Initial commit.

Almost there. We can currently calculate an ipv4, increment, convert to
int. Working on converting to string though. Also need slash syntax
expansion still.

7 files changed, 167 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..bdd4b77
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+obj
+netexpand
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..12e0bab
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,13 @@
+out = netexpand
+warn = -Wall -Wpedantic
+cc = cc
+std = c99
+
+
+all:
+	$(cc) $(warn) -std=$(std) $(dbg) $(CFLAGS) src/common.c -c -o obj/common.o
+	$(cc) $(warn) -std=$(std) $(dbg) $(CFLAGS) src/ipv4.c -c -o obj/ipv4.o
+	$(cc) $(warn) -std=$(std) $(dbg) $(CFLAGS) src/main.c -lm obj/*.o -o $(out)
+
+debug:
+	make all dbg='-g'
diff --git a/src/common.c b/src/common.c
new file mode 100644
index 0000000..4ae509a
--- /dev/null
+++ b/src/common.c
@@ -0,0 +1,34 @@
+#include "common.h"
+
+/**
+ * The complimentary function to the posix atoi. It turns an integer into a
+ * string.
+ *
+ * @param i Integer to be converted to string
+ * @param out Output char array. Be sure it has enough room for the output
+ *            string.
+ *
+ * @return int The character count of the output char array
+ */
+int itoa(int i, char* out) {
+  // To keep track of where we are in the array
+  int n = 0;
+  while(i > 9) {
+    printf("  %d\n", i);
+    // This is some crazy simple math here
+    out[n] = (i%10) + 48;
+    // It's an int, so the last number will be stripped
+    i = i/10;
+    n++;
+  }
+  // Have to do this one more time to ensure we get the last number on
+  // zero-ended ints
+  out[n] = (i%10) + 48;
+  // Account for the last char
+  n++;
+  // Annnd the null byte
+  out[n] = '\0';
+  n++;
+  return n;
+}
+
diff --git a/src/common.h b/src/common.h
new file mode 100644
index 0000000..e358cdf
--- /dev/null
+++ b/src/common.h
@@ -0,0 +1,2 @@
+#include <stdio.h>
+int itoa(int i, char* out);
diff --git a/src/ipv4.c b/src/ipv4.c
new file mode 100644
index 0000000..2d721de
--- /dev/null
+++ b/src/ipv4.c
@@ -0,0 +1,77 @@
+#include "ipv4.h"
+
+void ipv4_new(ipv4* ip) {
+  ip->octets[0] = 0;
+  ip->octets[1] = 0;
+  ip->octets[2] = 0;
+  ip->octets[3] = 0;
+}
+
+
+unsigned int ipv4_to_int(ipv4* addr) {
+  unsigned int out;
+  out =  addr->octets[3] * 16777216; // 2^24 or 256^3
+  out += addr->octets[2] * 65536;    // 2^16 or 256^2
+  out += addr->octets[1] * 256;      // 2^8  or 256^1
+  out += addr->octets[0];            // 2^1  or na
+  
+  return out;
+}
+
+
+ipv4 str_to_ipv4(char* ip) {
+  int octet  = 3;
+  int cursor = 0;
+  int i      = 0;
+  char buf[4];
+  ipv4 out;
+
+  // Initialize
+  ipv4_new(&out);
+
+  while(ip[i] != '\0') {
+    if(ip[i] == '.') {
+      // Copy the string contents
+      strncpy(buf, &ip[cursor], i-cursor);
+      // Place the trailing null byte
+      buf[i-cursor] = '\0';
+      // Convert string octet to int
+      out.octets[octet] = atoi(buf);
+
+      cursor = i+1;
+      octet--;
+    }
+    i++;
+  }
+  // For the last octet, one more do-over
+  strncpy(buf, &ip[cursor], i-cursor);
+  buf[i-cursor] = '\0';
+  out.octets[octet] = atoi(buf);
+
+  return out;
+}
+
+
+void ipv4_to_str(ipv4* ip, char* out) {
+  int octet = 3;
+  int cursor = 0;
+
+  out[0] = '\0';
+  while(octet >= 0) {
+    int len = itoa(ip->octets[octet], &out[cursor]);
+    cursor += len;
+    out[cursor] = '.';
+    cursor++;
+    printf("%d\n", octet);
+  }
+}
+
+
+void ipv4_inc(ipv4* ip) {
+  int octet = 0;
+  if(ip->octets[octet] == 255) {
+    ip->octets[octet] = 0;
+    octet++;
+  }
+  ip->octets[octet]++;
+}
diff --git a/src/ipv4.h b/src/ipv4.h
new file mode 100644
index 0000000..0d86a8a
--- /dev/null
+++ b/src/ipv4.h
@@ -0,0 +1,13 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "common.h"
+
+typedef struct {
+  int octets[4];
+} ipv4;
+
+unsigned int ipv4_to_int(ipv4*);
+ipv4 str_to_ipv4(char*);
+void ipv4_to_str(ipv4*, char*);
+void ipv4_inc(ipv4*);
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..35f3d5a
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,26 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "ipv4.h"
+
+
+int main(int argc, char* argv[]) {
+  if(argc == 1) {
+    printf("Please specify at least one ip address.\n");
+    return 1;
+  }
+
+  char buf[20];
+
+  ipv4 ip = str_to_ipv4(argv[1]);
+  printf("%u\n", ipv4_to_int(&ip));
+
+  ipv4_inc(&ip);
+
+  ipv4_to_str(&ip, buf);
+  printf("%s\n", buf);
+
+  // char test[40];
+  // ipv4_to_str(ip, test);
+  
+  return 0;
+}