Start 4211 fun

Signed-off-by: Matt Strapp <matt@mattstrapp.net>

1 files changed, 62 insertions, 0 deletions

diff --git a/csci4211/ipaddress.c b/csci4211/ipaddress.c
new file mode 100644
index 0000000..662bf99
--- /dev/null
+++ b/csci4211/ipaddress.c
@@ -0,0 +1,62 @@
+// Author Name: Matt Strapp
+// Date: 2022-01-26
+// x500: strap012
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int IPv4ToInt(char *ipv4, int isBigEndian) {
+  unsigned int ipv4Int = 0;
+  short int i = 0;
+  char *chunk = strtok(ipv4, ".");
+  while (chunk != NULL) {
+    int ipv4Segment = atoi(chunk);
+    if (ipv4Segment > 255 || ipv4Segment < 0) {
+      printf("ERROR\n");
+      exit(0);
+    }
+    ipv4Int = (isBigEndian) ? (ipv4Int << 8) | ipv4Segment
+                            : (ipv4Int >> 8) + (ipv4Segment << 24);
+    i++;
+    chunk = strtok(NULL, ".");
+  }
+  if (i != 4) {
+    printf("ERROR\n");
+    exit(0);
+  }
+  return ipv4Int;
+}
+
+char *IntToIPv4(long ipv4_int, int isBigEndian) {
+  if (ipv4_int > 4294967295 || ipv4_int < 0) {
+    printf("ERROR\n");
+    exit(0);
+  }
+  char *ipv4 = (char *)calloc(16, sizeof(char));
+  int i = 0;
+  while (i < 4) {
+    int ipv4Segment = (isBigEndian) ? (ipv4_int >> (8 * (3 - i))) & 255
+                                    : (ipv4_int >> (8 * i)) & 255;
+    sprintf(ipv4 + strlen(ipv4), "%d", ipv4Segment);
+    if (i != 3)
+      sprintf(ipv4 + strlen(ipv4), ".");
+    i++;
+  }
+  return ipv4;
+}
+
+int main(int argc, char **argv) {
+  int toHuman = atoi(argv[1]);
+  int isBigEndian = atoi(argv[3]);
+  if (toHuman) {
+    long toIpv4 = strtol(argv[2], NULL, 10);
+    char *ret = IntToIPv4(toIpv4, isBigEndian);
+    printf("%s\n", ret);
+    free(ret);
+  } else {
+    unsigned int ret = IPv4ToInt(argv[2], isBigEndian);
+    printf("%u\n", ret);
+    return 0;
+  }
+}
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