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List:       busybox
Subject:    Re: [PATCH] vi: improved handling of backspace in replace mode
From:       Denys Vlasenko <vda.linux () googlemail ! com>
Date:       2022-03-04 21:58:45
Message-ID: CAK1hOcOXM1ca8Am4njJMd6VSe70jWN_VDTOEVw0RPx6WrXfPOw () mail ! gmail ! com
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Applied, thank you

On Thu, Mar 3, 2022 at 12:41 PM Ron Yorston <rmy@pobox.com> wrote:
> 
> In replace mode ('R' command) the backspace character should get
> special treatment:
> 
> - backspace only goes back to the start of the replacement;
> - backspacing over replaced characters restores the original text.
> 
> Prior to this commit BusyBox vi deleted the characters both before
> and after the cursor in replace mode.
> 
> function                                             old     new   delta
> undo_pop                                               -     235    +235
> char_insert                                          858     884     +26
> indicate_error                                        81      84      +3
> find_range                                           654     657      +3
> static.text_yank                                      77      79      +2
> do_cmd                                              4486    4243    -243
> ------------------------------------------------------------------------------
> (add/remove: 1/0 grow/shrink: 4/1 up/down: 269/-243)           Total: 26 bytes
> 
> Signed-off-by: Ron Yorston <rmy@pobox.com>
> ---
> editors/vi.c | 24 ++++++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
> 
> diff --git a/editors/vi.c b/editors/vi.c
> index d37cd48a3..4257c0fdc 100644
> --- a/editors/vi.c
> +++ b/editors/vi.c
> @@ -224,6 +224,7 @@
> 
> #endif
> 
> +#define isbackspace(c) ((c) == term_orig.c_cc[VERASE] || (c) == 8 || (c) == 127)
> 
> enum {
> MAX_TABSTOP = 32, // sanity limit
> @@ -342,6 +343,7 @@ struct globals {
> int last_modified_count; // = -1;
> int cmdline_filecnt;     // how many file names on cmd line
> int cmdcnt;              // repetition count
> +       char *rstart;            // start of text in Replace mode
> unsigned rows, columns;  // the terminal screen is this size
> #if ENABLE_FEATURE_VI_ASK_TERMINAL
> int get_rowcol_error;
> @@ -474,6 +476,7 @@ struct globals {
> #define last_modified_count     (G.last_modified_count)
> #define cmdline_filecnt         (G.cmdline_filecnt    )
> #define cmdcnt                  (G.cmdcnt             )
> +#define rstart                  (G.rstart             )
> #define rows                    (G.rows               )
> #define columns                 (G.columns            )
> #define crow                    (G.crow               )
> @@ -1212,7 +1215,7 @@ static char *get_input_line(const char *prompt)
> c = get_one_char();
> if (c == '\n' || c == '\r' || c == 27)
> break;          // this is end of input
> -               if (c == term_orig.c_cc[VERASE] || c == 8 || c == 127) {
> +               if (isbackspace(c)) {
> // user wants to erase prev char
> write1("\b \b"); // erase char on screen
> buf[--i] = '\0';
> @@ -2174,8 +2177,16 @@ static char *char_insert(char *p, char c, int undo) // \
> insert the char c at 'p' p += 1 + stupid_insert(p, ' ');
> }
> #endif
> -       } else if (c == term_orig.c_cc[VERASE] || c == 8 || c == 127) { // Is this \
>                 a BS
> -               if (p > text) {
> +       } else if (isbackspace(c)) {
> +               if (cmd_mode == 2) {
> +                       // special treatment for backspace in Replace mode
> +                       if (p > rstart) {
> +                               p--;
> +#if ENABLE_FEATURE_VI_UNDO
> +                               undo_pop();
> +#endif
> +                       }
> +               } else if (p > text) {
> p--;
> p = text_hole_delete(p, p, ALLOW_UNDO_QUEUED);  // shrink buffer 1 char
> }
> @@ -3703,9 +3714,9 @@ static void do_cmd(int c)
> undo_queue_commit();
> } else {
> if (1 <= c || Isprint(c)) {
> -                               if (c != 27)
> -                                       dot = yank_delete(dot, dot, PARTIAL, \
>                 YANKDEL, ALLOW_UNDO);      // delete char
> -                               dot = char_insert(dot, c, ALLOW_UNDO_CHAIN);    // \
> insert new char +                               if (c != 27 && !isbackspace(c))
> +                                       dot = yank_delete(dot, dot, PARTIAL, \
> YANKDEL, ALLOW_UNDO); +                               dot = char_insert(dot, c, \
> ALLOW_UNDO_CHAIN); }
> goto dc1;
> }
> @@ -4264,6 +4275,7 @@ static void do_cmd(int c)
> dc5:
> cmd_mode = 2;
> undo_queue_commit();
> +               rstart = dot;
> break;
> case KEYCODE_DELETE:
> if (dot < end - 1)
> --
> 2.35.1
> 
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> busybox mailing list
> busybox@busybox.net
> http://lists.busybox.net/mailman/listinfo/busybox
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