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Merge pull request #8059 from berni44/rounding_a
std.format: Use rounding tool to round %a on floats.
This commit is contained in:
Razvan Nitu
GitHub
commit
dba3cbc88c
2 changed files with 95 additions and 125 deletions
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@ -104,7 +104,7 @@ if (is(T == float) || is(T == double)
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}
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// save integer part
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char[1] first = '0' + ((mnt >> (T.mant_dig - 1)) & 1);
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char first = '0' + ((mnt >> (T.mant_dig - 1)) & 1);
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mnt &= (1L << (T.mant_dig - 1)) - 1;
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static if (is(T == float) || (is(T == real) && T.mant_dig == 64))
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@ -117,8 +117,8 @@ if (is(T == float) || is(T == double)
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static assert(mant_len % 4 == 0, "mantissa with wrong length");
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// print full mantissa
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char[(mant_len - 1) / 4 + 2] hex_mant;
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size_t hex_mant_pos = 1;
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char[(mant_len - 1) / 4 + 3] hex_mant;
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size_t hex_mant_pos = 2;
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size_t pos = mant_len;
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auto gap = 39 - 32 * is_upper;
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@ -131,10 +131,11 @@ if (is(T == float) || is(T == double)
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// has been replaced with an expression without branches, doing the same
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hex_mant[hex_mant_pos++] = cast(char) (tmp + gap * ((tmp + 6) >> 4) + '0');
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}
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hex_mant[0] = '.';
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hex_mant[0] = first;
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hex_mant[1] = '.';
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if (f.precision == f.UNSPECIFIED)
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f.precision = cast(int) hex_mant_pos - 1;
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f.precision = cast(int) hex_mant_pos - 2;
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auto exp_sgn = exp >= 0 ? '+' : '-';
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if (exp < 0) exp = -exp;
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@ -158,88 +159,39 @@ if (is(T == float) || is(T == double)
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exp_str[--exp_pos] = exp_sgn;
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exp_str[--exp_pos] = is_upper ? 'P' : 'p';
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if (f.precision < hex_mant_pos - 1)
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if (f.precision < hex_mant_pos - 2)
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{
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enum roundType { ZERO, LOWER, FIVE, UPPER }
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roundType next;
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import std.format.internal.write : RoundingClass, round;
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if (hex_mant[f.precision + 1] == '0')
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next = roundType.ZERO;
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else if (hex_mant[f.precision + 1] < '8')
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next = roundType.LOWER;
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else if (hex_mant[f.precision + 1] > '8')
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next = roundType.UPPER;
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RoundingClass rc;
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if (hex_mant[f.precision + 2] == '0')
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rc = RoundingClass.ZERO;
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else if (hex_mant[f.precision + 2] < '8')
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rc = RoundingClass.LOWER;
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else if (hex_mant[f.precision + 2] > '8')
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rc = RoundingClass.UPPER;
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else
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next = roundType.FIVE;
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rc = RoundingClass.FIVE;
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if (next == roundType.ZERO || next == roundType.FIVE)
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if (rc == RoundingClass.ZERO || rc == RoundingClass.FIVE)
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{
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foreach (i;f.precision + 2 .. hex_mant_pos)
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foreach (i;f.precision + 3 .. hex_mant_pos)
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{
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if (hex_mant[i] > '0')
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{
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next = next == roundType.ZERO ? roundType.LOWER : roundType.UPPER;
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rc = rc == RoundingClass.ZERO ? RoundingClass.LOWER : RoundingClass.UPPER;
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break;
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}
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}
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}
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bool roundUp = false;
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hex_mant_pos = f.precision + 2;
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if (rm == RoundingMode.up)
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roundUp = next != roundType.ZERO && sgn != "-";
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else if (rm == RoundingMode.down)
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roundUp = next != roundType.ZERO && sgn == "-";
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else if (rm == RoundingMode.toZero)
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roundUp = false;
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else
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{
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assert(rm == RoundingMode.toNearestTiesToEven || rm == RoundingMode.toNearestTiesAwayFromZero,
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"RoundingMode is not toNearest");
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roundUp = next == roundType.UPPER;
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if (next == roundType.FIVE)
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{
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// IEEE754 allows for two different ways of implementing roundToNearest:
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// Round to nearest, ties away from zero
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if (rm == RoundingMode.toNearestTiesAwayFromZero)
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roundUp = true;
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else
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{
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// Round to nearest, ties to even
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auto last = f.precision == 0 ? first[0] : hex_mant[f.precision];
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roundUp = (last <= '9' && last % 2 != 0) || (last >= '9' && last % 2 == 0);
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}
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}
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}
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hex_mant_pos = f.precision + 1;
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if (roundUp)
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{
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foreach_reverse (i;0 .. hex_mant_pos)
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{
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if (hex_mant[i] == '.')
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{
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first[0]++;
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break;
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}
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if (hex_mant[i] == 'f' || hex_mant[i] == 'F')
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hex_mant[i] = '0';
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else
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{
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if (hex_mant[i] == '9')
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hex_mant[i] = is_upper ? 'A' : 'a';
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else
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hex_mant[i]++;
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break;
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}
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}
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}
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round(hex_mant, 0, hex_mant_pos, rc, sgn == "-", is_upper ? 'F' : 'f');
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}
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writeAligned(w, prefix[1 - sgn.length .. $], first[], hex_mant[0 .. hex_mant_pos],
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writeAligned(w, prefix[1 - sgn.length .. $], hex_mant[0 .. 1], hex_mant[1 .. hex_mant_pos],
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exp_str[exp_pos .. $], f, PrecisionType.fractionalDigits);
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}
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@ -532,64 +484,82 @@ if (is(T == float) || is(T == double)
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@safe unittest
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{
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auto f = FormatSpec!dchar("");
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f.spec = 'a';
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f.precision = 1;
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import std.math.hardware; // cannot be selective, because FloatingPointControl might not be defined
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assert(printFloat(0x1.18p0, f, RoundingMode.toNearestTiesAwayFromZero) == "0x1.2p+0");
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assert(printFloat(0x1.28p0, f, RoundingMode.toNearestTiesAwayFromZero) == "0x1.3p+0");
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assert(printFloat(0x1.1ap0, f, RoundingMode.toNearestTiesAwayFromZero) == "0x1.2p+0");
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assert(printFloat(0x1.16p0, f, RoundingMode.toNearestTiesAwayFromZero) == "0x1.1p+0");
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assert(printFloat(0x1.10p0, f, RoundingMode.toNearestTiesAwayFromZero) == "0x1.1p+0");
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assert(printFloat(-0x1.18p0, f, RoundingMode.toNearestTiesAwayFromZero) == "-0x1.2p+0");
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assert(printFloat(-0x1.28p0, f, RoundingMode.toNearestTiesAwayFromZero) == "-0x1.3p+0");
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assert(printFloat(-0x1.1ap0, f, RoundingMode.toNearestTiesAwayFromZero) == "-0x1.2p+0");
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assert(printFloat(-0x1.16p0, f, RoundingMode.toNearestTiesAwayFromZero) == "-0x1.1p+0");
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assert(printFloat(-0x1.10p0, f, RoundingMode.toNearestTiesAwayFromZero) == "-0x1.1p+0");
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// std.math's FloatingPointControl isn't available on all target platforms
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static if (is(FloatingPointControl))
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{
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FloatingPointControl fpctrl;
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assert(printFloat(0x1.18p0, f) == "0x1.2p+0");
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assert(printFloat(0x1.28p0, f) == "0x1.2p+0");
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assert(printFloat(0x1.1ap0, f) == "0x1.2p+0");
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assert(printFloat(0x1.16p0, f) == "0x1.1p+0");
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assert(printFloat(0x1.10p0, f) == "0x1.1p+0");
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assert(printFloat(-0x1.18p0, f) == "-0x1.2p+0");
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assert(printFloat(-0x1.28p0, f) == "-0x1.2p+0");
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assert(printFloat(-0x1.1ap0, f) == "-0x1.2p+0");
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assert(printFloat(-0x1.16p0, f) == "-0x1.1p+0");
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assert(printFloat(-0x1.10p0, f) == "-0x1.1p+0");
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auto f = FormatSpec!dchar("");
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f.spec = 'a';
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f.precision = 1;
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assert(printFloat(0x1.18p0, f, RoundingMode.toZero) == "0x1.1p+0");
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assert(printFloat(0x1.28p0, f, RoundingMode.toZero) == "0x1.2p+0");
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assert(printFloat(0x1.1ap0, f, RoundingMode.toZero) == "0x1.1p+0");
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assert(printFloat(0x1.16p0, f, RoundingMode.toZero) == "0x1.1p+0");
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assert(printFloat(0x1.10p0, f, RoundingMode.toZero) == "0x1.1p+0");
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assert(printFloat(-0x1.18p0, f, RoundingMode.toZero) == "-0x1.1p+0");
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assert(printFloat(-0x1.28p0, f, RoundingMode.toZero) == "-0x1.2p+0");
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assert(printFloat(-0x1.1ap0, f, RoundingMode.toZero) == "-0x1.1p+0");
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assert(printFloat(-0x1.16p0, f, RoundingMode.toZero) == "-0x1.1p+0");
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assert(printFloat(-0x1.10p0, f, RoundingMode.toZero) == "-0x1.1p+0");
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fpctrl.rounding = FloatingPointControl.roundToNearest;
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assert(printFloat(0x1.18p0, f, RoundingMode.up) == "0x1.2p+0");
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assert(printFloat(0x1.28p0, f, RoundingMode.up) == "0x1.3p+0");
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assert(printFloat(0x1.1ap0, f, RoundingMode.up) == "0x1.2p+0");
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assert(printFloat(0x1.16p0, f, RoundingMode.up) == "0x1.2p+0");
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assert(printFloat(0x1.10p0, f, RoundingMode.up) == "0x1.1p+0");
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assert(printFloat(-0x1.18p0, f, RoundingMode.up) == "-0x1.1p+0");
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assert(printFloat(-0x1.28p0, f, RoundingMode.up) == "-0x1.2p+0");
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assert(printFloat(-0x1.1ap0, f, RoundingMode.up) == "-0x1.1p+0");
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assert(printFloat(-0x1.16p0, f, RoundingMode.up) == "-0x1.1p+0");
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assert(printFloat(-0x1.10p0, f, RoundingMode.up) == "-0x1.1p+0");
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/* tiesAwayFromZero currently not supported
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assert(printFloat(0x1.18p0, f, RoundingMode.toNearestTiesAwayFromZero) == "0x1.2p+0");
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assert(printFloat(0x1.28p0, f, RoundingMode.toNearestTiesAwayFromZero) == "0x1.3p+0");
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assert(printFloat(0x1.1ap0, f, RoundingMode.toNearestTiesAwayFromZero) == "0x1.2p+0");
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assert(printFloat(0x1.16p0, f, RoundingMode.toNearestTiesAwayFromZero) == "0x1.1p+0");
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assert(printFloat(0x1.10p0, f, RoundingMode.toNearestTiesAwayFromZero) == "0x1.1p+0");
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assert(printFloat(-0x1.18p0, f, RoundingMode.toNearestTiesAwayFromZero) == "-0x1.2p+0");
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assert(printFloat(-0x1.28p0, f, RoundingMode.toNearestTiesAwayFromZero) == "-0x1.3p+0");
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assert(printFloat(-0x1.1ap0, f, RoundingMode.toNearestTiesAwayFromZero) == "-0x1.2p+0");
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assert(printFloat(-0x1.16p0, f, RoundingMode.toNearestTiesAwayFromZero) == "-0x1.1p+0");
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assert(printFloat(-0x1.10p0, f, RoundingMode.toNearestTiesAwayFromZero) == "-0x1.1p+0");
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*/
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assert(printFloat(0x1.18p0, f, RoundingMode.down) == "0x1.1p+0");
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assert(printFloat(0x1.28p0, f, RoundingMode.down) == "0x1.2p+0");
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assert(printFloat(0x1.1ap0, f, RoundingMode.down) == "0x1.1p+0");
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assert(printFloat(0x1.16p0, f, RoundingMode.down) == "0x1.1p+0");
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assert(printFloat(0x1.10p0, f, RoundingMode.down) == "0x1.1p+0");
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assert(printFloat(-0x1.18p0, f, RoundingMode.down) == "-0x1.2p+0");
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assert(printFloat(-0x1.28p0, f, RoundingMode.down) == "-0x1.3p+0");
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assert(printFloat(-0x1.1ap0, f, RoundingMode.down) == "-0x1.2p+0");
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assert(printFloat(-0x1.16p0, f, RoundingMode.down) == "-0x1.2p+0");
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assert(printFloat(-0x1.10p0, f, RoundingMode.down) == "-0x1.1p+0");
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assert(printFloat(0x1.18p0, f) == "0x1.2p+0");
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assert(printFloat(0x1.28p0, f) == "0x1.2p+0");
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assert(printFloat(0x1.1ap0, f) == "0x1.2p+0");
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assert(printFloat(0x1.16p0, f) == "0x1.1p+0");
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assert(printFloat(0x1.10p0, f) == "0x1.1p+0");
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assert(printFloat(-0x1.18p0, f) == "-0x1.2p+0");
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assert(printFloat(-0x1.28p0, f) == "-0x1.2p+0");
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assert(printFloat(-0x1.1ap0, f) == "-0x1.2p+0");
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assert(printFloat(-0x1.16p0, f) == "-0x1.1p+0");
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assert(printFloat(-0x1.10p0, f) == "-0x1.1p+0");
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fpctrl.rounding = FloatingPointControl.roundToZero;
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assert(printFloat(0x1.18p0, f, RoundingMode.toZero) == "0x1.1p+0");
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assert(printFloat(0x1.28p0, f, RoundingMode.toZero) == "0x1.2p+0");
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assert(printFloat(0x1.1ap0, f, RoundingMode.toZero) == "0x1.1p+0");
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assert(printFloat(0x1.16p0, f, RoundingMode.toZero) == "0x1.1p+0");
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assert(printFloat(0x1.10p0, f, RoundingMode.toZero) == "0x1.1p+0");
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assert(printFloat(-0x1.18p0, f, RoundingMode.toZero) == "-0x1.1p+0");
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assert(printFloat(-0x1.28p0, f, RoundingMode.toZero) == "-0x1.2p+0");
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assert(printFloat(-0x1.1ap0, f, RoundingMode.toZero) == "-0x1.1p+0");
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assert(printFloat(-0x1.16p0, f, RoundingMode.toZero) == "-0x1.1p+0");
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assert(printFloat(-0x1.10p0, f, RoundingMode.toZero) == "-0x1.1p+0");
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fpctrl.rounding = FloatingPointControl.roundUp;
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assert(printFloat(0x1.18p0, f, RoundingMode.up) == "0x1.2p+0");
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assert(printFloat(0x1.28p0, f, RoundingMode.up) == "0x1.3p+0");
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assert(printFloat(0x1.1ap0, f, RoundingMode.up) == "0x1.2p+0");
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assert(printFloat(0x1.16p0, f, RoundingMode.up) == "0x1.2p+0");
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assert(printFloat(0x1.10p0, f, RoundingMode.up) == "0x1.1p+0");
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assert(printFloat(-0x1.18p0, f, RoundingMode.up) == "-0x1.1p+0");
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assert(printFloat(-0x1.28p0, f, RoundingMode.up) == "-0x1.2p+0");
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assert(printFloat(-0x1.1ap0, f, RoundingMode.up) == "-0x1.1p+0");
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assert(printFloat(-0x1.16p0, f, RoundingMode.up) == "-0x1.1p+0");
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assert(printFloat(-0x1.10p0, f, RoundingMode.up) == "-0x1.1p+0");
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fpctrl.rounding = FloatingPointControl.roundDown;
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assert(printFloat(0x1.18p0, f, RoundingMode.down) == "0x1.1p+0");
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assert(printFloat(0x1.28p0, f, RoundingMode.down) == "0x1.2p+0");
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assert(printFloat(0x1.1ap0, f, RoundingMode.down) == "0x1.1p+0");
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assert(printFloat(0x1.16p0, f, RoundingMode.down) == "0x1.1p+0");
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assert(printFloat(0x1.10p0, f, RoundingMode.down) == "0x1.1p+0");
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assert(printFloat(-0x1.18p0, f, RoundingMode.down) == "-0x1.2p+0");
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assert(printFloat(-0x1.28p0, f, RoundingMode.down) == "-0x1.3p+0");
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assert(printFloat(-0x1.1ap0, f, RoundingMode.down) == "-0x1.2p+0");
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assert(printFloat(-0x1.16p0, f, RoundingMode.down) == "-0x1.2p+0");
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assert(printFloat(-0x1.10p0, f, RoundingMode.down) == "-0x1.1p+0");
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}
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}
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// for 100% coverage
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@ -3693,7 +3693,7 @@ private long getWidth(T)(T s)
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enum RoundingClass { ZERO, LOWER, FIVE, UPPER }
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bool round(T)(ref T sequence, size_t left, size_t right, RoundingClass type, bool negative, char max = '9')
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in (left > 0) // != 0 because we might need one carry
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in (left >= 0) // should be left > 0, but if you know ahead, that there's no carry, left == 0 is fine
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in (left < sequence.length)
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in (right >= 0)
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in (right <= sequence.length)
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