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