The CWI license is the license applied to early releases of Hack, as detailed here. CWI, the Centrum voor Wiskunde en Informatica, is the new name for the Stichting Mathematisch Centrum. It is a BSD-type license, and one-way (inclusion) compatible with the GNU GFDL. For the purposes of Wikihack, that is perfectly adequate.
NetHack 1.3d, 1.4f, 2.2a and 2.3e contain no explicit license statement, but include the line:
/* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
which probably means the CWI license applies.
License statement[]
Jay Fenlason has stated:
#include "hack.h"
4. #ifndef NOWORM
5. #include "def.wseg.h"
6.
7. struct wseg *wsegs[32]; /* linked list, tail first */
8. struct wseg *wheads[32];
9. long wgrowtime[32];
10.
11. getwn(mtmp) struct monst *mtmp; {
12. register tmp;
13. for(tmp=1; tmp<32; tmp++) if(!wsegs[tmp]) {
14. mtmp->wormno = tmp;
15. return(1);
16. }
17. return(0); /* level infested with worms */
18. }
19.
20. /* called to initialize a worm unless cut in half */
21. initworm(mtmp) struct monst *mtmp; {
22. register struct wseg *wtmp;
23. register tmp = mtmp->wormno;
24. if(!tmp) return;
25. wheads[tmp] = wsegs[tmp] = wtmp = newseg();
26. wgrowtime[tmp] = 0;
27. wtmp->wx = mtmp->mx;
28. wtmp->wy = mtmp->my;
29. /* wtmp->wdispl = 0;*/
30. wtmp->nseg = 0;
31. }
32.
33. worm_move(mtmp) struct monst *mtmp; {
34. register struct wseg *wtmp, *whd;
35. register tmp = mtmp->wormno;
36. wtmp = newseg();
37. wtmp->wx = mtmp->mx;
38. wtmp->wy = mtmp->my;
39. wtmp->nseg = 0;
40. /* wtmp->wdispl = 0;*/
41. (whd = wheads[tmp])->nseg = wtmp;
42. wheads[tmp] = wtmp;
43. if(cansee(whd->wx,whd->wy)){
44. unpmon(mtmp);
45. atl(whd->wx, whd->wy, '~');
46. whd->wdispl = 1;
47. } else whd->wdispl = 0;
48. if(wgrowtime[tmp] <= moves) {
49. if(!wgrowtime[tmp]) wgrowtime[tmp] = moves + rnd(5);
50. else wgrowtime[tmp] += 2+rnd(15);
51. mtmp->orig_hp++;
52. mtmp->mhp++;
53. return;
54. }
55. whd = wsegs[tmp];
56. wsegs[tmp] = whd->nseg;
57. remseg(whd);
58. }
59.
60. worm_nomove(mtmp) register struct monst *mtmp; {
61. register tmp;
62. register struct wseg *wtmp;
63. tmp = mtmp->wormno;
64. wtmp = wsegs[tmp];
65. if(wtmp == wheads[tmp]) return;
66. if(wtmp == 0 || wtmp->nseg == 0) panic("worm_nomove?");
67. wsegs[tmp] = wtmp->nseg;
68. remseg(wtmp);
69. mtmp->mhp--; /* orig_hp not changed ! */
70. }
71.
72. wormdead(mtmp) register struct monst *mtmp; {
73. register tmp = mtmp->wormno;
74. register struct wseg *wtmp, *wtmp2;
75. if(!tmp) return;
76. mtmp->wormno = 0;
77. for(wtmp = wsegs[tmp]; wtmp; wtmp = wtmp2){
78. wtmp2 = wtmp->nseg;
79. remseg(wtmp);
80. }
81. wsegs[tmp] = 0;
82. }
83.
84. wormhit(mtmp) register struct monst *mtmp; {
85. register tmp = mtmp->wormno;
86. register struct wseg *wtmp;
87. if(!tmp) return; /* worm without tail */
88. for(wtmp = wsegs[tmp]; wtmp; wtmp = wtmp->nseg)
89. (void) hitu(mtmp,1);
90. }
91.
92. wormsee(tmp) register unsigned tmp; {
93. register struct wseg *wtmp = wsegs[tmp];
94. if(!wtmp) panic("wormsee: wtmp==0");
95. for(; wtmp->nseg; wtmp = wtmp->nseg)
96. if(!cansee(wtmp->wx,wtmp->wy) && wtmp->wdispl){
97. newsym(wtmp->wx, wtmp->wy);
98. wtmp->wdispl = 0;
99. }
100. }
101.
102. pwseg(wtmp) register struct wseg *wtmp; {
103. if(!wtmp->wdispl){
104. atl(wtmp->wx, wtmp->wy, '~');
105. wtmp->wdispl = 1;
106. }
107. }
108.
109. cutworm(mtmp,x,y,weptyp)
110. register struct monst *mtmp;
111. register xchar x,y;
112. register uchar weptyp; /* uwep->otyp or 0 */
113. {
114. register struct wseg *wtmp, *wtmp2;
115. register struct monst *mtmp2;
116. register tmp,tmp2;
117. if(mtmp->mx == x && mtmp->my == y) return; /* hit headon */
118.
119. /* cutting goes best with axe or sword */
120. tmp = rnd(20);
121. if(weptyp == LONG_SWORD || weptyp == TWO_HANDED_SWORD ||
122. weptyp == AXE) tmp += 5;
123. if(tmp < 12) return;
124.
125. /* if tail then worm just loses a tail segment */
126. tmp = mtmp->wormno;
127. wtmp = wsegs[tmp];
128. if(wtmp->wx == x && wtmp->wy == y){
129. wsegs[tmp] = wtmp->nseg;
130. remseg(wtmp);
131. return;
132. }
133.
134. /* cut the worm in two halves */
135. mtmp2 = newmonst(0);
136. *mtmp2 = *mtmp;
137. mtmp2->mxlth = mtmp2->mnamelth = 0;
138.
139. /* sometimes the tail end dies */
140. if(rn2(3) || !getwn(mtmp2)){
141. monfree(mtmp2);
142. tmp2 = 0;
143. } else {
144. tmp2 = mtmp2->wormno;
145. wsegs[tmp2] = wsegs[tmp];
146. wgrowtime[tmp2] = 0;
147. }
148. do {
149. if(wtmp->nseg->wx == x && wtmp->nseg->wy == y){
150. if(tmp2) wheads[tmp2] = wtmp;
151. wsegs[tmp] = wtmp->nseg->nseg;
152. remseg(wtmp->nseg);
153. wtmp->nseg = 0;
154. if(tmp2){
155. pline("You cut the worm in half.");
156. mtmp2->orig_hp = mtmp2->mhp =
157. d(mtmp2->data->mlevel, 8);
158. mtmp2->mx = wtmp->wx;
159. mtmp2->my = wtmp->wy;
160. mtmp2->nmon = fmon;
161. fmon = mtmp2;
162. pmon(mtmp2);
163. } else {
164. pline("You cut off part of the worm's tail.");
165. remseg(wtmp);
166. }
167. mtmp->mhp /= 2;
168. return;
169. }
170. wtmp2 = wtmp->nseg;
171. if(!tmp2) remseg(wtmp);
172. wtmp = wtmp2;
173. } while(wtmp->nseg);
174. panic("Cannot find worm segment");
175. }
176.
177. remseg(wtmp) register struct wseg *wtmp; {
178. if(wtmp->wdispl)
179. newsym(wtmp->wx, wtmp->wy);
180. free((char *) wtmp);
181. }
182. #endif NOWORM
Furthermore, CWI has stated:
Copyright (c) 1985, Stichting Centrum voor Wiskunde en Informatica, Amsterdam All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. - Neither the name of the Stichting Centrum voor Wiskunde en Informatica, nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Dick Broekhuis, controller CWI