Method plusMod

output/java_guava/1.4.19/LongMath.java:1176–1178

Returns (a + b) mod m. Precondition: 0 <= a, b < m < 2^63.

(long a, long b, long m)

       * Returns (a + b) mod m. Precondition: 0 <= a, b < m < 2^63.
       */
      private long plusMod(long a, long b, long m) {
        return (a >= m - b) ? (a + b - m) : (a + b);
              }

      /**
       * Returns (a * 2^32) mod m. a may be any unsigned long.