From ec8b4501c7b0bfb286db7789635168d1b84f9105 Mon Sep 17 00:00:00 2001
From: Harald Welte <laforge@gnumonks.org>
Date: Sat, 20 Feb 2010 20:34:29 +0100
Subject: intial checkin of the libosmocore project

---
 src/bitvec.c | 170 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 170 insertions(+)
 create mode 100644 src/bitvec.c

(limited to 'src/bitvec.c')

diff --git a/src/bitvec.c b/src/bitvec.c
new file mode 100644
index 00000000..235c3ce1
--- /dev/null
+++ b/src/bitvec.c
@@ -0,0 +1,170 @@
+/* bit vector utility routines */
+
+/* (C) 2009 by Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+
+#include <errno.h>
+#include <stdint.h>
+
+#include <osmocore/bitvec.h>
+
+#define BITNUM_FROM_COMP(byte, bit)	((byte*8)+bit)
+
+static inline unsigned int bytenum_from_bitnum(unsigned int bitnum)
+{
+	unsigned int bytenum = bitnum / 8;
+
+	return bytenum;
+}
+
+/* convert ZERO/ONE/L/H to a bitmask at given pos in a byte */
+static uint8_t bitval2mask(enum bit_value bit, uint8_t bitnum)
+{
+	int bitval;
+
+	switch (bit) {
+	case ZERO:
+		bitval = (0 << bitnum);
+		break;
+	case ONE:
+		bitval = (1 << bitnum);
+		break;
+	case L:
+		bitval = ((0x2b ^ (0 << bitnum)) & (1 << bitnum));
+		break;
+	case H:
+		bitval = ((0x2b ^ (1 << bitnum)) & (1 << bitnum));
+		break;
+	default:
+		return 0;
+	}
+	return bitval;
+}
+
+/* check if the bit is 0 or 1 for a given position inside a bitvec */
+enum bit_value bitvec_get_bit_pos(struct bitvec *bv, unsigned int bitnr)
+{
+	unsigned int bytenum = bytenum_from_bitnum(bitnr);
+	unsigned int bitnum = 7 - (bitnr % 8);
+	uint8_t bitval;
+
+	if (bytenum >= bv->data_len)
+		return -EINVAL;
+
+	bitval = bitval2mask(ONE, bitnum);
+
+	if (bv->data[bytenum] & bitval)
+		return ONE;
+
+	return ZERO;
+}
+
+/* get the Nth set bit inside the bit vector */
+unsigned int bitvec_get_nth_set_bit(struct bitvec *bv, unsigned int n)
+{
+	unsigned int i, k = 0;
+
+	for (i = 0; i < bv->data_len*8; i++) {
+		if (bitvec_get_bit_pos(bv, i) == ONE) {
+			k++;
+			if (k == n)
+				return i;
+		}
+	}
+
+	return 0;
+}
+
+/* set the bit at a given position inside a bitvec */
+int bitvec_set_bit_pos(struct bitvec *bv, unsigned int bitnr,
+			enum bit_value bit)
+{
+	unsigned int bytenum = bytenum_from_bitnum(bitnr);
+	unsigned int bitnum = 7 - (bitnr % 8);
+	uint8_t bitval;
+
+	if (bytenum >= bv->data_len)
+		return -EINVAL;
+
+	/* first clear the bit */
+	bitval = bitval2mask(ONE, bitnum);
+	bv->data[bytenum] &= ~bitval;
+
+	/* then set it to desired value */
+	bitval = bitval2mask(bit, bitnum);
+	bv->data[bytenum] |= bitval;
+
+	return 0;
+}
+
+/* set the next bit inside a bitvec */
+int bitvec_set_bit(struct bitvec *bv, enum bit_value bit)
+{
+	int rc;
+
+	rc = bitvec_set_bit_pos(bv, bv->cur_bit, bit);
+	if (!rc)
+		bv->cur_bit++;
+
+	return rc;
+}
+
+/* set multiple bits (based on array of bitvals) at current pos */
+int bitvec_set_bits(struct bitvec *bv, enum bit_value *bits, int count)
+{
+	int i, rc;
+
+	for (i = 0; i < count; i++) {
+		rc = bitvec_set_bit(bv, bits[i]);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
+
+/* set multiple bits (based on numeric value) at current pos */
+int bitvec_set_uint(struct bitvec *bv, unsigned int ui, int num_bits)
+{
+	int i, rc;
+
+	for (i = 0; i < num_bits; i++) {
+		int bit = 0;
+		if (ui & (1 << (num_bits - i - 1)))
+			bit = 1;
+		rc = bitvec_set_bit(bv, bit);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
+
+/* pad all remaining bits up to num_bits */
+int bitvec_spare_padding(struct bitvec *bv, unsigned int up_to_bit)
+{
+	unsigned int i;
+
+	for (i = bv->cur_bit; i <= up_to_bit; i++)
+		bitvec_set_bit(bv, L);
+
+	return 0;
+}
-- 
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