1 files changed, 71 insertions, 0 deletions
diff --git a/contrib/ntp/libntp/mstolfp.c b/contrib/ntp/libntp/mstolfp.c
new file mode 100644
index 000000000000..428f71bdbae9
--- /dev/null
+++ b/contrib/ntp/libntp/mstolfp.c
@@ -0,0 +1,71 @@
+/*
+ * mstolfp - convert an ascii string in milliseconds to an l_fp number
+ */
+#include <config.h>
+#include <stdio.h>
+#include <ctype.h>
+
+#include "ntp_fp.h"
+#include "ntp_stdlib.h"
+
+int
+mstolfp(
+	const char *str,
+	l_fp *lfp
+	)
+{
+	int        ch, neg = 0; 
+	u_int32    q, r;
+
+	/*
+	 * We understand numbers of the form:
+	 *
+	 * [spaces][-|+][digits][.][digits][spaces|\n|\0]
+	 *
+	 * This is kinda hack.  We use 'atolfp' to do the basic parsing
+	 * (after some initial checks) and then divide the result by
+	 * 1000.  The original implementation avoided that by
+	 * hacking up the input string to move the decimal point, but
+	 * that needed string manipulations prone to buffer overruns.
+	 * To avoid that trouble we do the conversion first and adjust
+	 * the result.
+	 */
+	
+	while (isspace(ch = *(const unsigned char*)str))
+		++str;
+	
+	switch (ch) {
+	    case '-': neg = TRUE;
+	    case '+': ++str;
+	    default : break;
+	}
+	
+	if (!isdigit(ch = *(const unsigned char*)str) && (ch != '.'))
+		return 0;
+	if (!atolfp(str, lfp))
+		return 0;
+
+	/* now do a chained/overlapping division by 1000 to get from
+	 * seconds to msec. 1000 is small enough to go with temporary
+	 * 32bit accus for Q and R.
+	 */
+	q = lfp->l_ui / 1000u;
+	r = lfp->l_ui - (q * 1000u);
+	lfp->l_ui = q;
+
+	r = (r << 16) | (lfp->l_uf >> 16);
+	q = r / 1000u;
+	r = ((r - q * 1000) << 16) | (lfp->l_uf & 0x0FFFFu);
+	lfp->l_uf = q << 16;
+	q = r / 1000;
+	lfp->l_uf |= q;
+	r -= q * 1000u;
+
+	/* fix sign */
+	if (neg)
+		L_NEG(lfp);
+	/* round */
+	if (r >= 500)
+		L_ADDF(lfp, (neg ? -1 : 1));
+	return 1;
+}