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builtin: make 5 C functions trusted, tweak signatures (#8730)

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This commit is contained in:
Nick Treleaven
2021-02-14 18:37:32 +00:00
committed by GitHub
parent ea803113c3
commit b07f373433
2 changed files with 18 additions and 12 deletions
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12
vlib/rand/sys/system_rng.c.v
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@ -9,10 +9,11 @@ import rand.constants
// Implementation note:
// ====================
// C.rand() is okay to use within its defined range of C.RAND_MAX.
// C.rand returns a pseudorandom integer from 0 (inclusive) to C.RAND_MAX (exclusive)
// C.rand() is okay to use within its defined range.
// (See: https://web.archive.org/web/20180801210127/http://eternallyconfuzzled.com/arts/jsw_art_rand.aspx)
// The problem is, this value varies with the libc implementation. On windows,
// for example, RAND_MAX is usually a measly 32767, whereas on (newer) linux it's generaly
// for example, RAND_MAX is usually a measly 32767, whereas on (newer) linux it's generally
// 2147483647. The repetition period also varies wildly. In order to provide more entropy
// without altering the underlying algorithm too much, this implementation simply
// requests for more random bits until the necessary width for the integers is achieved.
@ -29,11 +30,6 @@ fn calculate_iterations_for(bits int) int {
return base + extra
}
// C.rand returns a pseudorandom integer from 0 (inclusive) to C.RAND_MAX (exclusive)
fn C.rand() int
// C.srand seeds the internal PRNG with the given int seed.
// fn C.srand(seed int)
// SysRNG is the PRNG provided by default in the libc implementiation that V uses.
pub struct SysRNG {
mut:
@ -47,7 +43,7 @@ pub fn (mut r SysRNG) seed(seed_data []u32) {
exit(1)
}
r.seed = seed_data[0]
unsafe { C.srand(int(r.seed)) }
C.srand(r.seed)
}
// r.default_rand() exposes the default behavior of the system's RNG