alone_encoder.c revision 292588 
1///////////////////////////////////////////////////////////////////////////////
2//
3/// \file       alone_decoder.c
4/// \brief      Decoder for LZMA_Alone files
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 "common.h"
14#include "lzma_encoder.h"
15
16
17#define ALONE_HEADER_SIZE (1 + 4 + 8)
18
19
20struct lzma_coder_s {
21	lzma_next_coder next;
22
23	enum {
24		SEQ_HEADER,
25		SEQ_CODE,
26	} sequence;
27
28	size_t header_pos;
29	uint8_t header[ALONE_HEADER_SIZE];
30};
31
32
33static lzma_ret
34alone_encode(lzma_coder *coder,
35		const lzma_allocator *allocator lzma_attribute((__unused__)),
36		const uint8_t *restrict in, size_t *restrict in_pos,
37		size_t in_size, uint8_t *restrict out,
38		size_t *restrict out_pos, size_t out_size,
39		lzma_action action)
40{
41	while (*out_pos < out_size)
42	switch (coder->sequence) {
43	case SEQ_HEADER:
44		lzma_bufcpy(coder->header, &coder->header_pos,
45				ALONE_HEADER_SIZE,
46				out, out_pos, out_size);
47		if (coder->header_pos < ALONE_HEADER_SIZE)
48			return LZMA_OK;
49
50		coder->sequence = SEQ_CODE;
51		break;
52
53	case SEQ_CODE:
54		return coder->next.code(coder->next.coder,
55				allocator, in, in_pos, in_size,
56				out, out_pos, out_size, action);
57
58	default:
59		assert(0);
60		return LZMA_PROG_ERROR;
61	}
62
63	return LZMA_OK;
64}
65
66
67static void
68alone_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
69{
70	lzma_next_end(&coder->next, allocator);
71	lzma_free(coder, allocator);
72	return;
73}
74
75
76// At least for now, this is not used by any internal function.
77static lzma_ret
78alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
79		const lzma_options_lzma *options)
80{
81	lzma_next_coder_init(&alone_encoder_init, next, allocator);
82
83	if (next->coder == NULL) {
84		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
85		if (next->coder == NULL)
86			return LZMA_MEM_ERROR;
87
88		next->code = &alone_encode;
89		next->end = &alone_encoder_end;
90		next->coder->next = LZMA_NEXT_CODER_INIT;
91	}
92
93	// Basic initializations
94	next->coder->sequence = SEQ_HEADER;
95	next->coder->header_pos = 0;
96
97	// Encode the header:
98	// - Properties (1 byte)
99	if (lzma_lzma_lclppb_encode(options, next->coder->header))
100		return LZMA_OPTIONS_ERROR;
101
102	// - Dictionary size (4 bytes)
103	if (options->dict_size < LZMA_DICT_SIZE_MIN)
104		return LZMA_OPTIONS_ERROR;
105
106	// Round up to the next 2^n or 2^n + 2^(n - 1) depending on which
107	// one is the next unless it is UINT32_MAX. While the header would
108	// allow any 32-bit integer, we do this to keep the decoder of liblzma
109	// accepting the resulting files.
110	uint32_t d = options->dict_size - 1;
111	d |= d >> 2;
112	d |= d >> 3;
113	d |= d >> 4;
114	d |= d >> 8;
115	d |= d >> 16;
116	if (d != UINT32_MAX)
117		++d;
118
119	unaligned_write32le(next->coder->header + 1, d);
120
121	// - Uncompressed size (always unknown and using EOPM)
122	memset(next->coder->header + 1 + 4, 0xFF, 8);
123
124	// Initialize the LZMA encoder.
125	const lzma_filter_info filters[2] = {
126		{
127			.init = &lzma_lzma_encoder_init,
128			.options = (void *)(options),
129		}, {
130			.init = NULL,
131		}
132	};
133
134	return lzma_next_filter_init(&next->coder->next, allocator, filters);
135}
136
137
138/*
139extern lzma_ret
140lzma_alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
141		const lzma_options_alone *options)
142{
143	lzma_next_coder_init(&alone_encoder_init, next, allocator, options);
144}
145*/
146
147
148extern LZMA_API(lzma_ret)
149lzma_alone_encoder(lzma_stream *strm, const lzma_options_lzma *options)
150{
151	lzma_next_strm_init(alone_encoder_init, strm, options);
152
153	strm->internal->supported_actions[LZMA_RUN] = true;
154	strm->internal->supported_actions[LZMA_FINISH] = true;
155
156	return LZMA_OK;
157}
158