cidr2ip

Small and simple program for converting a CIDR into a netmask
git clone git://git.noxz.tech/cidr2ip
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commit c9233ff08c56454f3bf8ba2dbe3ba98da8482804
parent a808568045b05c24347b8a26e523b00833d841dd
Author: z0noxz <chris@noxz.tech>
Date:   Fri, 10 Aug 2018 10:28:23 +0200

code optimization

Diffstat:
Mcidr2ip.c | 9++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/cidr2ip.c b/cidr2ip.c @@ -20,9 +20,12 @@ #include <string.h> #include <unistd.h> +const char *usage = "usage: cidr2ip <CIDR>"; + int main(int argc, char **argv) { - int ip, cidr, input_size; + int ip, cidr, + input_size; int buffer_size = 80; unsigned char mask[4]; char buffer[buffer_size]; @@ -44,12 +47,12 @@ main(int argc, char **argv) { /* no valid input, so show usage */ } else { - fprintf(stderr, "usage: cidr2ip CIDR\n"); + fprintf(stderr, "%s\n", usage); return 1; } if (sscanf(input, "%d", &cidr) == 1 && cidr >= 1 && cidr <= 32) { - ip = 4294967295 >> (32-cidr) << (32-cidr); + ip = 0xffffffffu >> (32-cidr) << (32-cidr); mask[0] = (ip >> 0) & 0xff; mask[1] = (ip >> 8) & 0xff; mask[2] = (ip >> 16) & 0xff;