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Diffstat (limited to 'src/rand.sh')
| -rw-r--r-- | src/rand.sh | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/src/rand.sh b/src/rand.sh new file mode 100644 index 0000000..872d3fb --- /dev/null +++ b/src/rand.sh @@ -0,0 +1,42 @@ +# Linear congruential pseudorandom number generator +# +# Copyright (C) 2014 Patrick "P. J." McDermott +# +# This file is part of the ProteanOS Development Kit. +# +# The ProteanOS Development Kit 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. +# +# The ProteanOS Development Kit 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 the ProteanOS Development Kit. If not, see +# <http://www.gnu.org/licenses/>. + +rand_x=1 + +srand() +{ + local x="${1}" + + case "${x}" in + *[!0-9]*) + warn "$(get_msg 'rand_bad_x')" + return 1 + ;; + esac + + rand_x=${x} +} + +rand() +{ + # Increment, multiplier, and modulus values are those used in glibc. + rand_x=$((1103515245 * $rand_x + 12345)) + rand_x=$(($rand_x % 4294967296)) +} |