Fixed FBX 7500 Binary reading

Seems that all FBX 7.5 Binary files uses 32 bits adresses. The code now is taking this in consideration. This commit fixes the https://github.com/assimp/assimp/issues/838 issue.

code/FBXBinaryTokenizer.cpp

@@ -56,47 +56,46 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 namespace Assimp {
 namespace FBX {
 
-enum Flag
-{
-   e_unknown_0 = 1 << 0,
-   e_unknown_1 = 1 << 1,
-   e_unknown_2 = 1 << 2,
-   e_unknown_3 = 1 << 3,
-   e_unknown_4 = 1 << 4,
-   e_unknown_5 = 1 << 5,
-   e_unknown_6 = 1 << 6,
-   e_unknown_7 = 1 << 7,
-   e_unknown_8 = 1 << 8,
-   e_unknown_9 = 1 << 9,
-   e_unknown_10 = 1 << 10,
-   e_unknown_11 = 1 << 11,
-   e_unknown_12 = 1 << 12,
-   e_unknown_13 = 1 << 13,
-   e_unknown_14 = 1 << 14,
-   e_unknown_15 = 1 << 15,
-   e_unknown_16 = 1 << 16,
-   e_unknown_17 = 1 << 17,
-   e_unknown_18 = 1 << 18,
-   e_unknown_19 = 1 << 19,
-   e_unknown_20 = 1 << 20,
-   e_unknown_21 = 1 << 21,
-   e_unknown_22 = 1 << 22,
-   e_unknown_23 = 1 << 23,
-   e_flag_field_size_64_bit = 1 << 24, // Not sure what is 
-   e_unknown_25 = 1 << 25,
-   e_unknown_26 = 1 << 26,
-   e_unknown_27 = 1 << 27,
-   e_unknown_28 = 1 << 28,
-   e_unknown_29 = 1 << 29,
-   e_unknown_30 = 1 << 30,
-   e_unknown_31 = 1 << 31
-};
-
-bool check_flag(uint32_t flags, Flag to_check)
-{
-   return (flags & to_check) != 0;
-}
-
+//enum Flag
+//{
+//   e_unknown_0 = 1 << 0,
+//   e_unknown_1 = 1 << 1,
+//   e_unknown_2 = 1 << 2,
+//   e_unknown_3 = 1 << 3,
+//   e_unknown_4 = 1 << 4,
+//   e_unknown_5 = 1 << 5,
+//   e_unknown_6 = 1 << 6,
+//   e_unknown_7 = 1 << 7,
+//   e_unknown_8 = 1 << 8,
+//   e_unknown_9 = 1 << 9,
+//   e_unknown_10 = 1 << 10,
+//   e_unknown_11 = 1 << 11,
+//   e_unknown_12 = 1 << 12,
+//   e_unknown_13 = 1 << 13,
+//   e_unknown_14 = 1 << 14,
+//   e_unknown_15 = 1 << 15,
+//   e_unknown_16 = 1 << 16,
+//   e_unknown_17 = 1 << 17,
+//   e_unknown_18 = 1 << 18,
+//   e_unknown_19 = 1 << 19,
+//   e_unknown_20 = 1 << 20,
+//   e_unknown_21 = 1 << 21,
+//   e_unknown_22 = 1 << 22,
+//   e_unknown_23 = 1 << 23,
+//   e_flag_field_size_64_bit = 1 << 24, // Not sure what is 
+//   e_unknown_25 = 1 << 25,
+//   e_unknown_26 = 1 << 26,
+//   e_unknown_27 = 1 << 27,
+//   e_unknown_28 = 1 << 28,
+//   e_unknown_29 = 1 << 29,
+//   e_unknown_30 = 1 << 30,
+//   e_unknown_31 = 1 << 31
+//};
+//
+//bool check_flag(uint32_t flags, Flag to_check)
+//{
+//	return (flags & to_check) != 0;
+//}
 // ------------------------------------------------------------------------------------------------
 Token::Token(const char* sbegin, const char* send, TokenType type, unsigned int offset)
     :
@@ -341,10 +340,11 @@ void ReadData(const char*& sbegin_out, const char*& send_out, const char* input,
 
 
 // ------------------------------------------------------------------------------------------------
-bool ReadScope(TokenList& output_tokens, const char* input, const char*& cursor, const char* end, uint32_t const flags)
+//TODO: Test FBX Binary files newer than the 7500 version to check if the 64 bits address behaviour is consistent
+bool ReadScope(TokenList& output_tokens, const char* input, const char*& cursor, const char* end, uint32_t const version)
 {
     // the first word contains the offset at which this block ends
-    const uint64_t end_offset = /*check_flag(flags, e_flag_field_size_64_bit) ? ReadDoubleWord(input, cursor, end) : */ReadWord(input, cursor, end);
+	const uint64_t end_offset = version == 7500 ? 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
@@ -362,10 +362,10 @@ bool ReadScope(TokenList& output_tokens, const char* input, const char*& cursor,
     }
 
     // the second data word contains the number of properties in the scope
-    const uint64_t prop_count = /*check_flag(flags, e_flag_field_size_64_bit) ? ReadDoubleWord(input, cursor, end) : */ReadWord(input, cursor, end);
+	const uint64_t prop_count = version == 7500 ? ReadDoubleWord(input, cursor, end) : ReadWord(input, cursor, end);
 
     // the third data word contains the length of the property list
-    const uint64_t prop_length = /*check_flag(flags, e_flag_field_size_64_bit) ? ReadDoubleWord(input, cursor, end) :*/ ReadWord(input, cursor, end);
+	const uint64_t prop_length = version == 7500 ? ReadDoubleWord(input, cursor, end) : ReadWord(input, cursor, end);
 
     // now comes the name of the scope/key
     const char* sbeg, *send;
@@ -392,7 +392,7 @@ bool ReadScope(TokenList& output_tokens, const char* input, const char*& 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 = /*check_flag(flags, e_flag_field_size_64_bit) ? (sizeof(uint64_t) * 3 + 1) : */(sizeof(uint32_t) * 3 + 1);
+	const size_t sentinel_block_length = version == 7500 ? (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) {
@@ -403,7 +403,7 @@ bool ReadScope(TokenList& output_tokens, const char* input, const char*& 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, flags);
+            ReadScope(output_tokens, input, cursor, input + end_offset - sentinel_block_length, version);
         }
         output_tokens.push_back(new_Token(cursor, cursor + 1, TokenType_CLOSE_BRACKET, Offset(input, cursor) ));
 
@@ -438,19 +438,16 @@ void TokenizeBinary(TokenList& output_tokens, const char* input, unsigned int le
         TokenizeError("magic bytes not found",0);
     }
 
-
-    //uint32_t offset = 0x15;
-    const char* cursor = input + 0x15;
-
-    const uint32_t flags = ReadWord(input, cursor, input + length);
-
-    const uint8_t padding_0 = ReadByte(input, cursor, input + length); // unused
-    (void) padding_0;
-    const uint8_t padding_1 = ReadByte(input, cursor, input + length); // unused
-    (void) padding_1;
+    const char* cursor = input + 18;
+	const uint8_t unknown_1 = ReadByte(input, cursor, input + length);
+	const uint8_t unknown_2 = ReadByte(input, cursor, input + length);
+	const uint8_t unknown_3 = ReadByte(input, cursor, input + length);
+	const uint8_t unknown_4 = ReadByte(input, cursor, input + length);
+	const uint8_t unknown_5 = ReadByte(input, cursor, input + length);
+	const uint32_t version = ReadWord(input, cursor, input + length);
     while (cursor < input + length)
     {
-        if(!ReadScope(output_tokens, input, cursor, input + length, flags)) {
+		if (!ReadScope(output_tokens, input, cursor, input + length, version)) {
             break;
         }
     }