| author | ecalot
<ecalot> 2005-02-17 02:10:35 UTC |
| committer | ecalot
<ecalot> 2005-02-17 02:10:35 UTC |
| parent | 9d32bbbc6d8af1d18ed8248242d7675b2bbeca95 |
| FP/doc/FormatSpecifications | +26 | -14 |
| FP/doc/FormatSpecifications.tex | +26 | -14 |
diff --git a/FP/doc/FormatSpecifications b/FP/doc/FormatSpecifications index 9e43eee..042823d 100644 --- a/FP/doc/FormatSpecifications +++ b/FP/doc/FormatSpecifications @@ -151,22 +151,34 @@ Table of Contents Index structures: The DAT header: Size = 6 bytes - Offset 0, size 4, type UL: IndexOffset (the location where the index - begins) - Offset 4, size 2, type US: IndexSize (the number of bytes the index has) - Note that the index size is 8*numberOfItems+2 + - Offset 0, size 4, type UL: IndexOffset + (the location where the index begins) + - Offset 4, size 2, type US: IndexSize + (the number of bytes the index has) + Note that IndexSize is 8*numberOfItems+2 + Note that IndexOffset+IndexSize=file size The DAT index: Size = IndexSize bytes - Offset IndexOffset, size 2, type US: NumberOfItems (resources count) - Offset IndexOffset+2, size 8*NumberOfItems: The index (a list of - NumberOfItems blocks of 8-bytes-index record) - - The 8-bytes-index record (one per item): Size = 8 bytes - Relative offset 0, size 2, type US: Item ID - Relative offset 2, size 4, type UL: Resource start absolute offset in - file - Relative offset 6, size 2, type US: Size of the item (not including - checksums) + - Offset IndexOffset, size 2, type US: NumberOfItems + (resources count) + - Offset IndexOffset+2, size NumberOfItems*8: The index + (a list of NumberOfItems blocks of 8-bytes-length index record) + + The 8-bytes-length index record (one per item): Size = 8 bytes + - Relative offset 0, size 2, type US: Item ID + - Relative offset 2, size 4, type UL: Resource start + (absolute offset in file) + - Relative offset 6, size 2, type US: Size of the item + (not including the checksum byte) + + Note: + POP1 doesn't validate a DAT file checking: + IndexOffset+IndexSize=FileSize + this means you can append data at the end of the file. + + PR validates that IndexOffset+IndexSize<=FileSize. + It also compares IndexSize with 8*numberOfItems+2 to determine if a file + is a valid POP1 DAT file. Checksum byte: There is a checksum byte for each item (resource), this is the first byte diff --git a/FP/doc/FormatSpecifications.tex b/FP/doc/FormatSpecifications.tex index 9e43eee..042823d 100644 --- a/FP/doc/FormatSpecifications.tex +++ b/FP/doc/FormatSpecifications.tex @@ -151,22 +151,34 @@ Table of Contents Index structures: The DAT header: Size = 6 bytes - Offset 0, size 4, type UL: IndexOffset (the location where the index - begins) - Offset 4, size 2, type US: IndexSize (the number of bytes the index has) - Note that the index size is 8*numberOfItems+2 + - Offset 0, size 4, type UL: IndexOffset + (the location where the index begins) + - Offset 4, size 2, type US: IndexSize + (the number of bytes the index has) + Note that IndexSize is 8*numberOfItems+2 + Note that IndexOffset+IndexSize=file size The DAT index: Size = IndexSize bytes - Offset IndexOffset, size 2, type US: NumberOfItems (resources count) - Offset IndexOffset+2, size 8*NumberOfItems: The index (a list of - NumberOfItems blocks of 8-bytes-index record) - - The 8-bytes-index record (one per item): Size = 8 bytes - Relative offset 0, size 2, type US: Item ID - Relative offset 2, size 4, type UL: Resource start absolute offset in - file - Relative offset 6, size 2, type US: Size of the item (not including - checksums) + - Offset IndexOffset, size 2, type US: NumberOfItems + (resources count) + - Offset IndexOffset+2, size NumberOfItems*8: The index + (a list of NumberOfItems blocks of 8-bytes-length index record) + + The 8-bytes-length index record (one per item): Size = 8 bytes + - Relative offset 0, size 2, type US: Item ID + - Relative offset 2, size 4, type UL: Resource start + (absolute offset in file) + - Relative offset 6, size 2, type US: Size of the item + (not including the checksum byte) + + Note: + POP1 doesn't validate a DAT file checking: + IndexOffset+IndexSize=FileSize + this means you can append data at the end of the file. + + PR validates that IndexOffset+IndexSize<=FileSize. + It also compares IndexSize with 8*numberOfItems+2 to determine if a file + is a valid POP1 DAT file. Checksum byte: There is a checksum byte for each item (resource), this is the first byte