--- /dev/null 2020-03-17 13:40:19.000000000 -0700 +++ new/test/jdk/jdk/internal/math/ToDecimal/java.base/jdk/internal/math/ToDecimalChecker.java 2020-03-17 13:40:18.000000000 -0700 @@ -0,0 +1,409 @@ +/* + * Copyright 2018-2020 Raffaello Giulietti + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +package jdk.internal.math; + +import java.io.IOException; +import java.io.StringReader; +import java.math.BigDecimal; +import java.math.BigInteger; + +import static java.math.BigInteger.*; + +/* +A checker for the Javadoc specification. +It just relies on straightforward use of (expensive) BigDecimal arithmetic, +not optimized at all. + */ +abstract class ToDecimalChecker extends BasicChecker { + + // The string to check + private final String s; + + // The decimal parsed from s is c 10^q + private long c; + private int q; + + // The number of digits parsed from s: 10^(len10-1) <= c < 10^len10 + private int len10; + + ToDecimalChecker(String s) { + this.s = s; + } + + /* + Returns e be such that 10^(e-1) <= v < 10^e. + */ + static int e(double v) { + // log10(v) + 1 is a first good approximation of e + int e = (int) Math.floor(Math.log10(v)) + 1; + + // Full precision search for e such that 10^(e-1) <= c 2^q < 10^e. + BigDecimal vp = new BigDecimal(v); + BigDecimal low = new BigDecimal(BigInteger.ONE, -(e - 1)); + while (low.compareTo(vp) > 0) { + e -= 1; + low = new BigDecimal(BigInteger.ONE, -(e - 1)); + } + BigDecimal high = new BigDecimal(BigInteger.ONE, -e); + while (vp.compareTo(high) >= 0) { + e += 1; + high = new BigDecimal(BigInteger.ONE, -e); + } + return e; + } + + static long cTiny(int qMin, int kMin) { + BigInteger[] qr = ONE.shiftLeft(-qMin) + .divideAndRemainder(TEN.pow(-(kMin + 1))); + BigInteger cTiny = qr[1].signum() > 0 ? qr[0].add(ONE) : qr[0]; + assertTrue(cTiny.bitLength() < Long.SIZE, "C_TINY"); + return cTiny.longValue(); + } + + void assertTrue() { + if (isOK()) { + return; + } + String msg = "toString applied to the bits " + + hexBits() + + " returns " + + "\"" + s + "\"" + + ", which is not correct according to the specification."; + if (FAILURE_THROWS_EXCEPTION) { + throw new RuntimeException(msg); + } + System.err.println(msg); + } + + /* + Returns whether s syntactically meets the expected output of + toString. It is restricted to finite positive outputs. + It is an unusually long method but rather straightforward, too. + Many conditionals could be merged, but KISS here. + */ + private boolean parse(String t) { + try { + // first determine interesting boundaries in the string + StringReader r = new StringReader(t); + int ch = r.read(); + + int i = 0; + while (ch == '0') { + ++i; + ch = r.read(); + } + // i is just after zeroes starting the integer + + int p = i; + while ('0' <= ch && ch <= '9') { + c = 10 * c + (ch - '0'); + if (c < 0) { + return false; + } + ++len10; + ++p; + ch = r.read(); + } + // p is just after digits ending the integer + + int fz = p; + if (ch == '.') { + ++fz; + ch = r.read(); + } + // fz is just after a decimal '.' + + int f = fz; + while (ch == '0') { + c = 10 * c + (ch - '0'); + if (c < 0) { + return false; + } + ++len10; + ++f; + ch = r.read(); + } + // f is just after zeroes starting the fraction + + if (c == 0) { + len10 = 0; + } + int x = f; + while ('0' <= ch && ch <= '9') { + c = 10 * c + (ch - '0'); + if (c < 0) { + return false; + } + ++len10; + ++x; + ch = r.read(); + } + // x is just after digits ending the fraction + + int g = x; + if (ch == 'E') { + ++g; + ch = r.read(); + } + // g is just after an exponent indicator 'E' + + int ez = g; + if (ch == '-') { + ++ez; + ch = r.read(); + } + // ez is just after a '-' sign in the exponent + + int e = ez; + while (ch == '0') { + ++e; + ch = r.read(); + } + // e is just after zeroes starting the exponent + + int z = e; + while ('0' <= ch && ch <= '9') { + q = 10 * q + (ch - '0'); + if (q < 0) { + return false; + } + ++z; + ch = r.read(); + } + // z is just after digits ending the exponent + + // No other char after the number + if (z != t.length()) { + return false; + } + + // The integer must be present + if (p == 0) { + return false; + } + + // The decimal '.' must be present + if (fz == p) { + return false; + } + + // The fraction must be present + if (x == fz) { + return false; + } + + // The fraction is not 0 or it consists of exactly one 0 + if (f == x && f - fz > 1) { + return false; + } + + // Plain notation, no exponent + if (x == z) { + // At most one 0 starting the integer + if (i > 1) { + return false; + } + + // If the integer is 0, at most 2 zeroes start the fraction + if (i == 1 && f - fz > 2) { + return false; + } + + // The integer cannot have more than 7 digits + if (p > 7) { + return false; + } + + q = fz - x; + + // OK for plain notation + return true; + } + + // Computerized scientific notation + + // The integer has exactly one nonzero digit + if (i != 0 || p != 1) { + return false; + } + + // + // There must be an exponent indicator + if (x == g) { + return false; + } + + // There must be an exponent + if (ez == z) { + return false; + } + + // The exponent must not start with zeroes + if (ez != e) { + return false; + } + + if (g != ez) { + q = -q; + } + + // The exponent must not lie in [-3, 7) + if (-3 <= q && q < 7) { + return false; + } + + q += fz - x; + + // OK for computerized scientific notation + return true; + } catch (IOException ex) { + // An IOException on a StringReader??? Please... + return false; + } + } + + private boolean isOK() { + if (isNaN()) { + return s.equals("NaN"); + } + String t = s; + if (isNegative()) { + if (s.isEmpty() || s.charAt(0) != '-') { + return false; + } + negate(); + t = s.substring(1); + } + if (isInfinity()) { + return t.equals("Infinity"); + } + if (isZero()) { + return t.equals("0.0"); + } + if (!parse(t)) { + return false; + } + if (len10 < 2) { + c *= 10; + q -= 1; + len10 += 1; + } + if (2 > len10 || len10 > maxLen10()) { + return false; + } + + // The exponent is bounded + if (minExp() > q + len10 || q + len10 > maxExp()) { + return false; + } + + // s must recover v + try { + if (!recovers(t)) { + return false; + } + } catch (NumberFormatException e) { + return false; + } + + // Get rid of trailing zeroes, still ensuring at least 2 digits + while (len10 > 2 && c % 10 == 0) { + c /= 10; + q += 1; + len10 -= 1; + } + + if (len10 > 2) { + // Try with a shorter number less than v... + if (recovers(BigDecimal.valueOf(c / 10, -q - 1))) { + return false; + } + + // ... and with a shorter number greater than v + if (recovers(BigDecimal.valueOf(c / 10 + 1, -q - 1))) { + return false; + } + } + + // Try with the decimal predecessor... + BigDecimal dp = c == 10 ? + BigDecimal.valueOf(99, -q + 1) : + BigDecimal.valueOf(c - 1, -q); + if (recovers(dp)) { + BigDecimal bv = toBigDecimal(); + BigDecimal deltav = bv.subtract(BigDecimal.valueOf(c, -q)); + if (deltav.signum() >= 0) { + return true; + } + BigDecimal delta = dp.subtract(bv); + if (delta.signum() >= 0) { + return false; + } + int cmp = deltav.compareTo(delta); + return cmp > 0 || cmp == 0 && (c & 0x1) == 0; + } + + // ... and with the decimal successor + BigDecimal ds = BigDecimal.valueOf(c + 1, -q); + if (recovers(ds)) { + BigDecimal bv = toBigDecimal(); + BigDecimal deltav = bv.subtract(BigDecimal.valueOf(c, -q)); + if (deltav.signum() <= 0) { + return true; + } + BigDecimal delta = ds.subtract(bv); + if (delta.signum() <= 0) { + return false; + } + int cmp = deltav.compareTo(delta); + return cmp < 0 || cmp == 0 && (c & 0x1) == 0; + } + + return true; + } + + abstract BigDecimal toBigDecimal(); + + abstract boolean recovers(BigDecimal b); + + abstract boolean recovers(String s); + + abstract String hexBits(); + + abstract int minExp(); + + abstract int maxExp(); + + abstract int maxLen10(); + + abstract boolean isZero(); + + abstract boolean isInfinity(); + + abstract void negate(); + + abstract boolean isNegative(); + + abstract boolean isNaN(); + +}