aboutsummaryrefslogtreecommitdiff
path: root/src/liblzma/common/block_encoder.c
blob: 3add45a9bbee5c78fbc8cd04529fc4b2edeed2aa (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
///////////////////////////////////////////////////////////////////////////////
//
/// \file       block_encoder.c
/// \brief      Encodes .lzma Blocks
//
//  Copyright (C) 2007 Lasse Collin
//
//  This library is free software; you can redistribute it and/or
//  modify it under the terms of the GNU Lesser General Public
//  License as published by the Free Software Foundation; either
//  version 2.1 of the License, or (at your option) any later version.
//
//  This library is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
//  Lesser General Public License for more details.
//
///////////////////////////////////////////////////////////////////////////////

#include "block_encoder.h"
#include "block_private.h"
#include "raw_encoder.h"
#include "check.h"


struct lzma_coder_s {
	/// The filters in the chain; initialized with lzma_raw_decoder_init().
	lzma_next_coder next;

	/// Encoding options; we also write Total Size, Compressed Size, and
	/// Uncompressed Size back to this structure when the encoding has
	/// been finished.
	lzma_options_block *options;

	enum {
		SEQ_CODE,
		SEQ_PADDING,
		SEQ_CHECK,
	} sequence;

	/// Compressed Size calculated while encoding
	lzma_vli compressed_size;

	/// Uncompressed Size calculated while encoding
	lzma_vli uncompressed_size;

	/// Position when writing out the Check field
	size_t check_pos;

	/// Check of the uncompressed data
	lzma_check check;
};


static lzma_ret
block_encode(lzma_coder *coder, lzma_allocator *allocator,
		const uint8_t *restrict in, size_t *restrict in_pos,
		size_t in_size, uint8_t *restrict out,
		size_t *restrict out_pos, size_t out_size, lzma_action action)
{
	// Check that our amount of input stays in proper limits.
	if (coder->options->uncompressed_size != LZMA_VLI_VALUE_UNKNOWN) {
		if (action == LZMA_FINISH) {
			if (coder->options->uncompressed_size
					- coder->uncompressed_size
					!= (lzma_vli)(in_size - *in_pos))
				return LZMA_PROG_ERROR;
		} else {
			if (coder->options->uncompressed_size
					- coder->uncompressed_size
					<  (lzma_vli)(in_size - *in_pos))
				return LZMA_PROG_ERROR;
		}
	} else if (LZMA_VLI_VALUE_MAX - coder->uncompressed_size
			< (lzma_vli)(in_size - *in_pos)) {
		return LZMA_PROG_ERROR;
	}

	// Main loop
	while (*out_pos < out_size
			&& (*in_pos < in_size || action != LZMA_RUN))
	switch (coder->sequence) {
	case SEQ_CODE: {
		const size_t in_start = *in_pos;
		const size_t out_start = *out_pos;

		const lzma_ret ret = coder->next.code(coder->next.coder,
				allocator, in, in_pos, in_size,
				out, out_pos, out_size, action);

		const size_t in_used = *in_pos - in_start;
		const size_t out_used = *out_pos - out_start;

		// FIXME We must also check that Total Size doesn't get
		// too big.
		if (update_size(&coder->compressed_size, out_used,
				coder->options->compressed_size))
			return LZMA_DATA_ERROR;

		// No need to check for overflow because we have already
		// checked it at the beginning of this function.
		coder->uncompressed_size += in_used;

		lzma_check_update(&coder->check, coder->options->check,
				in + in_start, in_used);

		if (ret != LZMA_STREAM_END || action == LZMA_SYNC_FLUSH)
			return ret;

		assert(*in_pos == in_size);
		coder->sequence = SEQ_PADDING;
		break;
	}

	case SEQ_PADDING:
		// Pad Compressed Data to a multiple of four bytes.
		if (coder->compressed_size & 3) {
			out[*out_pos] = 0x00;
			++*out_pos;

			if (update_size(&coder->compressed_size, 1,
					coder->options->compressed_size))
				return LZMA_DATA_ERROR;

			break;
		}

		// Compressed and Uncompressed Sizes are now at their final
		// values. Verify that they match the values given to us.
		if (!is_size_valid(coder->compressed_size,
					coder->options->compressed_size)
				|| !is_size_valid(coder->uncompressed_size,
					coder->options->uncompressed_size))
			return LZMA_DATA_ERROR;

		// Copy the values into coder->options. The caller
		// may use this information to construct Index.
		coder->options->compressed_size = coder->compressed_size;
		coder->options->uncompressed_size = coder->uncompressed_size;

		if (coder->options->check == LZMA_CHECK_NONE)
			return LZMA_STREAM_END;

		lzma_check_finish(&coder->check, coder->options->check);
		coder->sequence = SEQ_CHECK;

	// Fall through

	case SEQ_CHECK:
		out[*out_pos] = coder->check.buffer[coder->check_pos];
		++*out_pos;

		if (++coder->check_pos
				== lzma_check_sizes[coder->options->check])
			return LZMA_STREAM_END;

		break;

	default:
		return LZMA_PROG_ERROR;
	}

	return LZMA_OK;
}


static void
block_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
{
	lzma_next_coder_end(&coder->next, allocator);
	lzma_free(coder, allocator);
	return;
}


static lzma_ret
block_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
		lzma_options_block *options)
{
	// While lzma_block_total_size_get() is meant to calculate the Total
	// Size, it also validates the options excluding the filters.
	if (lzma_block_total_size_get(options) == 0)
		return LZMA_PROG_ERROR;

	// Allocate and initialize *next->coder if needed.
	if (next->coder == NULL) {
		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
		if (next->coder == NULL)
			return LZMA_MEM_ERROR;

		next->code = &block_encode;
		next->end = &block_encoder_end;
		next->coder->next = LZMA_NEXT_CODER_INIT;
	}

	// Basic initializations
	next->coder->sequence = SEQ_CODE;
	next->coder->options = options;
	next->coder->compressed_size = 0;
	next->coder->uncompressed_size = 0;

	// Initialize the check
	next->coder->check_pos = 0;
	return_if_error(lzma_check_init(&next->coder->check, options->check));

	// Initialize the requested filters.
	return lzma_raw_encoder_init(&next->coder->next, allocator,
			options->filters);
}


extern lzma_ret
lzma_block_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
		lzma_options_block *options)
{
	lzma_next_coder_init(block_encoder_init, next, allocator, options);
}


extern LZMA_API lzma_ret
lzma_block_encoder(lzma_stream *strm, lzma_options_block *options)
{
	lzma_next_strm_init(strm, block_encoder_init, options);

	strm->internal->supported_actions[LZMA_RUN] = true;
	strm->internal->supported_actions[LZMA_FINISH] = true;

	return LZMA_OK;
}