/*

 * utils.c - multibyte-string helpers

 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

#ifndef _XOPEN_SOURCE

#define _XOPEN_SOURCE

#endif

#include "aconfig.h"

#include <limits.h>

#include <stdlib.h>

#include <string.h>

#include <wchar.h>

#include <errno.h>

#include <stdio.h>

#include "utils.h"

#include "mem.h"

/*

 * mbs_at_width - compute screen position in a string

 *

 * For displaying strings on the screen, we have to know how many character

 * cells are occupied.  This function calculates the position in a multibyte

 * string that is at a desired position.

 *

 * Parameters:

 * s:     the string

 * width: on input, the desired number of character cells; on output, the actual

 *        position, in character cells, of the return value

 * dir:   -1 or 1; in which direction to round if a multi-column character goes

 *        over the desired width

 *

 * Return value:

 * Pointer to the place in the string that is as near the desired width as

 * possible.  If the string is too short, the return value points to the

 * terminating zero.  If the last character is a multi-column character that

 * goes over the desired width, the return value may be one character cell

 * earlier or later than desired, depending on the dir parameter.

 * In any case, the return value points after any zero-width characters that

 * follow the last character.

 */

const char *mbs_at_width(const char *s, int *width, int dir)

{

	size_t len;

	wchar_t wc;

	int bytes;

	int width_so_far, w;

	if (*width <= 0)

		return s;

	mbtowc(NULL, NULL, 0); /* reset shift state */

	len = strlen(s);

	width_so_far = 0;

	while (len && (bytes = mbtowc(&wc, s, len)) > 0) {

		w = wcwidth(wc);

		if (width_so_far + w > *width && dir < 0)

			break;

		if (w >= 0)

			width_so_far += w;

		s += bytes;

		len -= bytes;

		if (width_so_far >= *width) {

			while (len && (bytes = mbtowc(&wc, s, len)) > 0) {

				w = wcwidth(wc);

				if (w != 0)

					break;

				s += bytes;

				len -= bytes;

			}

			break;

		}

	}

	*width = width_so_far;

	return s;

}

/*

 * get_mbs_width - compute screen width of a string

 */

unsigned int get_mbs_width(const char *s)

{

	int width;

	width = INT_MAX;

	mbs_at_width(s, &width, 1);

	return width;

}

/*

 * get_max_mbs_width - get width of longest string in an array

 */

unsigned int get_max_mbs_width(const char *const *s, unsigned int count)

{

	unsigned int max_width, i, len;

	max_width = 0;

	for (i = 0; i < count; ++i) {

		len = get_mbs_width(s[i]);

		if (len > max_width)

			max_width = len;

	}

	return max_width;

}

#define MAX_FILE_SIZE 1048576

char *read_file(const char *file_name, unsigned int *file_size)

{

	FILE *f;

	int err;

	char *buf;

	unsigned int allocated = 2048;

	unsigned int bytes_read;

	f = fopen(file_name, "r");

	if (!f) {

		err = errno;

		errno = err;

		return NULL;

	}

	*file_size = 0;

	buf = NULL;

	do {

		allocated *= 2;

		buf = crealloc(buf, allocated);

		bytes_read = fread(buf + *file_size, 1, allocated - *file_size, f);

		*file_size += bytes_read;

	} while (*file_size == allocated && allocated < MAX_FILE_SIZE);

	fclose(f);

	if (*file_size > 0 && buf[*file_size - 1] != '\n' && *file_size < allocated) {

		buf[*file_size] = '\n';

		++*file_size;

	}

	return buf;

}