general speedups with larger buffers and bcmp

SCCS-vsn: usr.bin/cmp/cmp.c 4.3

diff --git a/usr/src/usr.bin/cmp/cmp.c b/usr/src/usr.bin/cmp/cmp.c
index 8339735..7cf10b2 100644 (file)
--- a/usr/src/usr.bin/cmp/cmp.c
+++ b/usr/src/usr.bin/cmp/cmp.c
@@ -1,122 +1,216 @@
-static char *sccsid = "@(#)cmp.c       4.2 (Berkeley) %G%";
+static char *sccsid = "@(#)cmp.c       4.3 (Berkeley) %G%";
+
+#include <sys/param.h>
+#include <sys/file.h>
+#include <sys/stat.h>

 #include <stdio.h>
 #include <ctype.h>
 
 #include <stdio.h>
 #include <ctype.h>
 

-FILE   *file1,*file2;
-int    eflg;
-int    lflg    = 1;
-long   line    = 1;
-long   chr     = 0;
-long   skip1;
-long   skip2;
+#define DIFF   1                       /* found differences */
+#define ERR    2                       /* error during run */
+#define NO     0                       /* no/false */
+#define OK     0                       /* didn't find differences */
+#define YES    1                       /* yes/true */

 
 

-long   otoi();
+static int     fd1,                    /* descriptor, file 1 */
+               fd2,                    /* descriptor, file 2 */
+               silent = NO;            /* if silent on error */
+static short   all = NO;               /* if report all differences */
+static u_char  buf1[MAXBSIZE],         /* read buffers */
+               buf2[MAXBSIZE];
+static char    *file1,                 /* name, file 1 */
+               *file2;                 /* name, file 2 */

 
 

-main(argc, argv)
-char **argv;
+main(argc,argv)
+int    argc;
+char   **argv;

 {
 {

-       register c1, c2;
-       char *arg;
+       extern char     *optarg;        /* getopt externals */
+       extern int      optind;
+       int     ch;                     /* arguments */
+       u_long  otoi();
+
+       while ((ch = getopt(argc,argv,"ls")) != EOF)
+               switch(ch) {
+                       case 'l':               /* print all differences */
+                               all = YES;
+                               break;
+                       case 's':               /* silent return */
+                               silent = YES;
+                               break;
+                       case '?':
+                       default:
+                               usage();
+               }
+       argv += optind;
+       argc -= optind;

 
 

-       if(argc < 3)
-               goto narg;
-       arg = argv[1];
-       if(arg[0] == '-' && arg[1] == 's') {
-               lflg--;
-               argv++;
-               argc--;
+       if (argc < 2 || argc > 4)
+               usage();
+
+       /* open up files; "-" is stdin */
+       file1 = argv[0];
+       if (strcmp(file1,"-") && (fd1 = open(file1,O_RDONLY)) < 0) {
+               if (!silent)
+                       perror(file1);
+               exit(ERR);

        }
        }

-       arg = argv[1];
-       if(arg[0] == '-' && arg[1] == 'l') {
-               lflg++;
-               argv++;
-               argc--;
+       file2 = argv[1];
+       if ((fd2 = open(file2,O_RDONLY)) < 0) {
+               if (!silent)
+                       perror(file2);
+               exit(ERR);

        }
        }

-       if(argc < 3)
-               goto narg;
-       arg = argv[1];
-       if( arg[0]=='-' && arg[1]==0 )
-               file1 = stdin;
-       else if((file1 = fopen(arg, "r")) == NULL)
-               goto barg;
-       arg = argv[2];
-       if((file2 = fopen(arg, "r")) == NULL)
-               goto barg;
-       if (argc>3)
-               skip1 = otoi(argv[3]);
-       if (argc>4)
-               skip2 = otoi(argv[4]);
-       while (skip1) {
-               if ((c1 = getc(file1)) == EOF) {
-                       arg = argv[1];
-                       goto earg;
-               }
-               skip1--;
+
+       /* handle skip arguments */
+       if (argc > 2) {
+               skip(otoi(argv[2]),fd1,file1);
+               if (argc == 4)
+                       skip(otoi(argv[3]),fd2,file2);

        }
        }

-       while (skip2) {
-               if ((c2 = getc(file2)) == EOF) {
-                       arg = argv[2];
-                       goto earg;
+       cmp();
+}
+
+/*
+ * skip --
+ *     skip first part of file
+ */
+static
+skip(dist,fd,fname)
+register u_long        dist;                   /* length in bytes, to skip */
+register int   fd;                     /* file descriptor */
+char   *fname;                         /* file name for error */
+{
+       register int    rlen;           /* read length */
+
+       for (;dist;dist -= rlen) {
+               rlen = MIN(dist,sizeof(buf1));
+               if (read(fd,buf1,rlen) != rlen) {
+                       if (!silent)
+                               printf("cmp: EOF on %s\n",fname);
+                       exit(DIFF);

                }
                }

-               skip2--;

        }
        }

+}

 
 

-loop:
-       chr++;
-       c1 = getc(file1);
-       c2 = getc(file2);
-       if(c1 == c2) {
-               if (c1 == '\n')
-                       line++;
-               if(c1 == EOF) {
-                       if(eflg)
-                               exit(1);
-                       exit(0);
+static
+cmp()
+{
+       register u_char *C1,            /* traveling pointers */
+                       *C2;
+       register int    cnt,            /* counter */
+                       len1,           /* read length 1 */
+                       len2;           /* read length 2 */
+       register long   byte,           /* byte count */
+                       line;           /* line count */
+       short   dfound = NO;            /* if difference found */
+
+       for (byte = 0,line = 1;;) {
+               switch(len1 = read(fd1,buf1,MAXBSIZE)) {
+                       case -1:
+                               if (!silent)
+                                       perror(file1);
+                               exit(ERR);
+                       case 0:
+                               /*
+                                * read of file 1 just failed, find out
+                                * if there's anything left in file 2
+                                */
+                               switch(read(fd2,buf2,1)) {
+                                       case -1:
+                                               if (!silent)
+                                                       perror(file2);
+                                               exit(ERR);
+                                       case 0:
+                                               exit(dfound ? DIFF : OK);
+                                       default:
+                                               if (!silent)
+                                                       printf("cmp: EOF on %s\n",file1);
+                                               exit(DIFF);
+                               }
+               }
+               /*
+                * file1 might be stdio, which means that a read of less than
+                * MAXBSIZE might not mean an EOF.  So, read whatever we read
+                * from file1 from file2.
+                */
+               if ((len2 = read(fd2,buf2,len1)) == -1)  {
+                       if (!silent)
+                               perror(file2);
+                       exit(ERR);
+               }
+               if (bcmp(buf1,buf2,len2)) {
+                       if (silent)
+                               exit(DIFF);
+                       if (all) {
+                               dfound = YES;
+                               for (C1 = buf1,C2 = buf2,cnt = len2;cnt--;++C1,++C2) {
+                                       ++byte;
+                                       if (*C1 != *C2)
+                                               printf("%6ld %3o %3o\n",byte,*C1,*C2);
+                               }
+                       }
+                       else
+                               for (C1 = buf1,C2 = buf2;;++C1,++C2) {
+                                       ++byte;
+                                       if (*C1 != *C2) {
+                                               printf("%s %s differ: char %ld, line %ld\n",file1,file2,byte,line);
+                                               exit(DIFF);
+                                       }
+                                       if (*C1 == '\n')
+                                               ++line;
+                               }
+               }
+               else {
+                       byte += len2;
+                       /*
+                        * here's the real performance problem, we've got to
+                        * count the stupid lines, which means that -l is a
+                        * *much* faster version, i.e., unless you really
+                        * *want* to know the line number, run -sl.
+                        */
+                       if (!all)
+                               for (C1 = buf1,cnt = len2;cnt--;)
+                                       if (*C1++ == '\n')
+                                               ++line;
+               }
+               /*
+                * couldn't read as much from file2 as from file1; checked
+                * here because there might be a difference before we got
+                * to this point, which would have precedence.
+                */
+               if (len2 < len1) {
+                       if (!silent)
+                               printf("cmp: EOF on %s\n",file2);
+                       exit(DIFF);

                }
                }

-               goto loop;
-       }
-       if(lflg == 0)
-               exit(1);
-       if(c1 == EOF) {
-               arg = argv[1];
-               goto earg;
-       }
-       if(c2 == EOF)
-               goto earg;
-       if(lflg == 1) {
-               printf("%s %s differ: char %ld, line %ld\n", argv[1], arg,
-                       chr, line);
-               exit(1);

        }
        }

-       eflg = 1;
-       printf("%6ld %3o %3o\n", chr, c1, c2);
-       goto loop;
-
-narg:
-       printf("cmp: arg count\n");
-       exit(2);
+}

 
 

-barg:
-       if (lflg)
-       perror(arg);
-       exit(2);
+/*
+ * otoi --
+ *     octal/decimal string to u_long
+ */
+static u_long
+otoi(C)
+register char  *C;             /* argument string */
+{
+       register u_long val;    /* return value */
+       register int    base;   /* number base */

 
 

-earg:
-       printf("cmp: EOF on %s\n", arg);
-       exit(1);
+       base = (*C == '0') ? 8 : 10;
+       for (val = 0;isdigit(*C);++C)
+               val = val * base + *C - '0';
+       return(val);

 }
 
 }
 

-long otoi(s)
-char *s;
+/*
+ * usage --
+ *     print usage and die
+ */
+static
+usage()

 {
 {

-       long v;
-       int base;
-
-       v = 0;
-       base = 10;
-       if (*s == '0')
-               base = 8;
-       while(isdigit(*s))
-               v = v*base + *s++ - '0';
-       return(v);
+       fputs("usage: cmp [-ls] file1 file2 [skip1] [skip2]",stderr);
+       exit(ERR);

 }
 }