SF_String.h

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/*
 * Copyright 2016 Autodesk, Inc. All rights reserved.
 * Use of this software is subject to the terms of the Autodesk license agreement and any attachments or Appendices thereto provided at the time of installation or download,
 * or which otherwise accompanies this software in either electronic or hard copy form, or which is signed by you and accepted by Autodesk.
 */

#pragma once

#include "gwnavruntime/kernel/SF_Alg.h"
#include "gwnavruntime/kernel/SF_Array.h"
#include "gwnavruntime/kernel/SF_Atomic.h"
#include "gwnavruntime/kernel/SF_Std.h"
#include "gwnavruntime/kernel/SF_Types.h"
#include "gwnavruntime/kernel/SF_UTF8Util.h"
#include <string.h>

namespace Kaim
{

// ***** Classes

class String;
class StringLH;
class StringDH;
class StringBuffer;
class StringDataPtr;

// ***** String Class

// String is UTF8 based string class with heap support. There are several
// versions of string used to manage different heaps:
//
//   String   - Allocates memory from global heap by default.
//
//   StringLH - Allocates memory from local heap based on 'this' pointer,
//              so it can only be constructed in allocated data structures.
//
//   StringDH - Allocates from a heap explicitly specified in constructor
//                 argument; mostly used for temporaries which are later assigned
//                 to the local heap strings.
//
// String is a base to the other two classes, allowing all string argument
// passing to be done by String&, passing a specific derived class is not
// necessary. Strings do NOT mutate heaps on assignment, so a data copy will
// be made if a string is copied to a different heap; this copy and allocation
// is avoided if heaps on both sides of assignment do match.
class String
{
    friend class StringLH;
    friend class StringDH;

protected:
    enum FlagConstants
    {
        // Flag_GetLength      = 0x7FFFFFFF,
        // This flag is set if GetLength() == GetSize() for a string.
        // Avoid extra scanning is Substring and indexing logic.
        Flag_LengthIsSizeShift = (sizeof(UPInt) * 8 - 1)
    };

    // Internal structure to hold string data
    struct DataDesc
    {
    private:
        DataDesc(const DataDesc&); // no copy constructor

    public:
        // constructor used in String::NullData(), the unused int param is there to indicate that it's not a default constructor
        DataDesc(int)
        {
            Size = (UPInt(1) << String::Flag_LengthIsSizeShift);
            RefCount = 1;
            Data[0] = 0;
        }

        // Number of bytes. Will be the same as the number of chars if the characters
        // are ascii, may not be equal to number of chars in case string data is UTF8.
        UPInt Size;
        std::atomic<SInt32> RefCount;
        char Data[1];

        void AddRef() { RefCount.fetch_add(1); }

        void Release()
        {
            if (RefCount.fetch_add(-1) - 1 == 0)
                KY_FREE(this);
        }

        static UPInt GetLengthFlagBit() { return UPInt(1) << Flag_LengthIsSizeShift; }
        UPInt GetSize() const { return Size & ~GetLengthFlagBit(); }
        UPInt GetLengthFlag() const { return Size & GetLengthFlagBit(); }
        bool LengthIsSize() const { return GetLengthFlag() != 0; }
    };

    // Heap type of the string is encoded in the lower bits.
    enum HeapType
    {
        HT_Global = 0, // Heap is global.
        HT_Local = 1, // SF::String_loc: Heap is determined based on string's address.
        HT_Dynamic = 2, // SF::String_temp: Heap is stored as a part of the class.
        HT_Mask = 3
    };

    union {
        DataDesc* pData;
        UPInt HeapTypeBits;
    };
    typedef union {
        DataDesc* pData;
        UPInt HeapTypeBits;
    } DataDescUnion;

    inline HeapType GetHeapType() const { return (HeapType)(HeapTypeBits & HT_Mask); }

    inline DataDesc* GetData() const
    {
        DataDescUnion u;
        u.pData = pData;
        u.HeapTypeBits = (u.HeapTypeBits & ~(UPInt)HT_Mask);
        return u.pData;
    }

    inline void SetData(DataDesc* pdesc)
    {
        HeapType ht = GetHeapType();
        pData = pdesc;
        KY_ASSERT((HeapTypeBits & HT_Mask) == 0);
        HeapTypeBits |= ht;
    }

    DataDesc* AllocData(MemoryHeap* pheap, UPInt size, UPInt lengthIsSize);
    DataDesc* AllocDataCopy1(MemoryHeap* pheap, UPInt size, UPInt lengthIsSize, const char* pdata, UPInt copySize);
    DataDesc* AllocDataCopy2(MemoryHeap* pheap, UPInt size, UPInt lengthIsSize, const char* pdata1, UPInt copySize1, const char* pdata2, UPInt copySize2);

    // Special constructor to avoid data initalization when used in derived class.
    struct NoConstructor
    {
    };
    String(const NoConstructor&) {}

public:
    static DataDesc& NullData();

    // For initializing string with dynamic buffer
    struct InitStruct
    {
        virtual ~InitStruct() {}
        virtual void InitString(char* pbuffer, UPInt size) const = 0;
    };

    // Constructors / Destructors.
    String();
    String(const char* data);
    String(const char* data1, const char* pdata2, const char* pdata3 = 0);
    String(const char* data, UPInt buflen);
    String(const String& src);
    String(const StringBuffer& src);
    String(const StringDataPtr src);
    String(const InitStruct& src, UPInt size);
    explicit String(const wchar_t* data);

    // Destructor (Captain Obvious guarantees!)
    ~String() { GetData()->Release(); }

    MemoryHeap* GetHeap() const;

    // *** General Functions

    void Clear();

    // For casting to a pointer to char.
    operator const char*() const { return GetData()->Data; }
    // Pointer to raw buffer.
    const char* ToCStr() const { return GetData()->Data; }

    // Returns number of bytes
    UPInt GetSize() const { return GetData()->GetSize(); }
    // Tells whether or not the string is empty
    bool IsEmpty() const { return GetSize() == 0; }

    // Returns  number of characters
    UPInt GetLength() const;

    // Returns  character at the specified index
    UInt32 GetCharAt(UPInt index) const;
    UInt32 GetFirstCharAt(UPInt index, const char** offset) const;
    UInt32 GetNextChar(const char** offset) const;

    // Appends a character
    void AppendChar(UInt32 ch);

    // Append a string
    void AppendString(const wchar_t* pstr, SPInt len = -1);
    void AppendString(const char* putf8str, SPInt utf8StrSz = -1);

    // Assigned a string with dynamic data (copied through initializer).
    void AssignString(const InitStruct& src, UPInt size);

    // Assigns string with known size.
    void AssignString(const char* putf8str, UPInt size);

    //  Resize the string to the new size
    //  void        Resize(UPInt _size);

    // Removes the character at posAt
    void Remove(UPInt posAt, SPInt len = 1);

    // Returns a String that's a substring of this.
    //  -start is the index of the first UTF8 character you want to include.
    //  -end is the index one past the last UTF8 character you want to include.
    String Substring(UPInt start, UPInt end) const;

    // Case-conversion
    String ToUpper() const;
    String ToLower() const;

    // Inserts substr at posAt
    String& Insert(const char* substr, UPInt posAt, SPInt len = -1);

    // Inserts character at posAt
    UPInt InsertCharAt(UInt32 c, UPInt posAt);

    // Get Byte index of the character at position = index
    UPInt GetByteIndex(UPInt index) const { return (UPInt)UTF8Util::GetByteIndex(index, GetData()->Data); }

    // Utility: case-insensitive string compare.  stricmp() & strnicmp() are not
    // ANSI or POSIX, do not seem to appear in Linux.
    static int CompareNoCase(const char* a, const char* b);
    static int CompareNoCase(const char* a, const char* b, SPInt len);

    // Hash function, case-insensitive
    static UPInt BernsteinHashFunctionCIS(const void* pdataIn, UPInt size, UPInt seed = 5381);

    // Hash function, case-sensitive
    static UPInt BernsteinHashFunction(const void* pdataIn, UPInt size, UPInt seed = 5381);

    // Encode/decode special html chars
    static void EscapeSpecialHTML(const char* psrc, UPInt length, String* pescapedStr);
    static void UnescapeSpecialHTML(const char* psrc, UPInt length, String* punescapedStr);

    // ***** File path parsing helper functions.
    // Implemented in KY_String_FilePath.cpp.

    // Absolute paths can star with:
    //  - protocols:        'file://', 'http://'
    //  - windows drive:    'c:\'
    //  - UNC share name:   '\\share'
    //  - unix root         '/'
    static bool HasAbsolutePath(const char* path);
    static bool HasExtension(const char* path);
    static bool HasProtocol(const char* path);

    bool HasAbsolutePath() const { return HasAbsolutePath(ToCStr()); }
    bool HasExtension() const { return HasExtension(ToCStr()); }
    bool HasProtocol() const { return HasProtocol(ToCStr()); }

    String GetProtocol() const; // Returns protocol, if any, with trailing '://'.
    String GetPath() const; // Returns path with trailing '/'.
    String GetFilename() const; // Returns filename, including extension.
    String GetExtension() const; // Returns extension with a dot.

    String& StripProtocol(); // Strips front protocol, if any, from the string.
    String& StripExtension(); // Strips off trailing extension.

    // Operators
    // Assignment
    void operator=(const char* str);
    void operator=(const wchar_t* str);
    void operator=(const String& src);
    void operator=(const StringBuffer& src);

    // Addition
    void operator+=(const String& src);
    void operator+=(const char* psrc) { AppendString(psrc); }
    void operator+=(const wchar_t* psrc) { AppendString(psrc); }
    void operator+=(char ch) { AppendChar(ch); }
    String operator+(const char* str) const;
    String operator+(const String& src) const;

    // Comparison
    bool operator==(const String& str) const { return (SFstrcmp(GetData()->Data, str.GetData()->Data) == 0); }
    bool operator!=(const String& str) const { return !operator==(str); }
    bool operator==(const char* str) const { return SFstrcmp(GetData()->Data, str) == 0; }
    bool operator!=(const char* str) const { return !operator==(str); }
    bool operator<(const char* pstr) const { return SFstrcmp(GetData()->Data, pstr) < 0; }
    bool operator<(const String& str) const { return *this < str.GetData()->Data; }
    bool operator>(const char* pstr) const { return SFstrcmp(GetData()->Data, pstr) > 0; }
    bool operator>(const String& str) const { return *this > str.GetData()->Data; }

    int CompareNoCase(const char* pstr) const { return CompareNoCase(GetData()->Data, pstr); }
    int CompareNoCase(const String& str) const { return CompareNoCase(GetData()->Data, str.ToCStr()); }

    // Accesses raw bytes
    const char& operator[](int index) const
    {
        KY_ASSERT(index >= 0 && (UPInt)index < GetSize());
        return GetData()->Data[index];
    }
    const char& operator[](UPInt index) const
    {
        KY_ASSERT(index < GetSize());
        return GetData()->Data[index];
    }

    // Case insensitive keys are used to look up insensitive string in hash tables
    // for SWF files with version before SWF 7.
    struct NoCaseKey
    {
        const String* pStr;
        NoCaseKey(const String& str) : pStr(&str){};
    };

    bool operator==(const NoCaseKey& strKey) const { return (CompareNoCase(ToCStr(), strKey.pStr->ToCStr()) == 0); }
    bool operator!=(const NoCaseKey& strKey) const { return !(CompareNoCase(ToCStr(), strKey.pStr->ToCStr()) == 0); }

    // Hash functor used for strings.
    struct HashFunctor
    {
        UPInt operator()(const String& data) const
        {
            UPInt size = data.GetSize();
            return String::BernsteinHashFunction((const char*)data, size);
        }
    };

    // Case-insensitive hash functor used for strings. Supports additional
    // lookup based on NoCaseKey.
    struct NoCaseHashFunctor
    {
        UPInt operator()(const String& data) const
        {
            UPInt size = data.GetSize();
            return String::BernsteinHashFunctionCIS((const char*)data, size);
        }
        UPInt operator()(const NoCaseKey& data) const
        {
            UPInt size = data.pStr->GetSize();
            return String::BernsteinHashFunctionCIS((const char*)data.pStr->ToCStr(), size);
        }
    };
};

// ***** Local Heap String - StringLH

// A structure-local version of String, which determined its own memory
// heap based on 'this' pointer location. This class can not be created on
// stack or outside of an allocated memory heap. If cross-heap string assignment
// takes place, a copy of string data may be created.
class StringLH : public String
{
    // Initializes pData with Local heap flag.
    void SetDataLcl(DataDesc* pdesc)
    {
        pData = pdesc;
        KY_ASSERT((HeapTypeBits & HT_Mask) == 0);
        HeapTypeBits |= HT_Local;
    }

    void CopyConstructHelper(const String& src);

public:
    // Constructors / Destructors.
    StringLH();
    StringLH(const char* data);
    StringLH(const char* data, UPInt buflen);
    // We MUST have copy constructor, or compiler will generate an incorrect one calling base.
    StringLH(const StringLH& src) : String(NoConstructor()) { CopyConstructHelper(src); }
    explicit StringLH(const String& src) : String(NoConstructor()) { CopyConstructHelper(src); }
    explicit StringLH(const InitStruct& src, UPInt size);
    explicit StringLH(const wchar_t* data);

    // Assignment
    void operator=(const char* str) { String::operator=(str); }
    void operator=(const wchar_t* str) { String::operator=(str); }
    void operator=(const String& src) { String::operator=(src); }
    void operator=(const StringBuffer& src) { String::operator=(src); }
};

// ***** Dynamic Heap String - StringDH

// A dynamic heap version of String, which stores its memory heap in an
// internal pointer. Note that assigning the string does NOT copy the heap.
class StringDH : public String
{
    MemoryHeap* pHeap;

    // Initializes pData with Local heap flag.
    void SetDataLcl(DataDesc* pdesc)
    {
        pData = pdesc;
        KY_ASSERT((HeapTypeBits & HT_Mask) == 0);
        HeapTypeBits |= HT_Dynamic;
    }

    void CopyConstructHelper(const String& src, MemoryHeap* pheap);

public:
    // Constructors / Destructors.
    StringDH(MemoryHeap* pheap = Memory::GetGlobalHeap());
    StringDH(MemoryHeap* pheap, const char* data);
    StringDH(MemoryHeap* pheap, const char* data1, const char* pdata2, const char* pdata3 = 0);
    StringDH(MemoryHeap* pheap, const char* data, UPInt buflen);
    StringDH(const StringDH& src) : String(NoConstructor()) { CopyConstructHelper(src, src.GetHeap()); }
    explicit StringDH(const String& src) : String(NoConstructor()) { CopyConstructHelper(src, 0); }
    explicit StringDH(MemoryHeap* pheap, const String& src) : String(NoConstructor()) { CopyConstructHelper(src, pheap); }
    explicit StringDH(MemoryHeap* pheap, const InitStruct& src, UPInt size);
    explicit StringDH(MemoryHeap* pheap, const wchar_t* data);

    void operator=(const char* str) { String::operator=(str); }
    void operator=(const wchar_t* str) { String::operator=(str); }
    void operator=(const String& src) { String::operator=(src); }
    void operator=(const StringBuffer& src) { String::operator=(src); }

    MemoryHeap* GetHeap() const { return pHeap; }
};

// ***** String Buffer used for Building Strings

class StringBuffer
{
    char* pData;
    UPInt Size;
    UPInt BufferSize;
    UPInt GrowSize;
    mutable bool LengthIsSize;
    MemoryHeap* pHeap;

public:
    // Constructors / Destructor.
    StringBuffer(MemoryHeap* pheap = Memory::GetGlobalHeap());
    explicit StringBuffer(UPInt growSize, MemoryHeap* pheap = Memory::GetGlobalHeap());
    StringBuffer(const char* data, MemoryHeap* pheap = Memory::GetGlobalHeap());
    StringBuffer(const char* data, UPInt buflen, MemoryHeap* pheap = Memory::GetGlobalHeap());
    StringBuffer(const String& src, MemoryHeap* pheap = Memory::GetGlobalHeap());
    StringBuffer(const StringBuffer& src, MemoryHeap* pheap = Memory::GetGlobalHeap());
    explicit StringBuffer(const wchar_t* data, MemoryHeap* pheap = Memory::GetGlobalHeap());
    ~StringBuffer();

    MemoryHeap* GetHeap() const { return pHeap; }

    // Modify grow size used for growing/shrinking the buffer.
    UPInt GetGrowSize() const { return GrowSize; }
    void SetGrowSize(UPInt growSize);

    // *** General Functions

    // Does not release memory, just sets Size to 0
    void Clear();

    // For casting to a pointer to char.
    operator const char*() const { return (pData) ? pData : ""; }

    // Pointer to raw buffer.
    const char* ToCStr() const { return (pData) ? pData : ""; }

    // Returns number of bytes.
    UPInt GetSize() const { return Size; }
    // Tells whether or not the string is empty.
    bool IsEmpty() const { return GetSize() == 0; }

    // Returns  number of characters
    UPInt GetLength() const;

    // Returns  character at the specified index
    UInt32 GetCharAt(UPInt index) const;
    UInt32 GetFirstCharAt(UPInt index, const char** offset) const;
    UInt32 GetNextChar(const char** offset) const;

    //  Resize the string to the new size
    void Resize(UPInt _size);
    void Reserve(UPInt _size);

    // Appends a character
    void AppendChar(UInt32 ch);

    // Append a string
    void AppendString(const wchar_t* pstr, SPInt len = -1);
    void AppendString(const char* putf8str, SPInt utf8StrSz = -1);

    // Inserts substr at posAt
    void Insert(const char* substr, UPInt posAt, SPInt len = -1);
    // Inserts character at posAt
    UPInt InsertCharAt(UInt32 c, UPInt posAt);

    // Assignment
    void operator=(const char* str);
    void operator=(const wchar_t* str);
    void operator=(const String& src);
    void operator=(const StringBuffer& src);

    // Addition
    void operator+=(const StringBuffer& buff) { AppendString(buff.ToCStr(), buff.GetSize()); }
    void operator+=(const String& src) { AppendString(src.ToCStr(), src.GetSize()); }
    void operator+=(const char* psrc) { AppendString(psrc); }
    void operator+=(const wchar_t* psrc) { AppendString(psrc); }
    void operator+=(char ch) { AppendChar(ch); }

    // Accesses raw bytes
    char& operator[](int index)
    {
        KY_ASSERT(((UPInt)index) < GetSize());
        return pData[index];
    }
    char& operator[](UPInt index)
    {
        KY_ASSERT(index < GetSize());
        return pData[index];
    }

    const char& operator[](int index) const
    {
        KY_ASSERT(((UPInt)index) < GetSize());
        return pData[index];
    }
    const char& operator[](UPInt index) const
    {
        KY_ASSERT(index < GetSize());
        return pData[index];
    }
};

// Wrapper for string data. The data must have a guaranteed
// lifespan throughout the usage of the wrapper. Not intended for
// cached usage. Not thread safe.
class StringDataPtr
{
public:
    StringDataPtr() : pStr(NULL), Size(0) {}
    StringDataPtr(const StringDataPtr& p) : pStr(p.pStr), Size(p.Size) {}
    StringDataPtr(const char* pstr, UPInt sz) : pStr(pstr), Size(sz) {}
    StringDataPtr(const char* pstr) : pStr(pstr), Size((pstr != NULL) ? SFstrlen(pstr) : 0) {}
    explicit StringDataPtr(const String& str) : pStr(str.ToCStr()), Size(str.GetSize()) {}
    template <typename T, int N>
    StringDataPtr(const T (&v)[N]) : pStr(v), Size(N) {}

public:
    // Accesses raw bytes
    char operator[](UPInt index) const
    {
        KY_ASSERT(index < GetSize());
        return pStr[index];
    }

    const char* ToCStr() const { return pStr; }
    UPInt GetSize() const { return Size; }
    bool IsEmpty() const { return GetSize() == 0; }

    // value is a prefix of this string
    // Character's values are not compared.
    bool IsPrefix(const StringDataPtr& value) const { return ToCStr() == value.ToCStr() && GetSize() >= value.GetSize(); }

    // value is a suffix of this string
    // Character's values are not compared.
    bool IsSuffix(const StringDataPtr& value) const { return ToCStr() <= value.ToCStr() && (End()) == (value.End()); }

    // Find first character.
    // init_ind - initial index.
    SPInt FindChar(char c, UPInt init_ind = 0) const
    {
        for (UPInt i = init_ind; i < GetSize(); ++i)
            if (pStr[i] == c)
                return static_cast<SPInt>(i);

        return -1;
    }

    // Find last character.
    // init_ind - initial index.
    SPInt FindLastChar(char c, UPInt init_ind = ~0) const;

    // Find first substring.
    SPInt FindSubstring(const StringDataPtr& s, UPInt init_ind = 0) const;

    // Create new object and trim size bytes from the left.
    StringDataPtr GetTrimLeft(UPInt size) const
    {
        size = Alg::PMin(GetSize(), size); // Limit trim to the size of the string.
        return StringDataPtr(ToCStr() + size, GetSize() - size);
    }
    // Create new object and trim size bytes from the right.
    StringDataPtr GetTrimRight(UPInt size) const
    {
        size = Alg::PMin(GetSize(), size); // Limit trim to the size of the string.
        return StringDataPtr(ToCStr(), GetSize() - size);
    }

    // Create new object, which contains next token. Useful for parsing.
    StringDataPtr GetNextToken(char separator = ':') const;

    // Trim size bytes from the left.
    StringDataPtr& TrimLeft(UPInt size)
    {
        size = Alg::PMin(GetSize(), size); // Limit trim size to the size of the string.
        pStr += size;
        Size -= size;
        return *this;
    }

    // Trim size bytes from the right.
    StringDataPtr& TrimRight(UPInt size)
    {
        size = Alg::PMin(GetSize(), size); // Limit trim to the size of the string.
        Size -= size;
        return *this;
    }

    // Create new object. Prefix of size "size".
    StringDataPtr GetPrefix(UPInt size) const
    {
        size = Alg::PMin(GetSize(), size); // Limit prefix size to the size of the string.
        return StringDataPtr(ToCStr(), size);
    }

    // Create new object. Suffix of size "size".
    StringDataPtr GetSuffix(UPInt size) const
    {
        size = Alg::PMin(GetSize(), size); // Limit suffix to the size of the string.
        return StringDataPtr(ToCStr() + GetSize() - size, size);
    }

    // Prefix of size "size".
    StringDataPtr& Prefix(UPInt size)
    {
        Size = Alg::PMin(GetSize(), size); // Limit prefix size to the size of the string.
        return *this;
    }
    // Suffix of size "size".
    StringDataPtr& Suffix(UPInt size)
    {
        // Limit suffix to the size of the string.
        size = Alg::PMin(GetSize(), size);
        pStr = ToCStr() + GetSize() - size;
        Size = size;
        return *this;
    }

    static bool IsWhiteSpace(UInt32 c);

    StringDataPtr GetTruncateWhitespace() const;

    StringDataPtr& TruncateWhitespace()
    {
        *this = GetTruncateWhitespace();
        return *this;
    }

    const char* Begin() const { return ToCStr(); }
    const char* End() const { return ToCStr() + GetSize(); }

    // Hash functor used string data pointers
    struct HashFunctor
    {
        UPInt operator()(const StringDataPtr& data) const { return String::BernsteinHashFunction(data.ToCStr(), data.GetSize()); }
    };

    bool operator==(const StringDataPtr& other) const { return (other.Size == Size && (other.pStr == pStr || (pStr && other.pStr && SFstrncmp(pStr, other.pStr, Size) == 0))); }
    bool operator!=(const StringDataPtr& other) const { return !operator==(other); }

public:
    static StringDataPtr Null;

protected:
    const char* pStr;
    UPInt Size;
};

}