commonMain.com.squareup.wire.internal.MathMethods.kt Maven / Gradle / Ivy

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/*
 * Copyright (c) 2016, the R8 project authors.
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 *
 * * Redistributions in binary form must reproduce the above copyright notice,
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 *   and/or other materials provided with the distribution.
 *
 * * Neither the name of Google Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived from
 *   this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// Methods from https://r8.googlesource.com/r8/+/master/src/test/java/com/android/tools/r8/ir/desugar/backports/MathMethods.java
package com.squareup.wire.internal

internal fun addExactLong(x: Long, y: Long): Long {
  val result: Long = x + y
  if ((x xor y < 0L) or ((x xor result) >= 0L)) {
    return result
  }
  throw ArithmeticException()
}

internal fun floorDivLong(dividend: Long, divisor: Long): Long {
  val div = dividend / divisor
  val rem = dividend - divisor * div
  if (rem == 0L) {
    return div
  }
  // Normal Java division rounds towards 0. We just have to deal with the cases where rounding
  // towards 0 is wrong, which typically depends on the sign of dividend / divisor.
  //
  // signum is 1 if dividend and divisor are both nonnegative or negative, and -1 otherwise.
  val signum = 1L or ((dividend xor divisor) shr Long.SIZE_BITS - 1)
  return if (signum < 0L) div - 1L else div
}

internal fun floorModLong(dividend: Long, divisor: Long): Long {
  val rem = dividend % divisor
  if (rem == 0L) {
    return 0L
  }
  // Normal Java remainder tracks the sign of the dividend. We just have to deal with the case
  // where the resulting sign is incorrect which is when the signs do not match.
  //
  // signum is 1 if dividend and divisor are both nonnegative or negative, and -1 otherwise.
  val signum = 1L or ((dividend xor divisor) shr Long.SIZE_BITS - 1)
  return if (signum > 0L) rem else rem + divisor
}

internal const val NANOS_PER_SECOND = 1000_000_000L