linux下的wc命令的源代码

/* wc - print the number of lines, words, and bytes in files

Copyright (C) 1985, 1991, 1995-2010 Free Software Foundation, Inc.

This program is free software: you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation, either version 3 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program. If not, see . */ /* Written by Paul Rubin, phr@https://www.360docs.net/doc/257187791.html,

and David MacKenzie, djm@https://www.360docs.net/doc/257187791.html,. */

#include

#include

#include

#include

#include

#include

#include

#include "system.h"

#include "argv-iter.h"

#include "error.h"

#include "mbchar.h"

#include "physmem.h"

#include "quote.h"

#include "quotearg.h"

#include "readtokens0.h"

#include "safe-read.h"

#include "xfreopen.h"

#if !defined iswspace && !HAVE_ISWSPACE

# define iswspace(wc) \

((wc) == to_uchar (wc) && isspace (to_uchar (wc)))

#endif

/* The official name of this program (e.g., no `g' prefix). */

#define PROGRAM_NAME "wc"

#define AUTHORS \

proper_name ("Paul Rubin"), \

proper_name ("David MacKenzie")

/* Size of atomic reads. */

#define BUFFER_SIZE (16 * 1024)

/* Cumulative number of lines, words, chars and bytes in all files so far.

max_line_length is the maximum over all files processed so far. */ static uintmax_t total_lines;

static uintmax_t total_words;

static uintmax_t total_chars;

static uintmax_t total_bytes;

static uintmax_t max_line_length;

/* Which counts to print. */

static bool print_lines, print_words, print_chars, print_bytes;

static bool print_linelength;

/* The print width of each count. */

static int number_width;

/* True if we have ever read the standard input. */

static bool have_read_stdin;

/* The result of calling fstat or stat on a file descriptor or file. */

struct fstatus

{

/* If positive, fstat or stat has not been called yet. Otherwise, this is the value returned from fstat or stat. */

int failed;

/* If FAILED is zero, this is the file's status. */

struct stat st;

};

/* For long options that have no equivalent short option, use a non-character as a pseudo short option, starting with CHAR_MAX + 1. */ enum

{

FILES0_FROM_OPTION = CHAR_MAX + 1

};

static struct option const longopts[] =

{

{"bytes", no_argument, NULL, 'c'},

{"chars", no_argument, NULL, 'm'},

{"lines", no_argument, NULL, 'l'},

{"words", no_argument, NULL, 'w'},

{"files0-from", required_argument, NULL, FILES0_FROM_OPTION}, {"max-line-length", no_argument, NULL, 'L'},

{GETOPT_HELP_OPTION_DECL},

{GETOPT_VERSION_OPTION_DECL},

{NULL, 0, NULL, 0}

};

void

usage (int status)

{

if (status != EXIT_SUCCESS)

fprintf (stderr, _("Try `%s --help' for more information.\n"),

program_name);

else

{

printf (_("\

Usage: %s [OPTION]... [FILE]...\n\

or: %s [OPTION]... --files0-from=F\n\

"),

program_name, program_name);

fputs (_("\

Print newline, word, and byte counts for each FILE, and a total line if\n\

more than one FILE is specified. With no FILE, or when FILE is -,\n\

read standard input.\n\

-c, --bytes print the byte counts\n\

-m, --chars print the character counts\n\

-l, --lines print the newline counts\n\

"), stdout);

fputs (_("\

--files0-from=F read input from the files specified by\n\

NUL-terminated names in file F;\n\

If F is - then read names from standard input\n\ -L, --max-line-length print the length of the longest line\n\

-w, --words print the word counts\n\

"), stdout);

fputs (HELP_OPTION_DESCRIPTION, stdout);

fputs (VERSION_OPTION_DESCRIPTION, stdout);

emit_ancillary_info ();

}

exit (status);

}

/* FILE is the name of the file (or NULL for standard input)

associated with the specified counters. */

static void

write_counts (uintmax_t lines,

uintmax_t words,

uintmax_t chars,

uintmax_t bytes,

uintmax_t linelength,

const char *file)

{

static char const format_sp_int[] = " %*s";

char const *format_int = format_sp_int + 1;

char buf[INT_BUFSIZE_BOUND (uintmax_t)];

if (print_lines)

{

printf (format_int, number_width, umaxtostr (lines, buf));

format_int = format_sp_int;

}

if (print_words)

{

printf (format_int, number_width, umaxtostr (words, buf));

format_int = format_sp_int;

}

if (print_chars)

{

printf (format_int, number_width, umaxtostr (chars, buf));

format_int = format_sp_int;

}

if (print_bytes)

{

printf (format_int, number_width, umaxtostr (bytes, buf));

format_int = format_sp_int;

}

if (print_linelength)

{

printf (format_int, number_width, umaxtostr (linelength, buf));

}

if (file)

printf (" %s", file);

putchar ('\n');

}

/* Count words. FILE_X is the name of the file (or NULL for standard input) that is open on descriptor FD. *FSTATUS is its status.

Return true if successful. */

static bool

wc (int fd, char const *file_x, struct fstatus *fstatus)

{

bool ok = true;

char buf[BUFFER_SIZE + 1];

size_t bytes_read;

uintmax_t lines, words, chars, bytes, linelength;

bool count_bytes, count_chars, count_complicated;

char const *file = file_x ? file_x : _("standard input");

lines = words = chars = bytes = linelength = 0;

/* If in the current locale, chars are equivalent to bytes, we prefer counting bytes, because that's easier. */

#if MB_LEN_MAX > 1

if (MB_CUR_MAX > 1)

{

count_bytes = print_bytes;

count_chars = print_chars;

}

else

#endif

{

count_bytes = print_bytes || print_chars;

count_chars = false;

}

count_complicated = print_words || print_linelength;

/* When counting only bytes, save some line- and word-counting overhead. If FD is a `regular' Unix file, using lseek is enough

to get its `size' in bytes. Otherwise, read blocks of BUFFER_SIZE

bytes at a time until EOF. Note that the `size' (number of bytes)

that wc reports is smaller than stats.st_size when the file is not

positioned at its beginning. That's why the lseek calls below are

necessary. For example the command

`(dd ibs=99k skip=1 count=0; ./wc -c) < /etc/group'

should make wc report `0' bytes. */

if (count_bytes && !count_chars && !print_lines && !count_complicated) {

off_t current_pos, end_pos;

if (0 < fstatus->failed)

fstatus->failed = fstat (fd, &fstatus->st);

if (! fstatus->failed && S_ISREG (fstatus->st.st_mode)

&& (current_pos = lseek (fd, (off_t) 0, SEEK_CUR)) != -1

&& (end_pos = lseek (fd, (off_t) 0, SEEK_END)) != -1)

{

/* Be careful here. The current position may actually be

beyond the end of the file. As in the example above. */ bytes = end_pos < current_pos ? 0 : end_pos - current_pos;

}

else

{

while ((bytes_read = safe_read (fd, buf, BUFFER_SIZE)) > 0)

{

if (bytes_read == SAFE_READ_ERROR)

{

error (0, errno, "%s", file);

ok = false;

break;

}

bytes += bytes_read;

}

}

}

else if (!count_chars && !count_complicated)

{

/* Use a separate loop when counting only lines or lines and bytes -- but not chars or words. */

while ((bytes_read = safe_read (fd, buf, BUFFER_SIZE)) > 0)

{

char *p = buf;

if (bytes_read == SAFE_READ_ERROR)

{

error (0, errno, "%s", file);

ok = false;

break;

}

while ((p = memchr (p, '\n', (buf + bytes_read) - p)))

{

++p;

++lines;

}

bytes += bytes_read;

}

}

#if MB_LEN_MAX > 1

# define SUPPORT_OLD_MBRTOWC 1

else if (MB_CUR_MAX > 1)

{

bool in_word = false;

uintmax_t linepos = 0;

DECLARE_ZEROED_AGGREGATE (mbstate_t, state);

bool in_shift = false;

# if SUPPORT_OLD_MBRTOWC

/* Back-up the state before each multibyte character conversion and move the last incomplete character of the buffer to the front

of the buffer. This is needed because we don't know whether

the `mbrtowc' function updates the state when it returns -2, -

this is the ISO C 99 and glibc-2.2 behaviour - or not - amended

ANSI C, glibc-2.1 and Solaris 5.7 behaviour. We don't have an

autoconf test for this, yet. */

size_t prev = 0; /* number of bytes carried over from previous round */ # else

const size_t prev = 0;

# endif

while ((bytes_read = safe_read (fd, buf + prev, BUFFER_SIZE - prev)) > 0)

{

const char *p;

# if SUPPORT_OLD_MBRTOWC

mbstate_t backup_state;

# endif

if (bytes_read == SAFE_READ_ERROR)

{

error (0, errno, "%s", file);

ok = false;

break;

}

bytes += bytes_read;

p = buf;

bytes_read += prev;

do

{

wchar_t wide_char;

size_t n;

if (!in_shift && is_basic (*p))

{

/* Handle most ASCII characters quickly, without calling

mbrtowc(). */

n = 1;

wide_char = *p;

}

else

{

in_shift = true;

# if SUPPORT_OLD_MBRTOWC

backup_state = state;

# endif

n = mbrtowc (&wide_char, p, bytes_read, &state);

if (n == (size_t) -2)

{

# if SUPPORT_OLD_MBRTOWC

state = backup_state;

# endif

break;

}

if (n == (size_t) -1)

{

/* Remember that we read a byte, but don't complain

about the error. Because of the decoding error,

this is a considered to be byte but not a

character (that is, chars is not incremented). */

p++;

bytes_read--;

continue;

}

if (mbsinit (&state))

in_shift = false;

if (n == 0)

{

wide_char = 0;

n = 1;

}

}

p += n;

bytes_read -= n;

chars++;

switch (wide_char)

{

case '\n':

lines++;

/* Fall through. */

case '\r':

case '\f':

if (linepos > linelength)

linelength = linepos;

linepos = 0;

goto mb_word_separator;

case '\t':

linepos += 8 - (linepos % 8);

goto mb_word_separator;

case ' ':

linepos++;

/* Fall through. */

case '\v':

mb_word_separator:

words += in_word;

in_word = false;

break;

default:

if (iswprint (wide_char))

{

int width = wcwidth (wide_char);

if (width > 0)

linepos += width;

if (iswspace (wide_char))

goto mb_word_separator;

in_word = true;

}

break;

}

}

while (bytes_read > 0);

# if SUPPORT_OLD_MBRTOWC

if (bytes_read > 0)

{

if (bytes_read == BUFFER_SIZE)

{

/* Encountered a very long redundant shift sequence. */

p++;

bytes_read--;

}

memmove (buf, p, bytes_read);

}

prev = bytes_read;

# endif

}

if (linepos > linelength)

linelength = linepos;

words += in_word;

}

#endif

else

{

bool in_word = false;

uintmax_t linepos = 0;

while ((bytes_read = safe_read (fd, buf, BUFFER_SIZE)) > 0) {

const char *p = buf;

if (bytes_read == SAFE_READ_ERROR)

{

error (0, errno, "%s", file);

ok = false;

break;

}

bytes += bytes_read;

do

{

switch (*p++)

{

case '\n':

lines++;

/* Fall through. */

case '\r':

case '\f':

if (linepos > linelength)

linelength = linepos;

linepos = 0;

goto word_separator;

case '\t':

linepos += 8 - (linepos % 8);

goto word_separator;

case ' ':

linepos++;

/* Fall through. */

case '\v':

word_separator:

words += in_word;

in_word = false;

break;

default:

if (isprint (to_uchar (p[-1])))

{

linepos++;

if (isspace (to_uchar (p[-1])))

goto word_separator;

in_word = true;

}

break;

}

}

while (--bytes_read);

}

if (linepos > linelength)

linelength = linepos;

words += in_word;

}

if (count_chars < print_chars)

chars = bytes;

write_counts (lines, words, chars, bytes, linelength, file_x); total_lines += lines;

total_words += words;

total_chars += chars;

total_bytes += bytes;

if (linelength > max_line_length)

max_line_length = linelength;

return ok;

}

static bool

wc_file (char const *file, struct fstatus *fstatus)

{

if (! file || STREQ (file, "-"))

{

have_read_stdin = true;

if (O_BINARY && ! isatty (STDIN_FILENO))

xfreopen (NULL, "rb", stdin);

return wc (STDIN_FILENO, file, fstatus);

}

else

{

int fd = open (file, O_RDONLY | O_BINARY);

if (fd == -1)

{

error (0, errno, "%s", file);

return false;

}

else

{

bool ok = wc (fd, file, fstatus);

if (close (fd) != 0)

{

error (0, errno, "%s", file);

return false;

}

return ok;

}

}

}

/* Return the file status for the NFILES files addressed by FILE.

Optimize the case where only one number is printed, for just one

file; in that case we can use a print width of 1, so we don't need

to stat the file. Handle the case of (nfiles == 0) in the same way;

that happens when we don't know how long the list of file names will be. */ static struct fstatus *

get_input_fstatus (int nfiles, char *const *file)

{

struct fstatus *fstatus = xnmalloc (nfiles ? nfiles : 1, sizeof *fstatus);

if (nfiles == 0

|| (nfiles == 1

&& ((print_lines + print_words + print_chars

+ print_bytes + print_linelength)

== 1)))

fstatus[0].failed = 1;

else

{

int i;

for (i = 0; i < nfiles; i++)

fstatus[i].failed = (! file[i] || STREQ (file[i], "-")

? fstat (STDIN_FILENO, &fstatus[i].st)

: stat (file[i], &fstatus[i].st));

}

return fstatus;

}

/* Return a print width suitable for the NFILES files whose status is recorded in FSTATUS. Optimize the same special case that

get_input_fstatus optimizes. */

static int

compute_number_width (int nfiles, struct fstatus const *fstatus) {

int width = 1;

if (0 < nfiles && fstatus[0].failed <= 0)

{

int minimum_width = 1;

uintmax_t regular_total = 0;

int i;

for (i = 0; i < nfiles; i++)

if (! fstatus[i].failed)

{

if (S_ISREG (fstatus[i].st.st_mode))

regular_total += fstatus[i].st.st_size;

else

minimum_width = 7;

}

for (; 10 <= regular_total; regular_total /= 10)

width++;

if (width < minimum_width)

width = minimum_width;

}

return width;

}

int

main (int argc, char **argv)

{

bool ok;

int optc;

int nfiles;

char **files;

char *files_from = NULL;

struct fstatus *fstatus;

struct Tokens tok;

initialize_main (&argc, &argv);

set_program_name (argv[0]);

setlocale (LC_ALL, "");

bindtextdomain (PACKAGE, LOCALEDIR);

textdomain (PACKAGE);

atexit (close_stdout);

/* Line buffer stdout to ensure lines are written atomically and immediately so that processes running in parallel do not intersperse their output. */ setvbuf (stdout, NULL, _IOLBF, 0);

print_lines = print_words = print_chars = print_bytes = false;

print_linelength = false;

total_lines = total_words = total_chars = total_bytes = max_line_length = 0; while ((optc = getopt_long (argc, argv, "clLmw", longopts, NULL)) != -1) switch (optc)

{

case 'c':

print_bytes = true;

break;

case 'm':

print_chars = true;

break;

case 'l':

print_lines = true;

break;

case 'w':

print_words = true;

break;

case 'L':

print_linelength = true;

break;

case FILES0_FROM_OPTION:

files_from = optarg;

break;

case_GETOPT_HELP_CHAR;

case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);

default:

usage (EXIT_FAILURE);

}

if (! (print_lines || print_words || print_chars || print_bytes

|| print_linelength))

print_lines = print_words = print_bytes = true;

bool read_tokens = false;

struct argv_iterator *ai;

if (files_from)

{

FILE *stream;

/* When using --files0-from=F, you may not specify any files

on the command-line. */

if (optind < argc)

{

error (0, 0, _("extra operand %s"), quote (argv[optind]));

fprintf (stderr, "%s\n",

_("file operands cannot be combined with --files0-from"));

usage (EXIT_FAILURE);

}

if (STREQ (files_from, "-"))

stream = stdin;

else

{

stream = fopen (files_from, "r");

if (stream == NULL)

error (EXIT_FAILURE, errno, _("cannot open %s for reading"),

quote (files_from));

}

/* Read the file list into RAM if we can detect its size and that

size is reasonable. Otherwise, we'll read a name at a time. */ struct stat st;

if (fstat (fileno (stream), &st) == 0

&& S_ISREG (st.st_mode)

&& st.st_size <= MIN (10 * 1024 * 1024, physmem_available () / 2))

{

read_tokens = true;

readtokens0_init (&tok);

if (! readtokens0 (stream, &tok) || fclose (stream) != 0)

error (EXIT_FAILURE, 0, _("cannot read file names from %s"),

quote (files_from));

files = tok.tok;

nfiles = tok.n_tok;

ai = argv_iter_init_argv (files);

}

else

{

files = NULL;

nfiles = 0;

ai = argv_iter_init_stream (stream);

}

}

else

{

static char *stdin_only[] = { NULL };

files = (optind < argc ? argv + optind : stdin_only);

nfiles = (optind < argc ? argc - optind : 1);

ai = argv_iter_init_argv (files);

}

fstatus = get_input_fstatus (nfiles, files);

number_width = compute_number_width (nfiles, fstatus);

int i;

ok = true;

for (i = 0; /* */; i++)

{

bool skip_file = false;

enum argv_iter_err ai_err;

char *file_name = argv_iter (ai, &ai_err);

if (ai_err == AI_ERR_EOF)

break;

if (!file_name)

{

switch (ai_err)

{

case AI_ERR_READ:

error (0, errno, _("%s: read error"), quote (files_from));

skip_file = true;

continue;

case AI_ERR_MEM:

xalloc_die ();

default:

assert (!"unexpected error code from argv_iter");

}

}

if (files_from && STREQ (files_from, "-") && STREQ (file_name, "-"))

{

/* Give a better diagnostic in an unusual case:

printf - | wc --files0-from=- */

error (0, 0, _("when reading file names from stdin, "

"no file name of %s allowed"),

quote (file_name));

skip_file = true;

}

if (!file_name[0])

{

/* Diagnose a zero-length file name. When it's one

among many, knowing the record number may help.

FIXME: currently print the record number only with

--files0-from=FILE. Maybe do it for argv, too? */

if (files_from == NULL)

error (0, 0, "%s", _("invalid zero-length file name"));

else

{

/* Using the standard `filename:line-number:' prefix here is

not totally appropriate, since NUL is the separator, not NL,

but it might be better than nothing. */

unsigned long int file_number = argv_iter_n_args (ai);

error (0, 0, "%s:%lu: %s", quotearg_colon (files_from),

file_number, _("invalid zero-length file name"));

}

skip_file = true;

}

if (skip_file)

ok = false;

else

ok &= wc_file (file_name, &fstatus[nfiles ? i : 0]);

}

/* No arguments on the command line is fine. That means read from stdin.

However, no arguments on the --files0-from input stream is an error means don't read anything. */

if (ok && !files_from && argv_iter_n_args (ai) == 0)

ok &= wc_file (NULL, &fstatus[0]);

if (read_tokens)

readtokens0_free (&tok);

if (1 < argv_iter_n_args (ai))

write_counts (total_lines, total_words, total_chars, total_bytes,

max_line_length, _("total"));

argv_iter_free (ai);

free (fstatus);

if (have_read_stdin && close (STDIN_FILENO) != 0)

error (EXIT_FAILURE, errno, "-");

exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);

}