source: MondoRescue/branches/stable/mindi-busybox/coreutils/tr.c@ 1770

/* vi: set sw=4 ts=4: */
/*
 * Mini tr implementation for busybox
 *
 ** Copyright (c) 1987,1997, Prentice Hall   All rights reserved.
 *
 * The name of Prentice Hall may not be used to endorse or promote
 * products derived from this software without specific prior
 * written permission.
 *
 * Copyright (c) Michiel Huisjes
 *
 * This version of tr is adapted from Minix tr and was modified
 * by Erik Andersen <andersen@codepoet.org> to be used in busybox.
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */
/* http://www.opengroup.org/onlinepubs/009695399/utilities/tr.html
 * TODO: xdigit, graph, print
 */
#include "libbb.h"

#define ASCII 0377

#define TR_OPT_complement   (1<<0)
#define TR_OPT_delete       (1<<1)
#define TR_OPT_squeeze_reps (1<<2)

static void map(char *pvector,
        unsigned char *string1, unsigned int string1_len,
        unsigned char *string2, unsigned int string2_len)
{
    char last = '0';
    unsigned int i, j;

    for (j = 0, i = 0; i < string1_len; i++) {
        if (string2_len <= j)
            pvector[string1[i]] = last;
        else
            pvector[string1[i]] = last = string2[j++];
    }
}

/* supported constructs:
 *   Ranges,  e.g.,  [0-9]  ==>  0123456789
 *   Escapes, e.g.,  \a     ==>  Control-G
 *   Character classes, e.g. [:upper:] ==> A ... Z
 */
static unsigned int expand(const char *arg, char *buffer)
{
    char *buffer_start = buffer;
    unsigned i; /* XXX: FIXME: use unsigned char? */
    unsigned char ac;
#define CLO ":]\0"
    static const char classes[] ALIGN1 =
        "alpha"CLO "alnum"CLO "digit"CLO "lower"CLO "upper"CLO "space"CLO
        "blank"CLO "punct"CLO "cntrl"CLO;
#define CLASS_invalid 0 /* we increment the retval */
#define CLASS_alpha 1
#define CLASS_alnum 2
#define CLASS_digit 3
#define CLASS_lower 4
#define CLASS_upper 5
#define CLASS_space 6
#define CLASS_blank 7
#define CLASS_punct 8
#define CLASS_cntrl 9
//#define CLASS_xdigit 10
//#define CLASS_graph 11
//#define CLASS_print 12
    while (*arg) {
        if (*arg == '\\') {
            arg++;
            *buffer++ = bb_process_escape_sequence(&arg);
        } else if (*(arg+1) == '-') {
            ac = *(arg+2);
            if (ac == 0) {
                *buffer++ = *arg++;
                continue;
            }
            i = *arg;
            while (i <= ac)
                *buffer++ = i++;
            arg += 3; /* Skip the assumed a-z */
        } else if (*arg == '[') {
            arg++;
            i = *arg++;
            if (ENABLE_FEATURE_TR_CLASSES && i == ':') {
                smalluint j;
                { /* not really pretty.. */
                    char *tmp = xstrndup(arg, 7); // warning: xdigit needs 8, not 7
                    j = index_in_strings(classes, tmp) + 1;
                    free(tmp);
                }
                if (j == CLASS_alnum || j == CLASS_digit) {
                    for (i = '0'; i <= '9'; i++)
                        *buffer++ = i;
                }
                if (j == CLASS_alpha || j == CLASS_alnum || j == CLASS_upper) {
                    for (i = 'A'; i <= 'Z'; i++)
                        *buffer++ = i;
                }
                if (j == CLASS_alpha || j == CLASS_alnum || j == CLASS_lower) {
                    for (i = 'a'; i <= 'z'; i++)
                        *buffer++ = i;
                }
                if (j == CLASS_space || j == CLASS_blank) {
                    *buffer++ = '\t';
                    if (j == CLASS_space) {
                        *buffer++ = '\n';
                        *buffer++ = '\v';
                        *buffer++ = '\f';
                        *buffer++ = '\r';
                    }
                    *buffer++ = ' ';
                }
                if (j == CLASS_punct || j == CLASS_cntrl) {
                    for (i = 0; i <= ASCII; i++)
                        if ((j == CLASS_punct &&
                             isprint(i) && (!isalnum(i)) && (!isspace(i))) ||
                            (j == CLASS_cntrl && iscntrl(i)))
                            *buffer++ = i;
                }
                if (j == CLASS_invalid) {
                    *buffer++ = '[';
                    *buffer++ = ':';
                    continue;
                }
                break;
            }
            if (ENABLE_FEATURE_TR_EQUIV && i == '=') {
                *buffer++ = *arg;
                arg += 3;   /* Skip the closing =] */
                continue;
            }
            if (*arg++ != '-') {
                *buffer++ = '[';
                arg -= 2;
                continue;
            }
            ac = *arg++;
            while (i <= ac)
                *buffer++ = i++;
            arg++;  /* Skip the assumed ']' */
        } else
            *buffer++ = *arg++;
    }
    return (buffer - buffer_start);
}

static int complement(char *buffer, int buffer_len)
{
    int i, j, ix;
    char conv[ASCII + 2];

    ix = 0;
    for (i = 0; i <= ASCII; i++) {
        for (j = 0; j < buffer_len; j++)
            if (buffer[j] == i)
                break;
        if (j == buffer_len)
            conv[ix++] = i & ASCII;
    }
    memcpy(buffer, conv, ix);
    return ix;
}

int tr_main(int argc, char **argv);
int tr_main(int argc, char **argv)
{
    unsigned char *ptr;
    int output_length = 0, input_length;
    int idx = 1;
    int i;
    smalluint flags = 0;
    size_t read_chars = 0, in_index = 0, out_index = 0, c, coded, last = -1;
    RESERVE_CONFIG_UBUFFER(output, BUFSIZ);
    RESERVE_CONFIG_BUFFER(vector, ASCII+1);
    RESERVE_CONFIG_BUFFER(invec,  ASCII+1);
    RESERVE_CONFIG_BUFFER(outvec, ASCII+1);

    if (argc > 1 && argv[idx][0] == '-') {
        for (ptr = (unsigned char *) &argv[idx][1]; *ptr; ptr++) {
            if (*ptr == 'c')
                flags |= TR_OPT_complement;
            else if (*ptr == 'd')
                flags |= TR_OPT_delete;
            else if (*ptr == 's')
                flags |= TR_OPT_squeeze_reps;
            else
                bb_show_usage();
        }
        idx++;
    }
    for (i = 0; i <= ASCII; i++) {
        vector[i] = i;
        invec[i] = outvec[i] = FALSE;
    }

#define tr_buf bb_common_bufsiz1
    if (argv[idx] != NULL) {
        input_length = expand(argv[idx++], tr_buf);
        if (flags & TR_OPT_complement)
            input_length = complement(tr_buf, input_length);
        if (argv[idx] != NULL) {
            if (*argv[idx] == '\0')
                bb_error_msg_and_die("STRING2 cannot be empty");
            output_length = expand(argv[idx], output);
            map(vector, tr_buf, input_length, output, output_length);
        }
        for (i = 0; i < input_length; i++)
            invec[(unsigned char)tr_buf[i]] = TRUE;
        for (i = 0; i < output_length; i++)
            outvec[output[i]] = TRUE;
    }

    for (;;) {
        /* If we're out of input, flush output and read more input. */
        if (in_index == read_chars) {
            if (out_index) {
                xwrite(STDOUT_FILENO, (char *)output, out_index);
                out_index = 0;
            }
            read_chars = read(STDIN_FILENO, tr_buf, BUFSIZ);
            if (read_chars <= 0) {
                if (write(STDOUT_FILENO, (char *)output, out_index) != out_index)
                    bb_perror_msg(bb_msg_write_error);
                exit(EXIT_SUCCESS);
            }
            in_index = 0;
        }
        c = tr_buf[in_index++];
        coded = vector[c];
        if ((flags & TR_OPT_delete) && invec[c])
            continue;
        if ((flags & TR_OPT_squeeze_reps) && last == coded &&
            (invec[c] || outvec[coded]))
            continue;
        output[out_index++] = last = coded;
    }
    /* NOTREACHED */
    return EXIT_SUCCESS;
}