BSD 4_3 release

[unix-history] / usr / src / bin / diff / diffh.c

static  char sccsid[] = "@(#)diffh.c 4.4 11/27/85";

#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>

#define C 3
#define RANGE 30
#define LEN 255
#define INF 16384

char *text[2][RANGE];
long lineno[2] = {1, 1};        /*no. of 1st stored line in each file*/
int ntext[2];           /*number of stored lines in each*/
long n0,n1;             /*scan pointer in each*/
int bflag;
int debug = 0;
FILE *file[2];

       /* return pointer to line n of file f*/
char *getl(f,n)
long n;
{
       register char *t;
       char *malloc();
       register delta, nt;
again:
       delta = n - lineno[f];
       nt = ntext[f];
       if(delta<0)
               progerr("1");
       if(delta<nt)
               return(text[f][delta]);
       if(delta>nt)
               progerr("2");
       if(nt>=RANGE)
               progerr("3");
       if(feof(file[f]))
               return(NULL);
       t = text[f][nt];
       if(t==0) {
               t = text[f][nt] = malloc(LEN+1);
               if(t==NULL)
                       if(hardsynch())
                               goto again;
                       else
                               progerr("5");
       }
       t = fgets(t,LEN,file[f]);
       if(t!=NULL)
               ntext[f]++;
       return(t);
}

       /*remove thru line n of file f from storage*/
clrl(f,n)
long n;
{
       register i,j;
       j = n-lineno[f]+1;
       for(i=0;i+j<ntext[f];i++)
               movstr(text[f][i+j],text[f][i]);
       lineno[f] = n+1;
       ntext[f] -= j;
}

movstr(s,t)
register char *s, *t;
{
       while(*t++= *s++)
               continue;
}

main(argc,argv)
char **argv;
{
       char *s0,*s1;
       FILE *dopen();
       register int status = 0;

       while(*argv[1]=='-') {
               argc--;
               argv++;
               while(*++argv[0])
                       if(*argv[0]=='b')
                               bflag++;
       }
       if(argc!=3)
               error("must have 2 file arguments","");
       file[0] = dopen(argv[1],argv[2]);
       file[1] = dopen(argv[2],argv[1]);
       for(;;) {
               s0 = getl(0,++n0);
               s1 = getl(1,++n1);
               if(s0==NULL||s1==NULL)
                       break;
               if(cmp(s0,s1)!=0) {
                       if(!easysynch()&&!hardsynch())
                               progerr("5");
                       status = 1;
               } else {
                       clrl(0,n0);
                       clrl(1,n1);
               }
       }
       if(s0==NULL&&s1==NULL)
               exit(status);
       if(s0==NULL)
               output(-1,INF);
       if(s1==NULL)
               output(INF,-1);
       exit(1);
}

       /* synch on C successive matches*/
easysynch()
{
       int i,j;
       register k,m;
       char *s0,*s1;
       for(i=j=1;i<RANGE&&j<RANGE;i++,j++) {
               s0 = getl(0,n0+i);
               if(s0==NULL)
                       return(output(INF,INF));
               for(k=C-1;k<j;k++) {
                       for(m=0;m<C;m++)
                               if(cmp(getl(0,n0+i-m),
                                       getl(1,n1+k-m))!=0)
                                       goto cont1;
                       return(output(i-C,k-C));
cont1:                  ;
               }
               s1 = getl(1,n1+j);
               if(s1==NULL)
                       return(output(INF,INF));
               for(k=C-1;k<=i;k++) {
                       for(m=0;m<C;m++)
                               if(cmp(getl(0,n0+k-m),
                                       getl(1,n1+j-m))!=0)
                                       goto cont2;
                       return(output(k-C,j-C));
cont2:                  ;
               }
       }
       return(0);
}

output(a,b)
{
       register i;
       char *s;
       if(a<0)
               change(n0-1,0,n1,b,"a");
       else if(b<0)
               change(n0,a,n1-1,0,"d");
       else
               change(n0,a,n1,b,"c");
       for(i=0;i<=a;i++) {
               s = getl(0,n0+i);
               if(s==NULL)
                       break;
               printf("< %s",s);
               clrl(0,n0+i);
       }
       n0 += i-1;
       if(a>=0&&b>=0)
               printf("---\n");
       for(i=0;i<=b;i++) {
               s = getl(1,n1+i);
               if(s==NULL)
                       break;
               printf("> %s",s);
               clrl(1,n1+i);
       }
       n1 += i-1;
       return(1);
}

change(a,b,c,d,s)
long a,c;
char *s;
{
       range(a,b);
       printf("%s",s);
       range(c,d);
       printf("\n");
}

range(a,b)
long a;
{
       if(b==INF)
               printf("%ld,$",a);
       else if(b==0)
               printf("%ld",a);
       else
               printf("%ld,%ld",a,a+b);
}

cmp(s,t)
char *s,*t;
{
       if(debug)
               printf("%s:%s\n",s,t);
       for(;;){
               if(bflag&&isspace(*s)&&isspace(*t)) {
                       while(isspace(*++s)) ;
                       while(isspace(*++t)) ;
               }
               if(*s!=*t||*s==0)
                       break;
               s++;
               t++;
       }
       return(*s-*t);
}

FILE *dopen(f1,f2)
char *f1,*f2;
{
       FILE *f;
       char b[100],*bptr,*eptr;
       struct stat statbuf;
       if(cmp(f1,"-")==0)
               if(cmp(f2,"-")==0)
                       error("can't do - -","");
               else
                       return(stdin);
       if(stat(f1,&statbuf)==-1)
               error("can't access ",f1);
       if((statbuf.st_mode&S_IFMT)==S_IFDIR) {
               for(bptr=b;*bptr= *f1++;bptr++) ;
               *bptr++ = '/';
               for(eptr=f2;*eptr;eptr++)
                       if(*eptr=='/'&&eptr[1]!=0&&eptr[1]!='/')
                               f2 = eptr+1;
               while(*bptr++= *f2++) ;
               f1 = b;
       }
       f = fopen(f1,"r");
       if(f==NULL)
               error("can't open",f1);
       return(f);
}


progerr(s)
char *s;
{
       error("program error ",s);
}

error(s,t)
char *s,*t;
{
       fprintf(stderr,"diffh: %s%s\n",s,t);
       exit(2);
}

       /*stub for resychronization beyond limits of text buf*/
hardsynch()
{
       change(n0,INF,n1,INF,"c");
       printf("---change record omitted\n");
       error("can't resynchronize","");
       return(0);
}