String.h

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#pragma once

#include "OnixS/CME/DropCopy/Export.h"
#include "OnixS/CME/DropCopy/Numeric.h"

#include <cstring>
#include <functional>
#include <ostream>
#include <stdexcept>
#include <string>

namespace OnixS { namespace CME { namespace DropCopy {

class StringRef;

/// Zero-terminated sequence of characters.
class ONIXS_CME_DROP_COPY_EXPORT String
{
public:
    /// Read-write access over characters.
    typedef char* iterator;

    /// Read-only access over characters.
    typedef const char* ConstIterator;

    /// Initializes empty string.
    String();

    /// Initializes as copy of another instance.
    String(const String& other);

    /// Initializes as copy of what is
    /// referred by StringRef instance.
    explicit String(const StringRef& strRef);

    /// Initializes as copy of std::string instance.
    explicit String(const std::string& stdStr);

    /// Initializes as copy of null-terminated C string.
    explicit String(const char* cStr);

    /// Initializes from sequence of give size.
    String(const char* text, size_t textSize);

    /// Cleans up internal resources.
    ~String();

    /// Indicates whether sequence is empty.
    bool empty() const;

    /// Number of characters in the sequence.
    size_t size() const;

    /// Number of characters that can be put into
    /// sequence without reallocating internal store.
    size_t capacity() const;

    /// Direct read-only access to buffer
    /// which holds the sequence.
    const char* data() const;

    /// Returns string as C string.
    const char* c_str() const;

    /// Points to the first element in the sequence.
    iterator begin();

    /// Points to the first element in the sequence.
    ConstIterator begin() const;

    /// Points to the location succeeding
    /// the last element in the sequence.
    iterator end();

    /// Points to the location succeeding
    /// the last element in the sequence.
    ConstIterator end() const;

    /// Reference to the character located at specified index.
    /// \note For a performance considerations does NOT check
    /// bounds of the character being accessed.
    char& operator[](size_t index);

    /// Const reference to the character located at specified index.
    /// \note For a performance considerations does NOT check
    /// bounds of the character being accessed.
    const char& operator[](size_t index) const;

    /// Provides safe access to the character
    /// via its reference located at specified index.
    char& at(size_t index);

    /// Provides safe access to the character
    /// via its reference located at specified index.
    const char& at(size_t index) const;

    /// Makes internal store to be capable of storing
    /// at least specified number of characters without
    /// necessity to reallocate it.
    void reserve(size_t capacity);

    /// Specifies new size for the sequence,
    /// appending or erasing elements as required.
    void resize(size_t size);

    /// Specifies new size for the sequence,
    /// appending or erasing elements as required.
    void resize(size_t size, char filler);

    /// Inserts subsequence at specified position.
    String& insert(size_t offset, const char* text, size_t textSize);

    /// Appends subsequence to the end.
    String& append(const char* text, size_t textSize);

    /// Re-initializes instance with given string.
    String& assign(const char* text, size_t textSize);

    /// Replaces subsequence of specified length at
    /// specified position with the new subsequence.
    String& replace(size_t offset, size_t count, const char* text, size_t textSize);

    /// Erases subsequence of specified
    /// length at specified position.
    void erase(size_t offset, size_t count);

    /// Erases all characters in the string.
    void clear();

    /// Implicit conversion to std::string type.
    operator std::string() const;

    /// Compares with other instance for equality.
    bool operator==(const String& other) const;

    /// Compares with other instance for inequality.
    bool operator!=(const String& other) const;

    /// Reinitializes instance as copy of another one.
    String& operator=(const String& other);

    /// Reinitializes instance as copy of another one.
    String& operator=(const std::string& other);

    /// Reinitializes instance as copy of another one.
    String& operator=(const char* other);

    /// Reinitializes instance as copy of another one.
    String& operator=(char other);

    /// Appends other string to the end.
    String& operator+=(const String& text);

    /// Appends other string to the end.
    String& operator+=(const char* text);

    /// Appends other string to the end.
    String& operator+=(const std::string& text);

    /// Appends other string to the end.
    String& operator+=(char character);

private:
    enum Traits
    {
        PreallocatedSize = 3 * sizeof(size_t)
    };

    char* text_;
    size_t size_;
    size_t capacity_;
    char preallocated_[PreallocatedSize];

    void grow(size_t delta);
    void shrink(size_t delta);
};

inline bool String::empty() const
{
    return (0 == size_);
}

inline size_t String::size() const
{
    return size_;
}

inline size_t String::capacity() const
{
    return (capacity_ - 1);
}

inline const char* String::data() const
{
    return text_;
}

inline const char* String::c_str() const
{
    return text_;
}

inline String::iterator String::begin()
{
    return text_;
}

inline String::ConstIterator String::begin() const
{
    return text_;
}

inline String::iterator String::end()
{
    return (text_ + size_);
}

inline String::ConstIterator String::end() const
{
    return (text_ + size_);
}

inline char& String::operator[](size_t index)
{
    return text_[index];
}

inline const char& String::operator[](size_t index) const
{
    return text_[index];
}

inline char& String::at(size_t index)
{
    if (index < size_)
    {
        return text_[index];
    }

    throw std::out_of_range("index");
}

inline const char& String::at(size_t index) const
{
    if (index < size_)
    {
        return text_[index];
    }

    throw std::out_of_range("index");
}

inline String::operator std::string() const
{
    return std::string(text_, size_);
}

inline String& String::operator=(const std::string& other)
{
    return assign(other.data(), other.size());
}

inline String& String::operator=(const char* other)
{
    if (other)
    {
        assign(other, strlen(other));
    }

    return *this;
}

inline String& String::operator=(char other)
{
    return assign(&other, 1);
}

inline String& String::operator+=(const String& text)
{
    return append(text.data(), text.size());
}

inline String& String::operator+=(const char* text)
{
    if (text)
    {
        append(text, strlen(text));
    }

    return *this;
}

inline String& String::operator+=(const std::string& text)
{
    return append(text.data(), text.size());
}

inline String& String::operator+=(char character)
{
    return append(&character, 1);
}

/// Provides efficient way of accessing text-based FIX field values.
class ONIXS_CME_DROP_COPY_EXPORT StringRef
{
public:
    /// Immutable iterator over chars.
    typedef const char* ConstIterator;

    /// Initializes blank instance.
    StringRef()
      : chars_(NULL)
      , size_(0)
    {
    }

    /// Full initialization.
    StringRef(const char* chars, size_t size)
      : chars_(chars)
      , size_(size)
    {
    }

    /// Initializes as clone of other instance.
    /// Data referenced by clone is not copied.
    /// Instead both instances will refer to same
    /// text segment.
    StringRef(const StringRef& other)
      : chars_(other.chars_)
      , size_(other.size_)
    {
    }

    /// Initializes instance from string content.
    explicit StringRef(const std::string& stdStr)
      : chars_(stdStr.c_str())
      , size_(stdStr.size())
    {
    }

    /// Initializes instance from string content.
    explicit StringRef(const String& ownStr)
      : chars_(ownStr.data())
      , size_(ownStr.size())
    {
    }

    /// Initializes instance from zero-terminated string.
    explicit StringRef(const char* cStr)
      : chars_(cStr)
      , size_(cStr ? strlen(cStr) : 0)
    {
    }

    /// Indicates whether array of zero length.
    bool empty() const
    {
        return (0 == size_);
    }

    /// Read-only content.
    const char* data() const
    {
        return chars_;
    }

    /// STL-like begin().
    ConstIterator begin() const
    {
        return chars_;
    }

    /// STL-like end().
    ConstIterator end() const
    {
        return chars_ + size_;
    }

    /// Number of chars.
    size_t size() const
    {
        return size_;
    }

    /// Resets reference to nothing.
    void reset()
    {
        reset(NULL, 0);
    }

    /// Updates data being referenced.
    void reset(const char* chars, size_t size)
    {
        chars_ = chars;
        size_ = size;
    }

    const char& operator[](size_t index) const
    {
        return chars_[index];
    }

    const char& at(size_t index) const
    {
        if (index < size_)
        {
            return chars_[index];
        }

        throw std::invalid_argument("index");
    }

    /// Returns number if text is string
    /// representation of an integer.
    template <typename NumericType>
    bool toNumber(NumericType& number) const
    {
        return OnixS::CME::DropCopy::Number::tryParse(chars_, size_, number);
    }

    // Appends copy of text to the std::string.
    void toString(std::string& str) const
    {
        str.append(chars_, size_);
    }

    // Return copy of text as std::string.
    std::string toString() const
    {
        return std::string(chars_, size_);
    }

    /// Implicit conversion to std::string.
    operator std::string() const
    {
        return std::string(chars_, size_);
    }

    /// Compares with another instance.
    bool operator==(const StringRef& other) const
    {
        return (size_ == other.size_ && 0 == memcmp(chars_, other.chars_, size_));
    }

    /// Compares with another instance.
    bool operator!=(const StringRef& other) const
    {
        return (size_ != other.size_ || 0 != memcmp(chars_, other.chars_, size_));
    }

    /// Reinitializes from another instance.
    StringRef& operator=(const StringRef& other)
    {
        chars_ = other.chars_;
        size_ = other.size_;

        return *this;
    }

    /// Swaps content with other instance.
    void swap(StringRef& other)
    {
        std::swap(chars_, other.chars_);
        std::swap(size_, other.size_);
    }

private:
    /// Items being referenced.
    const char* chars_;

    /// Number of chars being referenced.
    size_t size_;
};

inline bool operator==(const StringRef& ref, const String& str)
{
    return ref == StringRef(str);
}

inline bool operator!=(const StringRef& ref, const String& str)
{
    return ref != StringRef(str);
}

inline bool operator==(const String& str, const StringRef& ref)
{
    return ref == StringRef(str);
}

inline bool operator!=(const String& str, const StringRef& ref)
{
    return ref != StringRef(str);
}

inline bool operator==(const StringRef& ref, const std::string& str)
{
    return ref == StringRef(str);
}

inline bool operator!=(const StringRef& ref, const std::string& str)
{
    return ref != StringRef(str);
}

inline bool operator==(const std::string& str, const StringRef& ref)
{
    return ref == StringRef(str);
}

inline bool operator!=(const std::string& str, const StringRef& ref)
{
    return ref != StringRef(str);
}

inline bool operator==(const StringRef& ref, const char* str)
{
    return ref == StringRef(str);
}

inline bool operator!=(const StringRef& ref, const char* str)
{
    return ref != StringRef(str);
}

inline bool operator==(const char* str, const StringRef& ref)
{
    return ref == StringRef(str);
}

inline bool operator!=(const char* str, const StringRef& ref)
{
    return ref != StringRef(str);
}

}}}

namespace std {

/// Allows using of StringRef in collections like std::map.
template <>
struct ONIXS_CME_DROP_COPY_EXPORT less<OnixS::CME::DropCopy::StringRef>
{
    bool operator()(
        const OnixS::CME::DropCopy::StringRef& left,
        const OnixS::CME::DropCopy::StringRef& right
    ) const
    {
        ptrdiff_t compareResult = memcmp(
            left.data(), right.data(), left.size() < right.size() ? left.size() : right.size()
        );

        if (0 == compareResult)
        {
            compareResult = static_cast<ptrdiff_t>(left.size() - right.size());
        }

        return (0 > compareResult);
    }
};

/// Allows using of StringRef in collections like std::map.
template <>
struct ONIXS_CME_DROP_COPY_EXPORT less<OnixS::CME::DropCopy::String>
{
    bool operator()(
        const OnixS::CME::DropCopy::String& left,
        const OnixS::CME::DropCopy::String& right
    ) const
    {
        return std::less<OnixS::CME::DropCopy::StringRef>()(
            OnixS::CME::DropCopy::StringRef(left), OnixS::CME::DropCopy::StringRef(right)
        );
    }
};

inline std::ostream& operator<<(std::ostream& stream, const OnixS::CME::DropCopy::StringRef& text)
{
    stream.write(text.data(), text.size());
    return stream;
}

inline std::ostream& operator<<(std::ostream& stream, const OnixS::CME::DropCopy::String& text)
{
    stream.write(text.data(), text.size());
    return stream;
}

}