| 1 | static char sccsid[] = "@(#)old.c 4.2 %G%"; |
| 2 | /* |
| 3 | * sdb - a symbolic debugger for UNIX. |
| 4 | */ |
| 5 | |
| 6 | /* |
| 7 | * This file contains support routines for older versions of the system. |
| 8 | */ |
| 9 | |
| 10 | #ifndef VMUNIX |
| 11 | /* |
| 12 | * These routines are used only if the system |
| 13 | * doesn't have virtual memory. They |
| 14 | * are used only to read the symbol table, which |
| 15 | * is simply kept in VM on VMUNIX. |
| 16 | */ |
| 17 | #include <pagsiz.h> |
| 18 | #include "bio.h" |
| 19 | |
| 20 | bread(brs, buff, nbytes) |
| 21 | struct brbuf *brs; char *buff; { |
| 22 | register int k, nb; |
| 23 | |
| 24 | if (nbytes > 0) { |
| 25 | for (nb=nbytes; nb>0; nb--) { |
| 26 | if (brs->nr == 0) { |
| 27 | brs->nr = read(brs->fd, brs->next=brs->b, BSIZE); |
| 28 | brs->nl = 0; |
| 29 | if (brs->nr < 0) return(-1); |
| 30 | if (brs->nr == 0) return(nbytes-nb); |
| 31 | } |
| 32 | *buff++ = *brs->next++; |
| 33 | brs->nr--; |
| 34 | brs->nl++; |
| 35 | } |
| 36 | } |
| 37 | else { |
| 38 | nbytes = -nbytes; |
| 39 | for (nb=nbytes; nb>0; nb--) { |
| 40 | if (brs->nl == 0) { |
| 41 | if ((k=tell(brs->fd)) >= BSIZE + brs->nr) { |
| 42 | lseek(brs->fd, (long) -(BSIZE + brs->nr), 1); |
| 43 | brs->nl = read(brs->fd, brs->b, BSIZE); |
| 44 | } else { |
| 45 | lseek(brs->fd, 0L, 0); |
| 46 | k = k - brs->nr; |
| 47 | if (k < 0) k = 0; |
| 48 | brs->nl = read(brs->fd, brs->b, k); |
| 49 | } |
| 50 | if (brs->nl == 0) return(nbytes-nb); |
| 51 | brs->next = brs->b + brs->nl; |
| 52 | brs->nr = 0; |
| 53 | } |
| 54 | *--buff = *--brs->next; |
| 55 | brs->nr++; |
| 56 | brs->nl--; |
| 57 | } |
| 58 | } |
| 59 | return(nbytes); |
| 60 | } |
| 61 | |
| 62 | blseek(brs, offset, flag) |
| 63 | struct brbuf *brs; long offset; { |
| 64 | brs->nl = 0; |
| 65 | brs->nr = 0; |
| 66 | return(lseek(brs->fd,offset,flag)); |
| 67 | } |
| 68 | |
| 69 | binit(brs) |
| 70 | struct brbuf *brs; { |
| 71 | brs->nl = brs->nr = 0; |
| 72 | } |
| 73 | |
| 74 | long |
| 75 | tell(fildes) { |
| 76 | return(lseek(fildes, 0L, 1)); |
| 77 | } |
| 78 | #endif |