1 #if !defined(lint) && defined(DOSCCS)
2 static char sccsid[] = "@(#)diffh.c 4.4 11/27/85";
3 #endif
4
5 #include <stdio.h>
6 #include <ctype.h>
7 #include <sys/types.h>
8 #include <sys/stat.h>
9 #include <stdlib.h>
10
11 #define C 3
12 #define RANGE 30
13 #define LEN 255
14 #define INF 16384
15
16 char *text[2][RANGE];
17 long lineno[2] = {1, 1}; /*no. of 1st stored line in each file*/
18 int ntext[2]; /*number of stored lines in each*/
19 long n0,n1; /*scan pointer in each*/
20 int bflag;
21 int debug = 0;
22 FILE *file[2];
23
24 /* declarations */
25 void error(char *, char *);
26 char cmp(char *, char *);
27 void range(long, int);
28 void change(long, int, long, int, char *);
29 int output(int, int);
30 void progerr(char *);
31 int hardsynch();
32 int easysynch();
33 void movstr(char *, char *t);
34 void clrl(int, long);
35
36 /* return pointer to line n of file f*/
getl(f,n)37 char *getl(f,n)
38 long n;
39 {
40 register char *t;
41 register int delta, nt;
42 again:
43 delta = n - lineno[f];
44 nt = ntext[f];
45 if(delta<0)
46 progerr("1");
47 if(delta<nt)
48 return(text[f][delta]);
49 if(delta>nt)
50 progerr("2");
51 if(nt>=RANGE)
52 progerr("3");
53 if(feof(file[f]))
54 return(NULL);
55 t = text[f][nt];
56 if(t==0) {
57 t = text[f][nt] = malloc(LEN+1);
58 if(t==NULL) {
59 if(hardsynch())
60 goto again;
61 else
62 progerr("5");
63 }
64 }
65 t = fgets(t,LEN,file[f]);
66 if(t!=NULL)
67 ntext[f]++;
68 return(t);
69 }
70
71 /*remove thru line n of file f from storage*/
clrl(f,n)72 void clrl(f,n)
73 long n;
74 {
75 register int i,j;
76 j = n-lineno[f]+1;
77 for(i=0;i+j<ntext[f];i++)
78 movstr(text[f][i+j],text[f][i]);
79 lineno[f] = n+1;
80 ntext[f] -= j;
81 }
82
movstr(s,t)83 void movstr(s,t)
84 register char *s, *t;
85 {
86 while((*t++= *s++))
87 continue;
88 }
89
main(argc,argv)90 int main(argc,argv)
91 char **argv;
92 {
93 char *s0,*s1;
94 FILE *dopen();
95 register int status = 0;
96
97 while(*argv[1]=='-') {
98 argc--;
99 argv++;
100 while(*++argv[0])
101 if(*argv[0]=='b')
102 bflag++;
103 }
104 if(argc!=3)
105 error("must have 2 file arguments","");
106 file[0] = dopen(argv[1],argv[2]);
107 file[1] = dopen(argv[2],argv[1]);
108 for(;;) {
109 s0 = getl(0,++n0);
110 s1 = getl(1,++n1);
111 if(s0==NULL||s1==NULL)
112 break;
113 if(cmp(s0,s1)!=0) {
114 if(!easysynch()&&!hardsynch())
115 progerr("5");
116 status = 1;
117 } else {
118 clrl(0,n0);
119 clrl(1,n1);
120 }
121 }
122 if(s0==NULL&&s1==NULL)
123 exit(status);
124 if(s0==NULL)
125 output(-1,INF);
126 if(s1==NULL)
127 output(INF,-1);
128 exit(1);
129 }
130
131 /* synch on C successive matches*/
easysynch()132 int easysynch()
133 {
134 int i,j;
135 register int k,m;
136 char *s0,*s1;
137 for(i=j=1;i<RANGE&&j<RANGE;i++,j++) {
138 s0 = getl(0,n0+i);
139 if(s0==NULL)
140 return(output(INF,INF));
141 for(k=C-1;k<j;k++) {
142 for(m=0;m<C;m++)
143 if(cmp(getl(0,n0+i-m),
144 getl(1,n1+k-m))!=0)
145 goto cont1;
146 return(output(i-C,k-C));
147 cont1: ;
148 }
149 s1 = getl(1,n1+j);
150 if(s1==NULL)
151 return(output(INF,INF));
152 for(k=C-1;k<=i;k++) {
153 for(m=0;m<C;m++)
154 if(cmp(getl(0,n0+k-m),
155 getl(1,n1+j-m))!=0)
156 goto cont2;
157 return(output(k-C,j-C));
158 cont2: ;
159 }
160 }
161 return(0);
162 }
163
output(a,b)164 int output(a,b)
165 {
166 register int i;
167 char *s;
168 if(a<0)
169 change(n0-1,0,n1,b,"a");
170 else if(b<0)
171 change(n0,a,n1-1,0,"d");
172 else
173 change(n0,a,n1,b,"c");
174 for(i=0;i<=a;i++) {
175 s = getl(0,n0+i);
176 if(s==NULL)
177 break;
178 printf("< %s",s);
179 clrl(0,n0+i);
180 }
181 n0 += i-1;
182 if(a>=0&&b>=0)
183 printf("---\n");
184 for(i=0;i<=b;i++) {
185 s = getl(1,n1+i);
186 if(s==NULL)
187 break;
188 printf("> %s",s);
189 clrl(1,n1+i);
190 }
191 n1 += i-1;
192 return(1);
193 }
194
change(a,b,c,d,s)195 void change(a,b,c,d,s)
196 long a,c;
197 char *s;
198 {
199 range(a,b);
200 printf("%s",s);
201 range(c,d);
202 printf("\n");
203 }
204
range(a,b)205 void range(a,b)
206 long a;
207 {
208 if(b==INF)
209 printf("%ld,$",a);
210 else if(b==0)
211 printf("%ld",a);
212 else
213 printf("%ld,%ld",a,a+b);
214 }
215
cmp(s,t)216 char cmp(s,t)
217 char *s,*t;
218 {
219 if(debug)
220 printf("%s:%s\n",s,t);
221 for(;;){
222 if(bflag&&isspace(*s)&&isspace(*t)) {
223 while(isspace(*++s)) ;
224 while(isspace(*++t)) ;
225 }
226 if(*s!=*t||*s==0)
227 break;
228 s++;
229 t++;
230 }
231 return(*s-*t);
232 }
233
dopen(f1,f2)234 FILE *dopen(f1,f2)
235 char *f1,*f2;
236 {
237 FILE *f;
238 char b[100],*bptr,*eptr;
239 struct stat statbuf;
240 if(cmp(f1,"-")==0) {
241 if(cmp(f2,"-")==0)
242 error("can't do - -","");
243 else
244 return(stdin);
245 }
246 if(stat(f1,&statbuf)==-1)
247 error("can't access ",f1);
248 if((statbuf.st_mode&S_IFMT)==S_IFDIR) {
249 for(bptr=b;(*bptr= *f1++);bptr++) ;
250 *bptr++ = '/';
251 for(eptr=f2;*eptr;eptr++)
252 if(*eptr=='/'&&eptr[1]!=0&&eptr[1]!='/')
253 f2 = eptr+1;
254 while((*bptr++= *f2++)) ;
255 f1 = b;
256 }
257 f = fopen(f1,"r");
258 if(f==NULL)
259 error("can't open",f1);
260 return(f);
261 }
262
263
progerr(s)264 void progerr(s)
265 char *s;
266 {
267 error("program error ",s);
268 }
269
error(s,t)270 void error(s,t)
271 char *s,*t;
272 {
273 fprintf(stderr,"diffh: %s%s\n",s,t);
274 exit(2);
275 }
276
277 /*stub for resychronization beyond limits of text buf*/
hardsynch()278 int hardsynch()
279 {
280 change(n0,INF,n1,INF,"c");
281 printf("---change record omitted\n");
282 error("can't resynchronize","");
283 return(0);
284 }
285