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authorDenys Vlasenko <vda.linux@googlemail.com>2010-11-03 02:38:31 +0100
committerDenys Vlasenko <vda.linux@googlemail.com>2010-11-03 02:38:31 +0100
commit833d4e7f84f59099ee66eabfa3457ebb7d37eaa8 (patch)
tree3be84e1049707ce8077291065fe3689497c69b9c /archival/libarchive/unxz/xz.h
parent5e9934028aa030312a1a2e2e32d5ceade8672beb (diff)
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rename archival/libunarchive -> archival/libarchive; move bz/ into it
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
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diff --git a/archival/libarchive/unxz/xz.h b/archival/libarchive/unxz/xz.h
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1/*
2 * XZ decompressor
3 *
4 * Authors: Lasse Collin <lasse.collin@tukaani.org>
5 * Igor Pavlov <http://7-zip.org/>
6 *
7 * This file has been put into the public domain.
8 * You can do whatever you want with this file.
9 */
10
11#ifndef XZ_H
12#define XZ_H
13
14#ifdef __KERNEL__
15# include <linux/stddef.h>
16# include <linux/types.h>
17#else
18# include <stddef.h>
19# include <stdint.h>
20#endif
21
22/* In Linux, this is used to make extern functions static when needed. */
23#ifndef XZ_EXTERN
24# define XZ_EXTERN extern
25#endif
26
27/* In Linux, this is used to mark the functions with __init when needed. */
28#ifndef XZ_FUNC
29# define XZ_FUNC
30#endif
31
32/**
33 * enum xz_mode - Operation mode
34 *
35 * @XZ_SINGLE: Single-call mode. This uses less RAM than
36 * than multi-call modes, because the LZMA2
37 * dictionary doesn't need to be allocated as
38 * part of the decoder state. All required data
39 * structures are allocated at initialization,
40 * so xz_dec_run() cannot return XZ_MEM_ERROR.
41 * @XZ_PREALLOC: Multi-call mode with preallocated LZMA2
42 * dictionary buffer. All data structures are
43 * allocated at initialization, so xz_dec_run()
44 * cannot return XZ_MEM_ERROR.
45 * @XZ_DYNALLOC: Multi-call mode. The LZMA2 dictionary is
46 * allocated once the required size has been
47 * parsed from the stream headers. If the
48 * allocation fails, xz_dec_run() will return
49 * XZ_MEM_ERROR.
50 *
51 * It is possible to enable support only for a subset of the above
52 * modes at compile time by defining XZ_DEC_SINGLE, XZ_DEC_PREALLOC,
53 * or XZ_DEC_DYNALLOC. The xz_dec kernel module is always compiled
54 * with support for all operation modes, but the preboot code may
55 * be built with fewer features to minimize code size.
56 */
57enum xz_mode {
58 XZ_SINGLE,
59 XZ_PREALLOC,
60 XZ_DYNALLOC
61};
62
63/**
64 * enum xz_ret - Return codes
65 * @XZ_OK: Everything is OK so far. More input or more
66 * output space is required to continue. This
67 * return code is possible only in multi-call mode
68 * (XZ_PREALLOC or XZ_DYNALLOC).
69 * @XZ_STREAM_END: Operation finished successfully.
70 * @XZ_UNSUPPORTED_CHECK: Integrity check type is not supported. Decoding
71 * is still possible in multi-call mode by simply
72 * calling xz_dec_run() again.
73 * NOTE: This return value is used only if
74 * XZ_DEC_ANY_CHECK was defined at build time,
75 * which is not used in the kernel. Unsupported
76 * check types return XZ_OPTIONS_ERROR if
77 * XZ_DEC_ANY_CHECK was not defined at build time.
78 * @XZ_MEM_ERROR: Allocating memory failed. This return code is
79 * possible only if the decoder was initialized
80 * with XZ_DYNALLOC. The amount of memory that was
81 * tried to be allocated was no more than the
82 * dict_max argument given to xz_dec_init().
83 * @XZ_MEMLIMIT_ERROR: A bigger LZMA2 dictionary would be needed than
84 * allowed by the dict_max argument given to
85 * xz_dec_init(). This return value is possible
86 * only in multi-call mode (XZ_PREALLOC or
87 * XZ_DYNALLOC); the single-call mode (XZ_SINGLE)
88 * ignores the dict_max argument.
89 * @XZ_FORMAT_ERROR: File format was not recognized (wrong magic
90 * bytes).
91 * @XZ_OPTIONS_ERROR: This implementation doesn't support the requested
92 * compression options. In the decoder this means
93 * that the header CRC32 matches, but the header
94 * itself specifies something that we don't support.
95 * @XZ_DATA_ERROR: Compressed data is corrupt.
96 * @XZ_BUF_ERROR: Cannot make any progress. Details are slightly
97 * different between multi-call and single-call
98 * mode; more information below.
99 *
100 * In multi-call mode, XZ_BUF_ERROR is returned when two consecutive calls
101 * to XZ code cannot consume any input and cannot produce any new output.
102 * This happens when there is no new input available, or the output buffer
103 * is full while at least one output byte is still pending. Assuming your
104 * code is not buggy, you can get this error only when decoding a compressed
105 * stream that is truncated or otherwise corrupt.
106 *
107 * In single-call mode, XZ_BUF_ERROR is returned only when the output buffer
108 * is too small, or the compressed input is corrupt in a way that makes the
109 * decoder produce more output than the caller expected. When it is
110 * (relatively) clear that the compressed input is truncated, XZ_DATA_ERROR
111 * is used instead of XZ_BUF_ERROR.
112 */
113enum xz_ret {
114 XZ_OK,
115 XZ_STREAM_END,
116 XZ_UNSUPPORTED_CHECK,
117 XZ_MEM_ERROR,
118 XZ_MEMLIMIT_ERROR,
119 XZ_FORMAT_ERROR,
120 XZ_OPTIONS_ERROR,
121 XZ_DATA_ERROR,
122 XZ_BUF_ERROR
123};
124
125/**
126 * struct xz_buf - Passing input and output buffers to XZ code
127 * @in: Beginning of the input buffer. This may be NULL if and only
128 * if in_pos is equal to in_size.
129 * @in_pos: Current position in the input buffer. This must not exceed
130 * in_size.
131 * @in_size: Size of the input buffer
132 * @out: Beginning of the output buffer. This may be NULL if and only
133 * if out_pos is equal to out_size.
134 * @out_pos: Current position in the output buffer. This must not exceed
135 * out_size.
136 * @out_size: Size of the output buffer
137 *
138 * Only the contents of the output buffer from out[out_pos] onward, and
139 * the variables in_pos and out_pos are modified by the XZ code.
140 */
141struct xz_buf {
142 const uint8_t *in;
143 size_t in_pos;
144 size_t in_size;
145
146 uint8_t *out;
147 size_t out_pos;
148 size_t out_size;
149};
150
151/**
152 * struct xz_dec - Opaque type to hold the XZ decoder state
153 */
154struct xz_dec;
155
156/**
157 * xz_dec_init() - Allocate and initialize a XZ decoder state
158 * @mode: Operation mode
159 * @dict_max: Maximum size of the LZMA2 dictionary (history buffer) for
160 * multi-call decoding. This is ignored in single-call mode
161 * (mode == XZ_SINGLE). LZMA2 dictionary is always 2^n bytes
162 * or 2^n + 2^(n-1) bytes (the latter sizes are less common
163 * in practice), so other values for dict_max don't make sense.
164 * In the kernel, dictionary sizes of 64 KiB, 128 KiB, 256 KiB,
165 * 512 KiB, and 1 MiB are probably the only reasonable values,
166 * except for kernel and initramfs images where a bigger
167 * dictionary can be fine and useful.
168 *
169 * Single-call mode (XZ_SINGLE): xz_dec_run() decodes the whole stream at
170 * once. The caller must provide enough output space or the decoding will
171 * fail. The output space is used as the dictionary buffer, which is why
172 * there is no need to allocate the dictionary as part of the decoder's
173 * internal state.
174 *
175 * Because the output buffer is used as the workspace, streams encoded using
176 * a big dictionary are not a problem in single-call mode. It is enough that
177 * the output buffer is big enough to hold the actual uncompressed data; it
178 * can be smaller than the dictionary size stored in the stream headers.
179 *
180 * Multi-call mode with preallocated dictionary (XZ_PREALLOC): dict_max bytes
181 * of memory is preallocated for the LZMA2 dictionary. This way there is no
182 * risk that xz_dec_run() could run out of memory, since xz_dec_run() will
183 * never allocate any memory. Instead, if the preallocated dictionary is too
184 * small for decoding the given input stream, xz_dec_run() will return
185 * XZ_MEMLIMIT_ERROR. Thus, it is important to know what kind of data will be
186 * decoded to avoid allocating excessive amount of memory for the dictionary.
187 *
188 * Multi-call mode with dynamically allocated dictionary (XZ_DYNALLOC):
189 * dict_max specifies the maximum allowed dictionary size that xz_dec_run()
190 * may allocate once it has parsed the dictionary size from the stream
191 * headers. This way excessive allocations can be avoided while still
192 * limiting the maximum memory usage to a sane value to prevent running the
193 * system out of memory when decompressing streams from untrusted sources.
194 *
195 * On success, xz_dec_init() returns a pointer to struct xz_dec, which is
196 * ready to be used with xz_dec_run(). If memory allocation fails,
197 * xz_dec_init() returns NULL.
198 */
199XZ_EXTERN struct xz_dec * XZ_FUNC xz_dec_init(
200 enum xz_mode mode, uint32_t dict_max);
201
202/**
203 * xz_dec_run() - Run the XZ decoder
204 * @s: Decoder state allocated using xz_dec_init()
205 * @b: Input and output buffers
206 *
207 * The possible return values depend on build options and operation mode.
208 * See enum xz_ret for details.
209 *
210 * NOTE: If an error occurs in single-call mode (return value is not
211 * XZ_STREAM_END), b->in_pos and b->out_pos are not modified, and the
212 * contents of the output buffer from b->out[b->out_pos] onward are
213 * undefined. This is true even after XZ_BUF_ERROR, because with some filter
214 * chains, there may be a second pass over the output buffer, and this pass
215 * cannot be properly done if the output buffer is truncated. Thus, you
216 * cannot give the single-call decoder a too small buffer and then expect to
217 * get that amount valid data from the beginning of the stream. You must use
218 * the multi-call decoder if you don't want to uncompress the whole stream.
219 */
220XZ_EXTERN enum xz_ret XZ_FUNC xz_dec_run(struct xz_dec *s, struct xz_buf *b);
221
222/**
223 * xz_dec_reset() - Reset an already allocated decoder state
224 * @s: Decoder state allocated using xz_dec_init()
225 *
226 * This function can be used to reset the multi-call decoder state without
227 * freeing and reallocating memory with xz_dec_end() and xz_dec_init().
228 *
229 * In single-call mode, xz_dec_reset() is always called in the beginning of
230 * xz_dec_run(). Thus, explicit call to xz_dec_reset() is useful only in
231 * multi-call mode.
232 */
233XZ_EXTERN void XZ_FUNC xz_dec_reset(struct xz_dec *s);
234
235/**
236 * xz_dec_end() - Free the memory allocated for the decoder state
237 * @s: Decoder state allocated using xz_dec_init(). If s is NULL,
238 * this function does nothing.
239 */
240XZ_EXTERN void XZ_FUNC xz_dec_end(struct xz_dec *s);
241
242/*
243 * Standalone build (userspace build or in-kernel build for boot time use)
244 * needs a CRC32 implementation. For normal in-kernel use, kernel's own
245 * CRC32 module is used instead, and users of this module don't need to
246 * care about the functions below.
247 */
248#ifndef XZ_INTERNAL_CRC32
249# ifdef __KERNEL__
250# define XZ_INTERNAL_CRC32 0
251# else
252# define XZ_INTERNAL_CRC32 1
253# endif
254#endif
255
256#if XZ_INTERNAL_CRC32
257/*
258 * This must be called before any other xz_* function to initialize
259 * the CRC32 lookup table.
260 */
261XZ_EXTERN void XZ_FUNC xz_crc32_init(void);
262
263/*
264 * Update CRC32 value using the polynomial from IEEE-802.3. To start a new
265 * calculation, the third argument must be zero. To continue the calculation,
266 * the previously returned value is passed as the third argument.
267 */
268XZ_EXTERN uint32_t XZ_FUNC xz_crc32(
269 const uint8_t *buf, size_t size, uint32_t crc);
270#endif
271#endif
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