source: MondoRescue/branches/2.2.5/mindi-busybox/coreutils/fold.c@ 1765

/* 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 <bug1@iinet.net.au>

   Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
*/

#include "libbb.h"

static unsigned long flags;
#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(int column, char c)
{
    if (!(flags & FLAG_COUNT_BYTES)) {
        if (c == '\b') {
            if (column > 0)
                column--;
        } else if (c == '\r')
            column = 0;
        else if (c == '\t')
            column = column + 8 - column % 8;
        else            /* if (isprint (c)) */
            column++;
    } else
        column++;
    return column;
}

int fold_main(int argc, char **argv);
int fold_main(int argc, char **argv)
{
    char *line_out = NULL;
    int allocated_out = 0;
    char *w_opt;
    int width = 80;
    int i;
    int errs = 0;

    if (ENABLE_INCLUDE_SUSv2) {
        /* Turn any numeric options into -w options.  */
        for (i = 1; i < argc; i++) {
            char const *a = argv[i];

            if (*a++ == '-') {
                if (*a == '-' && !a[1])
                    break;
                if (isdigit(*a)) {
                    argv[i] = xasprintf("-w%s", a);
                }
            }
        }
    }

    flags = getopt32(argv, "bsw:", &w_opt);
    if (flags & FLAG_WIDTH)
        width = xatoul_range(w_opt, 1, 10000);

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

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

        if (istream == NULL) {
            errs |= EXIT_FAILURE;
            continue;
        }

        while ((c = getc(istream)) != EOF) {
            if (offset_out + 1 >= allocated_out) {
                allocated_out += 1024;
                line_out = xrealloc(line_out, allocated_out);
            }

            if (c == '\n') {
                line_out[offset_out++] = c;
                fwrite(line_out, sizeof(char), (size_t) offset_out, stdout);
                column = offset_out = 0;
                continue;
            }
 rescan:
            column = adjust_column(column, c);

            if (column > width) {
                /* This character would make the line too long.
                   Print the line plus a newline, and make this character
                   start the next line. */
                if (flags & FLAG_BREAK_SPACES) {
                    /* Look for the last blank. */
                    int logical_end;

                    for (logical_end = offset_out - 1; logical_end >= 0; logical_end--) {
                        if (isblank(line_out[logical_end])) {
                            break;
                        }
                    }
                    if (logical_end >= 0) {
                        /* Found a blank.  Don't output the part after it. */
                        logical_end++;
                        fwrite(line_out, sizeof(char), (size_t) logical_end, stdout);
                        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;
                    }
                } else {
                    if (offset_out == 0) {
                        line_out[offset_out++] = c;
                        continue;
                    }
                }
                line_out[offset_out++] = '\n';
                fwrite(line_out, sizeof(char), (size_t) offset_out, stdout);
                column = offset_out = 0;
                goto rescan;
            }

            line_out[offset_out++] = c;
        }

        if (offset_out) {
            fwrite(line_out, sizeof(char), (size_t) offset_out, stdout);
        }

        if (ferror(istream) || fclose_if_not_stdin(istream)) {
            bb_perror_msg("%s", *argv); /* Avoid multibyte problems. */
            errs |= EXIT_FAILURE;
        }
    } while (*++argv);

    fflush_stdout_and_exit(errs);
}