From: Karel Zak <kzak@redhat.com>
Date: Thu, 13 Oct 2022 08:25:25 +0000 (+0200)
Subject: libsmartcols: use local sqrt() implemenation
X-Git-Tag: v2.39-rc1~460
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ee4cab98def0f263a3929bb9b8a2282c00ddacaf;p=thirdparty%2Futil-linux.git

libsmartcols: use local sqrt() implemenation

We do not need any powerful and precise sqrt implementation, so
let's use local code rather than depend on an external library.

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/libsmartcols/src/Makemodule.am b/libsmartcols/src/Makemodule.am
index db3e68528f..2bb19fdbde 100644
--- a/libsmartcols/src/Makemodule.am
+++ b/libsmartcols/src/Makemodule.am
@@ -23,7 +23,7 @@ libsmartcols_la_SOURCES= \
 	libsmartcols/src/walk.c \
 	libsmartcols/src/init.c
 
-libsmartcols_la_LIBADD = $(LDADD) $(MATH_LIBS) libcommon.la
+libsmartcols_la_LIBADD = $(LDADD) libcommon.la
 
 libsmartcols_la_CFLAGS = \
 	$(AM_CFLAGS) \
diff --git a/libsmartcols/src/calculate.c b/libsmartcols/src/calculate.c
index b55d6c2ec9..b500d33945 100644
--- a/libsmartcols/src/calculate.c
+++ b/libsmartcols/src/calculate.c
@@ -1,8 +1,6 @@
 #include "smartcolsP.h"
 #include "mbsalign.h"
 
-#include <math.h>
-
 static void dbg_column(struct libscols_table *tb, struct libscols_column *cl)
 {
 	struct libscols_wstat *st;
@@ -87,6 +85,17 @@ static int walk_count_cell_width(struct libscols_table *tb,
 	return count_cell_width(tb, ln, cl, (struct ul_buffer *) data);
 }
 
+static double sqrtroot(double num)
+{
+	double tmp = 0, sq = num / 2;
+
+	while (sq != tmp){
+		tmp = sq;
+		sq = (num / tmp + tmp) / 2;
+	}
+	return sq;
+}
+
 static void count_column_deviation(struct libscols_table *tb, struct libscols_column *cl)
 {
 	struct libscols_wstat *st;
@@ -124,7 +133,7 @@ static void count_column_deviation(struct libscols_table *tb, struct libscols_co
 		}
 
 		variance = st->width_sqr_sum / (n - 1);
-		st->width_deviation = sqrt(variance);
+		st->width_deviation = sqrtroot(variance);
 	}
 
 	DBG(COL, ul_debugobj(cl, "%15s avg=%g, deviation=%g",