Formerly bitmap.c.~4~

1 files changed, 102 insertions, 2 deletions

diff --git a/ext2fs/bitmap.c b/ext2fs/bitmap.c
index b46c6dca..296c839b 100644
--- a/ext2fs/bitmap.c
+++ b/ext2fs/bitmap.c
@@ -1,5 +1,5 @@
 /*
- *  linux/fs/ext2/bitmap.c
+ *  linux/fs/ext2/bitmap.c (etc
  *
  * Copyright (C) 1992, 1993, 1994, 1995
  * Remy Card (card@masi.ibp.fr)
@@ -9,7 +9,7 @@
 
 static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
 
-unsigned long ext2_count_free (char * map, unsigned int numchars)
+unsigned long count_free (char * map, unsigned int numchars)
 {
 	unsigned int i;
 	unsigned long sum = 0;
@@ -21,3 +21,103 @@ unsigned long ext2_count_free (char * map, unsigned int numchars)
 			nibblemap[(map[i] >> 4) & 0xf];
 	return (sum);
 }
+
+/* ---------------------------------------------------------------- */
+
+static int ffz_nibble_map[] = {0, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0};
+
+inline unsigned long ffz(unsigned long word)
+{
+  int offset = 0;
+  if ((word & 0xFFFF) == 0xFFFF)
+    {
+      word >>= 16;
+      offset += 16;
+    }
+  if ((word & 0xFF) == 0xFF)
+    {
+      word >>= 8;
+      offset += 8;
+    }
+  if ((word & 0xF) == 0xF)
+    {
+      word >>= 4;
+      offset += 4;
+    }
+  return ffz_nibble_map[word] + offset;
+}
+
+/* ---------------------------------------------------------------- */
+
+/*
+ * Copyright 1994, David S. Miller (davem@caip.rutgers.edu).
+ */
+
+/* find_next_zero_bit() finds the first zero bit in a bit string of length
+ * 'size' bits, starting the search at bit 'offset'. This is largely based
+ * on Linus's ALPHA routines, which are pretty portable BTW.
+ */
+
+extern inline unsigned long
+find_next_zero_bit(void *addr, unsigned long size, unsigned long offset)
+{
+  unsigned long *p = ((unsigned long *) addr) + (offset >> 6);
+  unsigned long result = offset & ~31UL;
+  unsigned long tmp;
+
+  if (offset >= size)
+    return size;
+  size -= result;
+  offset &= 31UL;
+  if (offset) 
+    {
+      tmp = *(p++);
+      tmp |= ~0UL >> (32-offset);
+      if (size < 32)
+	goto found_first;
+      if (~tmp)
+	goto found_middle;
+      size -= 32;
+      result += 32;
+    }
+  while (size & ~32UL) 
+    {
+      if (~(tmp = *(p++)))
+	goto found_middle;
+      result += 32;
+      size -= 32;
+    }
+  if (!size)
+    return result;
+  tmp = *p;
+
+found_first:
+  tmp |= ~0UL << size;
+found_middle:
+  return result + ffz(tmp);
+}
+
+/* Linus sez that gcc can optimize the following correctly, we'll see if this
+ * holds on the Sparc as it does for the ALPHA.
+ */
+
+inline int
+find_first_zero_bit(void *buf, unsigned len)
+{
+  return find_next_zero_bit(buf, len, 0);
+}
+
+/* ---------------------------------------------------------------- */
+
+/* Returns a pointer to the first occurence of CH in the buffer BUF of len
+   LEN, or BUF + LEN if CH doesn't occur.  */
+void *memscan(void *buf, unsigned char ch, unsigned len)
+{
+  unsigned char *p = (unsigned char *)buf;
+  while (len-- > 0)
+    if (*p == ch)
+      break;
+    else
+      p++;
+  return (void *)p;
+}