Scrolling and file load working

csedit.c

@@ -1,12 +1,17 @@
 //
 // includes
 // --------
+#define _DEFAULT_SOURCE
+#define _BSD_SOURCE
+#define _GNU_SOURCE
+
 #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>
 
@@ -34,16 +39,25 @@ enum editorKey {
 // data
 // ----
 
+typedef struct erow {
+  int size;
+  char *chars;
+} erow;
+
 struct editorConfig {
-  struct termios orig_termios;
   enum editorMode mode;
+  int rowoff;
   int cx, cy;
   int screenRows;
   int screenCols;
+  int numRows;
+  erow *row;
+  struct termios orig_termios;
 };
 
 struct editorConfig E;
 
+
 //
 // terminal
 // --------
@@ -159,6 +173,42 @@ int getWindowSize(int *rows, int *cols) {
   return 0;
 }
 
+//
+// row ops
+// -------
+
+void editorAppendRow(char *s, size_t len) {
+  E.row = realloc(E.row, sizeof(erow) * (E.numRows + 1));
+
+  int at = E.numRows;
+  E.row[at].size = len;
+  E.row[at].chars = malloc(len + 1);
+  memcpy(E.row[at].chars, s, len);
+  E.row[at].chars[len] = '\0';
+  E.numRows++;
+}
+
+//
+// file io
+// -------
+
+void editorOpen(char *filename) {
+  FILE *fp = fopen(filename, "r");
+  if (!fp) die("Open file");
+
+  char *line = NULL;
+  size_t linecap = 0;
+  ssize_t linelen;
+  while ((linelen = getline(&line, &linecap, fp)) != -1) {
+    while (linelen > 0 && (line[linelen - 1] == '\n' || line[linelen - 1] == '\r'))
+      linelen--;
+    editorAppendRow(line, linelen);
+
+  }
+  free(line);
+  fclose(fp);
+}
+
 //
 // append buffer
 // -------------
@@ -185,22 +235,38 @@ void abFree(struct abuf *ab) {
 //
 // output
 // ------
+void editorScroll() {
+  if (E.cy < E.rowoff) {
+    E.rowoff = E.cy;
+  }
+  if (E.cy >= E.rowoff + E.screenRows) {
+    E.rowoff = E.cy - E.screenRows + 1;
+  }
+}
+
 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), "[ cs edit ] - version %s", CSEDIT_VERSION);
-      if (welcomelen > E.screenCols) welcomelen = E.screenCols;
-      int padding = (E.screenCols - welcomelen) / 2;
-      if (padding) {
+    int filerow = y + E.rowoff;
+    if (filerow >= E.numRows) {
+      if (E.numRows == 0 && y == E.screenRows / 3) {
+        char welcome[80];
+        int welcomelen = snprintf(welcome, sizeof(welcome), "[ cs edit ] - version %s", CSEDIT_VERSION);
+        if (welcomelen > E.screenCols) welcomelen = E.screenCols;
+        int padding = (E.screenCols - welcomelen) / 2;
+        if (padding) {
+          abAppend(ab, "~", 1);
+          padding--;
+        }
+        while (padding--) abAppend(ab, " ", 1); 
+        abAppend(ab, welcome, welcomelen);
+      } else {
         abAppend(ab, "~", 1);
-        padding--;
       }
-      while (padding--) abAppend(ab, " ", 1); 
-      abAppend(ab, welcome, welcomelen);
     } else {
-      abAppend(ab, "~", 1);
+      int len = E.row[filerow].size;
+      if (len > E.screenCols) len = E.screenCols;
+      abAppend(ab, E.row[filerow].chars, len);
     }
 
     abAppend(ab, "\033[K", 3);
@@ -212,6 +278,8 @@ void editorDrawRows(struct abuf *ab) {
 }
 
 void editorRefreshScreen() {
+  editorScroll();
+
   struct abuf ab = ABUF_INIT;
 
   abAppend(&ab, "\033[?25l", 6);
@@ -219,7 +287,7 @@ void editorRefreshScreen() {
   editorDrawRows(&ab);
 
   char buf[32];
-  snprintf(buf, sizeof(buf), "\033[%d;%dH", E.cy + 1, E.cx + 1);
+  snprintf(buf, sizeof(buf), "\033[%d;%dH", (E.cy - E.rowoff) + 1, E.cx + 1);
   abAppend(&ab, buf, strlen(buf));
 
   abAppend(&ab, "\033[?25h", 6);
@@ -235,7 +303,7 @@ void editorMoveCursor(int key) {
   switch (key) {
     case 'j':
     case ARROW_DOWN:
-      if (E.cy != E.screenRows - 1) {
+      if (E.cy < E.numRows) {
         E.cy++;
       }
       break;
@@ -285,6 +353,13 @@ void editorCommandKp(int c) {
     case 'l':
       editorMoveCursor(c);
       break;
+    case 'g':
+      E.cy = 0;
+      break;
+    case 'G':
+      E.cy = E.numRows - E.screenRows - 1;
+      editorPageCursor(PAGE_DOWN);
+      break;
     case 'i':
       E.mode = InputMode;
       break;
@@ -345,14 +420,20 @@ void editorProcessKeypress() {
 // ----
 void initEditor() {
   E.mode = CommandMode;
+  E.rowoff = 0;
+  E.numRows = 0;
+  E.row = NULL;
   E.cx = 0;
   E.cy = 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();