mirror/v
1
0
Fork 0
mirror of https://github.com/vlang/v.git synced 2023-08-10 21:13:21 +03:00
Code Issues Projects Releases Wiki Activity

rand: further bridge gap b/w rand module and PRNG interface (#13719)

Browse Source
This commit is contained in:
Subhomoy Haldar
2022-03-12 13:11:12 +05:30
committed by GitHub
parent a3e9409196
commit 40504e8600
4 changed files with 142 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
vlib/rand/rand.c.v
View File

@ -1,12 +1,14 @@
module rand
import time
const clock_seq_hi_and_reserved_valid_values = [`8`, `9`, `a`, `b`]
// uuid_v4 generates a random (v4) UUID
// See https://en.wikipedia.org/wiki/Universally_unique_identifier#Version_4_(random)
pub fn uuid_v4() string {
return internal_uuid_v4(mut default_rng)
}
fn internal_uuid_v4(mut rng PRNG) string {
buflen := 36
mut buf := unsafe { malloc_noscan(37) }
mut i_buf := 0
@ -14,7 +16,7 @@ pub fn uuid_v4() string {
mut d := byte(0)
for i_buf < buflen {
mut c := 0
x = default_rng.u64()
x = rng.u64()
// do most of the bit manipulation at once:
x &= 0x0F0F0F0F0F0F0F0F
x += 0x3030303030303030
@ -54,18 +56,7 @@ pub fn uuid_v4() string {
const ulid_encoding = '0123456789ABCDEFGHJKMNPQRSTVWXYZ'
// ulid generates an Unique Lexicographically sortable IDentifier.
// See https://github.com/ulid/spec .
// Note: ULIDs can leak timing information, if you make them public, because
// you can infer the rate at which some resource is being created, like
// users or business transactions.
// (https://news.ycombinator.com/item?id=14526173)
pub fn ulid() string {
return ulid_at_millisecond(u64(time.utc().unix_time_milli()))
}
// ulid_at_millisecond does the same as `ulid` but takes a custom Unix millisecond timestamp via `unix_time_milli`.
pub fn ulid_at_millisecond(unix_time_milli u64) string {
fn internal_ulid_at_millisecond(mut rng PRNG, unix_time_milli u64) string {
buflen := 26
mut buf := unsafe { malloc_noscan(27) }
mut t := unix_time_milli
@ -78,7 +69,7 @@ pub fn ulid_at_millisecond(unix_time_milli u64) string {
i--
}
// first rand set
mut x := default_rng.u64()
mut x := rng.u64()
i = 10
for i < 19 {
unsafe {
@ -88,7 +79,7 @@ pub fn ulid_at_millisecond(unix_time_milli u64) string {
i++
}
// second rand set
x = default_rng.u64()
x = rng.u64()
for i < 26 {
unsafe {
buf[i] = rand.ulid_encoding[x & 0x1F]
@ -102,8 +93,7 @@ pub fn ulid_at_millisecond(unix_time_milli u64) string {
}
}
// string_from_set returns a string of length `len` containing random characters sampled from the given `charset`
pub fn string_from_set(charset string, len int) string {
fn internal_string_from_set(mut rng PRNG, charset string, len int) string {
if len == 0 {
return ''
}
@ -119,21 +109,6 @@ pub fn string_from_set(charset string, len int) string {
return unsafe { buf.vstring_with_len(len) }
}
// string returns a string of length `len` containing random characters in range `[a-zA-Z]`.
pub fn string(len int) string {
return string_from_set(english_letters, len)
}
// hex returns a hexadecimal number of length `len` containing random characters in range `[a-f0-9]`.
pub fn hex(len int) string {
return string_from_set(hex_chars, len)
}
// ascii returns a random string of the printable ASCII characters with length `len`.
pub fn ascii(len int) string {
return string_from_set(ascii_chars, len)
}
fn deinit() {
unsafe {
default_rng.free() // free the implementation