alone_encoder.c revision 312518 
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
20typedef struct {
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} lzma_alone_coder;
31
32
33static lzma_ret
34alone_encode(void *coder_ptr,
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	lzma_alone_coder *coder = coder_ptr;
42
43	while (*out_pos < out_size)
44	switch (coder->sequence) {
45	case SEQ_HEADER:
46		lzma_bufcpy(coder->header, &coder->header_pos,
47				ALONE_HEADER_SIZE,
48				out, out_pos, out_size);
49		if (coder->header_pos < ALONE_HEADER_SIZE)
50			return LZMA_OK;
51
52		coder->sequence = SEQ_CODE;
53		break;
54
55	case SEQ_CODE:
56		return coder->next.code(coder->next.coder,
57				allocator, in, in_pos, in_size,
58				out, out_pos, out_size, action);
59
60	default:
61		assert(0);
62		return LZMA_PROG_ERROR;
63	}
64
65	return LZMA_OK;
66}
67
68
69static void
70alone_encoder_end(void *coder_ptr, const lzma_allocator *allocator)
71{
72	lzma_alone_coder *coder = coder_ptr;
73	lzma_next_end(&coder->next, allocator);
74	lzma_free(coder, allocator);
75	return;
76}
77
78
79// At least for now, this is not used by any internal function.
80static lzma_ret
81alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
82		const lzma_options_lzma *options)
83{
84	lzma_next_coder_init(&alone_encoder_init, next, allocator);
85
86	lzma_alone_coder *coder = next->coder;
87
88	if (coder == NULL) {
89		coder = lzma_alloc(sizeof(lzma_alone_coder), allocator);
90		if (coder == NULL)
91			return LZMA_MEM_ERROR;
92
93		next->coder = coder;
94		next->code = &alone_encode;
95		next->end = &alone_encoder_end;
96		coder->next = LZMA_NEXT_CODER_INIT;
97	}
98
99	// Basic initializations
100	coder->sequence = SEQ_HEADER;
101	coder->header_pos = 0;
102
103	// Encode the header:
104	// - Properties (1 byte)
105	if (lzma_lzma_lclppb_encode(options, coder->header))
106		return LZMA_OPTIONS_ERROR;
107
108	// - Dictionary size (4 bytes)
109	if (options->dict_size < LZMA_DICT_SIZE_MIN)
110		return LZMA_OPTIONS_ERROR;
111
112	// Round up to the next 2^n or 2^n + 2^(n - 1) depending on which
113	// one is the next unless it is UINT32_MAX. While the header would
114	// allow any 32-bit integer, we do this to keep the decoder of liblzma
115	// accepting the resulting files.
116	uint32_t d = options->dict_size - 1;
117	d |= d >> 2;
118	d |= d >> 3;
119	d |= d >> 4;
120	d |= d >> 8;
121	d |= d >> 16;
122	if (d != UINT32_MAX)
123		++d;
124
125	unaligned_write32le(coder->header + 1, d);
126
127	// - Uncompressed size (always unknown and using EOPM)
128	memset(coder->header + 1 + 4, 0xFF, 8);
129
130	// Initialize the LZMA encoder.
131	const lzma_filter_info filters[2] = {
132		{
133			.init = &lzma_lzma_encoder_init,
134			.options = (void *)(options),
135		}, {
136			.init = NULL,
137		}
138	};
139
140	return lzma_next_filter_init(&coder->next, allocator, filters);
141}
142
143
144/*
145extern lzma_ret
146lzma_alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
147		const lzma_options_alone *options)
148{
149	lzma_next_coder_init(&alone_encoder_init, next, allocator, options);
150}
151*/
152
153
154extern LZMA_API(lzma_ret)
155lzma_alone_encoder(lzma_stream *strm, const lzma_options_lzma *options)
156{
157	lzma_next_strm_init(alone_encoder_init, strm, options);
158
159	strm->internal->supported_actions[LZMA_RUN] = true;
160	strm->internal->supported_actions[LZMA_FINISH] = true;
161
162	return LZMA_OK;
163}
164