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52 lines
988 B
52 lines
988 B
package expr
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import (
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`fmt`
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)
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func idiv(v int64, d int64) (int64, error) {
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if d != 0 {
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return v / d, nil
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} else {
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return 0, newRuntimeError("division by zero")
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}
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}
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func imod(v int64, d int64) (int64, error) {
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if d != 0 {
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return v % d, nil
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} else {
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return 0, newRuntimeError("division by zero")
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}
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}
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func ipow(v int64, e int64) (int64, error) {
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mul := v
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ret := int64(1)
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/* value must be 0 or positive */
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if v < 0 {
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return 0, newRuntimeError(fmt.Sprintf("negative base value: %d", v))
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}
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/* exponent must be non-negative */
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if e < 0 {
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return 0, newRuntimeError(fmt.Sprintf("negative exponent: %d", e))
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}
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/* fast power first round */
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if (e & 1) != 0 {
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ret *= mul
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}
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/* fast power remaining rounds */
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for e >>= 1; e != 0; e >>= 1 {
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if mul *= mul; (e & 1) != 0 {
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ret *= mul
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}
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}
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/* all done */
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return ret, nil
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}
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