397 lines
9.3 KiB
Rust
397 lines
9.3 KiB
Rust
#[doc = "Operations and constants for `uint`"];
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/*
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Module: uint
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*/
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/*
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Const: min_value
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Return the minimal value for an uint.
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This is always 0
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*/
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const min_value: uint = 0u;
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/*
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Const: max_value
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Return the maximal value for an uint.
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This is 2^wordsize - 1
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*/
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const max_value: uint = 0u - 1u;
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/*
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Function: min
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*/
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pure fn min(x: uint, y: uint) -> uint {
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if x < y { x } else { y }
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}
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/*
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Function: max
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*/
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pure fn max(x: uint, y: uint) -> uint {
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if x > y { x } else { y }
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}
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/* Function: add */
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pure fn add(x: uint, y: uint) -> uint { ret x + y; }
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/* Function: sub */
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pure fn sub(x: uint, y: uint) -> uint { ret x - y; }
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/* Function: mul */
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pure fn mul(x: uint, y: uint) -> uint { ret x * y; }
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/* Function: div */
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pure fn div(x: uint, y: uint) -> uint { ret x / y; }
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/* Function: div_ceil
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Divide two numbers, return the result, rounded up.
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Parameters:
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x - an integer
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y - an integer distinct from 0u
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Return:
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The smallest integer `q` such that `x/y <= q`.
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*/
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pure fn div_ceil(x: uint, y: uint) -> uint {
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let div = div(x, y);
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if x % y == 0u { ret div;}
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else { ret div + 1u; }
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}
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/* Function: div_ceil
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Divide two numbers, return the result, rounded to the closest integer.
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Parameters:
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x - an integer
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y - an integer distinct from 0u
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Return:
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The integer `q` closest to `x/y`.
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*/
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pure fn div_round(x: uint, y: uint) -> uint {
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let div = div(x, y);
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if x % y * 2u < y { ret div;}
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else { ret div + 1u; }
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}
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/* Function: div_ceil
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Divide two numbers, return the result, rounded down.
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Parameters:
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x - an integer
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y - an integer distinct from 0u
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Note: This is the same function as `div`.
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Return:
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The smallest integer `q` such that `x/y <= q`. This
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is either `x/y` or `x/y + 1`.
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*/
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pure fn div_floor(x: uint, y: uint) -> uint { ret x / y; }
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/* Function: rem */
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pure fn rem(x: uint, y: uint) -> uint { ret x % y; }
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/* Predicate: lt */
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pure fn lt(x: uint, y: uint) -> bool { ret x < y; }
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/* Predicate: le */
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pure fn le(x: uint, y: uint) -> bool { ret x <= y; }
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/* Predicate: eq */
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pure fn eq(x: uint, y: uint) -> bool { ret x == y; }
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/* Predicate: ne */
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pure fn ne(x: uint, y: uint) -> bool { ret x != y; }
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/* Predicate: ge */
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pure fn ge(x: uint, y: uint) -> bool { ret x >= y; }
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/* Predicate: gt */
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pure fn gt(x: uint, y: uint) -> bool { ret x > y; }
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/*
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Function: hash
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Produce a uint suitable for use in a hash table
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*/
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fn hash(x: uint) -> uint { ret x; }
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/*
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Function: range
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Iterate over the range [`lo`..`hi`)
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*/
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fn range(lo: uint, hi: uint, it: fn(uint)) {
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let i = lo;
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while i < hi { it(i); i += 1u; }
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}
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/*
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Function: loop
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Iterate over the range [`lo`..`hi`), or stop when requested
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Parameters:
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lo - The integer at which to start the loop (included)
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hi - The integer at which to stop the loop (excluded)
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it - A block to execute with each consecutive integer of the range.
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Return `true` to continue, `false` to stop.
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Returns:
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`true` If execution proceeded correctly, `false` if it was interrupted,
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that is if `it` returned `false` at any point.
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*/
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fn loop(lo: uint, hi: uint, it: fn(uint) -> bool) -> bool {
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let i = lo;
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while i < hi {
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if (!it(i)) { ret false; }
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i += 1u;
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}
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ret true;
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}
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/*
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Function: next_power_of_two
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Returns the smallest power of 2 greater than or equal to `n`
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*/
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fn next_power_of_two(n: uint) -> uint {
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let halfbits: uint = sys::size_of::<uint>() * 4u;
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let tmp: uint = n - 1u;
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let shift: uint = 1u;
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while shift <= halfbits { tmp |= tmp >> shift; shift <<= 1u; }
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ret tmp + 1u;
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}
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/*
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Function: parse_buf
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Parse a buffer of bytes
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Parameters:
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buf - A byte buffer
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radix - The base of the number
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Failure:
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buf must not be empty
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*/
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fn parse_buf(buf: [u8], radix: uint) -> uint {
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if vec::len::<u8>(buf) == 0u {
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#error("parse_buf(): buf is empty");
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fail;
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}
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let i = vec::len::<u8>(buf) - 1u;
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let power = 1u;
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let n = 0u;
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while true {
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let digit = char::to_digit(buf[i] as char);
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if (digit as uint) >= radix {
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fail;
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}
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n += (digit as uint) * power;
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power *= radix;
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if i == 0u { ret n; }
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i -= 1u;
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}
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fail;
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}
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/*
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Function: from_str
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Parse a string to an int
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Failure:
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s must not be empty
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*/
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fn from_str(s: str) -> uint { parse_buf(str::bytes(s), 10u) }
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/*
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Function: to_str
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Convert to a string in a given base
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*/
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fn to_str(num: uint, radix: uint) -> str {
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let n = num;
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assert (0u < radix && radix <= 16u);
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fn digit(n: uint) -> char {
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ret alt n {
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0u { '0' }
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1u { '1' }
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2u { '2' }
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3u { '3' }
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4u { '4' }
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5u { '5' }
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6u { '6' }
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7u { '7' }
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8u { '8' }
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9u { '9' }
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10u { 'a' }
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11u { 'b' }
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12u { 'c' }
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13u { 'd' }
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14u { 'e' }
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15u { 'f' }
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_ { fail }
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};
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}
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if n == 0u { ret "0"; }
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let s: str = "";
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while n != 0u {
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s += str::from_byte(digit(n % radix) as u8);
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n /= radix;
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}
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let s1: str = "";
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let len: uint = str::len_bytes(s);
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while len != 0u { len -= 1u; s1 += str::from_byte(s[len]); }
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ret s1;
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}
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/*
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Function: str
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Convert to a string
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*/
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fn str(i: uint) -> str { ret to_str(i, 10u); }
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/*
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Function: compl
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Computes the bitwise complement.
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*/
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fn compl(i: uint) -> uint {
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max_value ^ i
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}
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#[cfg(test)]
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mod tests {
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#[test]
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fn test_from_str() {
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assert (uint::from_str("0") == 0u);
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assert (uint::from_str("3") == 3u);
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assert (uint::from_str("10") == 10u);
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assert (uint::from_str("123456789") == 123456789u);
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assert (uint::from_str("00100") == 100u);
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}
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#[test]
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#[should_fail]
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#[ignore(cfg(target_os = "win32"))]
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fn test_from_str_fail_1() {
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uint::from_str(" ");
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}
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#[test]
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#[should_fail]
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#[ignore(cfg(target_os = "win32"))]
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fn test_from_str_fail_2() {
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uint::from_str("x");
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}
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#[test]
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fn test_parse_buf() {
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import str::bytes;
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assert (uint::parse_buf(bytes("123"), 10u) == 123u);
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assert (uint::parse_buf(bytes("1001"), 2u) == 9u);
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assert (uint::parse_buf(bytes("123"), 8u) == 83u);
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assert (uint::parse_buf(bytes("123"), 16u) == 291u);
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assert (uint::parse_buf(bytes("ffff"), 16u) == 65535u);
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assert (uint::parse_buf(bytes("z"), 36u) == 35u);
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}
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#[test]
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#[should_fail]
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#[ignore(cfg(target_os = "win32"))]
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fn test_parse_buf_fail_1() {
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uint::parse_buf(str::bytes("Z"), 10u);
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}
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#[test]
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#[should_fail]
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#[ignore(cfg(target_os = "win32"))]
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fn test_parse_buf_fail_2() {
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uint::parse_buf(str::bytes("_"), 2u);
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}
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#[test]
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fn test_next_power_of_two() {
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assert (uint::next_power_of_two(0u) == 0u);
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assert (uint::next_power_of_two(1u) == 1u);
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assert (uint::next_power_of_two(2u) == 2u);
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assert (uint::next_power_of_two(3u) == 4u);
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assert (uint::next_power_of_two(4u) == 4u);
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assert (uint::next_power_of_two(5u) == 8u);
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assert (uint::next_power_of_two(6u) == 8u);
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assert (uint::next_power_of_two(7u) == 8u);
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assert (uint::next_power_of_two(8u) == 8u);
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assert (uint::next_power_of_two(9u) == 16u);
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assert (uint::next_power_of_two(10u) == 16u);
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assert (uint::next_power_of_two(11u) == 16u);
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assert (uint::next_power_of_two(12u) == 16u);
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assert (uint::next_power_of_two(13u) == 16u);
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assert (uint::next_power_of_two(14u) == 16u);
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assert (uint::next_power_of_two(15u) == 16u);
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assert (uint::next_power_of_two(16u) == 16u);
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assert (uint::next_power_of_two(17u) == 32u);
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assert (uint::next_power_of_two(18u) == 32u);
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assert (uint::next_power_of_two(19u) == 32u);
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assert (uint::next_power_of_two(20u) == 32u);
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assert (uint::next_power_of_two(21u) == 32u);
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assert (uint::next_power_of_two(22u) == 32u);
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assert (uint::next_power_of_two(23u) == 32u);
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assert (uint::next_power_of_two(24u) == 32u);
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assert (uint::next_power_of_two(25u) == 32u);
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assert (uint::next_power_of_two(26u) == 32u);
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assert (uint::next_power_of_two(27u) == 32u);
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assert (uint::next_power_of_two(28u) == 32u);
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assert (uint::next_power_of_two(29u) == 32u);
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assert (uint::next_power_of_two(30u) == 32u);
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assert (uint::next_power_of_two(31u) == 32u);
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assert (uint::next_power_of_two(32u) == 32u);
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assert (uint::next_power_of_two(33u) == 64u);
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assert (uint::next_power_of_two(34u) == 64u);
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assert (uint::next_power_of_two(35u) == 64u);
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assert (uint::next_power_of_two(36u) == 64u);
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assert (uint::next_power_of_two(37u) == 64u);
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assert (uint::next_power_of_two(38u) == 64u);
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assert (uint::next_power_of_two(39u) == 64u);
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}
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#[test]
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fn test_overflows() {
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assert (uint::max_value > 0u);
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assert (uint::min_value <= 0u);
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assert (uint::min_value + uint::max_value + 1u == 0u);
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}
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#[test]
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fn test_div() {
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assert(uint::div_floor(3u, 4u) == 0u);
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assert(uint::div_ceil(3u, 4u) == 1u);
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assert(uint::div_round(3u, 4u) == 1u);
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}
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}
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// Local Variables:
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// mode: rust;
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// fill-column: 78;
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// indent-tabs-mode: nil
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// c-basic-offset: 4
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// buffer-file-coding-system: utf-8-unix
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// End:
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