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Add a FastRandomContext::randrange and use it

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This commit is contained in:
Pieter Wuille
2017-02-25 12:16:58 -08:00
parent 16329224e7
commit 4fd2d2fc97
7 changed files with 75 additions and 2 deletions
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23
src/test/crypto_tests.cpp
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@@ -10,6 +10,7 @@
#include "crypto/sha512.h"
#include "crypto/hmac_sha256.h"
#include "crypto/hmac_sha512.h"
#include "random.h"
#include "utilstrencodings.h"
#include "test/test_bitcoin.h"
#include "test/test_random.h"
@@ -484,4 +485,26 @@ BOOST_AUTO_TEST_CASE(chacha20_testvector)
"fab78c9");
}
BOOST_AUTO_TEST_CASE(countbits_tests)
{
FastRandomContext ctx;
for (int i = 0; i <= 64; ++i) {
if (i == 0) {
// Check handling of zero.
BOOST_CHECK_EQUAL(CountBits(0), 0);
} else if (i < 10) {
for (uint64_t j = 1 << (i - 1); (j >> i) == 0; ++j) {
// Exhaustively test up to 10 bits
BOOST_CHECK_EQUAL(CountBits(j), i);
}
} else {
for (int k = 0; k < 1000; k++) {
// Randomly test 1000 samples of each length above 10 bits.
uint64_t j = ((uint64_t)1) << (i - 1) | ctx.randbits(i - 1);
BOOST_CHECK_EQUAL(CountBits(j), i);
}
}
}
}
BOOST_AUTO_TEST_SUITE_END()

15
src/test/random_tests.cpp
View File

@@ -35,4 +35,19 @@ BOOST_AUTO_TEST_CASE(fastrandom_tests)
BOOST_CHECK(ctx3.rand64() != ctx4.rand64()); // extremely unlikely to be equal
}
BOOST_AUTO_TEST_CASE(fastrandom_randbits)
{
FastRandomContext ctx1;
FastRandomContext ctx2;
for (int bits = 0; bits < 63; ++bits) {
for (int j = 0; j < 1000; ++j) {
uint64_t rangebits = ctx1.randbits(bits);
BOOST_CHECK_EQUAL(rangebits >> bits, 0);
uint64_t range = ((uint64_t)1) << bits | rangebits;
uint64_t rand = ctx2.randrange(range);
BOOST_CHECK(rand < range);
}
}
}
BOOST_AUTO_TEST_SUITE_END()