能否能过 fcntl() 获取文本文体的行数？？

cyberpsyche

不想手动去统计文件中'\n'的数量，因为文件很多，这样可能效率不高。请问能不能用fcntl()这样的函数实现这个功能。

不知道 wc 程序是如何得到文件行数的？？？

谢谢

gotop2004

fcntl()没有用过！不过实现这种功能的方法很多！

对于unix文本结尾处只有个'\n'
对于windows文本结尾处有'\r\n'！      这个是关键要注意！

知道了上面的东西后，你用什么函数来做都行，比如用fgetc（）来读入每个字符，根据条件比较！就ok了！

弥敦路九号

估计没啥好办法了吧.这段是在网在找的
/*  Example: Word Counting
        Source: K&R2, p.20
*/

#include <stdio.h>

#define IN 1 /* inside a word */
#define OUT 2 /* outside a word */

/* count lines, words, and characters in input */

void main () {
        int c, nl, nw, nc, state;

        state = OUT;
        nl = nw = nc = 0;
        while ((c = getchar()) != EOF) {
                ++nc;
                if (c == '\n')
                        ++nl;
                if (c == ' ' || c == '\n' || c == '\t')
                        state = OUT;
                else if (state == OUT) {
                        state = IN;
                        ++nw;
                }               
        }
        printf("%d %d %d\n", nl, nw, nc);
}

弥敦路九号

4.4bsd的wc也是统计\n的.

1. 
   
2. /*
   
3. * Copyright (c) 1980, 1987, 1991, 1993
   
4. *        The Regents of the University of California.  All rights reserved.
   
5. *
   
6. * Redistribution and use in source and binary forms, with or without
   
7. * modification, are permitted provided that the following conditions
   
8. * are met:
   
9. * 1. Redistributions of source code must retain the above copyright
   
10. *    notice, this list of conditions and the following disclaimer.
    
11. * 2. Redistributions in binary form must reproduce the above copyright
    
12. *    notice, this list of conditions and the following disclaimer in the
    
13. *    documentation and/or other materials provided with the distribution.
    
14. * 3. All advertising materials mentioning features or use of this software
    
15. *    must display the following acknowledgement:
    
16. *        This product includes software developed by the University of
    
17. *        California, Berkeley and its contributors.
    
18. * 4. Neither the name of the University nor the names of its contributors
    
19. *    may be used to endorse or promote products derived from this software
    
20. *    without specific prior written permission.
    
21. *
    
22. * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
    
23. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    
24. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    
25. * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
    
26. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    
27. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
    
28. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
    
29. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
    
30. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
    
31. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    
32. * SUCH DAMAGE.
    
33. */
    
34. 
    
35. #ifndef lint
    
36. static char copyright[] =
    
37. "@(#) Copyright (c) 1980, 1987, 1991, 1993\n\
    
38.         The Regents of the University of California.  All rights reserved.\n";
    
39. #endif /* not lint */
    
40. 
    
41. #ifndef lint
    
42. static char sccsid[] = "@(#)wc.c        8.2 (Berkeley) 5/2/95";
    
43. #endif /* not lint */
    
44. 
    
45. #include <sys/param.h>
    
46. #include <sys/stat.h>
    
47. #include <fcntl.h>
    
48. #include <unistd.h>
    
49. #include <errno.h>
    
50. #include <stdio.h>
    
51. #include <stdlib.h>
    
52. #include <string.h>
    
53. #include <ctype.h>
    
54. 
    
55. u_long tlinect, twordct, tcharct;
    
56. int doline, doword, dochar;
    
57. 
    
58. void cnt __P((char *));
    
59. void err __P((const char *, ...));
    
60. void usage __P((void));
    
61. 
    
62. int
    
63. main(argc, argv)
    
64.         int argc;
    
65.         char *argv[];
    
66. {
    
67.         register int ch;
    
68.         int total;
    
69. 
    
70.         while ((ch = getopt(argc, argv, "lwc")) != EOF)
    
71.                 switch((char)ch) {
    
72.                 case 'l':
    
73.                         doline = 1;
    
74.                         break;
    
75.                 case 'w':
    
76.                         doword = 1;
    
77.                         break;
    
78.                 case 'c':
    
79.                         dochar = 1;
    
80.                         break;
    
81.                 case '?':
    
82.                 default:
    
83.                         usage();
    
84.                 }
    
85.         argv += optind;
    
86.         argc -= optind;
    
87. 
    
88.         /* Wc's flags are on by default. */
    
89.         if (doline + doword + dochar == 0)
    
90.                 doline = doword = dochar = 1;
    
91. 
    
92.         total = 0;
    
93.         if (!*argv) {
    
94.                 cnt(NULL);
    
95.                 (void)printf("\n");
    
96.         }
    
97.         else do {
    
98.                 cnt(*argv);
    
99.                 (void)printf(" %s\n", *argv);
    
100.                 ++total;
     
101.         } while(*++argv);
     
102. 
     
103.         if (total > 1) {
     
104.                 if (doline)
     
105.                         (void)printf(" %7ld", tlinect);
     
106.                 if (doword)
     
107.                         (void)printf(" %7ld", twordct);
     
108.                 if (dochar)
     
109.                         (void)printf(" %7ld", tcharct);
     
110.                 (void)printf(" total\n");
     
111.         }
     
112.         exit(0);
     
113. }
     
114. 
     
115. void
     
116. cnt(file)
     
117.         char *file;
     
118. {
     
119.         register u_char *p;
     
120.         register short gotsp;
     
121.         register int ch, len;
     
122.         register u_long linect, wordct, charct;
     
123.         struct stat sb;
     
124.         int fd;
     
125.         u_char buf[MAXBSIZE];
     
126. 
     
127.         fd = STDIN_FILENO;
     
128.         linect = wordct = charct = 0;
     
129.         if (file) {
     
130.                 if ((fd = open(file, O_RDONLY, 0)) < 0)
     
131.                         err("%s: %s", file, strerror(errno));
     
132.                 if (doword)
     
133.                         goto word;
     
134.                 /*
     
135.                  * Line counting is split out because it's a lot faster to get
     
136.                  * lines than to get words, since the word count requires some
     
137.                  * logic.
     
138.                  */
     
139.                 if (doline) {
     
140.                         while (len = read(fd, buf, MAXBSIZE)) {
     
141.                                 if (len == -1)
     
142.                                         err("%s: %s", file, strerror(errno));
     
143.                                 charct += len;
     
144.                                 for (p = buf; len--; ++p)
     
145.                                         if (*p == '\n')
     
146.                                                 ++linect;
     
147.                         }
     
148.                         tlinect += linect;
     
149.                         (void)printf(" %7lu", linect);
     
150.                         if (dochar) {
     
151.                                 tcharct += charct;
     
152.                                 (void)printf(" %7lu", charct);
     
153.                         }
     
154.                         (void)close(fd);
     
155.                         return;
     
156.                 }
     
157.                 /*
     
158.                  * If all we need is the number of characters and it's a
     
159.                  * regular or linked file, just stat the puppy.
     
160.                  */
     
161.                 if (dochar) {
     
162.                         if (fstat(fd, &sb))
     
163.                                 err("%s: %s", file, strerror(errno));
     
164.                         if (S_ISREG(sb.st_mode)) {
     
165.                                 (void)printf(" %7qu", sb.st_size);
     
166.                                 tcharct += sb.st_size;
     
167.                                 (void)close(fd);
     
168.                                 return;
     
169.                         }
     
170.                 }
     
171.         }
     
172. 
     
173.         /* Do it the hard way... */
     
174. word:        for (gotsp = 1; len = read(fd, buf, MAXBSIZE);) {
     
175.                 if (len == -1)
     
176.                         err("%s: %s", file, strerror(errno));
     
177.                 /*
     
178.                  * This loses in the presence of multi-byte characters.
     
179.                  * To do it right would require a function to return a
     
180.                  * character while knowing how many bytes it consumed.
     
181.                  */
     
182.                 charct += len;
     
183.                 for (p = buf; len--;) {
     
184.                         ch = *p++;
     
185.                         if (ch == '\n')
     
186.                                 ++linect;
     
187.                         if (isspace(ch))
     
188.                                 gotsp = 1;
     
189.                         else if (gotsp) {
     
190.                                 gotsp = 0;
     
191.                                 ++wordct;
     
192.                         }
     
193.                 }
     
194.         }
     
195.         if (doline) {
     
196.                 tlinect += linect;
     
197.                 (void)printf(" %7lu", linect);
     
198.         }
     
199.         if (doword) {
     
200.                 twordct += wordct;
     
201.                 (void)printf(" %7lu", wordct);
     
202.         }
     
203.         if (dochar) {
     
204.                 tcharct += charct;
     
205.                 (void)printf(" %7lu", charct);
     
206.         }
     
207.         (void)close(fd);
     
208. }
     
209. 
     
210. void
     
211. usage()
     
212. {
     
213.         (void)fprintf(stderr, "usage: wc [-clw] [files]\n");
     
214.         exit(1);
     
215. }
     
216. 
     
217. #if __STDC__
     
218. #include <stdarg.h>
     
219. #else
     
220. #include <varargs.h>
     
221. #endif
     
222. 
     
223. void
     
224. #if __STDC__
     
225. err(const char *fmt, ...)
     
226. #else
     
227. err(fmt, va_alist)
     
228.         char *fmt;
     
229.         va_dcl
     
230. #endif
     
231. {
     
232.         va_list ap;
     
233. #if __STDC__
     
234.         va_start(ap, fmt);
     
235. #else
     
236.         va_start(ap);
     
237. #endif
     
238.         (void)fprintf(stderr, "wc: ");
     
239.         (void)vfprintf(stderr, fmt, ap);
     
240.         va_end(ap);
     
241.         (void)fprintf(stderr, "\n");
     
242.         exit(1);
     
243.         /* NOTREACHED */
     
244. }
     
245. 
     

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