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| author | Ben Wiederhake <BenWiederhake.GitHub@gmx.de> | 2020-08-23 00:35:36 +0200 |
|---|---|---|
| committer | Andreas Kling <kling@serenityos.org> | 2020-08-23 11:24:55 +0200 |
| commit | 0944f56181e0487c3a45185aa9730b0fde0a49a7 (patch) | |
| tree | 5f65dbf9cb92c2211e13fb94eff81539cf518910 /AK | |
| parent | f697d35fb1ffac42bddfd2a3224601142a880a7a (diff) | |
| download | serenity-0944f56181e0487c3a45185aa9730b0fde0a49a7.zip | |
AK: Fix human_readable_size corner cases
In particular: consistent rounding and extreme values.
Before, rounding was something like 'away from 0.999...', which led to
surprising corner cases in which the value was rounded up.
Now, rounding is always 'down'.
This even works for 0xffffffff, and also for 0xffffffffffffffffULL on 64-bit.
Diffstat (limited to 'AK')
| -rw-r--r-- | AK/NumberFormat.h | 12 | ||||
| -rw-r--r-- | AK/Tests/TestNumberFormat.cpp | 20 |
2 files changed, 16 insertions, 16 deletions
diff --git a/AK/NumberFormat.h b/AK/NumberFormat.h index 7a2d1a681a..0f172ed3bb 100644 --- a/AK/NumberFormat.h +++ b/AK/NumberFormat.h @@ -32,10 +32,10 @@ namespace AK { // FIXME: Remove this hackery once printf() supports floats. -static String number_string_with_one_decimal(float number, const char* suffix) +static String number_string_with_one_decimal(u64 number, u32 unit, const char* suffix) { - float decimals = number - (int)number; - return String::format("%d.%d %s", (int)number, (int)(decimals * 10), suffix); + int decimal = (number % unit) * 10 / unit; + return String::format("%llu.%d %s", number / unit, decimal, suffix); } static inline String human_readable_size(size_t size) @@ -43,10 +43,10 @@ static inline String human_readable_size(size_t size) if (size < 1 * KiB) return String::format("%zu B", size); if (size < 1 * MiB) - return number_string_with_one_decimal((float)size / (float)KiB, "KiB"); + return number_string_with_one_decimal(size, KiB, "KiB"); if (size < 1 * GiB) - return number_string_with_one_decimal((float)size / (float)MiB, "MiB"); - return number_string_with_one_decimal((float)size / (float)GiB, "GiB"); + return number_string_with_one_decimal(size, MiB, "MiB"); + return number_string_with_one_decimal(size, GiB, "GiB"); } } diff --git a/AK/Tests/TestNumberFormat.cpp b/AK/Tests/TestNumberFormat.cpp index fb9619ead5..f78e87bbeb 100644 --- a/AK/Tests/TestNumberFormat.cpp +++ b/AK/Tests/TestNumberFormat.cpp @@ -98,7 +98,7 @@ TEST_CASE(fraction_MiB) TEST_CASE(border_MiB_GiB) { EXPECT_EQ(human_readable_size(1000 * MiB), "1000.0 MiB"); - EXPECT_EQ(human_readable_size(1024 * MiB - 1), "1024.0 MiB"); // TODO + EXPECT_EQ(human_readable_size(1024 * MiB - 1), "1023.9 MiB"); EXPECT_EQ(human_readable_size(1024 * MiB), "1.0 GiB"); EXPECT_EQ(human_readable_size(1024 * MiB + 1), "1.0 GiB"); } @@ -114,9 +114,9 @@ TEST_CASE(fraction_GiB) EXPECT_EQ(human_readable_size(1154272461), "1.0 GiB"); EXPECT_EQ(human_readable_size(1181115968), "1.0 GiB"); - EXPECT_EQ(human_readable_size(1181115969), "1.1 GiB"); // TODO - EXPECT_EQ(human_readable_size(1181116000), "1.1 GiB"); // TODO - EXPECT_EQ(human_readable_size(1181116006), "1.1 GiB"); // TODO + EXPECT_EQ(human_readable_size(1181115969), "1.0 GiB"); + EXPECT_EQ(human_readable_size(1181116000), "1.0 GiB"); + EXPECT_EQ(human_readable_size(1181116006), "1.0 GiB"); // 1024 * 1024 * 1024 * 1.1 = 1181116006.4 EXPECT_EQ(human_readable_size(1181116007), "1.1 GiB"); EXPECT_EQ(human_readable_size(1202590842), "1.1 GiB"); @@ -124,9 +124,9 @@ TEST_CASE(fraction_GiB) TEST_CASE(extremes_4byte) { - EXPECT_EQ(human_readable_size(0x7fffffff), "2.0 GiB"); // TODO + EXPECT_EQ(human_readable_size(0x7fffffff), "1.9 GiB"); EXPECT_EQ(human_readable_size(0x80000000), "2.0 GiB"); - EXPECT_EQ(human_readable_size(0xffffffff), "4.0 GiB"); // TODO + EXPECT_EQ(human_readable_size(0xffffffff), "3.9 GiB"); } template<int> @@ -149,10 +149,10 @@ void actual_extremes_8byte<8>() EXPECT_EQ(human_readable_size(0x800000000ULL), "32.0 GiB"); EXPECT_EQ(human_readable_size(0x10000000000ULL), "1024.0 GiB"); - // Ehh, too bad. - EXPECT_EQ(human_readable_size(0x7fffffffffffffffULL), "-2147483648.-2147483648 GiB"); - EXPECT_EQ(human_readable_size(0x8000000000000000ULL), "-2147483648.-2147483648 GiB"); - EXPECT_EQ(human_readable_size(0xffffffffffffffffULL), "-2147483648.-2147483648 GiB"); + // Oh yeah! These are *correct*! + EXPECT_EQ(human_readable_size(0x7fffffffffffffffULL), "8589934591.9 GiB"); + EXPECT_EQ(human_readable_size(0x8000000000000000ULL), "8589934592.0 GiB"); + EXPECT_EQ(human_readable_size(0xffffffffffffffffULL), "17179869183.9 GiB"); } TEST_CASE(extremes_8byte) |