source: MondoRescue/branches/3.2/mindi-busybox/coreutils/fold.c@ 3186

/* vi: set sw=4 ts=4: */
/* fold -- wrap each input line to fit in specified width.

   Written by David MacKenzie, djm@gnu.ai.mit.edu.
   Copyright (C) 91, 1995-2002 Free Software Foundation, Inc.

   Modified for busybox based on coreutils v 5.0
   Copyright (C) 2003 Glenn McGrath

   Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
#include "libbb.h"
#include "unicode.h"

/* This is a NOEXEC applet. Be very careful! */

/* Must match getopt32 call */
#define FLAG_COUNT_BYTES        1
#define FLAG_BREAK_SPACES       2
#define FLAG_WIDTH              4

/* Assuming the current column is COLUMN, return the column that
   printing C will move the cursor to.
   The first column is 0. */
static int adjust_column(unsigned column, char c)
{
    if (option_mask32 & FLAG_COUNT_BYTES)
        return ++column;

    if (c == '\t')
        return column + 8 - column % 8;

    if (c == '\b') {
        if ((int)--column < 0)
            column = 0;
    }
    else if (c == '\r')
        column = 0;
    else { /* just a printable char */
        if (unicode_status != UNICODE_ON /* every byte is a new char */
         || (c & 0xc0) != 0x80 /* it isn't a 2nd+ byte of a Unicode char */
        ) {
            column++;
        }
    }
    return column;
}

/* Note that this function can write NULs, unlike fputs etc. */
static void write2stdout(const void *buf, unsigned size)
{
    fwrite(buf, 1, size, stdout);
}

int fold_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int fold_main(int argc UNUSED_PARAM, char **argv)
{
    char *line_out = NULL;
    const char *w_opt = "80";
    unsigned width;
    smallint exitcode = EXIT_SUCCESS;

    init_unicode();

    if (ENABLE_INCLUDE_SUSv2) {
        /* Turn any numeric options into -w options.  */
        int i;
        for (i = 1; argv[i]; i++) {
            const char *a = argv[i];
            if (*a == '-') {
                a++;
                if (*a == '-' && !a[1]) /* "--" */
                    break;
                if (isdigit(*a))
                    argv[i] = xasprintf("-w%s", a);
            }
        }
    }

    getopt32(argv, "bsw:", &w_opt);
    width = xatou_range(w_opt, 1, 10000);

    argv += optind;
    if (!*argv)
        *--argv = (char*)"-";

    do {
        FILE *istream = fopen_or_warn_stdin(*argv);
        int c;
        unsigned column = 0;     /* Screen column where next char will go */
        unsigned offset_out = 0; /* Index in 'line_out' for next char */

        if (istream == NULL) {
            exitcode = EXIT_FAILURE;
            continue;
        }

        while ((c = getc(istream)) != EOF) {
            /* We grow line_out in chunks of 0x1000 bytes */
            if ((offset_out & 0xfff) == 0) {
                line_out = xrealloc(line_out, offset_out + 0x1000);
            }
 rescan:
            line_out[offset_out] = c;
            if (c == '\n') {
                write2stdout(line_out, offset_out + 1);
                column = offset_out = 0;
                continue;
            }
            column = adjust_column(column, c);
            if (column <= width || offset_out == 0) {
                /* offset_out == 0 case happens
                 * with small width (say, 1) and tabs.
                 * The very first tab already goes to column 8,
                 * but we must not wrap it */
                offset_out++;
                continue;
            }

            /* This character would make the line too long.
             * Print the line plus a newline, and make this character
             * start the next line */
            if (option_mask32 & FLAG_BREAK_SPACES) {
                unsigned i;
                unsigned logical_end;

                /* Look for the last blank. */
                for (logical_end = offset_out - 1; (int)logical_end >= 0; logical_end--) {
                    if (!isblank(line_out[logical_end]))
                        continue;

                    /* Found a space or tab.
                     * Output up to and including it, and start a new line */
                    logical_end++;
                    /*line_out[logical_end] = '\n'; - NO! this nukes one buffered character */
                    write2stdout(line_out, logical_end);
                    putchar('\n');
                    /* Move the remainder to the beginning of the next line.
                     * The areas being copied here might overlap. */
                    memmove(line_out, line_out + logical_end, offset_out - logical_end);
                    offset_out -= logical_end;
                    for (column = i = 0; i < offset_out; i++) {
                        column = adjust_column(column, line_out[i]);
                    }
                    goto rescan;
                }
                /* No blank found, wrap will split the overlong word */
            }
            /* Output what we accumulated up to now, and start a new line */
            line_out[offset_out] = '\n';
            write2stdout(line_out, offset_out + 1);
            column = offset_out = 0;
            goto rescan;
        } /* while (not EOF) */

        if (offset_out) {
            write2stdout(line_out, offset_out);
        }

        if (fclose_if_not_stdin(istream)) {
            bb_simple_perror_msg(*argv);
            exitcode = EXIT_FAILURE;
        }
    } while (*++argv);

    fflush_stdout_and_exit(exitcode);
}