1 files changed, 88 insertions, 0 deletions

diff --git a/libbb/inode_hash.c b/libbb/inode_hash.c
new file mode 100644
index 000000000..2ac1623f4
--- /dev/null
+++ b/libbb/inode_hash.c
@@ -0,0 +1,88 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * Copyright (C) many different people.
+ * If you wrote this, please acknowledge your work.
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "libbb.h"
+
+#define HASH_SIZE       311             /* Should be prime */
+#define hash_inode(i)   ((i) % HASH_SIZE)
+
+typedef struct ino_dev_hash_bucket_struct {
+  struct ino_dev_hash_bucket_struct *next;
+  ino_t ino;
+  dev_t dev;
+  char name[1];
+} ino_dev_hashtable_bucket_t;
+
+static ino_dev_hashtable_bucket_t *ino_dev_hashtable[HASH_SIZE];
+
+/*
+ * Return 1 if statbuf->st_ino && statbuf->st_dev are recorded in
+ * `ino_dev_hashtable', else return 0
+ *
+ * If NAME is a non-NULL pointer to a character pointer, and there is
+ * a match, then set *NAME to the value of the name slot in that
+ * bucket.
+ */
+int is_in_ino_dev_hashtable(const struct stat *statbuf, char **name)
+{
+        ino_dev_hashtable_bucket_t *bucket;
+
+        bucket = ino_dev_hashtable[hash_inode(statbuf->st_ino)];
+        while (bucket != NULL) {
+          if ((bucket->ino == statbuf->st_ino) &&
+                  (bucket->dev == statbuf->st_dev))
+          {
+                if (name) *name = bucket->name;
+                return 1;
+          }
+          bucket = bucket->next;
+        }
+        return 0;
+}
+
+/* Add statbuf to statbuf hash table */
+void add_to_ino_dev_hashtable(const struct stat *statbuf, const char *name)
+{
+        int i;
+        size_t s;
+        ino_dev_hashtable_bucket_t *bucket;
+
+        i = hash_inode(statbuf->st_ino);
+        s = name ? strlen(name) : 0;
+        bucket = xmalloc(sizeof(ino_dev_hashtable_bucket_t) + s);
+        bucket->ino = statbuf->st_ino;
+        bucket->dev = statbuf->st_dev;
+        if (name)
+                strcpy(bucket->name, name);
+        else
+                bucket->name[0] = '\0';
+        bucket->next = ino_dev_hashtable[i];
+        ino_dev_hashtable[i] = bucket;
+}
+
+#ifdef CONFIG_FEATURE_CLEAN_UP
+/* Clear statbuf hash table */
+void reset_ino_dev_hashtable(void)
+{
+        int i;
+        ino_dev_hashtable_bucket_t *bucket;
+
+        for (i = 0; i < HASH_SIZE; i++) {
+                while (ino_dev_hashtable[i] != NULL) {
+                        bucket = ino_dev_hashtable[i]->next;
+                        free(ino_dev_hashtable[i]);
+                        ino_dev_hashtable[i] = bucket;
+                }
+        }
+}
+#endif