xz-utils (5.4.5)
1 /**
2 * \file lzma/index_hash.h
3 * \brief Validate Index by using a hash function
4 * \note Never include this file directly. Use <lzma.h> instead.
5 *
6 * Hashing makes it possible to use constant amount of memory to validate
7 * Index of arbitrary size.
8 */
9
10 /*
11 * Author: Lasse Collin
12 *
13 * This file has been put into the public domain.
14 * You can do whatever you want with this file.
15 */
16
17 #ifndef LZMA_H_INTERNAL
18 # error Never include this file directly. Use <lzma.h> instead.
19 #endif
20
21 /**
22 * \brief Opaque data type to hold the Index hash
23 */
24 typedef struct lzma_index_hash_s lzma_index_hash;
25
26
27 /**
28 * \brief Allocate and initialize a new lzma_index_hash structure
29 *
30 * If index_hash is NULL, this function allocates and initializes a new
31 * lzma_index_hash structure and returns a pointer to it. If allocation
32 * fails, NULL is returned.
33 *
34 * If index_hash is non-NULL, this function reinitializes the lzma_index_hash
35 * structure and returns the same pointer. In this case, return value cannot
36 * be NULL or a different pointer than the index_hash that was given as
37 * an argument.
38 *
39 * \param index_hash Pointer to a lzma_index_hash structure or NULL.
40 * \param allocator lzma_allocator for custom allocator functions.
41 * Set to NULL to use malloc() and free().
42 *
43 * \return Initialized lzma_index_hash structure on success or
44 * NULL on failure.
45 */
46 extern LZMA_API(lzma_index_hash *) lzma_index_hash_init(
47 lzma_index_hash *index_hash, const lzma_allocator *allocator)
48 lzma_nothrow lzma_attr_warn_unused_result;
49
50
51 /**
52 * \brief Deallocate lzma_index_hash structure
53 *
54 * \param index_hash Pointer to a lzma_index_hash structure to free.
55 * \param allocator lzma_allocator for custom allocator functions.
56 * Set to NULL to use malloc() and free().
57 */
58 extern LZMA_API(void) lzma_index_hash_end(
59 lzma_index_hash *index_hash, const lzma_allocator *allocator)
60 lzma_nothrow;
61
62
63 /**
64 * \brief Add a new Record to an Index hash
65 *
66 * \param index_hash Pointer to a lzma_index_hash structure
67 * \param unpadded_size Unpadded Size of a Block
68 * \param uncompressed_size Uncompressed Size of a Block
69 *
70 * \return Possible lzma_ret values:
71 * - LZMA_OK
72 * - LZMA_DATA_ERROR: Compressed or uncompressed size of the
73 * Stream or size of the Index field would grow too big.
74 * - LZMA_PROG_ERROR: Invalid arguments or this function is being
75 * used when lzma_index_hash_decode() has already been used.
76 */
77 extern LZMA_API(lzma_ret) lzma_index_hash_append(lzma_index_hash *index_hash,
78 lzma_vli unpadded_size, lzma_vli uncompressed_size)
79 lzma_nothrow lzma_attr_warn_unused_result;
80
81
82 /**
83 * \brief Decode and validate the Index field
84 *
85 * After telling the sizes of all Blocks with lzma_index_hash_append(),
86 * the actual Index field is decoded with this function. Specifically,
87 * once decoding of the Index field has been started, no more Records
88 * can be added using lzma_index_hash_append().
89 *
90 * This function doesn't use lzma_stream structure to pass the input data.
91 * Instead, the input buffer is specified using three arguments. This is
92 * because it matches better the internal APIs of liblzma.
93 *
94 * \param index_hash Pointer to a lzma_index_hash structure
95 * \param in Pointer to the beginning of the input buffer
96 * \param[out] in_pos in[*in_pos] is the next byte to process
97 * \param in_size in[in_size] is the first byte not to process
98 *
99 * \return Possible lzma_ret values:
100 * - LZMA_OK: So far good, but more input is needed.
101 * - LZMA_STREAM_END: Index decoded successfully and it matches
102 * the Records given with lzma_index_hash_append().
103 * - LZMA_DATA_ERROR: Index is corrupt or doesn't match the
104 * information given with lzma_index_hash_append().
105 * - LZMA_BUF_ERROR: Cannot progress because *in_pos >= in_size.
106 * - LZMA_PROG_ERROR
107 */
108 extern LZMA_API(lzma_ret) lzma_index_hash_decode(lzma_index_hash *index_hash,
109 const uint8_t *in, size_t *in_pos, size_t in_size)
110 lzma_nothrow lzma_attr_warn_unused_result;
111
112
113 /**
114 * \brief Get the size of the Index field as bytes
115 *
116 * This is needed to verify the Backward Size field in the Stream Footer.
117 *
118 * \param index_hash Pointer to a lzma_index_hash structure
119 *
120 * \return Size of the Index field in bytes.
121 */
122 extern LZMA_API(lzma_vli) lzma_index_hash_size(
123 const lzma_index_hash *index_hash)
124 lzma_nothrow lzma_attr_pure;
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