From 0d16dc668e25557ba8a3b5dec3adee5b47840511 Mon Sep 17 00:00:00 2001
From: Tyrel Souza <923113+tyrelsouza@users.noreply.github.com>
Date: Wed, 20 Oct 2021 23:53:18 -0400
Subject: [PATCH] read

---
 kilo.c | 83 ++++++++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 63 insertions(+), 20 deletions(-)

diff --git a/kilo.c b/kilo.c
index 59aa7ad..e32e879 100644
--- a/kilo.c
+++ b/kilo.c
@@ -1,14 +1,15 @@
-/*** Includes ***/
+/** Includes */
 #include <ctype.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/ioctl.h>
+#include <sys/types.h>
 #include <termios.h>
 #include <unistd.h>
 
-/** defines ***/
+/** defines */
 #define TYREL_VERSION "0.0.1"
 #define CTRL_KEY(k) ((k) & 0x1f)
 
@@ -25,16 +26,23 @@ enum editorKey {
 };
 
 
-/*** data ***/
+/** data */
+typedef struct erow {
+    int size;
+    char *chars;
+} erow;
+
 struct editorConfig {
     int cx, cy;
     int screenrows;
     int screencols;
+    int numrows;
+    erow row;
     struct termios orig_termios;
 };
 struct editorConfig E;
 
-/*** terminal ***/
+/** terminal */
 void die(const char *s) {
     write(STDOUT_FILENO, "\x1b[2J", 4);
     write(STDOUT_FILENO, "\x1b[H", 3);
@@ -154,7 +162,31 @@ int getWindowSize(int *rows, int *cols) {
     }
 }
 
-/*** append buffer ***/
+/** file i/o */
+
+void editorOpen(char *filename) {
+    FILE *fp = fopen(filename, "r");
+    if (!fp) die("fopen");
+
+    char *line = NULL;
+    ssize_t linecap = 0;
+    ssize_t linelen;
+    linelen = getline(&line, &linecap, fp);
+    if (linelen != -1) {
+        while (linelen > 0 && (line[linelen - 1] == '\r' ||
+                               line[linelen - 1] == '\r'))
+            linelen--;
+        E.row.size = linelen;
+        E.row.chars = malloc(linelen + 1);
+        memcpy(E.row.chars, line, linelen);
+        E.row.chars[linelen] = '\0';
+        E.numrows = 1;
+    }
+    free(line);
+    fclose(fp);
+}
+
+/** append buffer */
 struct abuf {
     char *b;
     int len;
@@ -175,24 +207,31 @@ void abFree(struct abuf *ab) {
 }
 
 
-/*** output ***/
+/** output */
 void editorDrawRows(struct abuf *ab) {
     int y;
     for (y = 0; y < E.screenrows; y++) {
-        if (y == E.screenrows / 3) {
-            char welcome[80];
-            int welcomelen = snprintf(welcome, sizeof welcome, "Tyrel Editor -- version %s", TYREL_VERSION);
-            int padding = (E.screencols - welcomelen) / 2;
-            if (padding) {
+        if (y >= E.numrows) { // Draw rows after buffer
+            if (y == E.screenrows / 3) {
+                char welcome[80];
+                int welcomelen = snprintf(welcome, sizeof welcome, "Tyrel Editor -- version %s", TYREL_VERSION);
+                int padding = (E.screencols - welcomelen) / 2;
+                if (padding) {
+                    abAppend(ab, "~", 1);
+                    padding--;
+                }
+                while (padding--) abAppend(ab, " ", 1);
+                if (welcomelen > E.screencols) welcomelen = E.screencols;
+                abAppend(ab, welcome, welcomelen);
+            } else {
                 abAppend(ab, "~", 1);
-                padding--;
             }
-            while (padding--) abAppend(ab, " ", 1);
-            if (welcomelen > E.screencols) welcomelen = E.screencols;
-            abAppend(ab, welcome, welcomelen);
-        } else {
-            abAppend(ab, "~", 1);
+        } else { // draw buffer
+            int len = E.row.size;
+            if (len > E.screencols) len = E.screencols; // truncate if further than columns
+            abAppend(ab, E.row.chars, len);
         }
+
         abAppend(ab, "\x1b[K", 3);
         if (y < E.screenrows - 1) {
             abAppend(ab, "\r\n", 2);
@@ -216,7 +255,7 @@ void editorRefreshScreen() {
 }
 
 
-/*** input ***/
+/** input */
 void editorMoveCursor(int key) {
     switch (key) {
         case ARROW_LEFT:
@@ -275,16 +314,20 @@ void editorProcessKeypress() {
     }
 }
 
-/*** init ***/
+/** init */
 void initEditor() {
     E.cx = 0;
     E.cy = 0;
+    E.numrows = 0;
     if (getWindowSize(&E.screenrows, &E.screencols) == -1) die("getWindowSize");
 }
 
-int main() {
+int main(int argc, char *argv[]) {
     enableRawMode();
     initEditor();
+    if (argc >= 2) {
+        editorOpen(argv[1]);
+    }
 
     while (1) {
         editorRefreshScreen();