lib/libalpm/filelist.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

/*
 *  filelist.c
 *
 *  Copyright (c) 2012-2016 Pacman Development Team <pacman-dev@archlinux.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <limits.h>
#include <string.h>
#include <sys/stat.h>

/* libalpm */
#include "filelist.h"
#include "util.h"

/* Returns the difference of the provided two lists of files.
 * Pre-condition: both lists are sorted!
 * When done, free the list but NOT the contained data.
 */
alpm_list_t *_alpm_filelist_difference(alpm_filelist_t *filesA,
                alpm_filelist_t *filesB)
{
        alpm_list_t *ret = NULL;
        size_t ctrA = 0, ctrB = 0;

        while(ctrA < filesA->count && ctrB < filesB->count) {
                char *strA = filesA->files[ctrA].name;
                char *strB = filesB->files[ctrB].name;

                int cmp = strcmp(strA, strB);
                if(cmp < 0) {
                        /* item only in filesA, qualifies as a difference */
                        ret = alpm_list_add(ret, strA);
                        ctrA++;
                } else if(cmp > 0) {
                        ctrB++;
                } else {
                        ctrA++;
                        ctrB++;
                }
        }

        /* ensure we have completely emptied pA */
        while(ctrA < filesA->count) {
                ret = alpm_list_add(ret, filesA->files[ctrA].name);
                ctrA++;
        }

        return ret;
}

static int _alpm_filelist_pathcmp(const char *p1, const char *p2)
{
        while(*p1 && *p1 == *p2) {
                p1++;
                p2++;
        }

        /* skip trailing '/' */
        if(*p1 == '\0' && *p2 == '/') {
                p2++;
        } else if(*p2 == '\0' && *p1 == '/') {
                p1++;
        }

        return *p1 - *p2;
}

/* Returns the intersection of the provided two lists of files.
 * Pre-condition: both lists are sorted!
 * When done, free the list but NOT the contained data.
 */
alpm_list_t *_alpm_filelist_intersection(alpm_filelist_t *filesA,
                alpm_filelist_t *filesB)
{
        alpm_list_t *ret = NULL;
        size_t ctrA = 0, ctrB = 0;
        alpm_file_t *arrA = filesA->files, *arrB = filesB->files;

        while(ctrA < filesA->count && ctrB < filesB->count) {
                const char *strA = arrA[ctrA].name, *strB = arrB[ctrB].name;
                int cmp = _alpm_filelist_pathcmp(strA, strB);
                if(cmp < 0) {
                        ctrA++;
                } else if(cmp > 0) {
                        ctrB++;
                } else {
                        /* when not directories, item in both qualifies as an intersect */
                        if(strA[strlen(strA) - 1] != '/' || strB[strlen(strB) - 1] != '/') {
                                ret = alpm_list_add(ret, arrA[ctrA].name);
                        }
                        ctrA++;
                        ctrB++;
                }
        }

        return ret;
}

/* Helper function for comparing files list entries
 */
int _alpm_files_cmp(const void *f1, const void *f2)
{
        const alpm_file_t *file1 = f1;
        const alpm_file_t *file2 = f2;
        return strcmp(file1->name, file2->name);
}

alpm_file_t SYMEXPORT *alpm_filelist_contains(alpm_filelist_t *filelist,
                const char *path)
{
        alpm_file_t key;

        if(!filelist) {
                return NULL;
        }

        key.name = (char *)path;

        return bsearch(&key, filelist->files, filelist->count,
                        sizeof(alpm_file_t), _alpm_files_cmp);
}

/* vim: set noet: */