diff options
Diffstat (limited to 'src/wc.c')
| -rw-r--r-- | src/wc.c | 112 |
1 files changed, 73 insertions, 39 deletions
@@ -1,5 +1,5 @@ /* wc - print the number of lines, words, and bytes in files - Copyright (C) 1985-2014 Free Software Foundation, Inc. + Copyright (C) 1985-2015 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 @@ -36,6 +36,7 @@ #include "quotearg.h" #include "readtokens0.h" #include "safe-read.h" +#include "stat-size.h" #include "xfreopen.h" #if !defined iswspace && !HAVE_ISWSPACE @@ -116,9 +117,14 @@ Usage: %s [OPTION]... [FILE]...\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. A word is a non-zero-length sequence of characters\n\ -delimited by white space.\n\ +more than one FILE is specified. A word is a non-zero-length sequence of\n\ +characters delimited by white space.\n\ +"), stdout); + + emit_stdin_note (); + + fputs (_("\ +\n\ The options below may be used to select which counts are printed, always in\n\ the following order: newline, word, character, byte, maximum line length.\n\ -c, --bytes print the byte counts\n\ @@ -129,12 +135,12 @@ the following order: newline, word, character, byte, maximum line length.\n\ --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\ + -L, --max-line-length print the maximum display width\n\ -w, --words print the word counts\n\ "), stdout); fputs (HELP_OPTION_DESCRIPTION, stdout); fputs (VERSION_OPTION_DESCRIPTION, stdout); - emit_ancillary_info (); + emit_ancillary_info (PROGRAM_NAME); } exit (status); } @@ -184,9 +190,10 @@ write_counts (uintmax_t lines, /* 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. + CURRENT_POS is the current file offset if known, negative if unknown. Return true if successful. */ static bool -wc (int fd, char const *file_x, struct fstatus *fstatus) +wc (int fd, char const *file_x, struct fstatus *fstatus, off_t current_pos) { bool ok = true; char buf[BUFFER_SIZE + 1]; @@ -229,42 +236,43 @@ wc (int fd, char const *file_x, struct fstatus *fstatus) 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, 0, SEEK_CUR)) != -1 - && (end_pos = lseek (fd, 0, SEEK_END)) != -1) + /* For sized files, seek to one st_blksize before EOF rather than to EOF. + This works better for files in proc-like file systems where + the size is only approximate. */ + if (! fstatus->failed && usable_st_size (&fstatus->st) + && 0 <= fstatus->st.st_size) { - /* 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; + size_t end_pos = fstatus->st.st_size; + off_t hi_pos = end_pos - end_pos % (ST_BLKSIZE (fstatus->st) + 1); + if (current_pos < 0) + current_pos = lseek (fd, 0, SEEK_CUR); + if (0 <= current_pos && current_pos < hi_pos + && 0 <= lseek (fd, hi_pos, SEEK_CUR)) + bytes = hi_pos - current_pos; } - else + + fdadvise (fd, 0, 0, FADVISE_SEQUENTIAL); + while ((bytes_read = safe_read (fd, buf, BUFFER_SIZE)) > 0) { - fdadvise (fd, 0, 0, FADVISE_SEQUENTIAL); - while ((bytes_read = safe_read (fd, buf, BUFFER_SIZE)) > 0) + if (bytes_read == SAFE_READ_ERROR) { - if (bytes_read == SAFE_READ_ERROR) - { - error (0, errno, "%s", file); - ok = false; - break; - } - bytes += bytes_read; + 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. */ + bool long_lines = false; while ((bytes_read = safe_read (fd, buf, BUFFER_SIZE)) > 0) { - char *p = buf; - if (bytes_read == SAFE_READ_ERROR) { error (0, errno, "%s", file); @@ -272,12 +280,38 @@ wc (int fd, char const *file_x, struct fstatus *fstatus) break; } - while ((p = memchr (p, '\n', (buf + bytes_read) - p))) + bytes += bytes_read; + + char *p = buf; + char *end = p + bytes_read; + uintmax_t plines = lines; + + if (! long_lines) { - ++p; - ++lines; + /* Avoid function call overhead for shorter lines. */ + while (p != end) + lines += *p++ == '\n'; } - bytes += bytes_read; + else + { + /* memchr is more efficient with longer lines. */ + while ((p = memchr (p, '\n', end - p))) + { + ++p; + ++lines; + } + } + + /* If the average line length in the block is >= 15, then use + memchr for the next block, where system specific optimizations + may outweigh function call overhead. + FIXME: This line length was determined in 2015, on both + x86_64 and ppc64, but it's worth re-evaluating in future with + newer compilers, CPUs, or memchr() implementations etc. */ + if (lines - plines <= bytes_read / 15) + long_lines = true; + else + long_lines = false; } } #if MB_LEN_MAX > 1 @@ -500,7 +534,7 @@ wc_file (char const *file, struct fstatus *fstatus) have_read_stdin = true; if (O_BINARY && ! isatty (STDIN_FILENO)) xfreopen (NULL, "rb", stdin); - return wc (STDIN_FILENO, file, fstatus); + return wc (STDIN_FILENO, file, fstatus, -1); } else { @@ -512,7 +546,7 @@ wc_file (char const *file, struct fstatus *fstatus) } else { - bool ok = wc (fd, file, fstatus); + bool ok = wc (fd, file, fstatus, 0); if (close (fd) != 0) { error (0, errno, "%s", file); @@ -530,7 +564,7 @@ wc_file (char const *file, struct fstatus *fstatus) 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) +get_input_fstatus (size_t nfiles, char *const *file) { struct fstatus *fstatus = xnmalloc (nfiles ? nfiles : 1, sizeof *fstatus); @@ -542,7 +576,7 @@ get_input_fstatus (int nfiles, char *const *file) fstatus[0].failed = 1; else { - int i; + size_t i; for (i = 0; i < nfiles; i++) fstatus[i].failed = (! file[i] || STREQ (file[i], "-") @@ -558,7 +592,7 @@ get_input_fstatus (int nfiles, char *const *file) get_input_fstatus optimizes. */ static int _GL_ATTRIBUTE_PURE -compute_number_width (int nfiles, struct fstatus const *fstatus) +compute_number_width (size_t nfiles, struct fstatus const *fstatus) { int width = 1; @@ -566,7 +600,7 @@ compute_number_width (int nfiles, struct fstatus const *fstatus) { int minimum_width = 1; uintmax_t regular_total = 0; - int i; + size_t i; for (i = 0; i < nfiles; i++) if (! fstatus[i].failed) @@ -592,7 +626,7 @@ main (int argc, char **argv) { bool ok; int optc; - int nfiles; + size_t nfiles; char **files; char *files_from = NULL; struct fstatus *fstatus; @@ -797,5 +831,5 @@ main (int argc, char **argv) if (have_read_stdin && close (STDIN_FILENO) != 0) error (EXIT_FAILURE, errno, "-"); - exit (ok ? EXIT_SUCCESS : EXIT_FAILURE); + return ok ? EXIT_SUCCESS : EXIT_FAILURE; } |