Add an internal hivex header file.

[hivex.git] / lib / hivex-internal.h

diff --git a/lib/hivex-internal.h b/lib/hivex-internal.h
new file mode 100644 (file)
index 0000000..dc23ba5
--- /dev/null
+++ b/lib/hivex-internal.h
@@ -0,0 +1,74 @@
+/* hivex internal header
+ * Copyright (C) 2009-2011 Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef HIVEX_INTERNAL_H_
+#define HIVEX_INTERNAL_H_
+
+#include <stddef.h>
+
+struct hive_h {
+  char *filename;
+  int fd;
+  size_t size;
+  int msglvl;
+  int writable;
+
+  /* Registry file, memory mapped if read-only, or malloc'd if writing. */
+  union {
+    char *addr;
+    struct ntreg_header *hdr;
+  };
+
+  /* Use a bitmap to store which file offsets are valid (point to a
+   * used block).  We only need to store 1 bit per 32 bits of the file
+   * (because blocks are 4-byte aligned).  We found that the average
+   * block size in a registry file is ~50 bytes.  So roughly 1 in 12
+   * bits in the bitmap will be set, making it likely a more efficient
+   * structure than a hash table.
+   */
+  char *bitmap;
+#define BITMAP_SET(bitmap,off) (bitmap[(off)>>5] |= 1 << (((off)>>2)&7))
+#define BITMAP_CLR(bitmap,off) (bitmap[(off)>>5] &= ~ (1 << (((off)>>2)&7)))
+#define BITMAP_TST(bitmap,off) (bitmap[(off)>>5] & (1 << (((off)>>2)&7)))
+#define IS_VALID_BLOCK(h,off)               \
+  (((off) & 3) == 0 &&                      \
+   (off) >= 0x1000 &&                       \
+   (off) < (h)->size &&                     \
+   BITMAP_TST((h)->bitmap,(off)))
+
+  /* Fields from the header, extracted from little-endianness hell. */
+  size_t rootoffs;              /* Root key offset (always an nk-block). */
+  size_t endpages;              /* Offset of end of pages. */
+  int64_t last_modified;        /* mtime of base block. */
+
+  /* For writing. */
+  size_t endblocks;             /* Offset to next block allocation (0
+                                   if not allocated anything yet). */
+};
+
+#define STREQ(a,b) (strcmp((a),(b)) == 0)
+#define STRCASEEQ(a,b) (strcasecmp((a),(b)) == 0)
+#define STRNEQ(a,b) (strcmp((a),(b)) != 0)
+#define STRCASENEQ(a,b) (strcasecmp((a),(b)) != 0)
+#define STREQLEN(a,b,n) (strncmp((a),(b),(n)) == 0)
+#define STRCASEEQLEN(a,b,n) (strncasecmp((a),(b),(n)) == 0)
+#define STRNEQLEN(a,b,n) (strncmp((a),(b),(n)) != 0)
+#define STRCASENEQLEN(a,b,n) (strncasecmp((a),(b),(n)) != 0)
+#define STRPREFIX(a,b) (strncmp((a),(b),strlen((b))) == 0)
+
+#endif /* HIVEX_INTERNAL_H_ */