e2e077c831
I consider the added complexity not justified at this point, and it interacts badly with the patches for issue #828. Feel free to discuss.
731 lines
15 KiB
Rust
731 lines
15 KiB
Rust
/*
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Module: float
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*/
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// Currently this module supports from -lm
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// C95 + log2 + log1p + trunc + round + rint
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export t;
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export consts;
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export
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acos, asin, atan, atan2, ceil, cos, cosh, exp, abs, floor, fmod, frexp,
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ldexp, ln, ln1p, log10, log2, modf, rint, round, pow, sin, sinh, sqrt,
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tan, tanh, trunc;
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export to_str_common, to_str_exact, to_str, from_str;
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export lt, le, eq, ne, gt, eq;
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export NaN, isNaN, infinity, neg_infinity;
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export pow_uint_to_uint_as_float;
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export min, max;
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export add, sub, mul, div;
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export positive, negative, nonpositive, nonnegative;
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import mtypes::m_float;
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import ctypes::c_int;
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import ptr;
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// PORT This must match in width according to architecture
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import f64;
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import m_float = f64;
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type t = m_float;
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/**
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* Section: String Conversions
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*/
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/*
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Function: to_str_common
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Converts a float to a string
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Parameters:
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num - The float value
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digits - The number of significant digits
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exact - Whether to enforce the exact number of significant digits
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*/
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fn to_str_common(num: float, digits: uint, exact: bool) -> str {
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let (num, accum) = num < 0.0 ? (-num, "-") : (num, "");
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let trunc = num as uint;
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let frac = num - (trunc as float);
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accum += uint::str(trunc);
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if frac == 0.0 || digits == 0u { ret accum; }
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accum += ".";
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let i = digits;
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let epsilon = 1. / pow_uint_to_uint_as_float(10u, i);
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while i > 0u && (frac >= epsilon || exact) {
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frac *= 10.0;
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epsilon *= 10.0;
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let digit = frac as uint;
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accum += uint::str(digit);
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frac -= digit as float;
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i -= 1u;
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}
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ret accum;
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}
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/*
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Function: to_str
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Converts a float to a string with exactly the number of provided significant
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digits
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Parameters:
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num - The float value
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digits - The number of significant digits
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*/
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fn to_str_exact(num: float, digits: uint) -> str {
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to_str_common(num, digits, true)
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}
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/*
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Function: to_str
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Converts a float to a string with a maximum number of significant digits
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Parameters:
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num - The float value
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digits - The number of significant digits
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*/
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fn to_str(num: float, digits: uint) -> str {
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to_str_common(num, digits, false)
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}
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/*
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Function: from_str
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Convert a string to a float
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This function accepts strings such as
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* "3.14"
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* "+3.14", equivalent to "3.14"
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* "-3.14"
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* "2.5E10", or equivalently, "2.5e10"
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* "2.5E-10"
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* "", or, equivalently, "." (understood as 0)
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* "5."
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* ".5", or, equivalently, "0.5"
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Leading and trailing whitespace are ignored.
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Parameters:
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num - A string, possibly empty.
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Returns:
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<NaN> If the string did not represent a valid number.
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Otherwise, the floating-point number represented [num].
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*/
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fn from_str(num: str) -> float {
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let num = str::trim(num);
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let pos = 0u; //Current byte position in the string.
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//Used to walk the string in O(n).
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let len = str::byte_len(num); //Length of the string, in bytes.
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if len == 0u { ret 0.; }
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let total = 0f; //Accumulated result
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let c = 'z'; //Latest char.
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//The string must start with one of the following characters.
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alt str::char_at(num, 0u) {
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'-' | '+' | '0' to '9' | '.' {}
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_ { ret NaN; }
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}
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//Determine if first char is '-'/'+'. Set [pos] and [neg] accordingly.
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let neg = false; //Sign of the result
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alt str::char_at(num, 0u) {
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'-' {
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neg = true;
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pos = 1u;
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}
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'+' {
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pos = 1u;
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}
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_ {}
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}
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//Examine the following chars until '.', 'e', 'E'
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while(pos < len) {
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let char_range = str::char_range_at(num, pos);
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c = char_range.ch;
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pos = char_range.next;
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alt c {
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'0' to '9' {
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total = total * 10f;
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total += ((c as int) - ('0' as int)) as float;
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}
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'.' | 'e' | 'E' {
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break;
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}
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_ {
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ret NaN;
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}
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}
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}
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if c == '.' {//Examine decimal part
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let decimal = 1f;
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while(pos < len) {
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let char_range = str::char_range_at(num, pos);
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c = char_range.ch;
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pos = char_range.next;
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alt c {
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'0' | '1' | '2' | '3' | '4' | '5' | '6'| '7' | '8' | '9' {
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decimal /= 10f;
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total += (((c as int) - ('0' as int)) as float)*decimal;
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}
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'e' | 'E' {
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break;
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}
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_ {
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ret NaN;
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}
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}
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}
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}
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if (c == 'e') | (c == 'E') {//Examine exponent
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let exponent = 0u;
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let neg_exponent = false;
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if(pos < len) {
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let char_range = str::char_range_at(num, pos);
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c = char_range.ch;
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alt c {
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'+' {
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pos = char_range.next;
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}
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'-' {
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pos = char_range.next;
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neg_exponent = true;
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}
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_ {}
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}
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while(pos < len) {
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let char_range = str::char_range_at(num, pos);
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c = char_range.ch;
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alt c {
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'0' | '1' | '2' | '3' | '4' | '5' | '6'| '7' | '8' | '9' {
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exponent *= 10u;
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exponent += ((c as uint) - ('0' as uint));
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}
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_ {
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break;
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}
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}
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pos = char_range.next;
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}
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let multiplier = pow_uint_to_uint_as_float(10u, exponent);
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//Note: not [int::pow], otherwise, we'll quickly
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//end up with a nice overflow
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if neg_exponent {
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total = total / multiplier;
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} else {
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total = total * multiplier;
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}
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} else {
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ret NaN;
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}
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}
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if(pos < len) {
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ret NaN;
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} else {
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if(neg) {
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total *= -1f;
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}
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ret total;
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}
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}
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/**
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* Section: Arithmetics
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*/
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/*
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Function: pow_uint_to_uint_as_float
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Compute the exponentiation of an integer by another integer as a float.
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Parameters:
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x - The base.
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pow - The exponent.
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Returns:
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<NaN> of both `x` and `pow` are `0u`, otherwise `x^pow`.
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*/
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fn pow_uint_to_uint_as_float(x: uint, pow: uint) -> float {
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if x == 0u {
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if pow == 0u {
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ret NaN;
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}
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ret 0.;
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}
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let my_pow = pow;
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let total = 1f;
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let multiplier = x as float;
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while (my_pow > 0u) {
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if my_pow % 2u == 1u {
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total = total * multiplier;
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}
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my_pow /= 2u;
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multiplier *= multiplier;
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}
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ret total;
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}
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/* Const: NaN */
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const NaN: float = 0./0.;
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/* Const: infinity */
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const infinity: float = 1./0.;
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/* Const: neg_infinity */
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const neg_infinity: float = -1./0.;
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/* Predicate: isNaN */
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pure fn isNaN(f: float) -> bool { f != f }
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/* Function: add */
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pure fn add(x: float, y: float) -> float { ret x + y; }
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/* Function: sub */
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pure fn sub(x: float, y: float) -> float { ret x - y; }
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/* Function: mul */
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pure fn mul(x: float, y: float) -> float { ret x * y; }
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/* Function: div */
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pure fn div(x: float, y: float) -> float { ret x / y; }
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/* Function: rem */
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pure fn rem(x: float, y: float) -> float { ret x % y; }
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/* Predicate: lt */
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pure fn lt(x: float, y: float) -> bool { ret x < y; }
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/* Predicate: le */
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pure fn le(x: float, y: float) -> bool { ret x <= y; }
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/* Predicate: eq */
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pure fn eq(x: float, y: float) -> bool { ret x == y; }
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/* Predicate: ne */
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pure fn ne(x: float, y: float) -> bool { ret x != y; }
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/* Predicate: ge */
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pure fn ge(x: float, y: float) -> bool { ret x >= y; }
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/* Predicate: gt */
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pure fn gt(x: float, y: float) -> bool { ret x > y; }
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/*
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Predicate: positive
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Returns true if `x` is a positive number, including +0.0 and +Infinity.
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*/
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pure fn positive(x: float) -> bool { ret x > 0. || (1./x) == infinity; }
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/*
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Predicate: negative
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Returns true if `x` is a negative number, including -0.0 and -Infinity.
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*/
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pure fn negative(x: float) -> bool { ret x < 0. || (1./x) == neg_infinity; }
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/*
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Predicate: nonpositive
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Returns true if `x` is a negative number, including -0.0 and -Infinity.
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(This is the same as `float::negative`.)
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*/
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pure fn nonpositive(x: float) -> bool {
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ret x < 0. || (1./x) == neg_infinity;
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}
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/*
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Predicate: nonnegative
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Returns true if `x` is a positive number, including +0.0 and +Infinity.
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(This is the same as `float::positive`.)
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*/
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pure fn nonnegative(x: float) -> bool {
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ret x > 0. || (1./x) == infinity;
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}
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/*
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Module: consts
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*/
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mod consts {
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/*
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Const: pi
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Archimedes' constant
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*/
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const pi: float = 3.14159265358979323846264338327950288;
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/*
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Const: frac_pi_2
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pi/2.0
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*/
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const frac_pi_2: float = 1.57079632679489661923132169163975144;
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/*
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Const: frac_pi_4
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pi/4.0
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*/
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const frac_pi_4: float = 0.785398163397448309615660845819875721;
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/*
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Const: frac_1_pi
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1.0/pi
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*/
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const frac_1_pi: float = 0.318309886183790671537767526745028724;
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/*
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Const: frac_2_pi
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2.0/pi
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*/
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const frac_2_pi: float = 0.636619772367581343075535053490057448;
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/*
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Const: frac_2_sqrtpi
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2.0/sqrt(pi)
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*/
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const frac_2_sqrtpi: float = 1.12837916709551257389615890312154517;
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/*
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Const: sqrt2
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sqrt(2.0)
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*/
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const sqrt2: float = 1.41421356237309504880168872420969808;
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/*
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Const: frac_1_sqrt2
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1.0/sqrt(2.0)
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*/
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const frac_1_sqrt2: float = 0.707106781186547524400844362104849039;
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/*
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Const: e
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Euler's number
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*/
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const e: float = 2.71828182845904523536028747135266250;
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/*
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Const: log2_e
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log2(e)
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*/
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const log2_e: float = 1.44269504088896340735992468100189214;
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/*
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Const: log10_e
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log10(e)
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*/
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const log10_e: float = 0.434294481903251827651128918916605082;
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/*
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Const: ln_2
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ln(2.0)
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*/
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const ln_2: float = 0.693147180559945309417232121458176568;
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/*
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Const: ln_10
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ln(10.0)
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*/
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const ln_10: float = 2.30258509299404568401799145468436421;
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}
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// FIXME min/max type specialize via libm when overloading works
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// (in theory fmax/fmin, fmaxf, fminf /should/ be faster)
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/*
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Function: min
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Returns the minimum of two values
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*/
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pure fn min<copy T>(x: T, y: T) -> T { x < y ? x : y }
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/*
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Function: max
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Returns the maximum of two values
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*/
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pure fn max<copy T>(x: T, y: T) -> T { x < y ? y : x }
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/*
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Function: acos
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Returns the arccosine of an angle (measured in rad)
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*/
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pure fn acos(x: float) -> float
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{ ret m_float::acos(x as m_float) as float }
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/*
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Function: asin
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Returns the arcsine of an angle (measured in rad)
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*/
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pure fn asin(x: float) -> float
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{ ret m_float::asin(x as m_float) as float }
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/*
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Function: atan
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Returns the arctangents of an angle (measured in rad)
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*/
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pure fn atan(x: float) -> float
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{ ret m_float::atan(x as m_float) as float }
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/*
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Function: atan2
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Returns the arctangent of an angle (measured in rad)
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*/
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pure fn atan2(y: float, x: float) -> float
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{ ret m_float::atan2(y as m_float, x as m_float) as float }
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/*
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Function: ceil
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Returns the smallest integral value less than or equal to `n`
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*/
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pure fn ceil(n: float) -> float
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{ ret m_float::ceil(n as m_float) as float }
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/*
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Function: cos
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Returns the cosine of an angle `x` (measured in rad)
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*/
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pure fn cos(x: float) -> float
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{ ret m_float::cos(x as m_float) as float }
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/*
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Function: cosh
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Returns the hyperbolic cosine of `x`
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*/
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pure fn cosh(x: float) -> float
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{ ret m_float::cosh(x as m_float) as float }
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/*
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Function: exp
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Returns `consts::e` to the power of `n*
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*/
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pure fn exp(n: float) -> float
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{ ret m_float::exp(n as m_float) as float }
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/*
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Function: abs
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Returns the absolute value of `n`
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*/
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pure fn abs(n: float) -> float
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{ ret m_float::abs(n as m_float) as float }
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/*
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Function: floor
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Returns the largest integral value less than or equal to `n`
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*/
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pure fn floor(n: float) -> float
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{ ret m_float::floor(n as m_float) as float }
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/*
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Function: fmod
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Returns the floating-point remainder of `x/y`
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*/
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pure fn fmod(x: float, y: float) -> float
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{ ret m_float::fmod(x as m_float, y as m_float) as float }
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/*
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Function: ln
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Returns the natural logaritm of `n`
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*/
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pure fn ln(n: float) -> float
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{ ret m_float::ln(n as m_float) as float }
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/*
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Function: ldexp
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Returns `x` multiplied by 2 to the power of `n`
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*/
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pure fn ldexp(n: float, i: int) -> float
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{ ret m_float::ldexp(n as m_float, i as c_int) as float }
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/*
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Function: ln1p
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Returns the natural logarithm of `1+n` accurately,
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even for very small values of `n`
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*/
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pure fn ln1p(n: float) -> float
|
|
{ ret m_float::ln1p(n as m_float) as float }
|
|
|
|
/*
|
|
Function: log10
|
|
|
|
Returns the logarithm to base 10 of `n`
|
|
*/
|
|
pure fn log10(n: float) -> float
|
|
{ ret m_float::log10(n as m_float) as float }
|
|
|
|
/*
|
|
Function: log2
|
|
|
|
Returns the logarithm to base 2 of `n`
|
|
*/
|
|
pure fn log2(n: float) -> float
|
|
{ ret m_float::log2(n as m_float) as float }
|
|
|
|
/*
|
|
Function: modf
|
|
|
|
Breaks `n` into integral and fractional parts such that both
|
|
have the same sign as `n`
|
|
|
|
The integral part is stored in `iptr`.
|
|
|
|
Returns:
|
|
|
|
The fractional part of `n`
|
|
*/
|
|
#[no(warn_trivial_casts)] // FIXME Implement
|
|
pure fn modf(n: float, &iptr: float) -> float { unsafe {
|
|
ret m_float::modf(n as m_float, ptr::addr_of(iptr) as *m_float) as float
|
|
} }
|
|
|
|
/*
|
|
Function: frexp
|
|
|
|
Breaks `n` into a normalized fraction and an integral power of 2
|
|
|
|
The inegral part is stored in iptr.
|
|
|
|
The functions return a number x such that x has a magnitude in the interval
|
|
[1/2, 1) or 0, and `n == x*(2 to the power of exp)`.
|
|
|
|
Returns:
|
|
|
|
The fractional part of `n`
|
|
*/
|
|
pure fn frexp(n: float, &exp: c_int) -> float
|
|
{ ret m_float::frexp(n as m_float, exp) as float }
|
|
|
|
/*
|
|
Function: pow
|
|
*/
|
|
pure fn pow(v: float, e: float) -> float
|
|
{ ret m_float::pow(v as m_float, e as m_float) as float }
|
|
|
|
|
|
/*
|
|
Function: rint
|
|
|
|
Returns the integral value nearest to `x` (according to the
|
|
prevailing rounding mode) in floating-point format
|
|
*/
|
|
pure fn rint(x: float) -> float
|
|
{ ret m_float::rint(x as m_float) as float }
|
|
|
|
/*
|
|
Function: round
|
|
|
|
|
|
Return the integral value nearest to `x` rounding half-way
|
|
cases away from zero, regardless of the current rounding direction.
|
|
*/
|
|
pure fn round(x: float) -> float
|
|
{ ret m_float::round(x as m_float) as float }
|
|
|
|
/*
|
|
Function: sin
|
|
|
|
Returns the sine of an angle `x` (measured in rad)
|
|
*/
|
|
pure fn sin(x: float) -> float
|
|
{ ret m_float::sin(x as m_float) as float }
|
|
|
|
/*
|
|
Function: sinh
|
|
|
|
Returns the hyperbolic sine of an angle `x` (measured in rad)
|
|
*/
|
|
pure fn sinh(x: float) -> float
|
|
{ ret m_float::sinh(x as m_float) as float }
|
|
|
|
/*
|
|
Function: sqrt
|
|
|
|
Returns the square root of `x`
|
|
*/
|
|
pure fn sqrt(x: float) -> float
|
|
{ ret m_float::sqrt(x as m_float) as float }
|
|
|
|
/*
|
|
Function: tan
|
|
|
|
Returns the tangent of an angle `x` (measured in rad)
|
|
|
|
*/
|
|
pure fn tan(x: float) -> float
|
|
{ ret m_float::tan(x as m_float) as float }
|
|
|
|
/*
|
|
Function: tanh
|
|
|
|
Returns the hyperbolic tangent of an angle `x` (measured in rad)
|
|
|
|
*/
|
|
pure fn tanh(x: float) -> float
|
|
{ ret m_float::tanh(x as m_float) as float }
|
|
|
|
/*
|
|
Function: trunc
|
|
|
|
Returns the integral value nearest to but no larger in magnitude than `x`
|
|
|
|
*/
|
|
pure fn trunc(x: float) -> float
|
|
{ ret m_float::trunc(x as m_float) as float }
|
|
|
|
//
|
|
// Local Variables:
|
|
// mode: rust
|
|
// fill-column: 78;
|
|
// indent-tabs-mode: nil
|
|
// c-basic-offset: 4
|
|
// buffer-file-coding-system: utf-8-unix
|
|
// End:
|
|
//
|