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library quiver.hashcode;
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/// Generates a hash code for multiple [objects].
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int hashObjects(Iterable objects) =>
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_finish(objects.fold(0, (h, i) => _combine(h, i.hashCode)));
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/// Generates a hash code for two objects.
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int hash2(a, b) => _finish(_combine(_combine(0, a.hashCode), b.hashCode));
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/// Generates a hash code for three objects.
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int hash3(a, b, c) => _finish(
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_combine(_combine(_combine(0, a.hashCode), b.hashCode), c.hashCode));
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/// Generates a hash code for four objects.
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int hash4(a, b, c, d) => _finish(_combine(
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_combine(_combine(_combine(0, a.hashCode), b.hashCode), c.hashCode),
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d.hashCode));
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// Jenkins hash functions
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int _combine(int hash, int value) {
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hash = 0x1fffffff & (hash + value);
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hash = 0x1fffffff & (hash + ((0x0007ffff & hash) << 10));
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return hash ^ (hash >> 6);
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}
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int _finish(int hash) {
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hash = 0x1fffffff & (hash + ((0x03ffffff & hash) << 3));
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hash = hash ^ (hash >> 11);
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return 0x1fffffff & (hash + ((0x00003fff & hash) << 15));
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}
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