X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/math/mpscan.c

diff --git a/math/mpscan.c b/math/mpscan.c
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+++ b/math/mpscan.c
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+/* -*-c-*-
+ *
+ * Sequential bit scan of multiprecision integers
+ *
+ * (c) 1999 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of Catacomb.
+ *
+ * Catacomb is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * Catacomb 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 Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with Catacomb; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include "mpscan.h"
+
+/*----- Right-to-left scanning --------------------------------------------*/
+
+/* --- @mpscan_initx@ --- *
+ *
+ * Arguments:	@mpscan *m@ = pointer to bitscanner structure
+ *		@const mpw *v, *vl@ = vector of words to scan
+ *
+ * Returns:	---
+ *
+ * Use:		Initializes a bitscanner from a low-level vector-and-length
+ *		representation of an integer.  Initially no bit is ready; you
+ *		must call @mpscan_step@ before anything useful will come
+ *		out.
+ */
+
+void mpscan_initx(mpscan *m, const mpw *v, const mpw *vl)
+{
+  MPSCAN_INITX(m, v, vl);
+}
+
+/* --- @mpscan_step@ --- *
+ *
+ * Arguments:	@mpscan *m@ = pointer to bitscanner
+ *
+ * Returns:	Nonzero if there is another bit to read.
+ *
+ * Use:		Steps on to the next bit in the integer.  The macro version
+ *		evaluates its argument multiple times.
+ */
+
+int mpscan_step(mpscan *m) { return (MPSCAN_STEP(m)); }
+
+/* --- @mpscan_bit@ --- *
+ *
+ * Arguments:	@const mpscan *m@ = pointer to bitscanner
+ *
+ * Returns:	The value of the current bit.
+ *
+ * Use:		Reads the value of the current bit looked at by a
+ *		bitscanner.
+ */
+
+int mpscan_bit(const mpscan *m) { return (MPSCAN_BIT(m)); }
+
+/*----- Left-to right-scanning --------------------------------------------*/
+
+/* --- @mpscan_rinitx@ --- *
+ *
+ * Arguments:	@mpscan *m@ = pointer to bitscanner structure
+ *		@const mpw *v, *vl@ = vector of words to scan
+ *
+ * Returns:	---
+ *
+ * Use:		Initializes a reverse bitscanner from a low-level
+ *		vector-and-length representation of an integer.  Initially no
+ *		bit is ready; you must call @mpscan_rstep@ before anything
+ *		useful will come out.
+ */
+
+void mpscan_rinitx(mpscan *m, const mpw *v, const mpw *vl)
+{
+  MPSCAN_RINITX(m, v, vl);
+}
+
+/* --- @mpscan_rstep@ --- *
+ *
+ * Arguments:	@mpscan *m@ = pointer to bitscanner
+ *
+ * Returns:	Nonzero if there is another bit to read.
+ *
+ * Use:		Steps on to the next bit in the integer.  The macro version
+ *		evaluates its argument multiple times.
+ */
+
+int mpscan_rstep(mpscan *m) { return (MPSCAN_RSTEP(m)); }
+
+/* --- @mpscan_rbit@ --- *
+ *
+ * Arguments:	@const mpscan *m@ = pointer to bitscanner
+ *
+ * Returns:	The value of the current bit.
+ *
+ * Use:		Reads the value of the current bit looked at by a
+ *		reverse bitscanner.
+ */
+
+int mpscan_rbit(const mpscan *m) { return (MPSCAN_RBIT(m)); }
+
+/*----- That's all, folks -------------------------------------------------*/