1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 /// \file stream_buffer_encoder.c
4 /// \brief Single-call .xz Stream encoder
5 //
6 // Author: Lasse Collin
7 //
8 // This file has been put into the public domain.
9 // You can do whatever you want with this file.
10 //
11 ///////////////////////////////////////////////////////////////////////////////
12
13 #include "index.h"
14
15
16 /// Maximum size of Index that has exactly one Record.
17 /// Index Indicator + Number of Records + Record + CRC32 rounded up to
18 /// the next multiple of four.
19 #define INDEX_BOUND ((1 + 1 + 2 * LZMA_VLI_BYTES_MAX + 4 + 3) & ~3)
20
21 /// Stream Header, Stream Footer, and Index
22 #define HEADERS_BOUND (2 * LZMA_STREAM_HEADER_SIZE + INDEX_BOUND)
23
24
25 extern LZMA_API(size_t)
lzma_stream_buffer_bound(size_t uncompressed_size)26 lzma_stream_buffer_bound(size_t uncompressed_size)
27 {
28 // Get the maximum possible size of a Block.
29 const size_t block_bound = lzma_block_buffer_bound(uncompressed_size);
30 if (block_bound == 0)
31 return 0;
32
33 // Catch the possible integer overflow and also prevent the size of
34 // the Stream exceeding LZMA_VLI_MAX (theoretically possible on
35 // 64-bit systems).
36 if (my_min(SIZE_MAX, LZMA_VLI_MAX) - block_bound < HEADERS_BOUND)
37 return 0;
38
39 return block_bound + HEADERS_BOUND;
40 }
41
42
43 extern LZMA_API(lzma_ret)
lzma_stream_buffer_encode(lzma_filter * filters,lzma_check check,const lzma_allocator * allocator,const uint8_t * in,size_t in_size,uint8_t * out,size_t * out_pos_ptr,size_t out_size)44 lzma_stream_buffer_encode(lzma_filter *filters, lzma_check check,
45 const lzma_allocator *allocator,
46 const uint8_t *in, size_t in_size,
47 uint8_t *out, size_t *out_pos_ptr, size_t out_size)
48 {
49 // Sanity checks
50 if (filters == NULL || (unsigned int)(check) > LZMA_CHECK_ID_MAX
51 || (in == NULL && in_size != 0) || out == NULL
52 || out_pos_ptr == NULL || *out_pos_ptr > out_size)
53 return LZMA_PROG_ERROR;
54
55 if (!lzma_check_is_supported(check))
56 return LZMA_UNSUPPORTED_CHECK;
57
58 // Note for the paranoids: Index encoder prevents the Stream from
59 // getting too big and still being accepted with LZMA_OK, and Block
60 // encoder catches if the input is too big. So we don't need to
61 // separately check if the buffers are too big.
62
63 // Use a local copy. We update *out_pos_ptr only if everything
64 // succeeds.
65 size_t out_pos = *out_pos_ptr;
66
67 // Check that there's enough space for both Stream Header and
68 // Stream Footer.
69 if (out_size - out_pos <= 2 * LZMA_STREAM_HEADER_SIZE)
70 return LZMA_BUF_ERROR;
71
72 // Reserve space for Stream Footer so we don't need to check for
73 // available space again before encoding Stream Footer.
74 out_size -= LZMA_STREAM_HEADER_SIZE;
75
76 // Encode the Stream Header.
77 lzma_stream_flags stream_flags = {
78 .version = 0,
79 .check = check,
80 };
81
82 if (lzma_stream_header_encode(&stream_flags, out + out_pos)
83 != LZMA_OK)
84 return LZMA_PROG_ERROR;
85
86 out_pos += LZMA_STREAM_HEADER_SIZE;
87
88 // Encode a Block but only if there is at least one byte of input.
89 lzma_block block = {
90 .version = 0,
91 .check = check,
92 .filters = filters,
93 };
94
95 if (in_size > 0)
96 return_if_error(lzma_block_buffer_encode(&block, allocator,
97 in, in_size, out, &out_pos, out_size));
98
99 // Index
100 {
101 // Create an Index. It will have one Record if there was
102 // at least one byte of input to encode. Otherwise the
103 // Index will be empty.
104 lzma_index *i = lzma_index_init(allocator);
105 if (i == NULL)
106 return LZMA_MEM_ERROR;
107
108 lzma_ret ret = LZMA_OK;
109
110 if (in_size > 0)
111 ret = lzma_index_append(i, allocator,
112 lzma_block_unpadded_size(&block),
113 block.uncompressed_size);
114
115 // If adding the Record was successful, encode the Index
116 // and get its size which will be stored into Stream Footer.
117 if (ret == LZMA_OK) {
118 ret = lzma_index_buffer_encode(
119 i, out, &out_pos, out_size);
120
121 stream_flags.backward_size = lzma_index_size(i);
122 }
123
124 lzma_index_end(i, allocator);
125
126 if (ret != LZMA_OK)
127 return ret;
128 }
129
130 // Stream Footer. We have already reserved space for this.
131 if (lzma_stream_footer_encode(&stream_flags, out + out_pos)
132 != LZMA_OK)
133 return LZMA_PROG_ERROR;
134
135 out_pos += LZMA_STREAM_HEADER_SIZE;
136
137 // Everything went fine, make the new output position available
138 // to the application.
139 *out_pos_ptr = out_pos;
140 return LZMA_OK;
141 }
142