Commit | Line | Data |
---|---|---|
d755da8b RC |
1 | /* setmat.c 4.1 83/03/09 */ |
2 | /* | |
3 | * setmat: set the value in m[r, c] to nval. | |
4 | */ | |
5 | ||
6 | #include "bit.h" | |
7 | ||
8 | setmat(m, rows, cols, r, c, nval) | |
9 | bitmat m; | |
10 | int rows, cols, r, c, nval; | |
11 | { | |
12 | register int offset, thisbit; | |
13 | ||
14 | if (r<0 || c<0 || r>=rows || c>=cols) { | |
15 | #ifdef TRACE | |
16 | if (trace) | |
17 | fprintf(trace, "setmat range error: (%d, %d) <- %d in a (%d, %d) matrix %x\n", r, c, nval, rows, cols, m); | |
18 | #endif | |
19 | ||
20 | return; | |
21 | } | |
22 | offset = r*((cols+7)>>3) + (c>>3); | |
23 | thisbit = 0x80 >> (c&7); | |
24 | if (nval) | |
25 | m[offset] |= thisbit; | |
26 | else | |
27 | m[offset] &= ~thisbit; | |
28 | } |