The previous algorithm would scan for all primes for a given number, which takes needlessly long.
Signed-off-by: Rolf Eike Beer <e...@sf-mail.de>
---
eclass/qmail.eclass | 45 ++++++++++++---------------------------------
1 file changed, 12 insertions(+), 33 deletions(-)
diff --git a/eclass/qmail.eclass b/eclass/qmail.eclass
index f42f0491515..aaec205a6bd 100644
--- a/eclass/qmail.eclass
+++ b/eclass/qmail.eclass
@@ -20,46 +20,25 @@ GENQMAIL_S="${WORKDIR}"/genqmail-${GENQMAIL_PV}
QMAIL_SPP_F=qmail-spp-${QMAIL_SPP_PV}.tar.gz
QMAIL_SPP_S="${WORKDIR}"/qmail-spp-${QMAIL_SPP_PV}
-# @FUNCTION: primes
-# @USAGE: <min> <max>
-# @DESCRIPTION:
-# Prints a list of primes between min and max inclusive
-# Note: this functions gets very slow when used with large numbers.
-primes() {
- local min=${1} max=${2}
- local result= primelist=2 i p
-
- [[ ${min} -le 2 ]] && result="${result} 2"
-
- for ((i = 3; i <= max; i += 2))
- do
- for p in ${primelist}
- do
- [[ $[i % p] == 0 || $[p * p] -gt ${i} ]] && \
- break
- done
- if [[ $[i % p] != 0 ]]
- then
- primelist="${primelist} ${i}"
- [[ ${i} -ge ${min} ]] && \
- result="${result} ${i}"
- fi
- done
-
- echo ${result}
-}
-
-# @FUNCTION: is_prima
+# @FUNCTION: is_prime
# @USAGE: <number>
# @DESCRIPTION:
# Checks wether a number is a prime number
is_prime() {
local number=${1} i
- for i in $(primes ${number} ${number})
+
+ if [[ $[number % 2] == 0 ]]; then
+ return 1
+ fi
+
+ for ((i = 3; i * i <= number; i += 2))
do
- [[ ${i} == ${number} ]] && return 0
+ if [[ $[number % i ] == 0 ]]; then
+ return 1
+ fi
done
- return 1
+
+ return 0
}
dospp() {
--
2.26.2
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