添加传统四舍五入实现

Author: TakWolf

src/sfnttools/utils/math.py

@@ -0,0 +1,12 @@
+import math
+
+
+def round_half_up(value: int | float, n_digits: int = 0) -> int | float:
+    positive = value >= 0
+    shift = 10 ** n_digits
+    value = math.floor(abs(value * shift) + 0.5) / shift
+    if not positive:
+        value *= -1
+    if n_digits == 0:
+        value = int(value)
+    return value

tests/utils/test_math.py

@@ -0,0 +1,37 @@
+from sfnttools.utils.math import round_half_up
+
+
+def test_round_half_up():
+    assert round_half_up(1.4) == 1
+    assert round_half_up(1.5) == 2
+    assert round_half_up(1.6) == 2
+    assert round_half_up(2.4) == 2
+    assert round_half_up(2.5) == 3
+    assert round_half_up(2.6) == 3
+    assert round_half_up(3.4) == 3
+    assert round_half_up(3.5) == 4
+    assert round_half_up(3.6) == 4
+    assert round_half_up(4.4) == 4
+    assert round_half_up(4.5) == 5
+    assert round_half_up(4.6) == 5
+
+    assert round_half_up(-1.4) == -1
+    assert round_half_up(-1.5) == -2
+    assert round_half_up(-1.6) == -2
+    assert round_half_up(-2.4) == -2
+    assert round_half_up(-2.5) == -3
+    assert round_half_up(-2.6) == -3
+    assert round_half_up(-3.4) == -3
+    assert round_half_up(-3.5) == -4
+    assert round_half_up(-3.6) == -4
+    assert round_half_up(-4.4) == -4
+    assert round_half_up(-4.5) == -5
+    assert round_half_up(-4.6) == -5
+
+    assert round_half_up(1.2445, 2) == 1.24
+    assert round_half_up(1.2455, 2) == 1.25
+    assert round_half_up(1.2465, 2) == 1.25
+
+    assert round_half_up(-1.2445, 2) == -1.24
+    assert round_half_up(-1.2455, 2) == -1.25
+    assert round_half_up(-1.2465, 2) == -1.25