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perf: map_ui16 - round to nearest for the precision, map_ui16: allow …
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…for inverted range similar to map_ui8, map_ui8/16, fix div by zero edge case map_ui16: uint16 argument types, Tests - hypothesis framework, covers whole range of values

(cherry picked from commit 3f2058d)
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@dzid26
dzid26 committed Jul 16, 2024
1 parent 9e18a7a commit 0261ca3
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76 changes: 44 additions & 32 deletions src/common.c
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Expand Up @@ -10,45 +10,57 @@
#include "stm8s.h"
#include "common.h"

int16_t map_ui16(int16_t x, int16_t in_min, int16_t in_max, int16_t out_min, int16_t out_max) {
// if input min is smaller than output min, return the output min value
if (x < in_min) {
return out_min;
}

// if input max is bigger than output max, return the output max value
else if (x > in_max) {
return out_max;
}

// map the input to the output range, round up if mapping bigger ranges to smaller ranges
else if ((in_max - in_min) > (out_max - out_min)) {
return (int16_t)(((int32_t)(x - in_min) * (out_max - out_min + 1)) / (in_max - in_min + 1)) + out_min;
}

// map the input to the output range, round down if mapping smaller ranges to bigger ranges
else {
return (int16_t)(((int32_t)(x - in_min) * (out_max - out_min)) / (in_max - in_min)) + out_min;
// Function to map a value from one range to another based on given input and output ranges.
// Uses nearest integer rounding for precision.
// Note: Input min has to be smaller than input max.
// Parameters:
// - in: Value to be mapped.
// - in_min: Minimum value of the input range.
// - in_max: Maximum value of the input range.
// - out_min: Minimum value of the output range.
// - out_max: Maximum value of the output range.
// Returns the mapped value within the specified output range.
uint16_t map_ui16(uint16_t in, uint16_t in_min, uint16_t in_max, uint16_t out_min, uint16_t out_max) {
// If input is out of bounds, clamp it to the nearest boundary value
if (in < in_min) {return out_min;}
if (in >= in_max) {return out_max;}

// Calculate the input and output ranges
uint16_t in_range = in_max - in_min;

uint16_t out;
if (out_max < out_min) {
out = out_min - (uint16_t)(uint32_t)(((uint32_t)((uint32_t)(uint16_t)(in - in_min) * (uint32_t)(uint16_t)(out_min - out_max)) + (uint32_t)(uint16_t)(in_range/2U)) / in_range);
} else {
out = out_min + (uint16_t)(uint32_t)(((uint32_t)((uint32_t)(uint16_t)(in - in_min) * (uint32_t)(uint16_t)(out_max - out_min)) + (uint32_t)(uint16_t)(in_range/2U)) / in_range);
}
return out;
}

uint8_t map_ui8(uint8_t x, uint8_t in_min, uint8_t in_max, uint8_t out_min, uint8_t out_max) {
// if input min is smaller than output min, return the output min value
if (x <= in_min) {
return out_min;
}

// if input max is bigger than output max, return the output max value
if (x >= in_max) {
return out_max;
// Function to map 8bit a values from one range to another based on given input and output ranges.
// Uses floor integer rounding for maximum performance.
// Note: Input min has to be smaller than input max.
// Parameters:
// - in: Value to be mapped.
// - in_min: Minimum value of the input range.
// - in_max: Maximum value of the input range.
// - out_min: Minimum value of the output range.
// - out_max: Maximum value of the output range.
// Returns the mapped value within the specified output range.
uint8_t map_ui8(uint8_t in, uint8_t in_min, uint8_t in_max, uint8_t out_min, uint8_t out_max) {
// If input is out of bounds, clamp it to the nearest boundary value
if (in < in_min) {return out_min;}
if (in >= in_max) {return out_max;}

if (out_max < out_min) {
return out_min - (uint8_t)(uint16_t)((uint16_t)((uint8_t)(in - in_min) * (uint8_t)(out_min - out_max)) / (uint8_t)(in_max - in_min)); // cppcheck-suppress misra-c2012-10.8 ; direct cast to a wider essential to ensure mul in,a usage
} else {
return out_min + (uint8_t)(uint16_t)((uint16_t)((uint8_t)(in - in_min) * (uint8_t)(out_max - out_min)) / (uint8_t)(in_max - in_min)); // cppcheck-suppress misra-c2012-10.8 ; direct cast to a wider essential to ensure mul in,a usage
}

if (out_max < out_min)
return (uint16_t)out_min - (uint16_t)((uint8_t)(x - in_min) * (uint8_t)(out_min - out_max)) / (uint8_t)(in_max - in_min);
else
return (uint16_t)out_min + (uint16_t)((uint8_t)(x - in_min) * (uint8_t)(out_max - out_min)) / (uint8_t)(in_max - in_min);
}


uint8_t ui8_min(uint8_t value_a, uint8_t value_b) {
if (value_a < value_b) {
return value_a;
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4 changes: 2 additions & 2 deletions src/common.h
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Expand Up @@ -49,8 +49,8 @@
//#define ADVANCED_MODE 1
//#define CALIBRATION_MODE 2

int16_t map_ui16(int16_t x, int16_t in_min, int16_t in_max, int16_t out_min, int16_t out_max);
uint8_t map_ui8(uint8_t x, uint8_t in_min, uint8_t in_max, uint8_t out_max, uint8_t out_min);
uint16_t map_ui16(uint16_t in, uint16_t in_min, uint16_t in_max, uint16_t out_min, uint16_t out_max);
uint8_t map_ui8(uint8_t in, uint8_t in_min, uint8_t in_max, uint8_t out_min, uint8_t out_max);
uint8_t ui8_max(uint8_t value_a, uint8_t value_b);
uint8_t ui8_min(uint8_t value_a, uint8_t value_b);
uint16_t filter(uint16_t ui16_new_value, uint16_t ui16_old_value, uint8_t ui8_alpha);
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75 changes: 75 additions & 0 deletions tests/test_map.py
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@@ -0,0 +1,75 @@
import pytest
from sim._tsdz2 import ffi, lib as ebike # module generated from c-code
import numpy as np
from hypothesis import given, assume, strategies as st


@pytest.mark.parametrize(
"x, in_min, in_max, out_min, out_max, expected", [
( 4, 0, 16, 16, 0, 12),
( 1, 0, 2, 3, 0, 1),
( 1, 0, 3, 0, 2, 1),
])
def test_maps_simple(x, in_min, in_max, out_min, out_max, expected):
map_ui8_result = ebike.map_ui8(x, in_min, in_max, out_min, out_max)
map_ui16_result = ebike.map_ui16(x, in_min, in_max, out_min, out_max)
assert map_ui8_result == pytest.approx(expected, abs=1), f'Expected map_ui8_result {expected}, got {map_ui8_result}'
assert map_ui16_result == expected, f'Expected map_ui16_result {expected}, got {map_ui16_result}'


# Parameterized test function with different ticks values
@pytest.mark.parametrize("x", range(20, 45))
def test_compare_ui8_ui16_map_input_smaller_than_output(x):
in_min = 23
in_max = 43
out_min = 5
out_max = 250
map_ui8_result = ebike.map_ui8(x, in_min, in_max, out_min, out_max)
map_ui16_result = ebike.map_ui16(x, in_min, in_max, out_min, out_max)
# ! map_ui8 has lower precision so allow for an error of 1
assert map_ui16_result == pytest.approx(map_ui8_result, abs=1), f'Expected map_ui8_result {map_ui8_result} == map_ui16_result {map_ui16_result}'

@pytest.mark.parametrize("x", range(20, 90))
def test_compare_ui8_ui16_map_input_greater_than_output(x):
in_min = 23
in_max = 87
out_min = 5
out_max = 50
map_ui8_result = ebike.map_ui8(x, in_min, in_max, out_min, out_max)
map_ui16_result = ebike.map_ui16(x, in_min, in_max, out_min, out_max)

# ! map_ui8 has lower precision so allow for an error of 1
assert map_ui16_result == pytest.approx(map_ui8_result, abs=1), f'Expected map_ui8_result {map_ui8_result} == map_ui16_result {map_ui16_result}'



# Define the hypothesis test for map_ui8
@given(
x=st.integers(min_value=0, max_value=65535),
in_min=st.integers(min_value=0, max_value=65535),
in_max=st.integers(min_value=0, max_value=65535),
out_min=st.integers(min_value=0, max_value=65535),
out_max=st.integers(min_value=0, max_value=65535))
def test_maps_full_ranges(x, in_min, in_max, out_min, out_max):
assume(in_min <= in_max)

expected = np.interp(x, [in_min, in_max], [out_min, out_max])
# !test map_ui8 only for 8 bit ranges
if max(x, in_min, in_max, out_min, out_max) < 2^8:
map_ui8_result = ebike.map_ui8(x, in_min, in_max, out_min, out_max)
# ! map_ui8 lowest precision is 1
assert map_ui8_result == pytest.approx(expected, abs=1), \
f"map_ui8({x}, {in_min}, {in_max}, {out_min}, {out_max}) returned {map_ui8_result}, expected {expected}"
else:
print(f'x={x}, in_min={in_min}, in_max={in_max}, out_min={out_min}, out_max={out_max}')

map_ui16_result = ebike.map_ui16(x, in_min, in_max, out_min, out_max)
# ! map_ui16 lowest precision is 0.5 (thanks to nearest rounding)
assert map_ui16_result == pytest.approx(expected, abs=.5), \
f"map_ui16({x}, {in_min}, {in_max}, {out_min}, {out_max}) returned {map_ui16_result}, expected {expected}"



# Run the tests
if __name__ == '__main__':
pytest.main()

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