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/*
Module: uint
*/
/*
Const: min_value
Return the minimal value for an uint.
This is always 0
*/
const min_value: uint = 0u;
/*
Const: max_value
Return the maximal value for an uint.
This is 2^wordsize - 1
*/
const max_value: uint = 0u - 1u;
/* Function: add */
pure fn add(x: uint, y: uint) -> uint { ret x + y; }
/* Function: sub */
pure fn sub(x: uint, y: uint) -> uint { ret x - y; }
/* Function: mul */
pure fn mul(x: uint, y: uint) -> uint { ret x * y; }
/* Function: div */
pure fn div(x: uint, y: uint) -> uint { ret x / y; }
/* Function: div_ceil
Divide two numbers, return the result, rounded up.
Parameters:
x - an integer
y - an integer distinct from 0u
Return:
The smallest integer `q` such that `x/y <= q`.
*/
pure fn div_ceil(x: uint, y: uint) -> uint {
let div = div(x, y);
if x % y == 0u { ret div;}
else { ret div + 1u; }
}
/* Function: div_ceil
Divide two numbers, return the result, rounded to the closest integer.
Parameters:
x - an integer
y - an integer distinct from 0u
Return:
The integer `q` closest to `x/y`.
*/
pure fn div_round(x: uint, y: uint) -> uint {
let div = div(x, y);
if x % y * 2u < y { ret div;}
else { ret div + 1u; }
}
/* Function: div_ceil
Divide two numbers, return the result, rounded down.
Parameters:
x - an integer
y - an integer distinct from 0u
Note: This is the same function as `div`.
Return:
The smallest integer `q` such that `x/y <= q`. This
is either `x/y` or `x/y + 1`.
*/
pure fn div_floor(x: uint, y: uint) -> uint { ret x / y; }
/* Function: rem */
pure fn rem(x: uint, y: uint) -> uint { ret x % y; }
/* Predicate: lt */
pure fn lt(x: uint, y: uint) -> bool { ret x < y; }
/* Predicate: le */
pure fn le(x: uint, y: uint) -> bool { ret x <= y; }
/* Predicate: eq */
pure fn eq(x: uint, y: uint) -> bool { ret x == y; }
/* Predicate: ne */
pure fn ne(x: uint, y: uint) -> bool { ret x != y; }
/* Predicate: ge */
pure fn ge(x: uint, y: uint) -> bool { ret x >= y; }
/* Predicate: gt */
pure fn gt(x: uint, y: uint) -> bool { ret x > y; }
/*
Function: range
Iterate over the range [`lo`..`hi`)
*/
fn range(lo: uint, hi: uint, it: block(uint)) {
let i = lo;
while i < hi { it(i); i += 1u; }
}
/*
Function: loop
Iterate over the range [`lo`..`hi`), or stop when requested
Parameters:
lo - The integer at which to start the loop (included)
hi - The integer at which to stop the loop (excluded)
it - A block to execute with each consecutive integer of the range.
Return `true` to continue, `false` to stop.
Returns:
`true` If execution proceeded correctly, `false` if it was interrupted,
that is if `it` returned `false` at any point.
*/
fn loop(lo: uint, hi: uint, it: block(uint) -> bool) -> bool {
let i = lo;
while i < hi {
if (!it(i)) { ret false; }
i += 1u;
}
ret true;
}
/*
Function: next_power_of_two
Returns the smallest power of 2 greater than or equal to `n`
*/
fn next_power_of_two(n: uint) -> uint {
let halfbits: uint = sys::size_of::<uint>() * 4u;
let tmp: uint = n - 1u;
let shift: uint = 1u;
while shift <= halfbits { tmp |= tmp >> shift; shift <<= 1u; }
ret tmp + 1u;
}
/*
Function: parse_buf
Parse a buffer of bytes
Parameters:
buf - A byte buffer
radix - The base of the number
Failure:
buf must not be empty
*/
fn parse_buf(buf: [u8], radix: uint) -> uint {
if vec::len::<u8>(buf) == 0u {
log_err "parse_buf(): buf is empty";
fail;
}
let i = vec::len::<u8>(buf) - 1u;
let power = 1u;
let n = 0u;
while true {
let digit = char::to_digit(buf[i] as char);
if (digit as uint) >= radix {
fail;
}
n += (digit as uint) * power;
power *= radix;
if i == 0u { ret n; }
i -= 1u;
}
fail;
}
/*
Function: from_str
Parse a string to an int
Failure:
s must not be empty
*/
fn from_str(s: str) -> uint { parse_buf(str::bytes(s), 10u) }
/*
Function: to_str
Convert to a string in a given base
*/
fn to_str(num: uint, radix: uint) -> str {
let n = num;
assert (0u < radix && radix <= 16u);
fn digit(n: uint) -> char {
ret alt n {
0u { '0' }
1u { '1' }
2u { '2' }
3u { '3' }
4u { '4' }
5u { '5' }
6u { '6' }
7u { '7' }
8u { '8' }
9u { '9' }
10u { 'a' }
11u { 'b' }
12u { 'c' }
13u { 'd' }
14u { 'e' }
15u { 'f' }
_ { fail }
};
}
if n == 0u { ret "0"; }
let s: str = "";
while n != 0u {
s += str::unsafe_from_byte(digit(n % radix) as u8);
n /= radix;
}
let s1: str = "";
let len: uint = str::byte_len(s);
while len != 0u { len -= 1u; s1 += str::unsafe_from_byte(s[len]); }
ret s1;
}
/*
Function: str
Convert to a string
*/
fn str(i: uint) -> str { ret to_str(i, 10u); }
// Local Variables:
// mode: rust;
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
|
