75 lines
2.0 KiB
C
75 lines
2.0 KiB
C
// ufn_round.h: More feature-rich rounding functions.
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// Under MIT-License. Copyright by Eric-Paul Ickhorn (epickh).
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#ifndef UFN_ROUND_H
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#define UFN_ROUND_H
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#include <stdint.h>
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/// @brief Rounds a value down to the last multiple of a stepping.
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/// @param value Value to round down (floor).
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/// @param stepping Stepping to round the value to.
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/// @return Rounded value
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int64_t ufn_floor_i64(int64_t value, int64_t stepping);
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/// @brief Rounds a value up to the next multiple of a stepping.
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/// @param value Value to round up (ceil).
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/// @param stepping Stepping to round the value to.
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/// @return Rounded value
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int64_t ufn_ceil_i64(int64_t value, int64_t stepping);
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/// @brief Rounds down (Floors) a value to the last power of 2.
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/// @param value Value to find the nearest lower power of 2 of.
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/// @return Power of 2 which is nearest lower one to 'value'.
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uint64_t ufn_floor_pow2(uint64_t value);
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/// @brief Rounds up (Ceils) a value to the next power of 2.
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/// @note Internally, this uses the 'ufn_floor_pow2'-function but multiplies
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/// its result by two to get the next higher power.
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/// @param value Value to round up to the next power of 2.
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/// @return Power of 2 which is the nearest higher one from 'value'.
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uint64_t ufn_ceil_pow2(uint64_t value);
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#ifdef UFN_IMPLEMENTATION
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int64_t ufn_floor_i64(int64_t value, int64_t stepping)
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{
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return value - (value % stepping);
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}
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int64_t ufn_ceil_i64(int64_t value, int64_t stepping)
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{
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return ufn_floor_i64(value, stepping) + stepping;
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}
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uint64_t ufn_floor_pow2(uint64_t value)
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{
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// Find highest-priority bit which is 1
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int8_t bit_index = 63;
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while(bit_index >= 0)
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{
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if(value & (1 << bit_index))
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{
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break;
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}
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--bit_index;
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}
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return 1 << bit_index;
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}
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uint64_t ufn_ceil_pow2(uint64_t value)
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{
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uint64_t floored = ufn_floor_pow2(value);
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if(value == floored)
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{
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return value;
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}
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return floored * 2;
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}
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#endif // UFN_IMPLEMENTATION
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#endif // UFN_ROUND_H
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