added instert line command

c_insertline.c

@@ -0,0 +1,22 @@
+void
+c_insertline(char *c) {
+        c += 2;
+        int line = atoi(c);
+        for(; *c != 0 && *c != ' '; c++);
+        c += 1; // start of text
+        Row *r = b_getline(buffer, line);
+        if (r == NULL) {
+                printf("%i, invalid line.\n", line);
+                return;
+        }
+        // ^ same as write line
+        r = b_insert(r);
+        // v same as write line
+        int i = 0;
+        for (;i < ROW_SIZE && c[i] != 0; i++) {
+                r->text[i] = c[i];
+        }
+        for(;i < ROW_SIZE; i++) {
+                r->text[i] = 0;
+        }
+}

commands.c

@@ -7,3 +7,4 @@ NULL,
 ['q'] = NULL,
 ['Q'] = c_quit,
 ['S'] = c_save,
+['i'] = c_insertline,

efn.c

@@ -21,3 +21,4 @@
 #include "b_getline.c"
 
 #include "c_save.c"
+#include "c_insertline.c"

efn.h

@@ -13,3 +13,4 @@ Row *b_insert(Row *);
 Row *b_getline(Row *, int);
 void c_writeline(char *);
 void c_save(char*);
+void c_insertline(char *);