1 // Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // ignore-lexer-test FIXME #15679
13 #![allow(missing_docs)]
15 pub use self::ExponentFormat::*;
16 pub use self::SignificantDigits::*;
17 pub use self::SignFormat::*;
23 use num::{Int, Float, FPNaN, FPInfinite, ToPrimitive};
24 use slice::{SlicePrelude, CloneSliceAllocPrelude};
29 /// A flag that specifies whether to use exponential (scientific) notation.
30 pub enum ExponentFormat {
31 /// Do not use exponential notation.
33 /// Use exponential notation with the exponent having a base of 10 and the
34 /// exponent sign being `e` or `E`. For example, 1000 would be printed
37 /// Use exponential notation with the exponent having a base of 2 and the
38 /// exponent sign being `p` or `P`. For example, 8 would be printed 1p3.
42 impl Copy for ExponentFormat {}
44 /// The number of digits used for emitting the fractional part of a number, if
46 pub enum SignificantDigits {
47 /// All calculable digits will be printed.
49 /// Note that bignums or fractions may cause a surprisingly large number
50 /// of digits to be printed.
53 /// At most the given number of digits will be printed, truncating any
57 /// Precisely the given number of digits will be printed.
61 impl Copy for SignificantDigits {}
63 /// How to emit the sign of a number.
65 /// No sign will be printed. The exponent sign will also be emitted.
67 /// `-` will be printed for negative values, but no sign will be emitted
68 /// for positive numbers.
70 /// `+` will be printed for positive values, and `-` will be printed for
75 impl Copy for SignFormat {}
78 * Converts an integral number to its string representation as a byte vector.
79 * This is meant to be a common base implementation for all integral string
80 * conversion functions like `to_string()` or `to_str_radix()`.
83 * - `num` - The number to convert. Accepts any number that
84 * implements the numeric traits.
85 * - `radix` - Base to use. Accepts only the values 2-36.
86 * - `sign` - How to emit the sign. Options are:
87 * - `SignNone`: No sign at all. Basically emits `abs(num)`.
88 * - `SignNeg`: Only `-` on negative values.
89 * - `SignAll`: Both `+` on positive, and `-` on negative numbers.
90 * - `f` - a callback which will be invoked for each ascii character
91 * which composes the string representation of this integer
94 * A tuple containing the byte vector, and a boolean flag indicating
95 * whether it represents a special value like `inf`, `-inf`, `NaN` or not.
96 * It returns a tuple because there can be ambiguity between a special value
97 * and a number representation at higher bases.
100 * - Fails if `radix` < 2 or `radix` > 36.
102 fn int_to_str_bytes_common<T: Int>(num: T, radix: uint, sign: SignFormat, f: |u8|) {
103 assert!(2 <= radix && radix <= 36);
105 let _0: T = Int::zero();
108 let radix_gen: T = num::cast(radix).unwrap();
110 let mut deccum = num;
111 // This is just for integral types, the largest of which is a u64. The
112 // smallest base that we can have is 2, so the most number of digits we're
113 // ever going to have is 64
114 let mut buf = [0u8, ..64];
117 // Loop at least once to make sure at least a `0` gets emitted.
119 // Calculate the absolute value of each digit instead of only
120 // doing it once for the whole number because a
121 // representable negative number doesn't necessary have an
122 // representable additive inverse of the same type
123 // (See twos complement). But we assume that for the
124 // numbers [-35 .. 0] we always have [0 .. 35].
125 let current_digit_signed = deccum % radix_gen;
126 let current_digit = if current_digit_signed < _0 {
127 _0 - current_digit_signed
131 buf[cur] = match current_digit.to_u8().unwrap() {
132 i @ 0...9 => b'0' + i,
133 i => b'a' + (i - 10),
137 deccum = deccum / radix_gen;
138 // No more digits to calculate for the non-fractional part -> break
139 if deccum == _0 { break; }
142 // Decide what sign to put in front
144 SignNeg | SignAll if neg => { f(b'-'); }
145 SignAll => { f(b'+'); }
149 // We built the number in reverse order, so un-reverse it here
156 /// Converts a number to its string representation as a byte vector.
157 /// This is meant to be a common base implementation for all numeric string
158 /// conversion functions like `to_string()` or `to_str_radix()`.
162 /// - `num` - The number to convert. Accepts any number that
163 /// implements the numeric traits.
164 /// - `radix` - Base to use. Accepts only the values 2-36. If the exponential notation
165 /// is used, then this base is only used for the significand. The exponent
166 /// itself always printed using a base of 10.
167 /// - `negative_zero` - Whether to treat the special value `-0` as
169 /// - `sign` - How to emit the sign. See `SignFormat`.
170 /// - `digits` - The amount of digits to use for emitting the fractional
171 /// part, if any. See `SignificantDigits`.
172 /// - `exp_format` - Whether or not to use the exponential (scientific) notation.
173 /// See `ExponentFormat`.
174 /// - `exp_capital` - Whether or not to use a capital letter for the exponent sign, if
175 /// exponential notation is desired.
179 /// A tuple containing the byte vector, and a boolean flag indicating
180 /// whether it represents a special value like `inf`, `-inf`, `NaN` or not.
181 /// It returns a tuple because there can be ambiguity between a special value
182 /// and a number representation at higher bases.
186 /// - Panics if `radix` < 2 or `radix` > 36.
187 /// - Panics if `radix` > 14 and `exp_format` is `ExpDec` due to conflict
188 /// between digit and exponent sign `'e'`.
189 /// - Panics if `radix` > 25 and `exp_format` is `ExpBin` due to conflict
190 /// between digit and exponent sign `'p'`.
191 pub fn float_to_str_bytes_common<T: Float>(
192 num: T, radix: uint, negative_zero: bool,
193 sign: SignFormat, digits: SignificantDigits, exp_format: ExponentFormat, exp_upper: bool
194 ) -> (Vec<u8>, bool) {
195 assert!(2 <= radix && radix <= 36);
197 ExpDec if radix >= DIGIT_E_RADIX // decimal exponent 'e'
198 => panic!("float_to_str_bytes_common: radix {} incompatible with \
199 use of 'e' as decimal exponent", radix),
200 ExpBin if radix >= DIGIT_P_RADIX // binary exponent 'p'
201 => panic!("float_to_str_bytes_common: radix {} incompatible with \
202 use of 'p' as binary exponent", radix),
206 let _0: T = Float::zero();
207 let _1: T = Float::one();
209 match num.classify() {
210 FPNaN => { return (b"NaN".to_vec(), true); }
211 FPInfinite if num > _0 => {
213 SignAll => (b"+inf".to_vec(), true),
214 _ => (b"inf".to_vec(), true)
217 FPInfinite if num < _0 => {
219 SignNone => (b"inf".to_vec(), true),
220 _ => (b"-inf".to_vec(), true),
226 let neg = num < _0 || (negative_zero && _1 / num == Float::neg_infinity());
227 let mut buf = Vec::new();
228 let radix_gen: T = num::cast(radix as int).unwrap();
230 let (num, exp) = match exp_format {
231 ExpNone => (num, 0i32),
236 let (exp, exp_base) = match exp_format {
237 ExpDec => (num.abs().log10().floor(), num::cast::<f64, T>(10.0f64).unwrap()),
238 ExpBin => (num.abs().log2().floor(), num::cast::<f64, T>(2.0f64).unwrap()),
239 ExpNone => unreachable!()
242 (num / exp_base.powf(exp), num::cast::<T, i32>(exp).unwrap())
247 // First emit the non-fractional part, looping at least once to make
248 // sure at least a `0` gets emitted.
249 let mut deccum = num.trunc();
251 // Calculate the absolute value of each digit instead of only
252 // doing it once for the whole number because a
253 // representable negative number doesn't necessary have an
254 // representable additive inverse of the same type
255 // (See twos complement). But we assume that for the
256 // numbers [-35 .. 0] we always have [0 .. 35].
257 let current_digit = (deccum % radix_gen).abs();
259 // Decrease the deccumulator one digit at a time
260 deccum = deccum / radix_gen;
261 deccum = deccum.trunc();
263 buf.push(char::from_digit(current_digit.to_int().unwrap() as uint, radix)
266 // No more digits to calculate for the non-fractional part -> break
267 if deccum == _0 { break; }
270 // If limited digits, calculate one digit more for rounding.
271 let (limit_digits, digit_count, exact) = match digits {
272 DigAll => (false, 0u, false),
273 DigMax(count) => (true, count+1, false),
274 DigExact(count) => (true, count+1, true)
277 // Decide what sign to put in front
279 SignNeg | SignAll if neg => {
290 // Remember start of the fractional digits.
291 // Points one beyond end of buf if none get generated,
292 // or at the '.' otherwise.
293 let start_fractional_digits = buf.len();
295 // Now emit the fractional part, if any
296 deccum = num.fract();
297 if deccum != _0 || (limit_digits && exact && digit_count > 0) {
301 // calculate new digits while
302 // - there is no limit and there are digits left
303 // - or there is a limit, it's not reached yet and
305 // - or it's a maximum, and there are still digits left
306 while (!limit_digits && deccum != _0)
307 || (limit_digits && dig < digit_count && (
309 || (!exact && deccum != _0)
312 // Shift first fractional digit into the integer part
313 deccum = deccum * radix_gen;
315 // Calculate the absolute value of each digit.
316 // See note in first loop.
317 let current_digit = deccum.trunc().abs();
319 buf.push(char::from_digit(
320 current_digit.to_int().unwrap() as uint, radix).unwrap() as u8);
322 // Decrease the deccumulator one fractional digit at a time
323 deccum = deccum.fract();
327 // If digits are limited, and that limit has been reached,
328 // cut off the one extra digit, and depending on its value
329 // round the remaining ones.
330 if limit_digits && dig == digit_count {
331 let ascii2value = |chr: u8| {
332 (chr as char).to_digit(radix).unwrap()
334 let value2ascii = |val: uint| {
335 char::from_digit(val, radix).unwrap() as u8
338 let extra_digit = ascii2value(buf.pop().unwrap());
339 if extra_digit >= radix / 2 { // -> need to round
340 let mut i: int = buf.len() as int - 1;
342 // If reached left end of number, have to
343 // insert additional digit:
345 || buf[i as uint] == b'-'
346 || buf[i as uint] == b'+' {
347 buf.insert((i + 1) as uint, value2ascii(1));
352 if buf[i as uint] == b'.' { i -= 1; continue; }
354 // Either increment the digit,
355 // or set to 0 if max and carry the 1.
356 let current_digit = ascii2value(buf[i as uint]);
357 if current_digit < (radix - 1) {
358 buf[i as uint] = value2ascii(current_digit+1);
361 buf[i as uint] = value2ascii(0);
369 // if number of digits is not exact, remove all trailing '0's up to
370 // and including the '.'
372 let buf_max_i = buf.len() - 1;
374 // index to truncate from
375 let mut i = buf_max_i;
377 // discover trailing zeros of fractional part
378 while i > start_fractional_digits && buf[i] == b'0' {
382 // Only attempt to truncate digits if buf has fractional digits
383 if i >= start_fractional_digits {
384 // If buf ends with '.', cut that too.
385 if buf[i] == b'.' { i -= 1 }
387 // only resize buf if we actually remove digits
389 buf = buf.slice(0, i + 1).to_vec();
392 } // If exact and trailing '.', just cut that
394 let max_i = buf.len() - 1;
395 if buf[max_i] == b'.' {
396 buf = buf.slice(0, max_i).to_vec();
403 buf.push(match exp_format {
404 ExpDec if exp_upper => 'E',
405 ExpDec if !exp_upper => 'e',
406 ExpBin if exp_upper => 'P',
407 ExpBin if !exp_upper => 'p',
411 int_to_str_bytes_common(exp, 10, sign, |c| buf.push(c));
419 * Converts a number to its string representation. This is a wrapper for
420 * `to_str_bytes_common()`, for details see there.
423 pub fn float_to_str_common<T: Float>(
424 num: T, radix: uint, negative_zero: bool,
425 sign: SignFormat, digits: SignificantDigits, exp_format: ExponentFormat, exp_capital: bool
426 ) -> (String, bool) {
427 let (bytes, special) = float_to_str_bytes_common(num, radix,
428 negative_zero, sign, digits, exp_format, exp_capital);
429 (String::from_utf8(bytes).unwrap(), special)
432 // Some constants for from_str_bytes_common's input validation,
433 // they define minimum radix values for which the character is a valid digit.
434 static DIGIT_P_RADIX: uint = ('p' as uint) - ('a' as uint) + 11u;
435 static DIGIT_E_RADIX: uint = ('e' as uint) - ('a' as uint) + 11u;
439 use string::ToString;
442 fn test_int_to_str_overflow() {
443 let mut i8_val: i8 = 127_i8;
444 assert_eq!(i8_val.to_string(), "127");
447 assert_eq!(i8_val.to_string(), "-128");
449 let mut i16_val: i16 = 32_767_i16;
450 assert_eq!(i16_val.to_string(), "32767");
453 assert_eq!(i16_val.to_string(), "-32768");
455 let mut i32_val: i32 = 2_147_483_647_i32;
456 assert_eq!(i32_val.to_string(), "2147483647");
459 assert_eq!(i32_val.to_string(), "-2147483648");
461 let mut i64_val: i64 = 9_223_372_036_854_775_807_i64;
462 assert_eq!(i64_val.to_string(), "9223372036854775807");
465 assert_eq!(i64_val.to_string(), "-9223372036854775808");
474 use super::test::Bencher;
475 use rand::{weak_rng, Rng};
479 fn to_string(x: uint, base: u8) {
480 format!("{}", fmt::radix(x, base));
484 fn to_str_bin(b: &mut Bencher) {
485 let mut rng = weak_rng();
486 b.iter(|| { to_string(rng.gen::<uint>(), 2); })
490 fn to_str_oct(b: &mut Bencher) {
491 let mut rng = weak_rng();
492 b.iter(|| { to_string(rng.gen::<uint>(), 8); })
496 fn to_str_dec(b: &mut Bencher) {
497 let mut rng = weak_rng();
498 b.iter(|| { to_string(rng.gen::<uint>(), 10); })
502 fn to_str_hex(b: &mut Bencher) {
503 let mut rng = weak_rng();
504 b.iter(|| { to_string(rng.gen::<uint>(), 16); })
508 fn to_str_base_36(b: &mut Bencher) {
509 let mut rng = weak_rng();
510 b.iter(|| { to_string(rng.gen::<uint>(), 36); })
515 use super::test::Bencher;
516 use rand::{weak_rng, Rng};
520 fn to_string(x: int, base: u8) {
521 format!("{}", fmt::radix(x, base));
525 fn to_str_bin(b: &mut Bencher) {
526 let mut rng = weak_rng();
527 b.iter(|| { to_string(rng.gen::<int>(), 2); })
531 fn to_str_oct(b: &mut Bencher) {
532 let mut rng = weak_rng();
533 b.iter(|| { to_string(rng.gen::<int>(), 8); })
537 fn to_str_dec(b: &mut Bencher) {
538 let mut rng = weak_rng();
539 b.iter(|| { to_string(rng.gen::<int>(), 10); })
543 fn to_str_hex(b: &mut Bencher) {
544 let mut rng = weak_rng();
545 b.iter(|| { to_string(rng.gen::<int>(), 16); })
549 fn to_str_base_36(b: &mut Bencher) {
550 let mut rng = weak_rng();
551 b.iter(|| { to_string(rng.gen::<int>(), 36); })
556 use super::test::Bencher;
557 use rand::{weak_rng, Rng};
561 fn float_to_string(b: &mut Bencher) {
562 let mut rng = weak_rng();
563 b.iter(|| { f64::to_string(rng.gen()); })