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Bring back old semantics to random and randomSeed, add secureRandom (#1710) (#2142)

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This commit is contained in:
Ivan Grokhotkov
2016-06-14 07:17:54 +08:00
committed by GitHub
parent b9dfe01903
commit a14ac2cbdd
3 changed files with 77 additions and 2 deletions
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24
cores/esp8266/WMath.cpp
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@ -28,9 +28,12 @@ extern "C" {
}
#include "esp8266_peri.h"
static bool s_randomSeedCalled = false;
void randomSeed(unsigned long seed) {
if(seed != 0) {
srand((seed ^ RANDOM_REG32));
srand(seed);
s_randomSeedCalled = true;
}
}
@ -38,7 +41,9 @@ long random(long howbig) {
if(howbig == 0) {
return 0;
}
return (rand() ^ RANDOM_REG32) % howbig;
// if randomSeed was called, fall back to software PRNG
uint32_t val = (s_randomSeedCalled) ? rand() : RANDOM_REG32;
return val % howbig;
}
long random(long howsmall, long howbig) {
@ -49,6 +54,21 @@ long random(long howsmall, long howbig) {
return random(diff) + howsmall;
}
long secureRandom(long howbig) {
if(howbig == 0) {
return 0;
}
return RANDOM_REG32 % howbig;
}
long secureRandom(long howsmall, long howbig) {
if(howsmall >= howbig) {
return howsmall;
}
long diff = howbig - howsmall;
return secureRandom(diff) + howsmall;
}
long map(long x, long in_min, long in_max, long out_min, long out_max) {
return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}