Add file hashing helpers

[fio.git] / filehash.c

diff --git a/filehash.c b/filehash.c
new file mode 100644 (file)
index 0000000..1bcfc6d
--- /dev/null
+++ b/filehash.c
@@ -0,0 +1,107 @@
+#include <stdlib.h>
+#include <assert.h>
+
+#include "fio.h"
+#include "list.h"
+#include "crc/crc16.h"
+
+#define HASH_BUCKETS   512
+#define HASH_MASK      (HASH_BUCKETS - 1)
+
+unsigned int file_hash_size = HASH_BUCKETS * sizeof(struct list_head);
+
+static struct list_head *file_hash;
+static struct fio_mutex *hash_lock;
+
+static void dump_hash(void)
+{
+       struct list_head *n;
+       unsigned int i;
+
+       for (i = 0; i < HASH_BUCKETS; i++) {
+               list_for_each(n, &file_hash[i]) {
+                       struct fio_file *f;
+
+                       f = list_entry(n, struct fio_file, hash_list);
+                       printf("%d: %s\n", i, f->file_name);
+               }
+       }
+}
+
+static unsigned short hash(const char *name)
+{
+       return crc16((const unsigned char *) name, strlen(name)) & HASH_MASK;
+}
+
+void remove_file_hash(struct fio_file *f)
+{
+       fio_mutex_down(hash_lock);
+
+       if (f->flags & FIO_FILE_HASHED) {
+               assert(!list_empty(&f->hash_list));
+               list_del_init(&f->hash_list);
+               f->flags &= ~FIO_FILE_HASHED;
+       }
+
+       fio_mutex_up(hash_lock);
+}
+
+static struct fio_file *__lookup_file_hash(const char *name)
+{
+       struct list_head *bucket = &file_hash[hash(name)];
+       struct list_head *n;
+
+       list_for_each(n, bucket) {
+               struct fio_file *f = list_entry(n, struct fio_file, hash_list);
+
+               if (!strcmp(f->file_name, name)) {
+                       assert(f->fd != -1);
+                       return f;
+               }
+       }
+
+       dump_hash();
+       return NULL;
+}
+
+struct fio_file *lookup_file_hash(const char *name)
+{
+       struct fio_file *f;
+
+       fio_mutex_down(hash_lock);
+       f = __lookup_file_hash(name);
+       fio_mutex_up(hash_lock);
+       return f;
+}
+
+struct fio_file *add_file_hash(struct fio_file *f)
+{
+       struct fio_file *alias;
+
+       if (f->flags & FIO_FILE_HASHED)
+               return NULL;
+
+       INIT_LIST_HEAD(&f->hash_list);
+
+       fio_mutex_down(hash_lock);
+
+       alias = __lookup_file_hash(f->file_name);
+       if (!alias) {
+               f->flags |= FIO_FILE_HASHED;
+               list_add_tail(&f->hash_list, &file_hash[hash(f->file_name)]);
+       }
+
+       fio_mutex_up(hash_lock);
+       return alias;
+}
+
+void file_hash_init(void *ptr)
+{
+       unsigned int i;
+
+       file_hash = ptr;
+       for (i = 0; i < HASH_BUCKETS; i++)
+               INIT_LIST_HEAD(&file_hash[i]);
+
+       hash_lock = fio_mutex_init(1);
+}