X-Git-Url: https://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Fbitmap%2Fbitmap.c;fp=ccan%2Fbitmap%2Fbitmap.c;h=a6058117985f8259aee36592993b4fd0e9ab3fce;hb=4e7f97a92ef78a956425f8d0d03e57230e131618;hp=0000000000000000000000000000000000000000;hpb=d91a3b8b416ed12bf7c0d5b0bda902b7ae769a40;p=ccan

diff --git a/ccan/bitmap/bitmap.c b/ccan/bitmap/bitmap.c
new file mode 100644
index 00000000..a6058117
--- /dev/null
+++ b/ccan/bitmap/bitmap.c
@@ -0,0 +1,60 @@
+/* Licensed under LGPLv2.1+ - see LICENSE file for details */
+
+#include "config.h"
+
+#include <ccan/bitmap/bitmap.h>
+
+#include <assert.h>
+
+#define BIT_ALIGN_DOWN(n)	((n) & ~(BITMAP_WORD_BITS - 1))
+#define BIT_ALIGN_UP(n)		BIT_ALIGN_DOWN((n) + BITMAP_WORD_BITS - 1)
+
+void bitmap_zero_range(bitmap *bitmap, unsigned long n, unsigned long m)
+{
+	unsigned long an = BIT_ALIGN_UP(n);
+	unsigned long am = BIT_ALIGN_DOWN(m);
+	bitmap_word headmask = -1ULL >> (n % BITMAP_WORD_BITS);
+	bitmap_word tailmask = ~(-1ULL >> (m % BITMAP_WORD_BITS));
+
+	assert(m >= n);
+
+	if (am < an) {
+		BITMAP_WORD(bitmap, n) &= ~bitmap_bswap(headmask & tailmask);
+		return;
+	}
+
+	if (an > n)
+		BITMAP_WORD(bitmap, n) &= ~bitmap_bswap(headmask);
+
+	if (am > an)
+		memset(&BITMAP_WORD(bitmap, an), 0,
+		       (am - an) / BITMAP_WORD_BITS * sizeof(bitmap_word));
+
+	if (m > am)
+		BITMAP_WORD(bitmap, m) &= ~bitmap_bswap(tailmask);
+}
+
+void bitmap_fill_range(bitmap *bitmap, unsigned long n, unsigned long m)
+{
+	unsigned long an = BIT_ALIGN_UP(n);
+	unsigned long am = BIT_ALIGN_DOWN(m);
+	bitmap_word headmask = -1ULL >> (n % BITMAP_WORD_BITS);
+	bitmap_word tailmask = ~(-1ULL >> (m % BITMAP_WORD_BITS));
+
+	assert(m >= n);
+
+	if (am < an) {
+		BITMAP_WORD(bitmap, n) |= bitmap_bswap(headmask & tailmask);
+		return;
+	}
+
+	if (an > n)
+		BITMAP_WORD(bitmap, n) |= bitmap_bswap(headmask);
+
+	if (am > an)
+		memset(&BITMAP_WORD(bitmap, an), 0xff,
+		       (am - an) / BITMAP_WORD_BITS * sizeof(bitmap_word));
+
+	if (m > am)
+		BITMAP_WORD(bitmap, m) |= bitmap_bswap(tailmask);
+}