From 675b4aa878f16291ce33fced48a2bc7425f635ae Mon Sep 17 00:00:00 2001 From: Alexander Harkness Date: Sun, 24 Nov 2013 14:19:41 +0000 Subject: Moved source to src --- src/WorldStorage/FastNBT.h | 293 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 293 insertions(+) create mode 100644 src/WorldStorage/FastNBT.h (limited to 'src/WorldStorage/FastNBT.h') diff --git a/src/WorldStorage/FastNBT.h b/src/WorldStorage/FastNBT.h new file mode 100644 index 000000000..7323c29cb --- /dev/null +++ b/src/WorldStorage/FastNBT.h @@ -0,0 +1,293 @@ + +// FastNBT.h + +// Interfaces to the fast NBT parser and writer + +/* +The fast parser parses the data into a vector of cFastNBTTag structures. These structures describe the NBT tree, +but themselves are allocated in a vector, thus minimizing reallocation. +The structures have a minimal constructor, setting all member "pointers" to "invalid". + +The fast writer doesn't need a NBT tree structure built beforehand, it is commanded to open, append and close tags +(just like XML); it keeps the internal tag stack and reports errors in usage. +It directly outputs a string containing the serialized NBT data. +*/ + + + + + +#pragma once + +#include "../Endianness.h" + + + + + +enum eTagType +{ + TAG_Min = 0, // The minimum value for a tag type + TAG_End = 0, + TAG_Byte = 1, + TAG_Short = 2, + TAG_Int = 3, + TAG_Long = 4, + TAG_Float = 5, + TAG_Double = 6, + TAG_ByteArray = 7, + TAG_String = 8, + TAG_List = 9, + TAG_Compound = 10, + TAG_IntArray = 11, + TAG_Max = 11, // The maximum value for a tag type +} ; + + + + + +/** This structure is used for all NBT tags. +It contains indices to the parent array of tags, building the NBT tree this way. +Also contains indices into the data stream being parsed, used for values; +NO dynamically allocated memory is used! +Structure (all with the tree structure it describes) supports moving in memory (std::vector reallocation) +*/ +struct cFastNBTTag +{ +public: + + eTagType m_Type; + + // The following members are indices into the data stream. m_DataLength == 0 if no data available + // They must not be pointers, because the datastream may be copied into another AString object in the meantime. + int m_NameStart; + int m_NameLength; + int m_DataStart; + int m_DataLength; + + // The following members are indices into the array returned; -1 if not valid + // They must not be pointers, because pointers would not survive std::vector reallocation + int m_Parent; + int m_PrevSibling; + int m_NextSibling; + int m_FirstChild; + int m_LastChild; + + cFastNBTTag(eTagType a_Type, int a_Parent) : + m_Type(a_Type), + m_NameLength(0), + m_DataLength(0), + m_Parent(a_Parent), + m_PrevSibling(-1), + m_NextSibling(-1), + m_FirstChild(-1), + m_LastChild(-1) + { + } + + cFastNBTTag(eTagType a_Type, int a_Parent, int a_PrevSibling) : + m_Type(a_Type), + m_NameLength(0), + m_DataLength(0), + m_Parent(a_Parent), + m_PrevSibling(a_PrevSibling), + m_NextSibling(-1), + m_FirstChild(-1), + m_LastChild(-1) + { + } +} ; + + + + + +/** Parses and contains the parsed data +Also implements data accessor functions for tree traversal and value getters +The data pointer passed in the constructor is assumed to be valid throughout the object's life. Care must be taken not to initialize from a temporary. +*/ +class cParsedNBT +{ +public: + cParsedNBT(const char * a_Data, int a_Length); + + bool IsValid(void) const {return m_IsValid; } + + int GetRoot(void) const {return 0; } + int GetFirstChild (int a_Tag) const { return m_Tags[a_Tag].m_FirstChild; } + int GetLastChild (int a_Tag) const { return m_Tags[a_Tag].m_LastChild; } + int GetNextSibling(int a_Tag) const { return m_Tags[a_Tag].m_NextSibling; } + int GetPrevSibling(int a_Tag) const { return m_Tags[a_Tag].m_PrevSibling; } + int GetDataLength (int a_Tag) const { return m_Tags[a_Tag].m_DataLength; } + + const char * GetData(int a_Tag) const + { + ASSERT(m_Tags[a_Tag].m_Type != TAG_List); + ASSERT(m_Tags[a_Tag].m_Type != TAG_Compound); + return m_Data + m_Tags[a_Tag].m_DataStart; + } + + int FindChildByName(int a_Tag, const AString & a_Name) const + { + return FindChildByName(a_Tag, a_Name.c_str(), a_Name.length()); + } + + int FindChildByName(int a_Tag, const char * a_Name, size_t a_NameLength = 0) const; + int FindTagByPath (int a_Tag, const AString & a_Path) const; + + eTagType GetType(int a_Tag) const { return m_Tags[a_Tag].m_Type; } + + /// Returns the children type for a list tag; undefined on other tags. If list empty, returns TAG_End + eTagType GetChildrenType(int a_Tag) const + { + ASSERT(m_Tags[a_Tag].m_Type == TAG_List); + return (m_Tags[a_Tag].m_FirstChild < 0) ? TAG_End : m_Tags[m_Tags[a_Tag].m_FirstChild].m_Type; + } + + inline unsigned char GetByte(int a_Tag) const + { + ASSERT(m_Tags[a_Tag].m_Type == TAG_Byte); + return (unsigned char)(m_Data[m_Tags[a_Tag].m_DataStart]); + } + + inline Int16 GetShort(int a_Tag) const + { + ASSERT(m_Tags[a_Tag].m_Type == TAG_Short); + return ntohs(*((Int16 *)(m_Data + m_Tags[a_Tag].m_DataStart))); + } + + inline Int32 GetInt(int a_Tag) const + { + ASSERT(m_Tags[a_Tag].m_Type == TAG_Int); + return ntohl(*((Int32 *)(m_Data + m_Tags[a_Tag].m_DataStart))); + } + + inline Int64 GetLong(int a_Tag) const + { + ASSERT(m_Tags[a_Tag].m_Type == TAG_Long); + return NetworkToHostLong8(m_Data + m_Tags[a_Tag].m_DataStart); + } + + inline float GetFloat(int a_Tag) const + { + ASSERT(m_Tags[a_Tag].m_Type == TAG_Float); + Int32 tmp = ntohl(*((Int32 *)(m_Data + m_Tags[a_Tag].m_DataStart))); + return *((float *)&tmp); + } + + inline double GetDouble(int a_Tag) const + { + ASSERT(m_Tags[a_Tag].m_Type == TAG_Double); + return NetworkToHostDouble8(m_Data + m_Tags[a_Tag].m_DataStart); + } + + inline AString GetString(int a_Tag) const + { + ASSERT(m_Tags[a_Tag].m_Type == TAG_String); + AString res; + res.assign(m_Data + m_Tags[a_Tag].m_DataStart, m_Tags[a_Tag].m_DataLength); + return res; + } + + inline AString GetName(int a_Tag) const + { + AString res; + res.assign(m_Data + m_Tags[a_Tag].m_NameStart, m_Tags[a_Tag].m_NameLength); + return res; + } + +protected: + const char * m_Data; + int m_Length; + std::vector m_Tags; + bool m_IsValid; // True if parsing succeeded + + // Used while parsing: + int m_Pos; + + bool Parse(void); + bool ReadString(int & a_StringStart, int & a_StringLen); // Reads a simple string (2 bytes length + data), sets the string descriptors + bool ReadCompound(void); // Reads the latest tag as a compound + bool ReadList(eTagType a_ChildrenType); // Reads the latest tag as a list of items of type a_ChildrenType + bool ReadTag(void); // Reads the latest tag, depending on its m_Type setting +} ; + + + + + +class cFastNBTWriter +{ +public: + cFastNBTWriter(const AString & a_RootTagName = ""); + + void BeginCompound(const AString & a_Name); + void EndCompound(void); + + void BeginList(const AString & a_Name, eTagType a_ChildrenType); + void EndList(void); + + void AddByte (const AString & a_Name, unsigned char a_Value); + void AddShort (const AString & a_Name, Int16 a_Value); + void AddInt (const AString & a_Name, Int32 a_Value); + void AddLong (const AString & a_Name, Int64 a_Value); + void AddFloat (const AString & a_Name, float a_Value); + void AddDouble (const AString & a_Name, double a_Value); + void AddString (const AString & a_Name, const AString & a_Value); + void AddByteArray(const AString & a_Name, const char * a_Value, size_t a_NumElements); + void AddIntArray (const AString & a_Name, const int * a_Value, size_t a_NumElements); + + void AddByteArray(const AString & a_Name, const AString & a_Value) + { + AddByteArray(a_Name, a_Value.data(), a_Value.size()); + } + + const AString & GetResult(void) const {return m_Result; } + + void Finish(void); + +protected: + + struct sParent + { + int m_Type; // TAG_Compound or TAG_List + int m_Pos; // for TAG_List, the position of the list count + int m_Count; // for TAG_List, the element count + eTagType m_ItemType; // for TAG_List, the element type + } ; + + static const int MAX_STACK = 50; // Highliy doubtful that an NBT would be constructed this many levels deep + + // These two fields emulate a stack. A raw array is used due to speed issues - no reallocations are allowed. + sParent m_Stack[MAX_STACK]; + int m_CurrentStack; + + AString m_Result; + + bool IsStackTopCompound(void) const { return (m_Stack[m_CurrentStack].m_Type == TAG_Compound); } + + void WriteString(const char * a_Data, short a_Length); + + inline void TagCommon(const AString & a_Name, eTagType a_Type) + { + // If we're directly inside a list, check that the list is of the correct type: + ASSERT((m_Stack[m_CurrentStack].m_Type != TAG_List) || (m_Stack[m_CurrentStack].m_ItemType == a_Type)); + + if (IsStackTopCompound()) + { + // Compound: add the type and name: + m_Result.push_back((char)a_Type); + WriteString(a_Name.c_str(), (short)a_Name.length()); + } + else + { + // List: add to the counter + m_Stack[m_CurrentStack].m_Count++; + } + } +} ; + + + + -- cgit v1.2.3