A modern Music Player Daemon based on Rockbox open source high quality audio player
tsiry-sandratraina.com
libadwaita
audio
rust
zig
deno
mpris
rockbox
mpd
1/*
2 * random.c: Internal random number generator, guaranteed to work
3 * the same way on all platforms. Used when generating an initial
4 * game state from a random game seed; required to ensure that game
5 * seeds can be exchanged between versions of a puzzle compiled for
6 * different platforms.
7 *
8 * The generator is based on SHA-1. This is almost certainly
9 * overkill, but I had the SHA-1 code kicking around and it was
10 * easier to reuse it than to do anything else!
11 */
12
13#include <assert.h>
14#include <string.h>
15#include <stdio.h>
16
17#include "puzzles.h"
18
19/* ----------------------------------------------------------------------
20 * Core SHA algorithm: processes 16-word blocks into a message digest.
21 */
22
23#define rol(x,y) ( ((x) << (y)) | (((uint32)x) >> (32-y)) )
24
25static void SHA_Core_Init(uint32 h[5])
26{
27 h[0] = 0x67452301;
28 h[1] = 0xefcdab89;
29 h[2] = 0x98badcfe;
30 h[3] = 0x10325476;
31 h[4] = 0xc3d2e1f0;
32}
33
34static void SHATransform(uint32 * digest, uint32 * block)
35{
36 uint32 w[80];
37 uint32 a, b, c, d, e;
38 int t;
39
40 for (t = 0; t < 16; t++)
41 w[t] = block[t];
42
43 for (t = 16; t < 80; t++) {
44 uint32 tmp = w[t - 3] ^ w[t - 8] ^ w[t - 14] ^ w[t - 16];
45 w[t] = rol(tmp, 1);
46 }
47
48 a = digest[0];
49 b = digest[1];
50 c = digest[2];
51 d = digest[3];
52 e = digest[4];
53
54 for (t = 0; t < 20; t++) {
55 uint32 tmp =
56 rol(a, 5) + ((b & c) | (d & ~b)) + e + w[t] + 0x5a827999;
57 e = d;
58 d = c;
59 c = rol(b, 30);
60 b = a;
61 a = tmp;
62 }
63 for (t = 20; t < 40; t++) {
64 uint32 tmp = rol(a, 5) + (b ^ c ^ d) + e + w[t] + 0x6ed9eba1;
65 e = d;
66 d = c;
67 c = rol(b, 30);
68 b = a;
69 a = tmp;
70 }
71 for (t = 40; t < 60; t++) {
72 uint32 tmp = rol(a,
73 5) + ((b & c) | (b & d) | (c & d)) + e + w[t] +
74 0x8f1bbcdc;
75 e = d;
76 d = c;
77 c = rol(b, 30);
78 b = a;
79 a = tmp;
80 }
81 for (t = 60; t < 80; t++) {
82 uint32 tmp = rol(a, 5) + (b ^ c ^ d) + e + w[t] + 0xca62c1d6;
83 e = d;
84 d = c;
85 c = rol(b, 30);
86 b = a;
87 a = tmp;
88 }
89
90 digest[0] += a;
91 digest[1] += b;
92 digest[2] += c;
93 digest[3] += d;
94 digest[4] += e;
95}
96
97/* ----------------------------------------------------------------------
98 * Outer SHA algorithm: take an arbitrary length byte string,
99 * convert it into 16-word blocks with the prescribed padding at
100 * the end, and pass those blocks to the core SHA algorithm.
101 */
102
103void SHA_Init(SHA_State * s)
104{
105 SHA_Core_Init(s->h);
106 s->blkused = 0;
107 s->lenhi = s->lenlo = 0;
108}
109
110void SHA_Bytes(SHA_State * s, const void *p, int len)
111{
112 const unsigned char *q = (const unsigned char *) p;
113 uint32 wordblock[16];
114 uint32 lenw = len;
115 int i;
116
117 /*
118 * Update the length field.
119 */
120 s->lenlo += lenw;
121 s->lenhi += (s->lenlo < lenw);
122
123 if (s->blkused && s->blkused + len < 64) {
124 /*
125 * Trivial case: just add to the block.
126 */
127 memcpy(s->block + s->blkused, q, len);
128 s->blkused += len;
129 } else {
130 /*
131 * We must complete and process at least one block.
132 */
133 while (s->blkused + len >= 64) {
134 memcpy(s->block + s->blkused, q, 64 - s->blkused);
135 q += 64 - s->blkused;
136 len -= 64 - s->blkused;
137 /* Now process the block. Gather bytes big-endian into words */
138 for (i = 0; i < 16; i++) {
139 wordblock[i] =
140 (((uint32) s->block[i * 4 + 0]) << 24) |
141 (((uint32) s->block[i * 4 + 1]) << 16) |
142 (((uint32) s->block[i * 4 + 2]) << 8) |
143 (((uint32) s->block[i * 4 + 3]) << 0);
144 }
145 SHATransform(s->h, wordblock);
146 s->blkused = 0;
147 }
148 memcpy(s->block, q, len);
149 s->blkused = len;
150 }
151}
152
153void SHA_Final(SHA_State * s, unsigned char *output)
154{
155 int i;
156 int pad;
157 unsigned char c[64];
158 uint32 lenhi, lenlo;
159
160 if (s->blkused >= 56)
161 pad = 56 + 64 - s->blkused;
162 else
163 pad = 56 - s->blkused;
164
165 lenhi = (s->lenhi << 3) | (s->lenlo >> (32 - 3));
166 lenlo = (s->lenlo << 3);
167
168 memset(c, 0, pad);
169 c[0] = 0x80;
170 SHA_Bytes(s, &c, pad);
171
172 c[0] = (unsigned char)((lenhi >> 24) & 0xFF);
173 c[1] = (unsigned char)((lenhi >> 16) & 0xFF);
174 c[2] = (unsigned char)((lenhi >> 8) & 0xFF);
175 c[3] = (unsigned char)((lenhi >> 0) & 0xFF);
176 c[4] = (unsigned char)((lenlo >> 24) & 0xFF);
177 c[5] = (unsigned char)((lenlo >> 16) & 0xFF);
178 c[6] = (unsigned char)((lenlo >> 8) & 0xFF);
179 c[7] = (unsigned char)((lenlo >> 0) & 0xFF);
180
181 SHA_Bytes(s, &c, 8);
182
183 for (i = 0; i < 5; i++) {
184 output[i * 4] = (unsigned char)((s->h[i] >> 24) & 0xFF);
185 output[i * 4 + 1] = (unsigned char)((s->h[i] >> 16) & 0xFF);
186 output[i * 4 + 2] = (unsigned char)((s->h[i] >> 8) & 0xFF);
187 output[i * 4 + 3] = (unsigned char)((s->h[i]) & 0xFF);
188 }
189}
190
191void SHA_Simple(const void *p, int len, unsigned char *output)
192{
193 SHA_State s;
194
195 SHA_Init(&s);
196 SHA_Bytes(&s, p, len);
197 SHA_Final(&s, output);
198}
199
200/* ----------------------------------------------------------------------
201 * The random number generator.
202 */
203
204struct random_state {
205 unsigned char seedbuf[40];
206 unsigned char databuf[20];
207 int pos;
208};
209
210random_state *random_new(const char *seed, int len)
211{
212 random_state *state;
213
214 state = snew(random_state);
215
216 SHA_Simple(seed, len, state->seedbuf);
217 SHA_Simple(state->seedbuf, 20, state->seedbuf + 20);
218 SHA_Simple(state->seedbuf, 40, state->databuf);
219 state->pos = 0;
220
221 return state;
222}
223
224random_state *random_copy(random_state *tocopy)
225{
226 random_state *result;
227 result = snew(random_state);
228 memcpy(result->seedbuf, tocopy->seedbuf, sizeof(result->seedbuf));
229 memcpy(result->databuf, tocopy->databuf, sizeof(result->databuf));
230 result->pos = tocopy->pos;
231 return result;
232}
233
234unsigned long random_bits(random_state *state, int bits)
235{
236 unsigned long ret = 0;
237 int n;
238
239 for (n = 0; n < bits; n += 8) {
240 if (state->pos >= 20) {
241 int i;
242
243 for (i = 0; i < 20; i++) {
244 if (state->seedbuf[i] != 0xFF) {
245 state->seedbuf[i]++;
246 break;
247 } else
248 state->seedbuf[i] = 0;
249 }
250 SHA_Simple(state->seedbuf, 40, state->databuf);
251 state->pos = 0;
252 }
253 ret = (ret << 8) | state->databuf[state->pos++];
254 }
255
256 /*
257 * `(1UL << bits) - 1' is not good enough, since if bits==32 on a
258 * 32-bit machine, behaviour is undefined and Intel has a nasty
259 * habit of shifting left by zero instead. We'll shift by
260 * bits-1 and then separately shift by one.
261 */
262 ret &= (1UL << (bits-1)) * 2 - 1;
263 return ret;
264}
265
266unsigned long random_upto(random_state *state, unsigned long limit)
267{
268 int bits = 0;
269 unsigned long max, divisor, data;
270
271 while ((limit >> bits) != 0)
272 bits++;
273
274 bits += 3;
275 assert(bits < 32);
276
277 max = 1L << bits;
278 divisor = max / limit;
279 max = limit * divisor;
280
281 do {
282 data = random_bits(state, bits);
283 } while (data >= max);
284
285 return data / divisor;
286}
287
288void random_free(random_state *state)
289{
290 sfree(state);
291}
292
293char *random_state_encode(random_state *state)
294{
295 char retbuf[256];
296 int len = 0, i;
297
298 for (i = 0; i < lenof(state->seedbuf); i++)
299 len += sprintf(retbuf+len, "%02x", state->seedbuf[i]);
300 for (i = 0; i < lenof(state->databuf); i++)
301 len += sprintf(retbuf+len, "%02x", state->databuf[i]);
302 len += sprintf(retbuf+len, "%02x", state->pos);
303
304 return dupstr(retbuf);
305}
306
307random_state *random_state_decode(const char *input)
308{
309 random_state *state;
310 int pos, byte, digits;
311
312 state = snew(random_state);
313
314 memset(state->seedbuf, 0, sizeof(state->seedbuf));
315 memset(state->databuf, 0, sizeof(state->databuf));
316 state->pos = 0;
317
318 byte = digits = 0;
319 pos = 0;
320 while (*input) {
321 int v = *input++;
322
323 if (v >= '0' && v <= '9')
324 v = v - '0';
325 else if (v >= 'A' && v <= 'F')
326 v = v - 'A' + 10;
327 else if (v >= 'a' && v <= 'f')
328 v = v - 'a' + 10;
329 else
330 v = 0;
331
332 byte = (byte << 4) | v;
333 digits++;
334
335 if (digits == 2) {
336 /*
337 * We have a byte. Put it somewhere.
338 */
339 if (pos < lenof(state->seedbuf))
340 state->seedbuf[pos++] = byte;
341 else if (pos < lenof(state->seedbuf) + lenof(state->databuf))
342 state->databuf[pos++ - lenof(state->seedbuf)] = byte;
343 else if (pos == lenof(state->seedbuf) + lenof(state->databuf) &&
344 byte <= lenof(state->databuf))
345 state->pos = byte;
346 byte = digits = 0;
347 }
348 }
349
350 return state;
351}