source: MondoRescue/branches/3.2/mindi-busybox/coreutils/tr.c@ 3232

/* 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 source tree.
 */
/* http://www.opengroup.org/onlinepubs/009695399/utilities/tr.html
 * TODO: graph, print
 */

//kbuild:lib-$(CONFIG_TR) += tr.o

//config:config TR
//config:   bool "tr"
//config:   default y
//config:   help
//config:     tr is used to squeeze, and/or delete characters from standard
//config:     input, writing to standard output.
//config:
//config:config FEATURE_TR_CLASSES
//config:   bool "Enable character classes (such as [:upper:])"
//config:   default y
//config:   depends on TR
//config:   help
//config:     Enable character classes, enabling commands such as:
//config:     tr [:upper:] [:lower:] to convert input into lowercase.
//config:
//config:config FEATURE_TR_EQUIV
//config:   bool "Enable equivalence classes"
//config:   default y
//config:   depends on TR
//config:   help
//config:     Enable equivalence classes, which essentially add the enclosed
//config:     character to the current set. For instance, tr [=a=] xyz would
//config:     replace all instances of 'a' with 'xyz'. This option is mainly
//config:     useful for cases when no other way of expressing a character
//config:     is possible.

//usage:#define tr_trivial_usage
//usage:       "[-cds] STRING1 [STRING2]"
//usage:#define tr_full_usage "\n\n"
//usage:       "Translate, squeeze, or delete characters from stdin, writing to stdout\n"
//usage:     "\n    -c  Take complement of STRING1"
//usage:     "\n    -d  Delete input characters coded STRING1"
//usage:     "\n    -s  Squeeze multiple output characters of STRING2 into one character"
//usage:
//usage:#define tr_example_usage
//usage:       "$ echo \"gdkkn vnqkc\" | tr [a-y] [b-z]\n"
//usage:       "hello world\n"

#include "libbb.h"

enum {
    ASCII = 256,
    /* string buffer needs to be at least as big as the whole "alphabet".
     * BUFSIZ == ASCII is ok, but we will realloc in expand
     * even for smallest patterns, let's avoid that by using *2:
     */
    TR_BUFSIZ = (BUFSIZ > ASCII*2) ? BUFSIZ : ASCII*2,
};

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

    for (j = 0, i = 0; i < string1_len; i++) {
        if (string2_len <= j)
            pvector[(unsigned char)(string1[i])] = last;
        else
            pvector[(unsigned char)(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
 *   Equiv classess, e.g. [=A=] ==> A   (hmmmmmmm?)
 * not supported:
 *   \ooo-\ooo - octal ranges
 *   [x*N] - repeat char x N times
 *   [x*] - repeat char x until it fills STRING2:
 * # echo qwe123 | /usr/bin/tr 123456789 '[d]'
 * qwe[d]
 * # echo qwe123 | /usr/bin/tr 123456789 '[d*]'
 * qweddd
 */
static unsigned expand(const char *arg, char **buffer_p)
{
    char *buffer = *buffer_p;
    unsigned pos = 0;
    unsigned size = TR_BUFSIZ;
    unsigned i; /* can't be unsigned char: must be able to hold 256 */
    unsigned char ac;

    while (*arg) {
        if (pos + ASCII > size) {
            size += ASCII;
            *buffer_p = buffer = xrealloc(buffer, size);
        }
        if (*arg == '\\') {
            arg++;
            buffer[pos++] = bb_process_escape_sequence(&arg);
            continue;
        }
        if (arg[1] == '-') { /* "0-9..." */
            ac = arg[2];
            if (ac == '\0') { /* "0-": copy verbatim */
                buffer[pos++] = *arg++; /* copy '0' */
                continue; /* next iter will copy '-' and stop */
            }
            i = (unsigned char) *arg;
            while (i <= ac) /* ok: i is unsigned _int_ */
                buffer[pos++] = i++;
            arg += 3; /* skip 0-9 */
            continue;
        }
        if ((ENABLE_FEATURE_TR_CLASSES || ENABLE_FEATURE_TR_EQUIV)
         && *arg == '['
        ) {
            arg++;
            i = (unsigned char) *arg++;
            /* "[xyz...". i=x, arg points to y */
            if (ENABLE_FEATURE_TR_CLASSES && i == ':') { /* [:class:] */
#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
                    "xdigit"CLO;
                enum {
                    CLASS_invalid = 0, /* we increment the retval */
                    CLASS_alpha = 1,
                    CLASS_alnum = 2,
                    CLASS_digit = 3,
                    CLASS_lower = 4,
                    CLASS_upper = 5,
                    CLASS_space = 6,
                    CLASS_blank = 7,
                    CLASS_punct = 8,
                    CLASS_cntrl = 9,
                    CLASS_xdigit = 10,
                    //CLASS_graph = 11,
                    //CLASS_print = 12,
                };
                smalluint j;
                char *tmp;

                /* xdigit needs 8, not 7 */
                i = 7 + (arg[0] == 'x');
                tmp = xstrndup(arg, i);
                j = index_in_strings(classes, tmp) + 1;
                free(tmp);

                if (j == CLASS_invalid)
                    goto skip_bracket;

                arg += i;
                if (j == CLASS_alnum || j == CLASS_digit || j == CLASS_xdigit) {
                    for (i = '0'; i <= '9'; i++)
                        buffer[pos++] = i;
                }
                if (j == CLASS_alpha || j == CLASS_alnum || j == CLASS_upper) {
                    for (i = 'A'; i <= 'Z'; i++)
                        buffer[pos++] = i;
                }
                if (j == CLASS_alpha || j == CLASS_alnum || j == CLASS_lower) {
                    for (i = 'a'; i <= 'z'; i++)
                        buffer[pos++] = i;
                }
                if (j == CLASS_space || j == CLASS_blank) {
                    buffer[pos++] = '\t';
                    if (j == CLASS_space) {
                        buffer[pos++] = '\n';
                        buffer[pos++] = '\v';
                        buffer[pos++] = '\f';
                        buffer[pos++] = '\r';
                    }
                    buffer[pos++] = ' ';
                }
                if (j == CLASS_punct || j == CLASS_cntrl) {
                    for (i = '\0'; i < ASCII; i++) {
                        if ((j == CLASS_punct && isprint_asciionly(i) && !isalnum(i) && !isspace(i))
                         || (j == CLASS_cntrl && iscntrl(i))
                        ) {
                            buffer[pos++] = i;
                        }
                    }
                }
                if (j == CLASS_xdigit) {
                    for (i = 'A'; i <= 'F'; i++) {
                        buffer[pos + 6] = i | 0x20;
                        buffer[pos++] = i;
                    }
                    pos += 6;
                }
                continue;
            }
            /* "[xyz...", i=x, arg points to y */
            if (ENABLE_FEATURE_TR_EQUIV && i == '=') { /* [=CHAR=] */
                buffer[pos++] = *arg; /* copy CHAR */
                if (!arg[0] || arg[1] != '=' || arg[2] != ']')
                    bb_show_usage();
                arg += 3;  /* skip CHAR=] */
                continue;
            }
            /* The rest of "[xyz..." cases is treated as normal
             * string, "[" has no special meaning here:
             * tr "[a-z]" "[A-Z]" can be written as tr "a-z" "A-Z",
             * also try tr "[a-z]" "_A-Z+" and you'll see that
             * [] is not special here.
             */
 skip_bracket:
            arg -= 2; /* points to "[" in "[xyz..." */
        }
        buffer[pos++] = *arg++;
    }
    return pos;
}

/* NB: buffer is guaranteed to be at least TR_BUFSIZE
 * (which is >= ASCII) big.
 */
static int complement(char *buffer, int buffer_len)
{
    int len;
    char conv[ASCII];
    unsigned char ch;

    len = 0;
    ch = '\0';
    while (1) {
        if (memchr(buffer, ch, buffer_len) == NULL)
            conv[len++] = ch;
        if (++ch == '\0')
            break;
    }
    memcpy(buffer, conv, len);
    return len;
}

int tr_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int tr_main(int argc UNUSED_PARAM, char **argv)
{
    int i;
    smalluint opts;
    ssize_t read_chars;
    size_t in_index, out_index;
    unsigned last = UCHAR_MAX + 1; /* not equal to any char */
    unsigned char coded, c;
    char *str1 = xmalloc(TR_BUFSIZ);
    char *str2 = xmalloc(TR_BUFSIZ);
    int str2_length;
    int str1_length;
    char *vector = xzalloc(ASCII * 3);
    char *invec  = vector + ASCII;
    char *outvec = vector + ASCII * 2;

#define TR_OPT_complement   (3 << 0)
#define TR_OPT_delete       (1 << 2)
#define TR_OPT_squeeze_reps (1 << 3)

    for (i = 0; i < ASCII; i++) {
        vector[i] = i;
        /*invec[i] = outvec[i] = FALSE; - done by xzalloc */
    }

    /* -C/-c difference is that -C complements "characters",
     * and -c complements "values" (binary bytes I guess).
     * In POSIX locale, these are the same.
     */

    opt_complementary = "-1";
    opts = getopt32(argv, "+Ccds"); /* '+': stop at first non-option */
    argv += optind;

    str1_length = expand(*argv++, &str1);
    str2_length = 0;
    if (opts & TR_OPT_complement)
        str1_length = complement(str1, str1_length);
    if (*argv) {
        if (argv[0][0] == '\0')
            bb_error_msg_and_die("STRING2 cannot be empty");
        str2_length = expand(*argv, &str2);
        map(vector, str1, str1_length,
                str2, str2_length);
    }
    for (i = 0; i < str1_length; i++)
        invec[(unsigned char)(str1[i])] = TRUE;
    for (i = 0; i < str2_length; i++)
        outvec[(unsigned char)(str2[i])] = TRUE;

    goto start_from;

    /* In this loop, str1 space is reused as input buffer,
     * str2 - as output one. */
    for (;;) {
        /* If we're out of input, flush output and read more input. */
        if ((ssize_t)in_index == read_chars) {
            if (out_index) {
                xwrite(STDOUT_FILENO, str2, out_index);
 start_from:
                out_index = 0;
            }
            read_chars = safe_read(STDIN_FILENO, str1, TR_BUFSIZ);
            if (read_chars <= 0) {
                if (read_chars < 0)
                    bb_perror_msg_and_die(bb_msg_read_error);
                break;
            }
            in_index = 0;
        }
        c = str1[in_index++];
        if ((opts & TR_OPT_delete) && invec[c])
            continue;
        coded = vector[c];
        if ((opts & TR_OPT_squeeze_reps) && last == coded
         && (invec[c] || outvec[coded])
        ) {
            continue;
        }
        str2[out_index++] = last = coded;
    }

    if (ENABLE_FEATURE_CLEAN_UP) {
        free(vector);
        free(str2);
        free(str1);
    }

    return EXIT_SUCCESS;
}