Re: [9fans] Small program "PlanKey" (paraphrase of DOSKey)

[Francisco J Ballesteros <nemo@lsub.org>]

Russ posted two script called " and "" time ago on this list,
IIRC.


On Fri, Jan 23, 2009 at 11:03 AM, pavel.klinkovsky@gmail.com
<pavel.klinkovsky@gmail.com> wrote:
> Hi all,
>
> In Plan9 I missed the simple way to repeat previous (or previous of
> previous etc.) command in the terminal.
> I prepared a very small (an stupid) program to allow that.
>
> Compile the following source code and run it in that way:
> 8.out | rc -i
>
> You can insert the commands, and if you want to walk through the
> "history", just press CTRL+K (backward) or CTRL+L (foreward).
>
> That is all, folks. ;-)
>
> Pavel
>
>
> #include <u.h>
> #include <libc.h>
>
> enum
> {
>        KCtrlD = 0x04,
>        KCtrlK = 0x0B,
>        KCtrlL = 0x0C,
>        KDelete = 0x7F,
>
>        MaxLen = 128,
>        MaxDepth = 10
> };
>
> struct Line
> {
>        int len;
>        char buf[MaxLen];
> };
> typedef struct Line Line;
>
> void
> main(void)
> {
>        // Console control file descriptor
>        int cfd;
>        // End flag
>        int end = 0;
>        // Actual read character
>        char c;
>        // Array of BackSpaces
>        char bs[MaxLen];
>        // Array of Lines
>        Line line[MaxDepth];
>        // Index of actual line
>        int act = 0;
>        // Index of stored line
>        int stored = 0;
>
>        memset(bs, '\b', sizeof(bs));
>        memset(line, 0, sizeof(line));
>
>        cfd = open("/dev/consctl", OWRITE);
>        if (cfd < 0)
>                sysfatal("%r");
>        write(cfd, "rawon", 5);
>
>        while (!end) {
>                if (read(0, &c, sizeof(c)) < 0)
>                        sysfatal("%r");
>
>                switch (c) {
>                case KCtrlD:
>                case KDelete:
>                        end++;
>                        break;
>
>                case '\b':
>                        if (line[act].len > 0) {
>                                line[act].len--;
>                                write(2, &c, sizeof(c));
>                        }
>                        break;
>
>                case '\n':
>                        if (line[act].len > 0)
>                                write(1, line[act].buf, line[act].len);
>                        write(1, &c, sizeof(c));
>                        write(2, &c, sizeof(c));
>                        act = stored = (act + 1) % MaxDepth;
>                        line[act].len = 0;
>                        break;
>
>                case KCtrlK:
>                        write(2, bs, line[act].len);
>                        stored = (stored + MaxDepth - 1) % MaxDepth;
>                        line[act] = line[stored];
>                        write(2, line[act].buf, line[act].len);
>                        break;
>
>                case KCtrlL:
>                        write(2, bs, line[act].len);
>                        stored = (stored + 1) % MaxDepth;
>                        line[act] = line[stored];
>                        write(2, line[act].buf, line[act].len);
>                        break;
>
>                case -0x11:
>                        read(0, &c, sizeof(c));
>                        read(0, &c, sizeof(c));
>                        break;
>
>                default:
>                        if (line[act].len < MaxLen) {
>                                line[act].buf[line[act].len++] = c;
>                                write(2, &c, sizeof(c));
>                        }
>                        break;
>                }
>        }
>
>        close(cfd);
>
>        exits(nil);
> }
>
>