busybox/coreutils/tr.c

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/* vi: set sw=4 ts=4: */
/*
* Mini tr implementation for busybox
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*
** 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.
*
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* 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.
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*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
/* 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.
#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,
};
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static void map(char *pvector,
char *string1, unsigned string1_len,
char *string2, unsigned string2_len)
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{
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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++];
}
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}
/* 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?)
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* 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)
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{
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++;
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}
return pos;
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}
/* NB: buffer is guaranteed to be at least TR_BUFSIZE
* (which is >= ASCII) big.
*/
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static int complement(char *buffer, int buffer_len)
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{
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;
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}
memcpy(buffer, conv, len);
return len;
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}
int tr_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int tr_main(int argc UNUSED_PARAM, char **argv)
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{
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int i;
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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 */
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}
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/* -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";
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opts = getopt32(argv, "+Ccds"); /* '+': stop at first non-option */
argv += optind;
str1_length = expand(*argv++, &str1);
str2_length = 0;
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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++];
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if ((opts & TR_OPT_delete) && invec[c])
continue;
coded = vector[c];
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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;
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}