From 35c8bc4c5807af41a37cc901dcbbfee7ab73f7bf Mon Sep 17 00:00:00 2001 From: "madmaxoft@gmail.com" Date: Mon, 7 May 2012 20:22:04 +0000 Subject: Fast NBT Parser (loading a chunk is now about 10 times faster) git-svn-id: http://mc-server.googlecode.com/svn/trunk@481 0a769ca7-a7f5-676a-18bf-c427514a06d6 --- source/FastNBT.h | 234 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 234 insertions(+) create mode 100644 source/FastNBT.h (limited to 'source/FastNBT.h') diff --git a/source/FastNBT.h b/source/FastNBT.h new file mode 100644 index 000000000..fd60fc671 --- /dev/null +++ b/source/FastNBT.h @@ -0,0 +1,234 @@ + +// 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); + } + +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(void); + + 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, unsigned char a_Value); + void AddInt (const AString & a_Name, unsigned char a_Value); + void AddLong (const AString & a_Name, unsigned char a_Value); + void AddFloat (const AString & a_Name, unsigned char a_Value); + void AddDouble (const AString & a_Name, unsigned char a_Value); + void AddString (const AString & a_Name, unsigned char a_Value); + void AddByteArray(const AString & a_Name, unsigned char a_Value); + void AddIntArray (const AString & a_Name, unsigned char a_Value); + + const AString & GetResult(void) const {return m_Result; } + +protected: + AString m_Result; +} ; + + + + -- cgit v1.2.3