diff options
| -rw-r--r-- | core/string/ustring.cpp | 27 | ||||
| -rw-r--r-- | doc/classes/String.xml | 15 | ||||
| -rw-r--r-- | tests/test_string.h | 24 |
3 files changed, 59 insertions, 7 deletions
diff --git a/core/string/ustring.cpp b/core/string/ustring.cpp index 2fdf6e84e5..d2d563c5dc 100644 --- a/core/string/ustring.cpp +++ b/core/string/ustring.cpp @@ -1396,7 +1396,13 @@ String String::num(double p_num, int p_decimals) { #ifndef NO_USE_STDLIB if (p_decimals < 0) { - p_decimals = 14 - (int)floor(log10(p_num)); + p_decimals = 14; + const double abs_num = ABS(p_num); + if (abs_num > 10) { + // We want to align the digits to the above sane default, so we only + // need to subtract log10 for numbers with a positive power of ten. + p_decimals -= (int)floor(log10(abs_num)); + } } if (p_decimals > MAX_DECIMALS) { p_decimals = MAX_DECIMALS; @@ -1625,24 +1631,31 @@ String String::num_real(double p_num, bool p_trailing) { String s; String sd; - /* integer part */ + + // Integer part. bool neg = p_num < 0; p_num = ABS(p_num); int intn = (int)p_num; - /* decimal part */ + // Decimal part. - if ((int)p_num != p_num) { - double dec = p_num - (double)((int)p_num); + if (intn != p_num) { + double dec = p_num - (double)(intn); int digit = 0; #if REAL_T_IS_DOUBLE - int decimals = 14 - (int)floor(log10(p_num)); + int decimals = 14; #else - int decimals = 6 - (int)floor(log10(p_num)); + int decimals = 6; #endif + // We want to align the digits to the above sane default, so we only + // need to subtract log10 for numbers with a positive power of ten. + if (p_num > 10) { + decimals -= (int)floor(log10(p_num)); + } + if (decimals > MAX_DECIMALS) { decimals = MAX_DECIMALS; } diff --git a/doc/classes/String.xml b/doc/classes/String.xml index 0376a3f96e..467e2f901f 100644 --- a/doc/classes/String.xml +++ b/doc/classes/String.xml @@ -410,6 +410,21 @@ <argument index="0" name="number" type="float" /> <argument index="1" name="decimals" type="int" default="-1" /> <description> + Converts a [float] to a string representation of a decimal number. + The number of decimal places can be specified with [code]decimals[/code]. If [code]decimals[/code] is [code]-1[/code] (default), decimal places will be automatically adjusted so that the string representation has 14 significant digits (counting both digits to the left and the right of the decimal point). + Trailing zeros are not included in the string. The last digit will be rounded and not truncated. + Some examples: + [codeblock] + String.num(3.141593) # "3.141593" + String.num(3.141593, 3) # "3.142" + String.num(3.14159300) # "3.141593", no trailing zeros. + # Last digit will be rounded up here, which reduces total digit count since + # trailing zeros are removed: + String.num(42.129999, 5) # "42.13" + # If `decimals` is not specified, the total amount of significant digits is 14: + String.num(-0.0000012345432123454321) # "-0.00000123454321" + String.num(-10000.0000012345432123454321) # "-10000.0000012345" + [/codeblock] </description> </method> <method name="num_scientific" qualifiers="static"> diff --git a/tests/test_string.h b/tests/test_string.h index 1982d8de60..79fdb7bb56 100644 --- a/tests/test_string.h +++ b/tests/test_string.h @@ -350,6 +350,9 @@ TEST_CASE("[String] Insertion") { } TEST_CASE("[String] Number to string") { + CHECK(String::num(0) == "0"); + CHECK(String::num(0.0) == "0"); // No trailing zeros. + CHECK(String::num(-0.0) == "-0"); // Includes sign even for zero. CHECK(String::num(3.141593) == "3.141593"); CHECK(String::num(3.141593, 3) == "3.142"); CHECK(String::num_real(3.141593) == "3.141593"); @@ -357,6 +360,27 @@ TEST_CASE("[String] Number to string") { CHECK(String::num_int64(3141593) == "3141593"); CHECK(String::num_int64(0xA141593, 16) == "a141593"); CHECK(String::num_int64(0xA141593, 16, true) == "A141593"); + CHECK(String::num(42.100023, 4) == "42.1"); // No trailing zeros. + + // Checks doubles with many decimal places. + CHECK(String::num(0.0000012345432123454321, -1) == "0.00000123454321"); // -1 uses 14 as sane default. + CHECK(String::num(0.0000012345432123454321) == "0.00000123454321"); // -1 is the default value. + CHECK(String::num(-0.0000012345432123454321) == "-0.00000123454321"); + CHECK(String::num(-10000.0000012345432123454321) == "-10000.0000012345"); + CHECK(String::num(0.0000000000012345432123454321) == "0.00000000000123"); + CHECK(String::num(0.0000000000012345432123454321, 3) == "0"); + + // Note: When relevant (remainder > 0.5), the last digit gets rounded up, + // which can also lead to not include a trailing zero, e.g. "...89" -> "...9". + CHECK(String::num(0.0000056789876567898765) == "0.00000567898766"); // Should round last digit. + CHECK(String::num(10000.000005678999999999) == "10000.000005679"); // We cut at ...789|99 which is rounded to ...79, so only 13 decimals. + CHECK(String::num(42.12999999, 6) == "42.13"); // Also happens with lower decimals count. + + // 32 is MAX_DECIMALS. We can't reliably store that many so we can't compare against a string, + // but we can check that the string length is 34 (32 + 2 for "0."). + CHECK(String::num(0.00000123456789987654321123456789987654321, 32).length() == 34); + CHECK(String::num(0.00000123456789987654321123456789987654321, 42).length() == 34); // Should enforce MAX_DECIMALS. + CHECK(String::num(10000.00000123456789987654321123456789987654321, 42).length() == 38); // 32 decimals + "10000.". } TEST_CASE("[String] String to integer") { |