::SpanTestSuite;
#endif

public:
    typedef ValueType value_type;
    typedef int32 difference_type;
    typedef uint32 index_type;
    typedef uint32 size_type;
    typedef SpanInternal::SpanIterator<derived_type, true> const_iterator;
    typedef SpanInternal::SpanIterator<derived_type, false> iterator;
    typedef value_type *pointer;
    typedef const value_type *const_pointer;
    typedef value_type &reference;
    typedef const value_type &const_reference;

    inline size_type byteSize() const { return impl().size() * sizeof(value_type); }

#if !defined(_MSC_VER)
protected:
#endif
    inline SpanBase() {}
    inline SpanBase(const SpanBase &) {}
    inline SpanBase &operator=(const SpanBase &) { return this->impl(); }
    inline ~SpanBase() {}

    inline const_derived_type &impl() const { return static_cast<const_derived_type &>(*this); }
    inline mutable_derived_type &impl() { return static_cast<mutable_derived_type &>(*this); }

#pragma mark -
#pragma mark SpanBase - Interface

#if !defined(_MSC_VER)
protected:
#endif
    inline void clear();

    inline size_type size() const;

    inline const_iterator cbegin() const;
    inline const_iterator cend() const;
    inline const_iterator begin() const;
    inline const_iterator end() const;
    inline iterator begin();
    inline iterator end();

    inline pointer data() const;

#pragma mark -
#pragma mark SpanBase - Data access functions

public:
    inline const_reference operator[](const index_type index) const {
        impl().validate(index, sizeof(value_type));
        return impl().data()[index];
    }

    inline reference operator[](const index_type index) {
        impl().validate(index, sizeof(value_type));
        return impl().data()[index];
    }

    inline int8 getInt8At(const index_type index) const {
        STATIC_ASSERT(sizeof(value_type) == sizeof(uint8), int8_can_only_be_read_from_byte_or_char_spans);
        return (int8)getUint8At(index);
    }

    inline uint8 getUint8At(const index_type index) const {
        STATIC_ASSERT(sizeof(value_type) == sizeof(uint8), uint8_can_only_be_read_from_byte_or_char_spans);
        impl().validate(index, sizeof(uint8));
        return (uint8)impl().data()[index];
    }

    inline int16 getInt16BEAt(const index_type index) const {
        STATIC_ASSERT(sizeof(value_type) <= sizeof(uint16), int16_can_only_be_read_from_int16_or_smaller_spans);
        return (int16)impl().getUint16BEAt(index);
    }

    inline int16 getInt16LEAt(const index_type index) const {
        STATIC_ASSERT(sizeof(value_type) <= sizeof(uint16), int16_can_only_be_read_from_int16_or_smaller_spans);
        return (int16)impl().getUint16LEAt(index);
    }

    inline uint16 getUint16BEAt(const index_type index) const {
        STATIC_ASSERT(sizeof(value_type) <= sizeof(uint16), uint16_can_only_be_read_from_int16_or_smaller_spans);
        impl().validate(index, sizeof(uint16));
        return READ_BE_UINT16(impl().data() + index);
    }

    inline uint16 getUint16LEAt(const index_type index) const {
        STATIC_ASSERT(sizeof(value_type) <= sizeof(uint16), uint16_can_only_be_read_from_int16_or_smaller_spans);
        impl().validate(index, sizeof(uint16));
        return READ_LE_UINT16(impl().data() + index);
    }

    inline uint32 getUint24LEAt(const index_type index) const {
        STATIC_ASSERT(sizeof(value_type) <= 3, uint24_can_only_be_read_from_int24_or_smaller_spans);
        impl().validate(index, 3);
        return READ_LE_UINT24(impl().data() + index);
    }

    inline uint32 getUint32At(const index_type index) const {
        STATIC_ASSERT(sizeof(value_type) <= sizeof(uint32), uint32_can_only_be_read_from_int32_or_smaller_spans);
        impl().validate(index, sizeof(uint32));
        return READ_UINT32(impl().data() + index);
    }

    inline int32 getInt32BEAt(const index_type index) const {
        STATIC_ASSERT(sizeof(value_type) <= sizeof(uint32), int32_can_only_be_read_from_int32_or_smaller_spans);
        return (int32)impl().getUint32BEAt(index);
    }

    inline int32 getInt32LEAt(const index_type index) const {
        STATIC_ASSERT(sizeof(value_type) <= sizeof(uint32), int32_can_only_be_read_from_int32_or_smaller_spans);
        return (int32)impl().getUint32LEAt(index);
    }

    inline uint32 getUint32BEAt(const index_type index) const {
        STATIC_ASSERT(sizeof(value_type) <= sizeof(uint32), uint32_can_only_be_read_from_int32_or_smaller_spans);
        impl().validate(index, sizeof(uint32));
        return READ_BE_UINT32(impl().data() + index);
    }

    inline uint32 getUint32LEAt(const index_type index) const {
        STATIC_ASSERT(sizeof(value_type) <= sizeof(uint32), uint32_can_only_be_read_from_int32_or_smaller_spans);
        impl().validate(index, sizeof(uint32));
        return READ_LE_UINT32(impl().data() + index);
    }

    inline String getStringAt(const index_type index, size_type numEntries = kSpanMaxSize) const {
        STATIC_ASSERT(sizeof(value_type) == sizeof(char), strings_can_only_be_read_from_byte_or_char_spans);
        const char *string = (const char *)impl().data() + index;

        if (numEntries == kSpanMaxSize) {
            numEntries = strnlen(string, impl().size() - index);
        }

        impl().validate(index, numEntries);
        return String(string, numEntries);
    }

    inline const_pointer getUnsafeDataAt(const index_type index, size_type numEntries = kSpanMaxSize) const {
        if (numEntries == kSpanMaxSize) {
            numEntries = impl().size() - index;
        }

        impl().validate(index, numEntries * sizeof(value_type));
        return impl().data() + index;
    }

    inline pointer getUnsafeDataAt(const index_type index, size_type numEntries = kSpanMaxSize) {
        if (numEntries == kSpanMaxSize) {
            numEntries = impl().size() - index;
        }

        impl().validate(index, numEntries * sizeof(value_type));
        return impl().data() + index;
    }

    inline MemoryReadStream toStream(const index_type index = 0, size_type numEntries = kSpanMaxSize) const {
        if (numEntries == kSpanMaxSize) {
            numEntries = impl().size() - index;
        }

        impl().validate(index, numEntries * sizeof(value_type));
        return MemoryReadStream(impl().data() + index, numEntries * sizeof(value_type), DisposeAfterUse::NO);
    }

#pragma mark -
#pragma mark SpanBase - Operators

public:
    template <typename Other>
    inline bool operator==(const Other &other) const {
        return impl().data() == other.impl().data() && impl().size() == other.impl().size();
    }

    template <typename Other>
    inline bool operator!=(const Other &other) const {
        return !operator==(other);
    }

    template <typename Other>
    inline difference_type operator-(const Other &other) const {
        return impl().data() - other.impl().data();
    }

    template <typename Other>
    inline bool operator<(const Other &other) const {
        return impl().data() < other.impl().data();
    }

    template <typename Other>
    inline bool operator<=(const Other &other) const {
        return !other.operator<(*this);
    }

    template <typename Other>
    inline bool operator>(const Other &other) const {
        return other.operator<(*this);
    }

    template <typename Other>
    inline bool operator>=(const Other &other) const {
        return !operator<(other);
    }

#if !defined(_MSC_VER)
protected:
#endif
    inline bool operator_bool() const { return impl().data() != nullptr; }

#pragma mark -
#pragma mark SpanBase - Copying

public:
    inline void unsafeCopyDataTo(void *target) const {
        memcpy(target, impl().data(), impl().byteSize());
    }

    template <typename Other>
    inline void copyDataTo(Other &target) const {
        assert((impl().byteSize() % sizeof(typename Other::value_type)) == 0);
        target.impl().validate(0, impl().byteSize(), kValidateWrite);
        memcpy(target.impl().data(), impl().data(), impl().byteSize());
    }

#pragma mark -
#pragma mark SpanBase - Validation

#if !defined(_MSC_VER)
protected:
#endif

    inline bool checkInvalidBounds(const index_type index, const difference_type deltaInBytes) const {
        // There is a potential that large bogus values may cause arithmetic
        // overflow, so the individual operands are checked separately first.
        // Values that are not allowed to be negative are treated as unsigned to
        // reduce the number of necessary comparisons
        const size_t maxByteOffset = index * (signed)sizeof(value_type) + deltaInBytes;
        return index > impl().size() || deltaInBytes > (difference_type)impl().byteSize() || maxByteOffset > impl().byteSize();
    }

    inline void validate(const index_type index, const difference_type deltaInBytes, const SpanValidationMode mode = kValidateRead) const {
        /* LCOV_EXCL_START */
        if (impl().checkInvalidBounds(index, deltaInBytes)) {
            error("%s", impl().getValidationMessage(index, deltaInBytes, mode).c_str());
        }
        /* LCOV_EXCL_STOP */
    }
};

#pragma mark -
#pragma mark SpanImpl

template <typename ValueType, template <typename> class Derived>
class SpanImpl : public SpanBase<ValueType, Derived> {
    typedef SpanBase<ValueType, Derived> super_type;
    typedef typename add_const<Derived<ValueType> >::type const_derived_type;
    typedef typename remove_const<Derived<ValueType> >::type mutable_derived_type;

    template <typename T, template <typename> class U> friend class SpanImpl;
#ifdef CXXTEST_RUNNING
    friend class ::SpanTestSuite;
#endif

public:
    COMMON_SPAN_TYPEDEFS;

    inline SpanImpl() : super_type(), _data(nullptr), _size(0) {}

    inline SpanImpl(const pointer data_, const size_type size_) :
        super_type(),
        _data(data_),
        _size(size_) {}

    template <typename Other>
    inline SpanImpl(const Other &other) :
        super_type(),
        _data(other.data()),
        _size(other.size()) {}

    inline void clear() {
        _data = nullptr;
        _size = 0;
    }

    inline size_type size() const { return _size; }
    inline pointer data() const { return _data; }

    inline const_iterator cbegin() const { return const_iterator(&this->impl(), 0); }
    inline const_iterator cend() const { return const_iterator(&this->impl(), size()); }
    inline const_iterator begin() const { return const_iterator(&this->impl(), 0); }
    inline const_iterator end() const { return const_iterator(&this->impl(), size()); }
    inline iterator begin() { return iterator(&this->impl(), 0); }
    inline iterator end() { return iterator(&this->impl(), size()); }

    const String name() const { return String::format("%p", static_cast<const void *>(data())); }

    String getValidationMessage(const index_type index, const difference_type deltaInBytes, const SpanValidationMode mode) const {
        const char *modeName = "unknown";
        switch (mode) {
            case kValidateRead:
                modeName = "reading";
                break;
            case kValidateWrite:
                modeName = "writing";
                break;
            case kValidateSeek:
                modeName = "seeking";
                break;
            default:
                break;
        }

        return String::format("Access violation %s %s: %u + %d > %u",
                              modeName,
                              this->impl().name().c_str(),
                              index,
                              deltaInBytes / (int)sizeof(value_type),
                              size());
    }

#pragma mark -
#pragma mark SpanImpl - Subspan

public:
    template <typename NewValueType>
    inline const Derived<NewValueType> subspan(const index_type index, size_type numEntries = kSpanMaxSize) const {
        Derived<NewValueType> span;
        populateSubspan(span, index, numEntries);
        return span;
    }

    template <typename NewValueType>
    inline Derived<NewValueType> subspan(const index_type index, size_type numEntries = kSpanMaxSize) {
        Derived<NewValueType> span;
        populateSubspan(span, index, numEntries);
        return span;
    }

    inline const_derived_type subspan(const index_type index, const size_type numEntries = kSpanMaxSize) const {
        return subspan<value_type>(index, numEntries);
    }

    inline mutable_derived_type subspan(const index_type index, const size_type numEntries = kSpanMaxSize) {
        return subspan<value_type>(index, numEntries);
    }

#if !defined(_MSC_VER)
protected:
#endif
    template <typename NewValueType>
    void populateSubspan(Derived<NewValueType> &span, const index_type index, size_type numEntries) const {
        if (numEntries == kSpanMaxSize) {
            numEntries = CLIP<size_type>(size() - index, 0, size());
        }

        assert(numEntries * sizeof(value_type) % sizeof(NewValueType) == 0);
        this->validate(index, numEntries * sizeof(value_type), kValidateSeek);

        span._data = (NewValueType *)const_cast<mutable_value_type *>(_data + index);
        span._size = numEntries * sizeof(value_type) / sizeof(NewValueType);
    }

#pragma mark -
#pragma mark SpanImpl - Allocation

private:
    typedef typename remove_const<value_type>::type mutable_value_type;
    typedef Derived<mutable_value_type> mutable_value_derived_type;

public:
    mutable_value_derived_type &allocate(const size_type numEntries) {
        assert(_data == nullptr);
        assert(numEntries != kSpanMaxSize);
        _data = new mutable_value_type[numEntries];
        _size = numEntries;
        return reinterpret_cast<mutable_value_derived_type &>(const_cast<Derived<value_type> &>(this->impl()));
    }

    template <typename Other>
    mutable_value_derived_type &allocateFromSpan(const Other &other) {
        assert(_data == nullptr);
        assert(sizeof(value_type) == sizeof(typename Other::value_type));
        _data = new mutable_value_type[other.size()];
        _size = other.size();
        copy(other.begin(), other.end(), const_cast<mutable_value_type *>(_data));
        return reinterpret_cast<mutable_value_derived_type &>(const_cast<Derived<value_type> &>(this->impl()));
    }

    mutable_value_derived_type &allocateFromStream(SeekableReadStream &stream, size_type numEntries = kSpanMaxSize) {
        if (numEntries == kSpanMaxSize) {
            numEntries = (stream.size() - stream.pos()) / sizeof(value_type);
        }

        const uint32 bytesRequested = numEntries * sizeof(value_type);
        assert(stream.pos() + bytesRequested <= (uint)stream.size());
        allocate(numEntries);
        const uint32 bytesRead = stream.read((void *)const_cast<mutable_value_type *>(_data), bytesRequested);
        assert(bytesRead == bytesRequested);
        (void)bytesRead;
        return reinterpret_cast<mutable_value_derived_type &>(const_cast<Derived<value_type> &>(this->impl()));
    }

    value_type *_data;
    size_type _size;
};

#pragma mark -
#pragma mark Span

template <typename ValueType>
class Span : public SpanImpl<ValueType, Span> {
    typedef SpanImpl<ValueType, ::Common::Span> super_type;
    typedef typename add_const<Span<ValueType> >::type const_derived_type;
    typedef typename remove_const<Span<ValueType> >::type mutable_derived_type;
    template <typename T> friend class Span;

public:
    COMMON_SPAN_TYPEDEFS;

    inline Span() : super_type() {}

    inline Span(const pointer data_, const size_type size_) : super_type(data_, size_) {}

    // Allows unrelated sibling classes like NamedSpan to assign to superclass
    // siblings like Span
    template <typename Other>
    inline Span(const Other &other) : super_type(other) {}
};

#pragma mark -
#pragma mark NamedSpanImpl

template <typename ValueType, template <typename> class Derived>
class NamedSpanImpl : public SpanImpl<ValueType, Derived> {
    typedef SpanImpl<ValueType, Derived> super_type;
    typedef typename add_const<Derived<ValueType> >::type const_derived_type;
    typedef typename remove_const<Derived<ValueType> >::type mutable_derived_type;

    template <typename T, template <typename> class U> friend class NamedSpanImpl;
#ifdef CXXTEST_RUNNING
    friend class ::SpanTestSuite;
#endif

public:
    COMMON_SPAN_TYPEDEFS;

    inline NamedSpanImpl() = default;

    inline NamedSpanImpl(const pointer data_,
                         const size_type size_,
                         const String &name_ = String(),
                         const size_type sourceByteOffset_ = 0) :
        super_type(data_, size_),
        _name(name_),
        _sourceByteOffset(sourceByteOffset_) {}

    template <typename Other>
    inline NamedSpanImpl(const Other &other) :
        super_type(other),
        _name(other.name()),
        _sourceByteOffset(other.sourceByteOffset()) {}

    inline void clear() {
        super_type::clear();
        _name.clear();
        _sourceByteOffset = 0;
    }

    const String &name() const { return _name; }
    String &name() { return _name; }

    const size_type &sourceByteOffset() const { return _sourceByteOffset; }
    size_type &sourceByteOffset() { return _sourceByteOffset; }

private:
    String _name;
    size_type _sourceByteOffset = 0;

#pragma mark -
#pragma mark NamedSpanImpl - Subspan

public:
    template <typename NewValueType>
    inline const Derived<NewValueType> subspan(const index_type index, const size_type numEntries = kSpanMaxSize, const String &name_ = String(), const size_type sourceByteOffset_ = kSpanKeepOffset) const {
        Derived<NewValueType> span;
        populateSubspan(span, index, numEntries, name_, sourceByteOffset_);
        return span;
    }

    template <typename NewValueType>
    inline Derived<NewValueType> subspan(const index_type index, const size_type numEntries = kSpanMaxSize, const String &name_ = String(), const size_type sourceByteOffset_ = kSpanKeepOffset) {
        Derived<NewValueType> span;
        populateSubspan(span, index, numEntries, name_, sourceByteOffset_);
        return span;
    }

    inline const_derived_type subspan(const index_type index, const size_type numEntries = kSpanMaxSize, const String &name_ = String(), const size_type sourceByteOffset_ = kSpanKeepOffset) const {
        return subspan<value_type>(index, numEntries, name_, sourceByteOffset_);
    }

    inline mutable_derived_type subspan(const index_type index, const size_type numEntries = kSpanMaxSize, const String &name_ = String(), const size_type sourceByteOffset_ = kSpanKeepOffset) {
        return subspan<value_type>(index, numEntries, name_, sourceByteOffset_);
    }

#if !defined(_MSC_VER)
protected:
#endif
    template <typename NewValueType>
    void populateSubspan(Derived<NewValueType> &span, const index_type index, size_type numEntries, const String &name_, const size_type sourceByteOffset_ = kSpanKeepOffset) const {
        super_type::template populateSubspan<NewValueType>(span, index, numEntries);

        if (name_.empty()) {
            span._name = _name;
        } else {
            span._name = name_;
        }

        if (sourceByteOffset_ == kSpanKeepOffset) {
            span._sourceByteOffset = _sourceByteOffset + index * sizeof(value_type);
        } else {
            span._sourceByteOffset = sourceByteOffset_;
        }
    }

#pragma mark -
#pragma mark NamedSpanImpl - Validation

public:
    String getValidationMessage(const index_type index, const difference_type deltaInBytes, const SpanValidationMode mode) const {
        const index_type indexInBytes = index * sizeof(value_type);
        const size_type maxSizeInBytes = this->impl().byteSize();

        return super_type::getValidationMessage(index, deltaInBytes, mode) +
            String::format(" (abs: %u + %d > %u)",
                           this->impl().sourceByteOffset() + indexInBytes,
                           deltaInBytes,
                           this->impl().sourceByteOffset() + maxSizeInBytes);
    }

#pragma mark -
#pragma mark NamedSpanImpl - Allocation

private:
    typedef typename remove_const<value_type>::type mutable_value_type;
    typedef Derived<mutable_value_type> mutable_value_derived_type;

public:
    mutable_value_derived_type &allocate(const size_type numEntries, const String &name_ = String()) {
        super_type::allocate(numEntries);
        _name = name_;
        _sourceByteOffset = 0;
        return reinterpret_cast<mutable_value_derived_type &>(const_cast<Derived<value_type> &>(this->impl()));
    }

    template <typename OtherValueType>
    mutable_value_derived_type &allocateFromSpan(const NamedSpanImpl<OtherValueType, Derived> &other) {
        super_type::allocateFromSpan(other);
        _name = other.name();
        _sourceByteOffset = other.sourceByteOffset();
        return reinterpret_cast<mutable_value_derived_type &>(const_cast<Derived<value_type> &>(this->impl()));
    }

    template <typename OtherValueType, template <typename> class OtherDerived>
    mutable_value_derived_type &allocateFromSpan(const SpanImpl<OtherValueType, OtherDerived> &other) {
        super_type::allocateFromSpan(other);
        return reinterpret_cast<mutable_value_derived_type &>(const_cast<Derived<value_type> &>(this->impl()));
    }

    mutable_value_derived_type &allocateFromStream(SeekableReadStream &stream, size_type numEntries = kSpanMaxSize, const String &name_ = String()) {
        super_type::allocateFromStream(stream, numEntries);
        _name = name_;
        _sourceByteOffset = 0;
        return reinterpret_cast<mutable_value_derived_type &>(const_cast<Derived<value_type> &>(this->impl()));
    }

    mutable_value_derived_type &allocateFromStream(File &file, const size_type numEntries = kSpanMaxSize) {
        return allocateFromStream(file, numEntries, file.getName());
    }
};

#pragma mark -
#pragma mark NamedSpan

template <typename ValueType>
class NamedSpan : public NamedSpanImpl<ValueType, NamedSpan> {
    typedef NamedSpanImpl<ValueType, ::Common::NamedSpan> super_type;

    template <typename T> friend class NamedSpan;

public:
    COMMON_SPAN_TYPEDEFS;

    inline NamedSpan() = default;

    inline NamedSpan(const pointer data_,
                     const size_type size_,
                     const String &name_ = String(),
                     const size_type sourceByteOffset_ = 0) :
        super_type(data_, size_, name_, sourceByteOffset_) {}

    template <typename Other>
    inline NamedSpan(const Other &other) : super_type(other) {}
};

#pragma mark -
#pragma mark SpanOwner

template <typename OwnedSpan>
class SpanOwner : public SafeBool<SpanOwner<OwnedSpan> > {
    typedef typename OwnedSpan::value_type value_type;
    typedef typename OwnedSpan::size_type size_type;
    typedef typename OwnedSpan::index_type index_type;
    typedef typename OwnedSpan::pointer pointer;
    typedef typename OwnedSpan::reference reference;
    typedef typename OwnedSpan::const_reference const_reference;

    template <typename T, typename U> friend struct SafeBool;

public:
    inline SpanOwner() : _span() {}

    inline SpanOwner(const OwnedSpan &span) : _span(span) {}

    inline SpanOwner(const SpanOwner &other) {
        // Allocating memory when copy-constructing from an unallocated owner
        // will break the new owner by making it appear allocated even though
        // it doesn't (and shouldn't) contain data
        if (!other) {
            SpanOwner();
            return;
        }

        _span.allocateFromSpan(other._span);
    }

    inline SpanOwner &operator=(const SpanOwner &other) {
        if (this == &other) {
            return *this;
        }

        delete[] const_cast<typename remove_const<value_type>::type *>(_span.data());
        _span.clear();

        // Allocating memory when copy-assigning from an unallocated owner
        // will break the new owner by making it appear allocated even though
        // it doesn't (and shouldn't) contain data
        if (other) {
            _span.allocateFromSpan(other._span);
        }

        return *this;
    }

    inline ~SpanOwner() {
        delete[] const_cast<typename remove_const<value_type>::type *>(_span.data());
    }

    inline SpanOwner &moveFrom(SpanOwner &other) {
        if (this == &other) {
            return *this;
        }

        delete[] const_cast<typename remove_const<value_type>::type *>(_span.data());
        _span = other._span;
        other.release();
        return *this;
    }

    inline pointer release() {
        pointer data = _span.data();
        _span.clear();
        return data;
    }

    inline void clear() {
        delete[] const_cast<typename remove_const<value_type>::type *>(_span.data());
        _span.clear();
    }

#if !defined(_MSC_VER)
protected:
#endif
    inline bool operator_bool() const { return _span; }

private:
    OwnedSpan _span;

#pragma mark -
#pragma mark SpanOwner - Data access

public:
    inline const OwnedSpan &operator*() const { return _span; }
    inline OwnedSpan &operator*() { return _span; }

    inline const OwnedSpan *operator->() const { return &_span; }
    inline OwnedSpan *operator->() { return &_span; }

    inline const_reference operator[](const index_type index) const { return _span[index]; }
    inline reference operator[](const index_type index) { return _span[index]; }
};

} // End of namespace Common

#endif