add abs, labs, llabs, and imaxabs

Signed-off-by: Mattias Andrée <maandree@operamail.com>

1 files changed, 71 insertions, 0 deletions

diff --git a/src/stdlib/abs.c b/src/stdlib/abs.c
new file mode 100644
index 0000000..13e545e
--- /dev/null
+++ b/src/stdlib/abs.c
@@ -0,0 +1,71 @@
+/**
+ * slibc — Yet another C library
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdlib.h>
+
+
+
+/**
+ * Return the absolute value of an integer.
+ * 
+ * Be aware, if the value is `INT_MIN` and
+ * `-INT_MAX != -INT_MIN`, the result will
+ * overflow, and `INT_MIN` will (probably)
+ * be returned.
+ * 
+ * @param   value  The integer.
+ * @return         The absolute value of the integer.
+ */
+int abs(int value)
+{
+  return value < 0 ? -value : value;
+}
+
+
+/**
+ * Return the absolute value of an integer.
+ * 
+ * Be aware, if the value is `LONG_MIN` and
+ * `-LONG_MAX != -LONG_MIN`, the result will
+ * overflow, and `LONG_MIN` will (probably)
+ * be returned.
+ * 
+ * @param   value  The integer.
+ * @return         The absolute value of the integer.
+ */
+long int labs(long int value)
+{
+  return value < 0 ? -value : value;
+}
+
+
+/**
+ * Return the absolute value of an integer.
+ * 
+ * Be aware, if the value is `LLONG_MIN` and
+ * `-LLONG_MAX != -LLONG_MIN`, the result will
+ * overflow, and `LLONG_MIN` will (probably)
+ * be returned.
+ * 
+ * @param   value  The integer.
+ * @return         The absolute value of the integer.
+ */
+long long int llabs(long long int value)
+{
+  return value < 0 ? -value : value;
+}
+