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Diffstat (limited to 'src/WorldStorage/FastNBT.cpp')
| -rw-r--r-- | src/WorldStorage/FastNBT.cpp | 547 |
1 files changed, 547 insertions, 0 deletions
diff --git a/src/WorldStorage/FastNBT.cpp b/src/WorldStorage/FastNBT.cpp new file mode 100644 index 000000000..e55011069 --- /dev/null +++ b/src/WorldStorage/FastNBT.cpp @@ -0,0 +1,547 @@ + +// FastNBT.cpp + +// Implements the fast NBT parser and writer + +#include "Globals.h" +#include "FastNBT.h" + + + + + +// The number of NBT tags that are reserved when an NBT parsing is started. +// You can override this by using a cmdline define +#ifndef NBT_RESERVE_SIZE + #define NBT_RESERVE_SIZE 200 +#endif // NBT_RESERVE_SIZE + +#define RETURN_FALSE_IF_FALSE(X) do { if (!X) return false; } while (0) + + + + + +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// +// cParsedNBT: + +#define NEEDBYTES(N) \ + if (m_Length - m_Pos < N) \ + { \ + return false; \ + } + + + + + +cParsedNBT::cParsedNBT(const char * a_Data, int a_Length) : + m_Data(a_Data), + m_Length(a_Length), + m_Pos(0) +{ + m_IsValid = Parse(); +} + + + + + +bool cParsedNBT::Parse(void) +{ + if (m_Length < 3) + { + // Data too short + return false; + } + if (m_Data[0] != TAG_Compound) + { + // The top-level tag must be a Compound + return false; + } + + m_Tags.reserve(NBT_RESERVE_SIZE); + + m_Tags.push_back(cFastNBTTag(TAG_Compound, -1)); + + m_Pos = 1; + + RETURN_FALSE_IF_FALSE(ReadString(m_Tags.back().m_NameStart, m_Tags.back().m_NameLength)); + RETURN_FALSE_IF_FALSE(ReadCompound()); + + return true; +} + + + + + +bool cParsedNBT::ReadString(int & a_StringStart, int & a_StringLen) +{ + NEEDBYTES(2); + a_StringStart = m_Pos + 2; + a_StringLen = ntohs(*((short *)(m_Data + m_Pos))); + if (a_StringLen < 0) + { + // Invalid string length + return false; + } + m_Pos += 2 + a_StringLen; + return true; +} + + + + + +bool cParsedNBT::ReadCompound(void) +{ + // Reads the latest tag as a compound + int ParentIdx = m_Tags.size() - 1; + int PrevSibling = -1; + while (true) + { + NEEDBYTES(1); + eTagType TagType = (eTagType)(m_Data[m_Pos]); + m_Pos++; + if (TagType == TAG_End) + { + break; + } + m_Tags.push_back(cFastNBTTag(TagType, ParentIdx, PrevSibling)); + if (PrevSibling >= 0) + { + m_Tags[PrevSibling].m_NextSibling = m_Tags.size() - 1; + } + else + { + m_Tags[ParentIdx].m_FirstChild = m_Tags.size() - 1; + } + PrevSibling = m_Tags.size() - 1; + RETURN_FALSE_IF_FALSE(ReadString(m_Tags.back().m_NameStart, m_Tags.back().m_NameLength)); + RETURN_FALSE_IF_FALSE(ReadTag()); + } // while (true) + m_Tags[ParentIdx].m_LastChild = PrevSibling; + return true; +} + + + + + +bool cParsedNBT::ReadList(eTagType a_ChildrenType) +{ + // Reads the latest tag as a list of items of type a_ChildrenType + + // Read the count: + NEEDBYTES(4); + int Count = ntohl(*((int *)(m_Data + m_Pos))); + m_Pos += 4; + if (Count < 0) + { + return false; + } + + // Read items: + int ParentIdx = m_Tags.size() - 1; + int PrevSibling = -1; + for (int i = 0; i < Count; i++) + { + m_Tags.push_back(cFastNBTTag(a_ChildrenType, ParentIdx, PrevSibling)); + if (PrevSibling >= 0) + { + m_Tags[PrevSibling].m_NextSibling = m_Tags.size() - 1; + } + else + { + m_Tags[ParentIdx].m_FirstChild = m_Tags.size() - 1; + } + PrevSibling = m_Tags.size() - 1; + RETURN_FALSE_IF_FALSE(ReadTag()); + } // for (i) + m_Tags[ParentIdx].m_LastChild = PrevSibling; + return true; +} + + + + + +#define CASE_SIMPLE_TAG(TAGTYPE, LEN) \ + case TAG_##TAGTYPE: \ + { \ + NEEDBYTES(LEN); \ + Tag.m_DataStart = m_Pos; \ + Tag.m_DataLength = LEN; \ + m_Pos += LEN; \ + return true; \ + } + +bool cParsedNBT::ReadTag(void) +{ + cFastNBTTag & Tag = m_Tags.back(); + switch (Tag.m_Type) + { + CASE_SIMPLE_TAG(Byte, 1) + CASE_SIMPLE_TAG(Short, 2) + CASE_SIMPLE_TAG(Int, 4) + CASE_SIMPLE_TAG(Long, 8) + CASE_SIMPLE_TAG(Float, 4) + CASE_SIMPLE_TAG(Double, 8) + + case TAG_String: + { + return ReadString(Tag.m_DataStart, Tag.m_DataLength); + } + + case TAG_ByteArray: + { + NEEDBYTES(4); + int len = ntohl(*((int *)(m_Data + m_Pos))); + m_Pos += 4; + if (len < 0) + { + // Invalid length + return false; + } + NEEDBYTES(len); + Tag.m_DataLength = len; + Tag.m_DataStart = m_Pos; + m_Pos += len; + return true; + } + + case TAG_List: + { + NEEDBYTES(1); + eTagType ItemType = (eTagType)m_Data[m_Pos]; + m_Pos++; + RETURN_FALSE_IF_FALSE(ReadList(ItemType)); + return true; + } + + case TAG_Compound: + { + RETURN_FALSE_IF_FALSE(ReadCompound()); + return true; + } + + case TAG_IntArray: + { + NEEDBYTES(4); + int len = ntohl(*((int *)(m_Data + m_Pos))); + m_Pos += 4; + if (len < 0) + { + // Invalid length + return false; + } + len *= 4; + NEEDBYTES(len); + Tag.m_DataLength = len; + Tag.m_DataStart = m_Pos; + m_Pos += len; + return true; + } + + default: + { + ASSERT(!"Unhandled NBT tag type"); + return false; + } + } // switch (iType) +} + +#undef CASE_SIMPLE_TAG + + + + + +int cParsedNBT::FindChildByName(int a_Tag, const char * a_Name, size_t a_NameLength) const +{ + if (a_Tag < 0) + { + return -1; + } + if (m_Tags[a_Tag].m_Type != TAG_Compound) + { + return -1; + } + + if (a_NameLength == 0) + { + a_NameLength = strlen(a_Name); + } + for (int Child = m_Tags[a_Tag].m_FirstChild; Child != -1; Child = m_Tags[Child].m_NextSibling) + { + if ( + (m_Tags[Child].m_NameLength == a_NameLength) && + (memcmp(m_Data + m_Tags[Child].m_NameStart, a_Name, a_NameLength) == 0) + ) + { + return Child; + } + } // for Child - children of a_Tag + return -1; +} + + + + + +int cParsedNBT::FindTagByPath(int a_Tag, const AString & a_Path) const +{ + if (a_Tag < 0) + { + return -1; + } + size_t Begin = 0; + size_t Length = a_Path.length(); + int Tag = a_Tag; + for (size_t i = 0; i < Length; i++) + { + if (a_Path[i] != '\\') + { + continue; + } + Tag = FindChildByName(Tag, a_Path.c_str() + Begin, i - Begin - 1); + if (Tag < 0) + { + return -1; + } + Begin = i + 1; + } // for i - a_Path[] + + if (Begin < Length) + { + Tag = FindChildByName(Tag, a_Path.c_str() + Begin, Length - Begin); + } + return Tag; +} + + + + + +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// +// cFastNBTWriter: + +cFastNBTWriter::cFastNBTWriter(const AString & a_RootTagName) : + m_CurrentStack(0) +{ + m_Stack[0].m_Type = TAG_Compound; + m_Result.reserve(100 * 1024); + m_Result.push_back(TAG_Compound); + WriteString(a_RootTagName.data(), a_RootTagName.size()); +} + + + + + +void cFastNBTWriter::BeginCompound(const AString & a_Name) +{ + if (m_CurrentStack >= MAX_STACK) + { + ASSERT(!"Stack overflow"); + return; + } + + TagCommon(a_Name, TAG_Compound); + + ++m_CurrentStack; + m_Stack[m_CurrentStack].m_Type = TAG_Compound; +} + + + + + +void cFastNBTWriter::EndCompound(void) +{ + ASSERT(m_CurrentStack > 0); + ASSERT(IsStackTopCompound()); + + m_Result.push_back(TAG_End); + --m_CurrentStack; +} + + + + + +void cFastNBTWriter::BeginList(const AString & a_Name, eTagType a_ChildrenType) +{ + if (m_CurrentStack >= MAX_STACK) + { + ASSERT(!"Stack overflow"); + return; + } + + TagCommon(a_Name, TAG_List); + + m_Result.push_back((char)a_ChildrenType); + m_Result.append(4, (char)0); + + ++m_CurrentStack; + m_Stack[m_CurrentStack].m_Type = TAG_List; + m_Stack[m_CurrentStack].m_Pos = m_Result.size() - 4; + m_Stack[m_CurrentStack].m_Count = 0; + m_Stack[m_CurrentStack].m_ItemType = a_ChildrenType; +} + + + + + +void cFastNBTWriter::EndList(void) +{ + ASSERT(m_CurrentStack > 0); + ASSERT(m_Stack[m_CurrentStack].m_Type == TAG_List); + + // Update the list count: + *((int *)(m_Result.c_str() + m_Stack[m_CurrentStack].m_Pos)) = htonl(m_Stack[m_CurrentStack].m_Count); + + --m_CurrentStack; +} + + + + + +void cFastNBTWriter::AddByte(const AString & a_Name, unsigned char a_Value) +{ + TagCommon(a_Name, TAG_Byte); + m_Result.push_back(a_Value); +} + + + + + +void cFastNBTWriter::AddShort(const AString & a_Name, Int16 a_Value) +{ + TagCommon(a_Name, TAG_Short); + Int16 Value = htons(a_Value); + m_Result.append((const char *)&Value, 2); +} + + + + + +void cFastNBTWriter::AddInt(const AString & a_Name, Int32 a_Value) +{ + TagCommon(a_Name, TAG_Int); + Int32 Value = htonl(a_Value); + m_Result.append((const char *)&Value, 4); +} + + + + + +void cFastNBTWriter::AddLong(const AString & a_Name, Int64 a_Value) +{ + TagCommon(a_Name, TAG_Long); + Int64 Value = HostToNetwork8(&a_Value); + m_Result.append((const char *)&Value, 8); +} + + + + + +void cFastNBTWriter::AddFloat(const AString & a_Name, float a_Value) +{ + TagCommon(a_Name, TAG_Float); + Int32 Value = HostToNetwork4(&a_Value); + m_Result.append((const char *)&Value, 4); +} + + + + + +void cFastNBTWriter::AddDouble(const AString & a_Name, double a_Value) +{ + TagCommon(a_Name, TAG_Double); + Int64 Value = HostToNetwork8(&a_Value); + m_Result.append((const char *)&Value, 8); +} + + + + + +void cFastNBTWriter::AddString(const AString & a_Name, const AString & a_Value) +{ + TagCommon(a_Name, TAG_String); + Int16 len = htons((short)(a_Value.size())); + m_Result.append((const char *)&len, 2); + m_Result.append(a_Value.c_str(), a_Value.size()); +} + + + + + +void cFastNBTWriter::AddByteArray(const AString & a_Name, const char * a_Value, size_t a_NumElements) +{ + TagCommon(a_Name, TAG_ByteArray); + Int32 len = htonl(a_NumElements); + m_Result.append((const char *)&len, 4); + m_Result.append(a_Value, a_NumElements); +} + + + + + +void cFastNBTWriter::AddIntArray(const AString & a_Name, const int * a_Value, size_t a_NumElements) +{ + TagCommon(a_Name, TAG_IntArray); + Int32 len = htonl(a_NumElements); + m_Result.append((const char *)&len, 4); +#if defined(ANDROID_NDK) + // Android has alignment issues - cannot byteswap (htonl) an int that is not 32-bit-aligned, which happens in the regular version + for (size_t i = 0; i < a_NumElements; i++) + { + int Element = htonl(a_Value[i]); + m_Result.append((const char *)&Element, 4); + } +#else + int * Elements = (int *)(m_Result.data() + m_Result.size()); + m_Result.append(a_NumElements * 4, (char)0); + for (size_t i = 0; i < a_NumElements; i++) + { + Elements[i] = htonl(a_Value[i]); + } +#endif +} + + + + + +void cFastNBTWriter::Finish(void) +{ + ASSERT(m_CurrentStack == 0); + m_Result.push_back(TAG_End); +} + + + + + +void cFastNBTWriter::WriteString(const char * a_Data, short a_Length) +{ + Int16 Len = htons(a_Length); + m_Result.append((const char *)&Len, 2); + m_Result.append(a_Data, a_Length); +} + + + + |