src/rand.sh: New file

2 files changed, 45 insertions, 0 deletions

diff --git a/src/local.mk b/src/local.mk
index e6679af..0ce1d77 100644
--- a/src/local.mk
+++ b/src/local.mk
@@ -3,6 +3,7 @@ firman_SOURCES += \
 	src/dist.sh \
 	src/flashrom.sh \
 	src/main.sh \
+	src/rand.sh \
 	src/ui.sh
 
 include $(top_srcdir)/src/action/local.mk
diff --git a/src/rand.sh b/src/rand.sh
new file mode 100644
index 0000000..160e49e
--- /dev/null
+++ b/src/rand.sh
@@ -0,0 +1,44 @@
+# Linear congruential pseudorandom number generator
+#
+# Copyright (C) 2014  Patrick "P. J." McDermott
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+rand_x=1
+rand_seeded=false
+
+srand()
+{
+	local x="${1}"
+	shift 1
+
+	rand_x=${x}
+	rand_seeded=true
+
+	return 0
+}
+
+rand()
+{
+	# Automatically seed the LCG.
+	if ! ${rand_seeded}; then
+		srand $(expr ${$} + $(date '+%s'))
+	fi
+
+	# Increment, multiplier, and modulus values are those used in glibc.
+	rand_x=$((1103515245 * $rand_x + 12345))
+	rand_x=$(($rand_x % 4294967296))
+
+	return 0
+}