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-rw-r--r--lib/libalpm/filelist.c109
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diff --git a/lib/libalpm/filelist.c b/lib/libalpm/filelist.c
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+/*
+ * filelist.c
+ *
+ * Copyright (c) 2012 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 <string.h>
+
+/* libalpm */
+#include "filelist.h"
+
+/* Returns a set operation on the provided two lists of files.
+ * Pre-condition: both lists are sorted!
+ * When done, free the list but NOT the contained data.
+ *
+ * Operations:
+ * DIFFERENCE - a difference operation is performed. filesA - filesB.
+ * INTERSECT - an intersection operation is performed. filesA & filesB.
+ */
+alpm_list_t *_alpm_filelist_operation(alpm_filelist_t *filesA,
+ alpm_filelist_t *filesB, enum filelist_op operation)
+{
+ alpm_list_t *ret = NULL;
+ size_t ctrA = 0, ctrB = 0;
+
+ while(ctrA < filesA->count && ctrB < filesB->count) {
+ alpm_file_t *fileA = filesA->files + ctrA;
+ alpm_file_t *fileB = filesB->files + ctrB;
+ const char *strA = fileA->name;
+ const char *strB = fileB->name;
+ /* skip directories, we don't care about them */
+ if(strA[strlen(strA)-1] == '/') {
+ ctrA++;
+ } else if(strB[strlen(strB)-1] == '/') {
+ ctrB++;
+ } else {
+ int cmp = strcmp(strA, strB);
+ if(cmp < 0) {
+ if(operation == DIFFERENCE) {
+ /* item only in filesA, qualifies as a difference */
+ ret = alpm_list_add(ret, fileA);
+ }
+ ctrA++;
+ } else if(cmp > 0) {
+ ctrB++;
+ } else {
+ if(operation == INTERSECT) {
+ /* item in both, qualifies as an intersect */
+ ret = alpm_list_add(ret, fileA);
+ }
+ ctrA++;
+ ctrB++;
+ }
+ }
+ }
+
+ /* if doing a difference, ensure we have completely emptied pA */
+ while(operation == DIFFERENCE && ctrA < filesA->count) {
+ alpm_file_t *fileA = filesA->files + ctrA;
+ const char *strA = fileA->name;
+ /* skip directories */
+ if(strA[strlen(strA)-1] != '/') {
+ ret = alpm_list_add(ret, fileA);
+ }
+ ctrA++;
+ }
+
+ 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 *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 ts=2 sw=2 noet: */