Re: [PATCH 08/11] tty: vt: simplify some unicode conditions

Ilpo Järvinen
2023-01-12T09:55:31Z

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On Thu, 12 Jan 2023, Jiri Slaby (SUSE) wrote:

> After previous patches, we can simply test vc->vc_uni_lines, so do so in
> many unicode functions. This makes the code more compact. And even use
> if (!)
> return;
> in vc_uniscr_scroll(), so that the whole code is indented on the left.
>
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
> ---
> drivers/tty/vt/vt.c | 85 +++++++++++++++++++--------------------------
> 1 file changed, 36 insertions(+), 49 deletions(-)
>
> diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
> index db72375141b0..74db07b32abe 100644
> --- a/drivers/tty/vt/vt.c
> +++ b/drivers/tty/vt/vt.c
> @@ -357,18 +357,14 @@ static void vc_uniscr_set(struct vc_data *vc, u32 **new_uni_lines)
>
> static void vc_uniscr_putc(struct vc_data *vc, u32 uc)
> {
> - u32 **uni_lines = vc->vc_uni_lines;
> -
> - if (uni_lines)
> - uni_lines[vc->state.y][vc->state.x] = uc;
> + if (vc->vc_uni_lines)
> + vc->vc_uni_lines[vc->state.y][vc->state.x] = uc;
> }
>
> static void vc_uniscr_insert(struct vc_data *vc, unsigned int nr)
> {
> - u32 **uni_lines = vc->vc_uni_lines;
> -
> - if (uni_lines) {
> - u32 *ln = uni_lines[vc->state.y];
> + if (vc->vc_uni_lines) {
> + u32 *ln = vc->vc_uni_lines[vc->state.y];
> unsigned int x = vc->state.x, cols = vc->vc_cols;
>
> memmove(&ln[x + nr], &ln[x], (cols - x - nr) * sizeof(*ln));
> @@ -378,10 +374,8 @@ static void vc_uniscr_insert(struct vc_data *vc, unsigned int nr)
>
> static void vc_uniscr_delete(struct vc_data *vc, unsigned int nr)
> {
> - u32 **uni_lines = vc->vc_uni_lines;
> -
> - if (uni_lines) {
> - u32 *ln = uni_lines[vc->state.y];
> + if (vc->vc_uni_lines) {
> + u32 *ln = vc->vc_uni_lines[vc->state.y];
> unsigned int x = vc->state.x, cols = vc->vc_cols;
>
> memcpy(&ln[x], &ln[x + nr], (cols - x - nr) * sizeof(*ln));
> @@ -392,59 +386,52 @@ static void vc_uniscr_delete(struct vc_data *vc, unsigned int nr)
> static void vc_uniscr_clear_line(struct vc_data *vc, unsigned int x,
> unsigned int nr)
> {
> - u32 **uni_lines = vc->vc_uni_lines;
> -
> - if (uni_lines) {
> - u32 *ln = uni_lines[vc->state.y];
> -
> - memset32(&ln[x], ' ', nr);
> - }
> + if (vc->vc_uni_lines)
> + memset32(&vc->vc_uni_lines[vc->state.y][x], ' ', nr);
> }
>
> static void vc_uniscr_clear_lines(struct vc_data *vc, unsigned int y,
> unsigned int nr)
> {
> - u32 **uni_lines = vc->vc_uni_lines;
> -
> - if (uni_lines) {
> - unsigned int cols = vc->vc_cols;
> -
> + if (vc->vc_uni_lines)
> while (nr--)
> - memset32(uni_lines[y++], ' ', cols);
> - }
> + memset32(vc->vc_uni_lines[y++], ' ', vc->vc_cols);
> }
>
> static void vc_uniscr_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
> enum con_scroll dir, unsigned int nr)
> {
> u32 **uni_lines = vc->vc_uni_lines;
> + unsigned int i, j, k, sz, d, clear;
>
> - if (uni_lines) {
> - unsigned int i, j, k, sz, d, clear;
> + if (!uni_lines)
> + return;
>
> - sz = b - t;
> - clear = b - nr;
> - d = nr;
> - if (dir == SM_DOWN) {
> - clear = t;
> - d = sz - nr;
> - }
> - for (i = 0; i < gcd(d, sz); i++) {
> - u32 *tmp = uni_lines[t + i];
> - j = i;
> - while (1) {
> - k = j + d;
> - if (k >= sz)
> - k -= sz;
> - if (k == i)
> - break;
> - uni_lines[t + j] = uni_lines[t + k];
> - j = k;
> - }
> - uni_lines[t + j] = tmp;
> + sz = b - t;
> + clear = b - nr;
> + d = nr;
> +
> + if (dir == SM_DOWN) {
> + clear = t;
> + d = sz - nr;
> + }
> +
> + for (i = 0; i < gcd(d, sz); i++) {
> + u32 *tmp = uni_lines[t + i];
> + j = i;
> + while (1) {
> + k = j + d;
> + if (k >= sz)
> + k -= sz;
> + if (k == i)
> + break;
> + uni_lines[t + j] = uni_lines[t + k];
> + j = k;
> }
> - vc_uniscr_clear_lines(vc, clear, nr);
> + uni_lines[t + j] = tmp;
> }
> +
> + vc_uniscr_clear_lines(vc, clear, nr);
> }
>
> static void vc_uniscr_copy_area(u32 **dst_lines,
>

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

With the note that increased density of "vc[-_]" per line feels a step
backwards on readability even if the number of lines is less, IMHO.

--
i.