| 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 | } |