ref: e55cb65c247a9cdfa0528d34dec70d435898d098
dir: /sys/src/cmd/comm.c/
#include <u.h> #include <libc.h> #include <bio.h> #define LB 2048 int one; int two; int three; char *ldr[3]; Biobuf *ib1; Biobuf *ib2; Biobuf *openfil(char*); int rd(Biobuf*, char*); void wr(char*, int); void copy(Biobuf*, char*, int); int compare(char*, char*); void main(int argc, char *argv[]) { int l; char lb1[LB],lb2[LB]; ldr[0] = ""; ldr[1] = "\t"; ldr[2] = "\t\t"; l = 1; ARGBEGIN{ case '1': if(!one) { one = 1; ldr[1][0] = ldr[2][l--] = '\0'; } break; case '2': if(!two) { two = 1; ldr[2][l--] = '\0'; } break; case '3': three = 1; break; default: goto Usage; }ARGEND if(argc < 2) { Usage: fprint(2, "usage: comm [-123] file1 file2\n"); exits("usage"); } ib1 = openfil(argv[0]); ib2 = openfil(argv[1]); if(rd(ib1,lb1) < 0){ if(rd(ib2,lb2) < 0) exits(0); copy(ib2,lb2,2); } if(rd(ib2,lb2) < 0) copy(ib1,lb1,1); for(;;){ switch(compare(lb1,lb2)) { case 0: wr(lb1,3); if(rd(ib1,lb1) < 0) { if(rd(ib2,lb2) < 0) exits(0); copy(ib2,lb2,2); } if(rd(ib2,lb2) < 0) copy(ib1,lb1,1); continue; case 1: wr(lb1,1); if(rd(ib1,lb1) < 0) copy(ib2,lb2,2); continue; case 2: wr(lb2,2); if(rd(ib2,lb2) < 0) copy(ib1,lb1,1); continue; } } } int rd(Biobuf *file, char *buf) { int i, c; i = 0; while((c = Bgetc(file)) != Beof) { *buf = c; if(c == '\n' || i > LB-2) { *buf = '\0'; return 0; } i++; buf++; } return -1; } void wr(char *str, int n) { switch(n){ case 1: if(one) return; break; case 2: if(two) return; break; case 3: if(three) return; } print("%s%s\n", ldr[n-1],str); } void copy(Biobuf *ibuf, char *lbuf, int n) { do wr(lbuf,n); while(rd(ibuf,lbuf) >= 0); exits(0); } int compare(char *a, char *b) { while(*a == *b){ if(*a == '\0') return 0; a++; b++; } if(*a < *b) return 1; return 2; } Biobuf* openfil(char *s) { Biobuf *b; if(s[0]=='-' && s[1]==0) s = "/fd/0"; b = Bopen(s, OREAD); if(b) return b; fprint(2,"comm: cannot open %s: %r\n",s); exits("open"); return 0; /* shut up ken */ }