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view.c

/*
 * view.c -- a silly little viewer program
 *
 * written by Eric S. Raymond <esr@snark.thyrsus.com> December 1994
 * to test the scrolling code in ncurses.
 *
 * modified by Thomas Dickey <dickey@clark.net> July 1995 to demonstrate
 * the use of 'resizeterm()', and May 2000 to illustrate wide-character
 * handling.
 *
 * Takes a filename argument.  It's a simple file-viewer with various
 * scroll-up and scroll-down commands.
 *
 * n  -- scroll one line forward
 * p  -- scroll one line back
 *
 * Either command accepts a numeric prefix interpreted as a repeat count.
 * Thus, typing `5n' should scroll forward 5 lines in the file.
 *
 * The way you can tell this is working OK is that, in the trace file,
 * there should be one scroll operation plus a small number of line
 * updates, as opposed to a whole-page update.  This means the physical
 * scroll operation worked, and the refresh() code only had to do a
 * partial repaint.
 *
 * $Id: view.c,v 1.57 2003/05/17 21:58:43 tom Exp $
 */

#include <time.h>

#include <test.priv.h>

#if HAVE_TERMIOS_H
# include <termios.h>
#else
# include <sgtty.h>
#endif

#if !defined(sun) || !HAVE_TERMIOS_H
# if HAVE_SYS_IOCTL_H
#  include <sys/ioctl.h>
# endif
#endif

#define my_pair 1

/* This is needed to compile 'struct winsize' */
#if NEED_PTEM_H
#include <sys/stream.h>
#include <sys/ptem.h>
#endif

static RETSIGTYPE finish(int sig) GCC_NORETURN;
static void show_all(const char *tag);

#if defined(SIGWINCH) && defined(TIOCGWINSZ) && HAVE_RESIZE_TERM
#define CAN_RESIZE 1
#else
#define CAN_RESIZE 0
#endif

#if CAN_RESIZE
static RETSIGTYPE adjust(int sig);
static int interrupted;
#endif

static bool waiting = FALSE;
static int shift = 0;
static bool try_color = FALSE;

static char *fname;
static NCURSES_CH_T **my_lines;
static NCURSES_CH_T **lptr;

static void
usage(void)
{
    static const char *msg[] =
    {
      "Usage: view [options] file"
      ,""
      ,"Options:"
      ," -c       use color if terminal supports it"
      ," -i       ignore INT, QUIT, TERM signals"
      ," -n NUM   specify maximum number of lines (default 1000)"
#if defined(KEY_RESIZE)
      ," -r       use old-style sigwinch handler rather than KEY_RESIZE"
#endif
#ifdef TRACE
      ," -t       trace screen updates"
      ," -T NUM   specify trace mask"
#endif
    };
    size_t n;
    for (n = 0; n < SIZEOF(msg); n++)
      fprintf(stderr, "%s\n", msg[n]);
    ExitProgram(EXIT_FAILURE);
}

static int
ch_len(NCURSES_CH_T * src)
{
    int result = 0;
#if USE_WIDEC_SUPPORT
#endif

#if USE_WIDEC_SUPPORT
    while (getcchar(src++, NULL, NULL, NULL, NULL) > 0)
      result++;
#else
    while (*src++)
      result++;
#endif
    return result;
}

/*
 * Allocate a string into an array of chtype's.  If UTF-8 mode is
 * active, translate the string accordingly.
 */
static NCURSES_CH_T *
ch_dup(char *src)
{
    unsigned len = strlen(src);
    NCURSES_CH_T *dst = typeMalloc(NCURSES_CH_T, len + 1);
    unsigned j, k;
#if USE_WIDEC_SUPPORT
    wchar_t wstr[CCHARW_MAX + 1];
    wchar_t wch;
    int l = 0;
    mbstate_t state;
    size_t rc;
    int width;
#endif

#if USE_WIDEC_SUPPORT
    memset(&state, 0, sizeof(state));
#endif
    for (j = k = 0; j < len; j++) {
#if USE_WIDEC_SUPPORT
      rc = mbrtowc(&wch, src + j, len - j, &state);
      if (rc == (size_t) -1 || rc == (size_t) -2)
          break;
      j += rc - 1;
      if ((width = wcwidth(wch)) < 0)
          break;
      if ((width > 0 && l > 0) || l == CCHARW_MAX) {
          wstr[l] = L'\0';
          l = 0;
          if (setcchar(dst + k, wstr, 0, 0, NULL) != OK)
            break;
          ++k;
      }
      if (width == 0 && l == 0)
          wstr[l++] = L' ';
      wstr[l++] = wch;
#else
      dst[k++] = src[j];
#endif
    }
#if USE_WIDEC_SUPPORT
    if (l > 0) {
      wstr[l] = L'\0';
      if (setcchar(dst + k, wstr, 0, 0, NULL) == OK)
          ++k;
    }
    setcchar(dst + k, L"", 0, 0, NULL);
#else
    dst[k] = 0;
#endif
    return dst;
}

int
main(int argc, char *argv[])
{
    int MAXLINES = 1000;
    FILE *fp;
    char buf[BUFSIZ];
    int i;
    int my_delay = 0;
    NCURSES_CH_T **olptr;
    int length = 0;
    int value = 0;
    bool done = FALSE;
    bool got_number = FALSE;
#if CAN_RESIZE
    bool nonposix_resize = FALSE;
#endif
    const char *my_label = "Input";

    setlocale(LC_ALL, "");

#ifndef NCURSES_VERSION
    /*
     * We know ncurses will catch SIGINT if we don't establish our own handler.
     * Other versions of curses may/may not catch it.
     */
    (void) signal(SIGINT, finish);  /* arrange interrupts to terminate */
#endif

    while ((i = getopt(argc, argv, "cin:rtT:")) != EOF) {
      switch (i) {
      case 'c':
          try_color = TRUE;
          break;
      case 'i':
          signal(SIGINT, SIG_IGN);
          signal(SIGQUIT, SIG_IGN);
          signal(SIGTERM, SIG_IGN);
          break;
      case 'n':
          if ((MAXLINES = atoi(optarg)) < 1)
            usage();
          break;
#if CAN_RESIZE
      case 'r':
          nonposix_resize = TRUE;
          break;
#endif
#ifdef TRACE
      case 'T':
          trace(atoi(optarg));
          break;
      case 't':
          trace(TRACE_CALLS);
          break;
#endif
      default:
          usage();
      }
    }
    if (optind + 1 != argc)
      usage();

    if ((my_lines = typeMalloc(NCURSES_CH_T *, MAXLINES + 2)) == 0)
      usage();

    fname = argv[optind];
    if ((fp = fopen(fname, "r")) == 0) {
      perror(fname);
      ExitProgram(EXIT_FAILURE);
    }
#if CAN_RESIZE
    if (nonposix_resize)
      (void) signal(SIGWINCH, adjust);    /* arrange interrupts to resize */
#endif

    /* slurp the file */
    for (lptr = &my_lines[0]; (lptr - my_lines) < MAXLINES; lptr++) {
      char temp[BUFSIZ], *s, *d;
      int col;

      if (fgets(buf, sizeof(buf), fp) == 0)
          break;

      /* convert tabs so that shift will work properly */
      for (s = buf, d = temp, col = 0; (*d = *s) != '\0'; s++) {
          if (*d == '\n') {
            *d = '\0';
            break;
          } else if (*d == '\t') {
            col = (col | 7) + 1;
            while ((d - temp) != col)
                *d++ = ' ';
          } else
#if USE_WIDEC_SUPPORT
            col++, d++;
#else
          if (isprint(UChar(*d))) {
            col++;
            d++;
          } else {
            sprintf(d, "\\%03o", UChar(*s));
            d += strlen(d);
            col = (d - temp);
          }
#endif
      }
      *lptr = ch_dup(temp);
    }
    (void) fclose(fp);
    length = lptr - my_lines;

    (void) initscr();         /* initialize the curses library */
    keypad(stdscr, TRUE);     /* enable keyboard mapping */
    (void) nonl();            /* tell curses not to do NL->CR/NL on output */
    (void) cbreak();          /* take input chars one at a time, no wait for \n */
    (void) noecho();          /* don't echo input */
    nodelay(stdscr, TRUE);
    idlok(stdscr, TRUE);      /* allow use of insert/delete line */

    if (try_color) {
      if (has_colors()) {
          start_color();
          init_pair(my_pair, COLOR_WHITE, COLOR_BLUE);
          bkgd(COLOR_PAIR(my_pair));
      } else {
          try_color = FALSE;
      }
    }

    lptr = my_lines;
    while (!done) {
      int n, c;

      if (!got_number)
          show_all(my_label);

      n = 0;
      for (;;) {
#if CAN_RESIZE
          if (interrupted) {
            adjust(0);
            my_label = "interrupt";
          }
#endif
          waiting = TRUE;
          c = getch();
          waiting = FALSE;
          if ((c < 127) && isdigit(c)) {
            if (!got_number) {
                mvprintw(0, 0, "Count: ");
                clrtoeol();
            }
            addch(c);
            value = 10 * value + (c - '0');
            got_number = TRUE;
          } else
            break;
      }
      if (got_number && value) {
          n = value;
      } else {
          n = 1;
      }

      if (c != ERR)
          my_label = keyname(c);
      switch (c) {
      case KEY_DOWN:
      case 'n':
          olptr = lptr;
          for (i = 0; i < n; i++)
            if ((lptr - my_lines) < (length - LINES + 1))
                lptr++;
            else
                break;
          wscrl(stdscr, lptr - olptr);
          break;

      case KEY_UP:
      case 'p':
          olptr = lptr;
          for (i = 0; i < n; i++)
            if (lptr > my_lines)
                lptr--;
            else
                break;
          wscrl(stdscr, lptr - olptr);
          break;

      case 'h':
      case KEY_HOME:
          lptr = my_lines;
          break;

      case 'e':
      case KEY_END:
          if (length > LINES)
            lptr = my_lines + length - LINES + 1;
          else
            lptr = my_lines;
          break;

      case 'r':
      case KEY_RIGHT:
          shift += n;
          break;

      case 'l':
      case KEY_LEFT:
          shift -= n;
          if (shift < 0) {
            shift = 0;
            beep();
          }
          break;

      case 'q':
          done = TRUE;
          break;

#ifdef KEY_RESIZE
      case KEY_RESIZE:  /* ignore this; ncurses will repaint */
          break;
#endif
      case 's':
          if (got_number) {
            halfdelay(my_delay = n);
          } else {
            nodelay(stdscr, FALSE);
            my_delay = -1;
          }
          break;
      case ' ':
          nodelay(stdscr, TRUE);
          my_delay = 0;
          break;
      case ERR:
          if (!my_delay)
            napms(50);
          break;
      default:
          beep();
          break;
      }
      if (c >= KEY_MIN || (c > 0 && !isdigit(c))) {
          got_number = FALSE;
          value = 0;
      }
    }

    finish(0);                /* we're done */
}

static RETSIGTYPE
finish(int sig)
{
    endwin();
    ExitProgram(sig != 0 ? EXIT_FAILURE : EXIT_SUCCESS);
}

#if CAN_RESIZE
/*
 * This uses functions that are "unsafe", but it seems to work on SunOS and
 * Linux.  Usually:  the "unsafe" refers to the functions that POSIX lists
 * which may be called from a signal handler.  Those do not include buffered
 * I/O, which is used for instance in wrefresh().  To be really portable, you
 * should use the KEY_RESIZE return (which relies on ncurses' sigwinch
 * handler).
 *
 * The 'wrefresh(curscr)' is needed to force the refresh to start from the top
 * of the screen -- some xterms mangle the bitmap while resizing.
 */
static RETSIGTYPE
adjust(int sig)
{
    if (waiting || sig == 0) {
      struct winsize size;

      if (ioctl(fileno(stdout), TIOCGWINSZ, &size) == 0) {
          resize_term(size.ws_row, size.ws_col);
          wrefresh(curscr);   /* Linux needs this */
          show_all(sig ? "SIGWINCH" : "interrupt");
      }
      interrupted = FALSE;
    } else {
      interrupted = TRUE;
    }
    (void) signal(SIGWINCH, adjust);      /* some systems need this */
}
#endif /* CAN_RESIZE */

static void
show_all(const char *tag)
{
    int i;
    char temp[BUFSIZ];
    NCURSES_CH_T *s;
    time_t this_time;

#if CAN_RESIZE
    sprintf(temp, "%s (%3dx%3d) col %d ", tag, LINES, COLS, shift);
    i = strlen(temp);
    sprintf(temp + i, "view %.*s", (int) (sizeof(temp) - 7 - i), fname);
#else
    sprintf(temp, "view %.*s", (int) sizeof(temp) - 7, fname);
#endif
    move(0, 0);
    printw("%.*s", COLS, temp);
    clrtoeol();
    this_time = time((time_t *) 0);
    strcpy(temp, ctime(&this_time));
    if ((i = strlen(temp)) != 0) {
      temp[--i] = 0;
      if (move(0, COLS - i - 2) != ERR)
          printw("  %s", temp);
    }

    scrollok(stdscr, FALSE);  /* prevent screen from moving */
    for (i = 1; i < LINES; i++) {
      move(i, 0);
      printw("%3ld:", (long) (lptr + i - my_lines));
      clrtoeol();
      if ((s = lptr[i - 1]) != 0) {
          int len = ch_len(s);
          if (len > shift) {
#if USE_WIDEC_SUPPORT
            add_wchstr(s + shift);
#else
            addchstr(s + shift);
#endif
          }
#if defined(NCURSES_VERSION) || defined(HAVE_WCHGAT)
          if (try_color)
            wchgat(stdscr, -1, A_NORMAL, my_pair, NULL);
#endif
      }
    }
    setscrreg(1, LINES - 1);
    scrollok(stdscr, TRUE);
    refresh();
}

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