-
Notifications
You must be signed in to change notification settings - Fork 0
/
file_info.c
261 lines (216 loc) · 7.45 KB
/
file_info.c
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
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
/* Copyright (c) 2012 Francis Russell <francis@unchartedbackwaters.co.uk>
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include "file_info.h"
#include "checksum.h"
#include "errors.h"
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <sys/types.h>
static int hit_buffer_end(const file_info_t *info);
inline int hit_buffer_end(const file_info_t *const info)
{
return info->internal_offset >= info->buffer_use;
}
status_t open_input_file(file_info_t *const info,
const char *const path,
const size_t checksum_length)
{
status_t _status = LF_INTERNAL_ERROR;
FAIL_PRED(checksum_length > BUFFER_SIZE, LF_INVALID_WINDOW_SIZE);
info->prev_buffer = info->buffer = NULL;
FAIL_SYS((info->prev_buffer = malloc(BUFFER_SIZE)) == NULL);
FAIL_SYS((info->buffer = malloc(BUFFER_SIZE)) == NULL);
init_checksum(&info->checksum, checksum_length);
info->file = fopen(path, "rb");
FAIL_SYS(info->file == NULL);
FAIL_SYS(fseeko(info->file, 0, SEEK_END) == -1);
info->total_length = ftello(info->file);
FAIL_FORWARD(seek_file(info, 0));
return LF_OK;
fail:
free(info->buffer);
free(info->prev_buffer);
return _status;
}
status_t seek_file(file_info_t *const info, const off_t offset)
{
status_t _status = LF_INTERNAL_ERROR;
info->block_offset = offset;
info->buffer_use = 0;
info->internal_offset = 0;
memset(info->prev_buffer, 0, BUFFER_SIZE);
memset(info->buffer, 0, BUFFER_SIZE);
reset_checksum(&info->checksum);
FAIL_SYS(fseeko(info->file, offset, SEEK_SET) == -1);
return LF_OK;
fail:
return _status;
}
status_t close_input_file(file_info_t *const info)
{
status_t _status = LF_INTERNAL_ERROR;
free(info->prev_buffer);
free(info->buffer);
FAIL_SYS(fclose(info->file) == EOF);
return LF_OK;
fail:
return _status;
}
status_t populate_forwards(file_info_t *const file)
{
status_t _status = LF_INTERNAL_ERROR;
if (!hit_buffer_end(file))
return LF_OK;
file->block_offset += file->buffer_use;
file->internal_offset = 0;
unsigned char *const new_prev_buffer = file->buffer;
file->buffer = file->prev_buffer;
file->prev_buffer = new_prev_buffer;
FAIL_SYS(fseeko(file->file, file->block_offset, SEEK_SET) == -1);
file->buffer_use = fread(file->buffer, 1, BUFFER_SIZE, file->file);
FAIL_SYS(file->buffer_use != BUFFER_SIZE && ferror(file->file));
return LF_OK;
fail:
return _status;
}
status_t find_checksum_match(const file_info_t *const f1_info, file_info_t *const f2_info, int *const success)
{
*success = 0;
do
{
const status_t status = advance_location(f2_info);
if (status != LF_OK)
return status;
if (checksum_equal(&f1_info->checksum, &f2_info->checksum))
{
*success = 1;
return LF_OK;
}
}
while(!hit_file_end(f2_info));
return LF_OK;
}
status_t advance_location(file_info_t *const file)
{
status_t _status = LF_INTERNAL_ERROR;
FAIL_PRED(hit_file_end(file), LF_INTERNAL_ERROR);
if (hit_buffer_end(file))
FAIL_FORWARD(populate_forwards(file));
add_char_checksum(&file->checksum,
get_byte(file, -checksum_length(&file->checksum)),
get_byte(file, 0));
++file->internal_offset;
return LF_OK;
fail:
return _status;
}
status_t validate_match(file_info_t *const f1_info, file_info_t *const f2_info, int *const is_valid)
{
status_t _status = LF_INTERNAL_ERROR;
const size_t cs_length = checksum_length(&f1_info->checksum);
assert(cs_length == checksum_length(&f2_info->checksum));
FAIL_SYS(fseeko(f1_info->file, f1_info->block_offset + f1_info->internal_offset - cs_length, SEEK_SET) == -1);
FAIL_SYS(fseeko(f2_info->file, f2_info->block_offset + f2_info->internal_offset - cs_length, SEEK_SET) == -1);
match_info_t match_info;
FAIL_FORWARD(compute_match_info(f1_info->file, f2_info->file, &match_info));
*is_valid = (match_info.matching_bytes == match_info.total_bytes);
return LF_OK;
fail:
return _status;
}
status_t get_match_info(file_info_t *const f1_info, file_info_t *const f2_info, match_info_t *const info)
{
status_t _status = LF_INTERNAL_ERROR;
const off_t f2_offset = characters_handled(f2_info);
const off_t f1_start = f1_info->total_length - (f2_offset > f1_info->total_length ? f1_info->total_length : f2_offset);
const off_t f2_start = f2_offset - (f1_info->total_length - f1_start);
FAIL_SYS(fseeko(f1_info->file, f1_start, SEEK_SET) == -1);
FAIL_SYS(fseeko(f2_info->file, f2_start, SEEK_SET) == -1);
FAIL_FORWARD(compute_match_info(f1_info->file, f2_info->file, info));
return LF_OK;
fail:
return _status;
}
status_t compute_match_info(FILE *const f1, FILE *const f2, match_info_t *const info)
{
status_t _status = LF_INTERNAL_ERROR;
info->matching_bytes = 0;
info->total_bytes = 0;
unsigned char *buffer1 = NULL;
unsigned char *buffer2 = NULL;
FAIL_SYS((buffer1 = malloc(BUFFER_SIZE)) == NULL);
FAIL_SYS((buffer2 = malloc(BUFFER_SIZE)) == NULL);
while(!feof(f1) && !feof(f2))
{
const size_t read1 = fread(buffer1, 1, BUFFER_SIZE, f1);
FAIL_SYS(read1 != BUFFER_SIZE && ferror(f1));
const size_t read2 = fread(buffer2, 1, BUFFER_SIZE, f2);
FAIL_SYS(read2 != BUFFER_SIZE && ferror(f2));
const size_t length = (read1 < read2 ? read1 : read2);
info->total_bytes += length;
long offset = length - 1;
while(offset >=0 && (buffer1[offset] == buffer2[offset]))
--offset;
if (offset == -1)
info->matching_bytes += length;
else
info->matching_bytes = length - offset - 1;
}
_status = LF_OK;
fail:
free(buffer1);
free(buffer2);
return _status;
}
status_t write_merged_file(file_info_t *const f1_info, file_info_t *const f2_info, FILE *const out)
{
status_t _status = LF_INTERNAL_ERROR;
unsigned char *buffer = NULL;
FAIL_SYS(fseeko(f1_info->file, 0, SEEK_SET) == -1);
FAIL_SYS((buffer = malloc(BUFFER_SIZE)) == NULL);
size_t read;
do
{
read = fread(buffer, 1, BUFFER_SIZE, f1_info->file);
FAIL_SYS(read != BUFFER_SIZE && ferror(f1_info->file));
const size_t written = fwrite(buffer, 1, read, out);
FAIL_SYS(written != read);
}
while(read != 0);
FAIL_SYS(fseeko(f2_info->file, f2_info->block_offset + f2_info->internal_offset, SEEK_SET) == -1);
do
{
read = fread(buffer, 1, BUFFER_SIZE, f2_info->file);
FAIL_SYS(read != BUFFER_SIZE && ferror(f2_info->file));
const size_t written = fwrite(buffer, 1, read, out);
FAIL_SYS(written != read);
}
while(read != 0);
_status=LF_OK;
fail:
free(buffer);
return _status;
}