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7c7720a3ab
With this assumption, we can replace 'a % b' with 'a & (b - 1)'. In terms of instructions, this means a fast 'and' instead of a slow 'div'. Further optimize scrolling by: * not double-initializing empty rows. Previously, grid_row_alloc() called calloc(), which was then followed by a memset() when scrolling. This is of course unnecessary. * Don't loop the entire set of visible rows (this was done to ensure all visible rows had been allocated, and to prefetch the cell contents). This isn't necessary; only newly pulled in rows can be NULL. For now, don't prefetch at all.
49 lines
1.1 KiB
C
49 lines
1.1 KiB
C
#pragma once
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#include <stddef.h>
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#include "terminal.h"
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void grid_swap_row(struct grid *grid, int row_a, int row_b, bool initialize);
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struct row *grid_row_alloc(int cols, bool initialize);
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void grid_row_free(struct row *row);
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static inline struct row *
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_grid_row_maybe_alloc(struct grid *grid, int row_no, bool alloc_if_null)
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{
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assert(grid->offset >= 0);
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int real_row = (grid->offset + row_no) & (grid->num_rows - 1);
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struct row *row = grid->rows[real_row];
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if (row == NULL && alloc_if_null) {
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row = grid_row_alloc(grid->num_cols, false);
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grid->rows[real_row] = row;
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}
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assert(row != NULL);
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return row;
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}
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static inline struct row *
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grid_row(struct grid *grid, int row_no)
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{
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return _grid_row_maybe_alloc(grid, row_no, false);
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}
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static inline struct row *
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grid_row_and_alloc(struct grid *grid, int row_no)
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{
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return _grid_row_maybe_alloc(grid, row_no, true);
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}
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static inline struct row *
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grid_row_in_view(struct grid *grid, int row_no)
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{
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assert(grid->view >= 0);
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int real_row = (grid->view + row_no) & (grid->num_rows - 1);
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struct row *row = grid->rows[real_row];
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assert(row != NULL);
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return row;
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}
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