path: root/src/getstring.c

/*
 * Calcurse - text-based organizer
 *
 * Copyright (c) 2004-2013 calcurse Development Team <misc@calcurse.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the
 *        following disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the
 *        following disclaimer in the documentation and/or other
 *        materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Send your feedback or comments to : misc@calcurse.org
 * Calcurse home page : http://calcurse.org
 *
 */

#include "calcurse.h"

struct getstr_charinfo {
  unsigned int offset, dpyoff;
};

struct getstr_status {
  char *s;
  struct getstr_charinfo *ci;
  int pos, len;
  int scrpos;
};

/* Print the string at the desired position. */
static void getstr_print(WINDOW * win, int x, int y, struct getstr_status *st)
{
  char c = 0;

  /* print string */
  mvwaddnstr(win, y, x, &st->s[st->ci[st->scrpos].offset], -1);
  wclrtoeol(win);

  /* print scrolling indicator */
  if (st->scrpos > 0 && st->ci[st->len].dpyoff -
      st->ci[st->scrpos].dpyoff > col - 2)
    c = '*';
  else if (st->scrpos > 0)
    c = '<';
  else if (st->ci[st->len].dpyoff - st->ci[st->scrpos].dpyoff > col - 2)
    c = '>';
  mvwprintw(win, y, col - 2, " %c", c);

  /* print cursor */
  wmove(win, y, st->ci[st->pos].dpyoff - st->ci[st->scrpos].dpyoff);
  wchgat(win, 1, A_REVERSE, COLR_CUSTOM, NULL);
}

/* Delete a character at the given position in string. */
static void getstr_del_char(struct getstr_status *st)
{
  char *str = st->s + st->ci[st->pos].offset;
  int cl = st->ci[st->pos + 1].offset - st->ci[st->pos].offset;
  int cw = st->ci[st->pos + 1].dpyoff - st->ci[st->pos].dpyoff;
  int i;

  memmove(str, str + cl, strlen(str) + 1);

  st->len--;
  for (i = st->pos; i <= st->len; i++) {
    st->ci[i].offset = st->ci[i + 1].offset - cl;
    st->ci[i].dpyoff = st->ci[i + 1].dpyoff - cw;
  }
}

/* Add a character at the given position in string. */
static void getstr_ins_char(struct getstr_status *st, char *c)
{
  char *str = st->s + st->ci[st->pos].offset;
  int cl = UTF8_LENGTH(c[0]);
  int cw = utf8_width(c);
  int i;

  memmove(str + cl, str, strlen(str) + 1);
  for (i = 0; i < cl; i++, str++)
    *str = c[i];

  for (i = st->len; i >= st->pos; i--) {
    st->ci[i + 1].offset = st->ci[i].offset + cl;
    st->ci[i + 1].dpyoff = st->ci[i].dpyoff + cw;
  }
  st->len++;
}

static void bell(void)
{
  putchar('\a');
}

/* Initialize getstring data structure. */
static void
getstr_init(struct getstr_status *st, char *str, struct getstr_charinfo *ci)
{
  int width;

  st->s = str;
  st->ci = ci;

  st->len = width = 0;
  while (*str) {
    st->ci[st->len].offset = str - st->s;
    st->ci[st->len].dpyoff = width;

    st->len++;
    width += utf8_width(str);
    str += UTF8_LENGTH(*str);
  }
  st->ci[st->len].offset = str - st->s;
  st->ci[st->len].dpyoff = width;

  st->pos = st->len;
  st->scrpos = 0;
}

/* Scroll left/right if the cursor moves outside the window range. */
static void getstr_fixscr(struct getstr_status *st)
{
  const int pgsize = col / 3;
  int pgskip;

  while (st->pos < st->scrpos) {
    pgskip = 0;
    while (pgskip < pgsize && st->scrpos > 0) {
      st->scrpos--;
      pgskip += st->ci[st->scrpos + 1].dpyoff - st->ci[st->scrpos].dpyoff;
    }
  }
  while (st->ci[st->pos].dpyoff - st->ci[st->scrpos].dpyoff > col - 2) {
    pgskip = 0;
    while (pgskip < pgsize && st->scrpos < st->len) {
      pgskip += st->ci[st->scrpos + 1].dpyoff - st->ci[st->scrpos].dpyoff;
      st->scrpos++;
    }
  }
}

/*
 * Getstring allows to get user input and to print it on a window,
 * even if noecho() is on. This function is also used to modify an existing
 * text (the variable string can be non-NULL).
 * We need to do the echoing manually because of the multi-threading
 * environment, otherwise the cursor would move from place to place without
 * control.
 */
enum getstr getstring(WINDOW * win, char *str, int l, int x, int y)
{
  struct getstr_status st;
  struct getstr_charinfo ci[l + 1];

  int ch, k;
  char c[UTF8_MAXLEN];

  getstr_init(&st, str, ci);
  custom_apply_attr(win, ATTR_HIGHEST);

  for (;;) {
    getstr_fixscr(&st);
    getstr_print(win, x, y, &st);
    wins_doupdate();

    if ((ch = wgetch(win)) == '\n')
      break;
    switch (ch) {
    case KEY_BACKSPACE:        /* delete one character */
    case 330:
    case 127:
    case CTRL('H'):
      if (st.pos > 0) {
        st.pos--;
        getstr_del_char(&st);
      } else
        bell();
      break;
    case CTRL('D'):            /* delete next character */
      if (st.pos < st.len)
        getstr_del_char(&st);
      else
        bell();
      break;
    case CTRL('W'):            /* delete a word */
      if (st.pos > 0) {
        while (st.pos && st.s[st.ci[st.pos - 1].offset] == ' ') {
          st.pos--;
          getstr_del_char(&st);
        }
        while (st.pos && st.s[st.ci[st.pos - 1].offset] != ' ') {
          st.pos--;
          getstr_del_char(&st);
        }
      } else
        bell();
      break;
    case CTRL('K'):            /* delete to end-of-line */
      st.s[st.ci[st.pos].offset] = 0;
      st.len = st.pos;
      break;
    case CTRL('A'):            /* go to begginning of string */
      st.pos = 0;
      break;
    case CTRL('E'):            /* go to end of string */
      st.pos = st.len;
      break;
    case KEY_LEFT:             /* move one char backward  */
    case CTRL('B'):
      if (st.pos > 0)
        st.pos--;
      break;
    case KEY_RIGHT:            /* move one char forward */
    case CTRL('F'):
      if (st.pos < st.len)
        st.pos++;
      break;
    case ESCAPE:               /* cancel editing */
      return GETSTRING_ESC;
      break;
    default:                   /* insert one character */
      c[0] = ch;
      for (k = 1; k < MIN(UTF8_LENGTH(c[0]), UTF8_MAXLEN); k++)
        c[k] = (unsigned char)wgetch(win);
      if (st.ci[st.len].offset + k < l) {
        getstr_ins_char(&st, c);
        st.pos++;
      }
    }
  }

  custom_remove_attr(win, ATTR_HIGHEST);

  return st.len == 0 ? GETSTRING_RET : GETSTRING_VALID;
}

/* Update an already existing string. */
int updatestring(WINDOW * win, char **str, int x, int y)
{
  int len = strlen(*str);
  char *buf;
  enum getstr ret;

  EXIT_IF(len + 1 > BUFSIZ, _("Internal error: line too long"));

  buf = mem_malloc(BUFSIZ);
  memcpy(buf, *str, len + 1);

  ret = getstring(win, buf, BUFSIZ, x, y);

  if (ret == GETSTRING_VALID) {
    len = strlen(buf);
    *str = mem_realloc(*str, len + 1, 1);
    EXIT_IF(*str == NULL, _("out of memory"));
    memcpy(*str, buf, len + 1);
  }

  mem_free(buf);
  return ret;
}