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| -rw-r--r-- | doc/xz-file-format.txt | 29 |
1 files changed, 22 insertions, 7 deletions
diff --git a/doc/xz-file-format.txt b/doc/xz-file-format.txt index fa2b3340..998f0f8b 100644 --- a/doc/xz-file-format.txt +++ b/doc/xz-file-format.txt @@ -2,7 +2,7 @@ The .xz File Format =================== -Version 1.0.0 (2009-01-14) +Version 1.0.1 (2009-06-01) 0. Preface @@ -92,7 +92,12 @@ Version 1.0.0 (2009-01-14) 0.3. Version History Version Date Description - 1.0.0 2008-01-14 The first official version + + 1.0.1 2009-06-01 Typo fix in Section 0.3 and minor + clarifications to Sections 2, 2.2, + 3.3, 4.4, and 5.3.2 + + 1.0.0 2009-01-14 The first official version 1. Conventions @@ -233,6 +238,10 @@ Version 1.0.0 (2009-01-14) | Stream | Stream Padding | Stream | Stream Padding | ... +========+================+========+================+ + The sizes of Stream and Stream Padding are always multiples + of four bytes, thus the size of every valid .xz file MUST be + a multiple of four bytes. + While a typical file contains only one Stream and no Stream Padding, a decoder handling standalone .xz files SHOULD support files that have more than one Stream or Stream Padding. @@ -431,7 +440,8 @@ Version 1.0.0 (2009-01-14) Stream Padding MUST contain only null bytes. To preserve the four-byte alignment of consecutive Streams, the size of Stream Padding MUST be a multiple of four bytes. Empty Stream Padding - is allowed. + is allowed. If these requirements are not met, the decoder MUST + indicate an error. Note that non-empty Stream Padding is allowed at the end of the file; there doesn't need to be a new Stream after non-empty @@ -597,7 +607,9 @@ Version 1.0.0 (2009-01-14) Block Padding MUST contain 0-3 null bytes to make the size of the Block a multiple of four bytes. This can be needed when - the size of Compressed Data is not a multiple of four. + the size of Compressed Data is not a multiple of four. If any + of the bytes in Block Padding are not null bytes, the decoder + MUST indicate an error. 3.4. Check @@ -709,7 +721,8 @@ Version 1.0.0 (2009-01-14) 4.4. Index Padding This field MUST contain 0-3 null bytes to pad the Index to - a multiple of four bytes. + a multiple of four bytes. If any of the bytes are not null + bytes, the decoder MUST indicate an error. 4.5. CRC32 @@ -901,8 +914,10 @@ Version 1.0.0 (2009-01-14) If the size of Filter Properties is four bytes, the Filter Properties field contains the start offset used for address conversions. It is stored as an unsigned 32-bit little endian - integer. If the size of Filter Properties is zero, the start - offset is zero. + integer. The start offset MUST be a multiple of the alignment + of the filter as listed in the table above; if it isn't, the + decoder MUST indicate an error. If the size of Filter + Properties is zero, the start offset is zero. Setting the start offset may be useful if an executable has multiple sections, and there are many cross-section calls. |