include/linux/xz.h

5  *          Igor Pavlov <https://7-zip.org/>
28  * enum xz_mode - Operation mode
30  * @XZ_SINGLE:              Single-call mode. This uses less RAM than
31  *                          multi-call modes, because the LZMA2
36  * @XZ_PREALLOC:            Multi-call mode with preallocated LZMA2
40  * @XZ_DYNALLOC:            Multi-call mode. The LZMA2 dictionary is
59  * enum xz_ret - Return codes
62  *                          return code is possible only in multi-call mode
66  *                          is still possible in multi-call mode by simply
81  *                          only in multi-call mode (XZ_PREALLOC or
82  *                          XZ_DYNALLOC); the single-call mode (XZ_SINGLE)
92  *                          different between multi-call and single-call
95  * In multi-call mode, XZ_BUF_ERROR is returned when two consecutive calls
102  * In single-call mode, XZ_BUF_ERROR is returned only when the output buffer
121  * struct xz_buf - Passing input and output buffers to XZ code
147  * struct xz_dec - Opaque type to hold the XZ decoder state
152  * xz_dec_init() - Allocate and initialize a XZ decoder state
155  *              multi-call decoding. This is ignored in single-call mode
157  *              or 2^n + 2^(n-1) bytes (the latter sizes are less common
164  * Single-call mode (XZ_SINGLE): xz_dec_run() decodes the whole stream at
171  * a big dictionary are not a problem in single-call mode. It is enough that
175  * Multi-call mode with preallocated dictionary (XZ_PREALLOC): dict_max bytes
183  * Multi-call mode with dynamically allocated dictionary (XZ_DYNALLOC):
197  * xz_dec_run() - Run the XZ decoder
204  * Note that if an error occurs in single-call mode (return value is not
205  * XZ_STREAM_END), b->in_pos and b->out_pos are not modified and the
206  * contents of the output buffer from b->out[b->out_pos] onward are
210  * cannot give the single-call decoder a too small buffer and then expect to
212  * the multi-call decoder if you don't want to uncompress the whole stream.
217  * xz_dec_reset() - Reset an already allocated decoder state
220  * This function can be used to reset the multi-call decoder state without
223  * In single-call mode, xz_dec_reset() is always called in the beginning of
225  * multi-call mode.
230  * xz_dec_end() - Free the memory allocated for the decoder state
232  *              this function does nothing.
245  * struct xz_dec_microlzma - Opaque type to hold the MicroLZMA decoder state
250  * xz_dec_microlzma_alloc() - Allocate memory for the MicroLZMA decoder
255  * In contrast to xz_dec_init(), this function only allocates the memory
267  * whose first byte (always 0x00) has been replaced with bitwise-negation
270  * Just like with LZMA2, lc + lp <= 4 must be true. The LZMA end-of-stream
279  * xz_dec_microlzma_reset() - Reset the MicroLZMA decoder state
297  * xz_dec_microlzma_run() - Run the MicroLZMA decoder
305  * XZ_DATA_ERROR. This function cannot return XZ_BUF_ERROR: if no progress
306  * is possible due to lack of input data or output space, this function will
318  * With XZ_PREALLOC only: As an extra feature, b->out may be NULL to skip over
323  * is also possible and thus XZ_SINGLE is actually a limited multi-call mode.
325  * It is possible to continue decoding but the variables b->out and b->out_pos
326  * MUST NOT be changed by the caller. Increasing the value of b->out_size is
330  * provided from non-contiguous memory.
336  * xz_dec_microlzma_end() - Free the memory allocated for the decoder state
338  *              If s is NULL, this function does nothing.
343  * Standalone build (userspace build or in-kernel build for boot time use)
344  * needs a CRC32 implementation. For normal in-kernel use, kernel's own
358  * This must be called before any other xz_* function to initialize
364  * Update CRC32 value using the polynomial from IEEE-802.3. To start a new