projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| a5f90adb KM |
1 | /* Copyright (c) 1979 Regents of the University of California */ |
| 2 | ||
| 3 | static char sccsid[] = "@(#)PACK.c 1.1 %G%"; | |
| 4 | ||
| 5 | #include "h01errs.h" | |
| 6 | ||
| 7 | /* | |
| 8 | * pack(a,i,z) | |
| 9 | * | |
| 10 | * with: a: array[m..n] of t | |
| 11 | * z: packed array[u..v] of t | |
| 12 | * | |
| 13 | * semantics: for j := u to v do | |
| 14 | * z[j] := a[j-u+i]; | |
| 15 | * | |
| 16 | * need to check: | |
| 17 | * 1. i >= m | |
| 18 | * 2. i+(v-u) <= n (i.e. i-m <= (n-m)-(v-u)) | |
| 19 | * | |
| 20 | * on stack: lv(z), lv(a), rv(i) (len 4) | |
| 21 | * | |
| 22 | * move w(t)*(v-u+1) bytes from lv(a)+w(t)*(i-m) to lv(z) | |
| 23 | */ | |
| 24 | ||
| 25 | PACK(i, a, z, size_a, lb_a, ub_a, size_z) | |
| 26 | ||
| 27 | int i; /* subscript into a to begin packing */ | |
| 28 | char *a; /* pointer to structure a */ | |
| 29 | char *z; /* pointer to structure z */ | |
| 30 | int size_a; /* sizeof(a_type) */ | |
| 31 | int lb_a; /* lower bound of structure a */ | |
| 32 | int ub_a; /* (upper bound of a) - (lb_a + sizeof(z_type)) */ | |
| 33 | int size_z; /* sizeof(z_type) */ | |
| 34 | { | |
| 35 | int subscr; | |
| 36 | register char *cp; | |
| 37 | register char *zp = z; | |
| 38 | register char *limit; | |
| 39 | ||
| 40 | subscr = i - lb_a; | |
| 41 | if (subscr < 0 || subscr > ub_a) { | |
| 42 | ERROR(EPACK, i); | |
| 43 | return; | |
| 44 | } | |
| 45 | cp = &a[subscr * size_a]; | |
| 46 | limit = cp + size_z; | |
| 47 | do { | |
| 48 | *zp++ = *cp++; | |
| 49 | } while (cp < limit); | |
| 50 | } |