| /** |
| * \file lzma/stream_flags.h |
| * \brief .xz Stream Header and Stream Footer encoder and decoder |
| */ |
| |
| /* |
| * Author: Lasse Collin |
| * |
| * This file has been put into the public domain. |
| * You can do whatever you want with this file. |
| * |
| * See ../lzma.h for information about liblzma as a whole. |
| */ |
| |
| #ifndef LZMA_H_INTERNAL |
| # error Never include this file directly. Use <lzma.h> instead. |
| #endif |
| |
| |
| /** |
| * \brief Size of Stream Header and Stream Footer |
| * |
| * Stream Header and Stream Footer have the same size and they are not |
| * going to change even if a newer version of the .xz file format is |
| * developed in future. |
| */ |
| #define LZMA_STREAM_HEADER_SIZE 12 |
| |
| |
| /** |
| * \brief Options for encoding/decoding Stream Header and Stream Footer |
| */ |
| typedef struct { |
| /** |
| * \brief Stream Flags format version |
| * |
| * To prevent API and ABI breakages if new features are needed in |
| * Stream Header or Stream Footer, a version number is used to |
| * indicate which fields in this structure are in use. For now, |
| * version must always be zero. With non-zero version, the |
| * lzma_stream_header_encode() and lzma_stream_footer_encode() |
| * will return LZMA_OPTIONS_ERROR. |
| * |
| * lzma_stream_header_decode() and lzma_stream_footer_decode() |
| * will always set this to the lowest value that supports all the |
| * features indicated by the Stream Flags field. The application |
| * must check that the version number set by the decoding functions |
| * is supported by the application. Otherwise it is possible that |
| * the application will decode the Stream incorrectly. |
| */ |
| uint32_t version; |
| |
| /** |
| * \brief Backward Size |
| * |
| * Backward Size must be a multiple of four bytes. In this Stream |
| * format version, Backward Size is the size of the Index field. |
| * |
| * Backward Size isn't actually part of the Stream Flags field, but |
| * it is convenient to include in this structure anyway. Backward |
| * Size is present only in the Stream Footer. There is no need to |
| * initialize backward_size when encoding Stream Header. |
| * |
| * lzma_stream_header_decode() always sets backward_size to |
| * LZMA_VLI_UNKNOWN so that it is convenient to use |
| * lzma_stream_flags_compare() when both Stream Header and Stream |
| * Footer have been decoded. |
| */ |
| lzma_vli backward_size; |
| # define LZMA_BACKWARD_SIZE_MIN 4 |
| # define LZMA_BACKWARD_SIZE_MAX (LZMA_VLI_C(1) << 34) |
| |
| /** |
| * \brief Check ID |
| * |
| * This indicates the type of the integrity check calculated from |
| * uncompressed data. |
| */ |
| lzma_check check; |
| |
| /* |
| * Reserved space to allow possible future extensions without |
| * breaking the ABI. You should not touch these, because the |
| * names of these variables may change. |
| * |
| * (We will never be able to use all of these since Stream Flags |
| * is just two bytes plus Backward Size of four bytes. But it's |
| * nice to have the proper types when they are needed.) |
| */ |
| lzma_reserved_enum reserved_enum1; |
| lzma_reserved_enum reserved_enum2; |
| lzma_reserved_enum reserved_enum3; |
| lzma_reserved_enum reserved_enum4; |
| lzma_bool reserved_bool1; |
| lzma_bool reserved_bool2; |
| lzma_bool reserved_bool3; |
| lzma_bool reserved_bool4; |
| lzma_bool reserved_bool5; |
| lzma_bool reserved_bool6; |
| lzma_bool reserved_bool7; |
| lzma_bool reserved_bool8; |
| uint32_t reserved_int1; |
| uint32_t reserved_int2; |
| |
| } lzma_stream_flags; |
| |
| |
| /** |
| * \brief Encode Stream Header |
| * |
| * \param options Stream Header options to be encoded. |
| * options->backward_size is ignored and doesn't |
| * need to be initialized. |
| * \param out Beginning of the output buffer of |
| * LZMA_STREAM_HEADER_SIZE bytes. |
| * |
| * \return - LZMA_OK: Encoding was successful. |
| * - LZMA_OPTIONS_ERROR: options->version is not supported by |
| * this liblzma version. |
| * - LZMA_PROG_ERROR: Invalid options. |
| */ |
| extern LZMA_API(lzma_ret) lzma_stream_header_encode( |
| const lzma_stream_flags *options, uint8_t *out) |
| lzma_nothrow lzma_attr_warn_unused_result; |
| |
| |
| /** |
| * \brief Encode Stream Footer |
| * |
| * \param options Stream Footer options to be encoded. |
| * \param out Beginning of the output buffer of |
| * LZMA_STREAM_HEADER_SIZE bytes. |
| * |
| * \return - LZMA_OK: Encoding was successful. |
| * - LZMA_OPTIONS_ERROR: options->version is not supported by |
| * this liblzma version. |
| * - LZMA_PROG_ERROR: Invalid options. |
| */ |
| extern LZMA_API(lzma_ret) lzma_stream_footer_encode( |
| const lzma_stream_flags *options, uint8_t *out) |
| lzma_nothrow lzma_attr_warn_unused_result; |
| |
| |
| /** |
| * \brief Decode Stream Header |
| * |
| * \param options Target for the decoded Stream Header options. |
| * \param in Beginning of the input buffer of |
| * LZMA_STREAM_HEADER_SIZE bytes. |
| * |
| * options->backward_size is always set to LZMA_VLI_UNKNOWN. This is to |
| * help comparing Stream Flags from Stream Header and Stream Footer with |
| * lzma_stream_flags_compare(). |
| * |
| * \return - LZMA_OK: Decoding was successful. |
| * - LZMA_FORMAT_ERROR: Magic bytes don't match, thus the given |
| * buffer cannot be Stream Header. |
| * - LZMA_DATA_ERROR: CRC32 doesn't match, thus the header |
| * is corrupt. |
| * - LZMA_OPTIONS_ERROR: Unsupported options are present |
| * in the header. |
| * |
| * \note When decoding .xz files that contain multiple Streams, it may |
| * make sense to print "file format not recognized" only if |
| * decoding of the Stream Header of the _first_ Stream gives |
| * LZMA_FORMAT_ERROR. If non-first Stream Header gives |
| * LZMA_FORMAT_ERROR, the message used for LZMA_DATA_ERROR is |
| * probably more appropriate. |
| * |
| * For example, Stream decoder in liblzma uses LZMA_DATA_ERROR if |
| * LZMA_FORMAT_ERROR is returned by lzma_stream_header_decode() |
| * when decoding non-first Stream. |
| */ |
| extern LZMA_API(lzma_ret) lzma_stream_header_decode( |
| lzma_stream_flags *options, const uint8_t *in) |
| lzma_nothrow lzma_attr_warn_unused_result; |
| |
| |
| /** |
| * \brief Decode Stream Footer |
| * |
| * \param options Target for the decoded Stream Header options. |
| * \param in Beginning of the input buffer of |
| * LZMA_STREAM_HEADER_SIZE bytes. |
| * |
| * \return - LZMA_OK: Decoding was successful. |
| * - LZMA_FORMAT_ERROR: Magic bytes don't match, thus the given |
| * buffer cannot be Stream Footer. |
| * - LZMA_DATA_ERROR: CRC32 doesn't match, thus the Stream Footer |
| * is corrupt. |
| * - LZMA_OPTIONS_ERROR: Unsupported options are present |
| * in Stream Footer. |
| * |
| * \note If Stream Header was already decoded successfully, but |
| * decoding Stream Footer returns LZMA_FORMAT_ERROR, the |
| * application should probably report some other error message |
| * than "file format not recognized", since the file more likely |
| * is corrupt (possibly truncated). Stream decoder in liblzma |
| * uses LZMA_DATA_ERROR in this situation. |
| */ |
| extern LZMA_API(lzma_ret) lzma_stream_footer_decode( |
| lzma_stream_flags *options, const uint8_t *in) |
| lzma_nothrow lzma_attr_warn_unused_result; |
| |
| |
| /** |
| * \brief Compare two lzma_stream_flags structures |
| * |
| * backward_size values are compared only if both are not |
| * LZMA_VLI_UNKNOWN. |
| * |
| * \return - LZMA_OK: Both are equal. If either had backward_size set |
| * to LZMA_VLI_UNKNOWN, backward_size values were not |
| * compared or validated. |
| * - LZMA_DATA_ERROR: The structures differ. |
| * - LZMA_OPTIONS_ERROR: version in either structure is greater |
| * than the maximum supported version (currently zero). |
| * - LZMA_PROG_ERROR: Invalid value, e.g. invalid check or |
| * backward_size. |
| */ |
| extern LZMA_API(lzma_ret) lzma_stream_flags_compare( |
| const lzma_stream_flags *a, const lzma_stream_flags *b) |
| lzma_nothrow lzma_attr_pure; |
