CE improve editor performace by reducing amount of copying

ce/ce.c

@@ -147,7 +147,7 @@ void app_main (void) {
 
     mprintf ("\n");
 
-    render = gapbuffer_get_string (&warena_malloc, &arena, &edit_line.gb);
+    render = gapbuffer_string_at (&warena_malloc, &arena, &edit_line.gb, 0);
 
     if (render != NULL)
       exec_line (render);

ce/edit.c

@@ -123,19 +123,40 @@ void edit_start (const char* file_path, const char* text) {
       bbptr += w;
       bb_remaining -= w;
 
-      char* render = gapbuffer_get_string (&warena_malloc, &temp_arena, &line->gb);
-      size_t len = strlen (render);
+      size_t part1_len = line->gb.gap_start;
+      size_t part2_len = line->gb.size - line->gb.gap_end;
 
-      if (len > editor.col_offset) {
-        char* visible = render + editor.col_offset;
-        size_t visible_len = len - editor.col_offset;
+      size_t current_col = 0;
 
-        if (visible_len > cols)
-          visible_len = cols;
+      if (part1_len > editor.col_offset) {
+        size_t start = editor.col_offset;
+        size_t len = part1_len - start;
 
-        w = snprintf (bbptr, bb_remaining, "%.*s", (int)visible_len, visible);
+        if (len > cols)
+          len = cols;
+
+        w = snprintf (bbptr, bb_remaining, "%.*s", (int)len, &line->gb.buffer[start]);
         bbptr += w;
         bb_remaining -= w;
+        current_col += len;
+      }
+
+      if (current_col < cols && part2_len > 0) {
+        size_t skip = 0;
+        if (editor.col_offset > part1_len)
+          skip = editor.col_offset - part1_len;
+
+        if (skip < part2_len) {
+          size_t len = part2_len - skip;
+
+          if (current_col + len > cols)
+            len = cols - current_col;
+
+          w = snprintf (bbptr, bb_remaining, "%.*s", (int)len,
+                        &line->gb.buffer[line->gb.gap_end + skip]);
+          bbptr += w;
+          bb_remaining -= w;
+        }
       }
 
       w = snprintf (bbptr, bb_remaining, ANSIQ_SCR_CLR2END "\n");
@@ -166,31 +187,35 @@ void edit_start (const char* file_path, const char* text) {
     uint8_t ch = 0;
     mail_receive (&ch, 1);
 
-    gapbuffer_move (&editor.current_line->gb, editor.cursor.col);
-
     switch (ch) {
     case '\b':
       if (editor.cursor.col > 0) {
+        gapbuffer_move (&editor.current_line->gb, editor.cursor.col);
         editor.cursor.col--;
         gapbuffer_backspace (&editor.current_line->gb);
       }
       break;
     case '\n': {
+      gapbuffer_move (&editor.current_line->gb, editor.cursor.col);
+
       struct edit_line* new_line = malloc (sizeof (*new_line));
       memset (new_line, 0, sizeof (*new_line));
 
       char* tail = gapbuffer_string_at (&warena_malloc, &temp_arena, &editor.current_line->gb,
                                         editor.cursor.col);
       size_t tail_size = strlen (tail);
+      size_t init_cap = tail_size > 0 ? tail_size : 32;
 
-      gapbuffer_init (&wmalloc, NULL, &new_line->gb, tail_size > 0 ? tail_size : 32);
+      gapbuffer_init (&wmalloc, NULL, &new_line->gb, init_cap);
 
-      for (size_t i = 0; i < tail_size; i++) {
-        char chr = gapbuffer_at (&editor.current_line->gb, editor.cursor.col);
-        gapbuffer_delete_at (&editor.current_line->gb, editor.cursor.col);
-        gapbuffer_insert (&wrealloc, NULL, &new_line->gb, chr);
+      if (tail_size > 0) {
+        memcpy (new_line->gb.buffer,
+                editor.current_line->gb.buffer + editor.current_line->gb.gap_end, tail_size);
+        new_line->gb.gap_start = tail_size;
       }
 
+      editor.current_line->gb.gap_end = editor.current_line->gb.size;
+
       list_insert_after (editor.lines, &editor.current_line->lines_link, &new_line->lines_link);
 
       editor.cursor.col = 0;
@@ -198,8 +223,10 @@ void edit_start (const char* file_path, const char* text) {
       editor.current_line = new_line;
     } break;
     case KB_DELETE:
-      if (editor.cursor.col < gapbuffer_length (&editor.current_line->gb))
+      if (editor.cursor.col < gapbuffer_length (&editor.current_line->gb)) {
+        gapbuffer_move (&editor.current_line->gb, editor.cursor.col);
         editor.current_line->gb.gap_end++;
+      }
       break;
     case KB_LEFT:
       if (editor.cursor.col > 0)
@@ -240,6 +267,7 @@ void edit_start (const char* file_path, const char* text) {
       break;
     default:
       if (isprint (ch)) {
+        gapbuffer_move (&editor.current_line->gb, editor.cursor.col);
         gapbuffer_insert (&wrealloc, NULL, &editor.current_line->gb, ch);
         editor.cursor.col++;
       }

ce/gapbuffer.c

@@ -72,22 +72,6 @@ void gapbuffer_backspace (struct gapbuffer* gb) {
     gb->gap_start--;
 }
 
-char* gapbuffer_get_string (gb_malloc_func_t mallocfn, void* ctx, struct gapbuffer* gb) {
-  size_t size = gb->size - (gb->gap_end - gb->gap_start);
-
-  char* str = mallocfn (ctx, size + 1);
-
-  if (str == NULL)
-    return NULL;
-
-  memcpy (str, gb->buffer, gb->gap_start);
-
-  memcpy (str + gb->gap_start, gb->buffer + gb->gap_end, gb->size - gb->gap_end);
-
-  str[size] = '\0';
-  return str;
-}
-
 size_t gapbuffer_length (struct gapbuffer* gb) { return gb->size - (gb->gap_end - gb->gap_start); }
 
 char* gapbuffer_string_at (gb_malloc_func_t mallocfn, void* ctx, struct gapbuffer* gb, size_t pos) {
@@ -128,17 +112,3 @@ char* gapbuffer_string_at (gb_malloc_func_t mallocfn, void* ctx, struct gapbuffe
   res[written] = '\0';
   return res;
 }
-
-char gapbuffer_at (struct gapbuffer* gb, size_t index) {
-  if (index < gb->gap_start)
-    return gb->buffer[index];
-  else
-    return gb->buffer[index + (gb->gap_end - gb->gap_start)];
-}
-
-void gapbuffer_delete_at (struct gapbuffer* gb, size_t index) {
-  gapbuffer_move (gb, index);
-
-  if (gb->gap_end < gb->size)
-    gb->gap_end++;
-}

ce/gapbuffer.h

@@ -29,14 +29,8 @@ void gapbuffer_backspace (struct gapbuffer* gb);
 
 void gapbuffer_grow (gb_realloc_func_t reallocfn, void* ctx, struct gapbuffer* gb);
 
-char* gapbuffer_get_string (gb_malloc_func_t mallocfn, void* ctx, struct gapbuffer* gb);
-
 size_t gapbuffer_length (struct gapbuffer* gb);
 
 char* gapbuffer_string_at (gb_malloc_func_t mallocfn, void* ctx, struct gapbuffer* gb, size_t pos);
 
-char gapbuffer_at (struct gapbuffer* gb, size_t index);
-
-void gapbuffer_delete_at (struct gapbuffer* gb, size_t index);
-
 #endif // _GAPBUFFER_H