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rand: further speed up of rand.uuid_v4

pull/5983/head
Delyan Angelov 2020-07-25 20:20:37 +03:00
parent 3d2fd471b6
commit ee3ebed23c
1 changed files with 3 additions and 5 deletions
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8
vlib/rand/rand.v
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@ -131,12 +131,11 @@ pub fn f64_in_range(min, max f64) f64 {
const ( const (
chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ' chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
hex_chars = '0123456789abcdef'
) )
pub fn string(len int) string { pub fn string(len int) string {
mut buf := malloc(len) mut buf := malloc(len)
for i in 0..len { for i in 0 .. len {
unsafe { unsafe {
buf[i] = chars[intn(chars.len)] buf[i] = chars[intn(chars.len)]
} }
@ -154,9 +153,6 @@ pub fn uuid_v4() string {
mut c := 0 mut c := 0
for c < 16 && i_buf < 36 { for c < 16 && i_buf < 36 {
mut d := byte(x) & 0x0F mut d := byte(x) & 0x0F
if i_buf == 19 {
d = (d & 0x03) + 0x08
}
unsafe { unsafe {
buf[i_buf] = if d > 9 { d + 87 } else { d + 48 } buf[i_buf] = if d > 9 { d + 87 } else { d + 48 }
} }
@ -165,11 +161,13 @@ pub fn uuid_v4() string {
x = x >> 4 x = x >> 4
} }
} }
n := ((byte(default_rng.u64()) & 0x0F) & 0x03) + 0x08
unsafe { unsafe {
buf[8] = `-` buf[8] = `-`
buf[13] = `-` buf[13] = `-`
buf[14] = `4` buf[14] = `4`
buf[18] = `-` buf[18] = `-`
buf[19] = if n > 9 { n + 87 } else { n + 48 }
buf[23] = `-` buf[23] = `-`
buf[36] = 0 buf[36] = 0
} }