/*************************************************************************/ /* FBXBinaryTokenizer.cpp */ /*************************************************************************/ /* This file is part of: */ /* GODOT ENGINE */ /* https://godotengine.org */ /*************************************************************************/ /* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */ /* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md). */ /* */ /* Permission is hereby granted, free of charge, to any person obtaining */ /* a copy of this software and associated documentation files (the */ /* "Software"), to deal in the Software without restriction, including */ /* without limitation the rights to use, copy, modify, merge, publish, */ /* distribute, sublicense, and/or sell copies of the Software, and to */ /* permit persons to whom the Software is furnished to do so, subject to */ /* the following conditions: */ /* */ /* The above copyright notice and this permission notice shall be */ /* included in all copies or substantial portions of the Software. */ /* */ /* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */ /* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */ /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/ /* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */ /* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */ /* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */ /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /*************************************************************************/ /* Open Asset Import Library (assimp) ---------------------------------------------------------------------- Copyright (c) 2006-2019, assimp team All rights reserved. Redistribution and use of this software in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the assimp team, nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission of the assimp team. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ---------------------------------------------------------------------- */ /** @file FBXBinaryTokenizer.cpp * @brief Implementation of a fake lexer for binary fbx files - * we emit tokens so the parser needs almost no special handling * for binary files. */ #include "ByteSwapper.h" #include "FBXTokenizer.h" #include "core/print_string.h" #include namespace FBXDocParser { // ------------------------------------------------------------------------------------------------ Token::Token(const char *sbegin, const char *send, TokenType type, size_t offset) : sbegin(sbegin), send(send), type(type), line(offset), column(BINARY_MARKER) { #ifdef DEBUG_ENABLED contents = std::string(sbegin, static_cast(send - sbegin)); #endif // calc length // measure from sBegin to sEnd and validate? } namespace { // ------------------------------------------------------------------------------------------------ // signal tokenization error void TokenizeError(const std::string &message, size_t offset) { print_error("[FBX-Tokenize] " + String(message.c_str()) + ", offset " + itos(offset)); } // ------------------------------------------------------------------------------------------------ size_t Offset(const char *begin, const char *cursor) { //ai_assert(begin <= cursor); return cursor - begin; } // ------------------------------------------------------------------------------------------------ void TokenizeError(const std::string &message, const char *begin, const char *cursor) { TokenizeError(message, Offset(begin, cursor)); } // ------------------------------------------------------------------------------------------------ uint32_t ReadWord(const char *input, const char *&cursor, const char *end) { const size_t k_to_read = sizeof(uint32_t); if (Offset(cursor, end) < k_to_read) { TokenizeError("cannot ReadWord, out of bounds", input, cursor); } uint32_t word; ::memcpy(&word, cursor, 4); AI_SWAP4(word); cursor += k_to_read; return word; } // ------------------------------------------------------------------------------------------------ uint64_t ReadDoubleWord(const char *input, const char *&cursor, const char *end) { const size_t k_to_read = sizeof(uint64_t); if (Offset(cursor, end) < k_to_read) { TokenizeError("cannot ReadDoubleWord, out of bounds", input, cursor); } uint64_t dword /*= *reinterpret_cast(cursor)*/; ::memcpy(&dword, cursor, sizeof(uint64_t)); AI_SWAP8(dword); cursor += k_to_read; return dword; } // ------------------------------------------------------------------------------------------------ uint8_t ReadByte(const char *input, const char *&cursor, const char *end) { if (Offset(cursor, end) < sizeof(uint8_t)) { TokenizeError("cannot ReadByte, out of bounds", input, cursor); } uint8_t word; /* = *reinterpret_cast< const uint8_t* >( cursor )*/ ::memcpy(&word, cursor, sizeof(uint8_t)); ++cursor; return word; } // ------------------------------------------------------------------------------------------------ unsigned int ReadString(const char *&sbegin_out, const char *&send_out, const char *input, const char *&cursor, const char *end, bool long_length = false, bool allow_null = false) { const uint32_t len_len = long_length ? 4 : 1; if (Offset(cursor, end) < len_len) { TokenizeError("cannot ReadString, out of bounds reading length", input, cursor); } const uint32_t length = long_length ? ReadWord(input, cursor, end) : ReadByte(input, cursor, end); if (Offset(cursor, end) < length) { TokenizeError("cannot ReadString, length is out of bounds", input, cursor); } sbegin_out = cursor; cursor += length; send_out = cursor; if (!allow_null) { for (unsigned int i = 0; i < length; ++i) { if (sbegin_out[i] == '\0') { TokenizeError("failed ReadString, unexpected NUL character in string", input, cursor); } } } return length; } // ------------------------------------------------------------------------------------------------ void ReadData(const char *&sbegin_out, const char *&send_out, const char *input, const char *&cursor, const char *end) { if (Offset(cursor, end) < 1) { TokenizeError("cannot ReadData, out of bounds reading length", input, cursor); } const char type = *cursor; sbegin_out = cursor++; switch (type) { // 16 bit int case 'Y': cursor += 2; break; // 1 bit bool flag (yes/no) case 'C': cursor += 1; break; // 32 bit int case 'I': // <- fall through // float case 'F': cursor += 4; break; // double case 'D': cursor += 8; break; // 64 bit int case 'L': cursor += 8; break; // note: do not write cursor += ReadWord(...cursor) as this would be UB // raw binary data case 'R': { const uint32_t length = ReadWord(input, cursor, end); cursor += length; break; } case 'b': // TODO: what is the 'b' type code? Right now we just skip over it / // take the full range we could get cursor = end; break; // array of * case 'f': case 'd': case 'l': case 'i': case 'c': { const uint32_t length = ReadWord(input, cursor, end); const uint32_t encoding = ReadWord(input, cursor, end); const uint32_t comp_len = ReadWord(input, cursor, end); // compute length based on type and check against the stored value if (encoding == 0) { uint32_t stride = 0; switch (type) { case 'f': case 'i': stride = 4; break; case 'd': case 'l': stride = 8; break; case 'c': stride = 1; break; default: break; }; //ai_assert(stride > 0); if (length * stride != comp_len) { TokenizeError("cannot ReadData, calculated data stride differs from what the file claims", input, cursor); } } // zip/deflate algorithm (encoding==1)? take given length. anything else? die else if (encoding != 1) { TokenizeError("cannot ReadData, unknown encoding", input, cursor); } cursor += comp_len; break; } // string case 'S': { const char *sb, *se; // 0 characters can legally happen in such strings ReadString(sb, se, input, cursor, end, true, true); break; } default: TokenizeError("cannot ReadData, unexpected type code: " + std::string(&type, 1), input, cursor); } if (cursor > end) { TokenizeError("cannot ReadData, the remaining size is too small for the data type: " + std::string(&type, 1), input, cursor); } // the type code is contained in the returned range send_out = cursor; } // ------------------------------------------------------------------------------------------------ bool ReadScope(TokenList &output_tokens, const char *input, const char *&cursor, const char *end, bool const is64bits) { // the first word contains the offset at which this block ends const uint64_t end_offset = is64bits ? ReadDoubleWord(input, cursor, end) : ReadWord(input, cursor, end); // we may get 0 if reading reached the end of the file - // fbx files have a mysterious extra footer which I don't know // how to extract any information from, but at least it always // starts with a 0. if (!end_offset) { return false; } if (end_offset > Offset(input, end)) { TokenizeError("block offset is out of range", input, cursor); } else if (end_offset < Offset(input, cursor)) { TokenizeError("block offset is negative out of range", input, cursor); } // the second data word contains the number of properties in the scope const uint64_t prop_count = is64bits ? ReadDoubleWord(input, cursor, end) : ReadWord(input, cursor, end); // the third data word contains the length of the property list const uint64_t prop_length = is64bits ? ReadDoubleWord(input, cursor, end) : ReadWord(input, cursor, end); // now comes the name of the scope/key const char *sbeg, *send; ReadString(sbeg, send, input, cursor, end); output_tokens.push_back(new_Token(sbeg, send, TokenType_KEY, Offset(input, cursor))); // now come the individual properties const char *begin_cursor = cursor; for (unsigned int i = 0; i < prop_count; ++i) { ReadData(sbeg, send, input, cursor, begin_cursor + prop_length); output_tokens.push_back(new_Token(sbeg, send, TokenType_DATA, Offset(input, cursor))); if (i != prop_count - 1) { output_tokens.push_back(new_Token(cursor, cursor + 1, TokenType_COMMA, Offset(input, cursor))); } } if (Offset(begin_cursor, cursor) != prop_length) { TokenizeError("property length not reached, something is wrong", input, cursor); } // at the end of each nested block, there is a NUL record to indicate // that the sub-scope exists (i.e. to distinguish between P: and P : {}) // this NUL record is 13 bytes long on 32 bit version and 25 bytes long on 64 bit. const size_t sentinel_block_length = is64bits ? (sizeof(uint64_t) * 3 + 1) : (sizeof(uint32_t) * 3 + 1); if (Offset(input, cursor) < end_offset) { if (end_offset - Offset(input, cursor) < sentinel_block_length) { TokenizeError("insufficient padding bytes at block end", input, cursor); } output_tokens.push_back(new_Token(cursor, cursor + 1, TokenType_OPEN_BRACKET, Offset(input, cursor))); // XXX this is vulnerable to stack overflowing .. while (Offset(input, cursor) < end_offset - sentinel_block_length) { ReadScope(output_tokens, input, cursor, input + end_offset - sentinel_block_length, is64bits); } output_tokens.push_back(new_Token(cursor, cursor + 1, TokenType_CLOSE_BRACKET, Offset(input, cursor))); for (unsigned int i = 0; i < sentinel_block_length; ++i) { if (cursor[i] != '\0') { TokenizeError("failed to read nested block sentinel, expected all bytes to be 0", input, cursor); } } cursor += sentinel_block_length; } if (Offset(input, cursor) != end_offset) { TokenizeError("scope length not reached, something is wrong", input, cursor); } return true; } } // anonymous namespace // ------------------------------------------------------------------------------------------------ // TODO: Test FBX Binary files newer than the 7500 version to check if the 64 bits address behaviour is consistent void TokenizeBinary(TokenList &output_tokens, const char *input, size_t length) { if (length < 0x1b) { //TokenizeError("file is too short",0); } if (strncmp(input, "Kaydara FBX Binary", 18)) { TokenizeError("magic bytes not found", 0); } const char *cursor = input + 18; /*Result ignored*/ ReadByte(input, cursor, input + length); /*Result ignored*/ ReadByte(input, cursor, input + length); /*Result ignored*/ ReadByte(input, cursor, input + length); /*Result ignored*/ ReadByte(input, cursor, input + length); /*Result ignored*/ ReadByte(input, cursor, input + length); const uint32_t version = ReadWord(input, cursor, input + length); print_verbose("FBX Version: " + itos(version)); //ASSIMP_LOG_DEBUG_F("FBX version: ", version); const bool is64bits = version >= 7500; const char *end = input + length; while (cursor < end) { if (!ReadScope(output_tokens, input, cursor, input + length, is64bits)) { break; } } } } // namespace FBXDocParser