scrolling: initial reverse scrolling support - no scroll regions

grid.c

@@ -8,12 +8,15 @@
 #include "log.h"
 
 struct cell *
-grid_get_range(struct grid *grid, size_t start, size_t *length)
+grid_get_range(struct grid *grid, int start, int *length)
 {
 #define min(x, y) ((x) < (y) ? (x) : (y))
     assert(*length <= grid->size);
 
-    size_t real_start = (grid->offset + start) % grid->size;
+    int real_start = (grid->offset + start) % grid->size;
+    if (real_start < 0)
+        real_start += grid->size;
+    assert(real_start >= 0);
     assert(real_start < grid->size);
 
     *length = min(*length, grid->size - real_start);
@@ -24,11 +27,11 @@ grid_get_range(struct grid *grid, size_t start, size_t *length)
 }
 
 void
-grid_memset(struct grid *grid, size_t start, int c, size_t length)
+grid_memset(struct grid *grid, int start, int c, int length)
 {
-    size_t left = length;
+    int left = length;
     while (left > 0) {
-        size_t count = left;
+        int count = left;
         struct cell *cells = grid_get_range(grid, start, &count);
 
         assert(count > 0);
@@ -42,14 +45,14 @@ grid_memset(struct grid *grid, size_t start, int c, size_t length)
 }
 
 void
-grid_memmove(struct grid *grid, size_t dst, size_t src, size_t length)
+grid_memmove(struct grid *grid, int dst, int src, int length)
 {
-    size_t left = length;
-    size_t copy_idx = 0;
+    int left = length;
+    int copy_idx = 0;
     struct cell copy[left];
 
     while (left > 0) {
-        size_t count = left;
+        int count = left;
         struct cell *src_cells = grid_get_range(grid, src, &count);
 
         memcpy(&copy[copy_idx], src_cells, count * sizeof(copy[0]));
@@ -63,7 +66,7 @@ grid_memmove(struct grid *grid, size_t dst, size_t src, size_t length)
     copy_idx = 0;
 
     while (left > 0) {
-        size_t count = left;
+        int count = left;
         struct cell *dst_cells = grid_get_range(grid, dst, &count);
 
         memcpy(dst_cells, &copy[copy_idx], count * sizeof(copy[0]));

grid.h

@@ -3,6 +3,6 @@
 #include <stddef.h>
 #include "terminal.h"
 
-struct cell *grid_get_range(struct grid *grid, size_t start, size_t *length);
-void grid_memset(struct grid *grid, size_t start, int c, size_t length);
-void grid_memmove(struct grid *grid, size_t dst, size_t src, size_t length);
+struct cell *grid_get_range(struct grid *grid, int start, int *length);
+void grid_memset(struct grid *grid, int start, int c, int length);
+void grid_memmove(struct grid *grid, int dst, int src, int length);

main.c

@@ -118,10 +118,19 @@ grid_render_update(struct context *c, struct buffer *buf, const struct damage *d
              row += col == 0 ? 1 : 0)
     {
 
-        //LOG_DBG("UPDATE: %d (%dx%d)", linear_cursor, row, col);
+        assert(row >= 0);
+        assert(row < c->term.rows);
+        assert(col >= 0);
+        assert(col < c->term.cols);
 
-        const struct cell *cell
-            = &c->term.grid->cells[linear_cursor % c->term.grid->size];
+        int cell_idx = linear_cursor % c->term.grid->size;
+        if (cell_idx < 0)
+            cell_idx += c->term.grid->size;
+
+        assert(cell_idx >= 0);
+        assert(cell_idx < c->term.rows * c->term.cols);
+
+        const struct cell *cell = &c->term.grid->cells[cell_idx];
 
         /* Cursor here? */
         bool has_cursor
@@ -376,7 +385,7 @@ grid_render_scroll_reverse(struct context *c, struct buffer *buf,
     struct damage erase = {
         .type = DAMAGE_ERASE,
         .range = {
-            .start = dmg->scroll.region.start * cols,
+            .start = c->term.grid->offset + dmg->scroll.region.start * cols,
             .length = min(dmg->scroll.region.end - dmg->scroll.region.start,
                           dmg->scroll.lines) * cols,
         },
@@ -461,6 +470,8 @@ grid_render(struct context *c)
     last_cursor = c->term.grid->offset + c->term.cursor.linear;
 
     c->term.grid->offset %= c->term.grid->size;
+    if (c->term.grid->offset < 0)
+        c->term.grid->offset += c->term.grid->size;
 
     //cairo_surface_flush(buf->cairo_surface);
     wl_surface_attach(c->wl.surface, buf->wl_buf, 0, 0);

terminal.c

@@ -134,8 +134,7 @@ term_damage_scroll(struct terminal *term, enum damage_type damage_type,
             } else
                 break;
         }
-    } else
-        assert(false);
+    }
 
     if (tll_length(term->grid->scroll_damage) > 0) {
         struct damage *dmg = &tll_back(term->grid->scroll_damage);
@@ -187,11 +186,11 @@ term_cursor_to(struct terminal *term, int row, int col)
     term->cursor.col = col;
     term->cursor.row = row;
 
-    size_t len = term->cols;
+    int len = term->cols;
     term->grid->cur_line = grid_get_range(
         term->grid, term->cursor.linear - col, &len);
 
-    assert(len == (size_t)term->cols);
+    assert(len == term->cols);
 }
 
 void
@@ -277,11 +276,11 @@ term_scroll_partial(struct terminal *term, struct scroll_region region, int rows
 
     term_damage_scroll(term, DAMAGE_SCROLL, region, rows);
 
-    size_t len = term->cols;
+    int len = term->cols;
     term->grid->cur_line = grid_get_range(
         term->grid, term->cursor.linear - term->cursor.col, &len);
 
-    assert(len == (size_t)term->cols);
+    assert(len == term->cols);
 }
 
 void
@@ -294,37 +293,20 @@ void
 term_scroll_reverse_partial(struct terminal *term,
                             struct scroll_region region, int rows)
 {
-    if (rows >= region.end - region.start) {
-        assert(false && "todo");
-        return;
-    }
-
-#if 0
-    int cell_dst = (region.start + rows) * term->cols;
-    int cell_src = (region.start + 0) * term->cols;
-    int cell_count = (region.end - region.start - rows) * term->cols;
-
-    LOG_DBG("moving %d lines from row %d to row %d", cell_count / term->cols,
-            cell_src / term->cols, cell_dst / term->cols);
-
-    const int bytes = cell_count * sizeof(term->grid->cells[0]);
-    memmove(
-        &term->grid->cells[cell_dst], &term->grid->cells[cell_src],
-        bytes);
-
-    memset(&term->grid->cells[cell_src], 0,
-           rows * term->cols * sizeof(term->grid->cells[0]));
-
-    term_damage_scroll(term, DAMAGE_SCROLL_REVERSE, region, rows);
-#else
-    /* TODO */
-    assert(false);
-    assert(region.start == 0 && region.end == 0);
-    assert(rows < term->rows);
+    assert(region.start == 0);
+    assert(region.end == term->rows);
 
     term->grid->offset -= rows * term->cols;
+
+    grid_memset(term->grid, region.start * term->cols, 0, rows * term->cols);
+
     term_damage_scroll(term, DAMAGE_SCROLL_REVERSE, region, rows);
-#endif
+
+    int len = term->cols;
+    term->grid->cur_line = grid_get_range(
+        term->grid, term->cursor.linear - term->cursor.col, &len);
+
+    assert(len == term->cols);
 }
 
 void