inline fn less_than_5(x: u32) u32 x: u32117
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134inline fn less_than_5(x: u32) u32 {
// Similar to log10u8, when adding one of these constants to val,
// we get two possible bit patterns above the low 17 bits,
// depending on whether val is below or above the threshold.
const C1: u32 = 0b011_00000000000000000 - 10; // 393206
const C2: u32 = 0b100_00000000000000000 - 100; // 524188
const C3: u32 = 0b111_00000000000000000 - 1000; // 916504
const C4: u32 = 0b100_00000000000000000 - 10000; // 514288
// Value of top bits:
// +c1 +c2 1&2 +c3 +c4 3&4 ^
// 0..=9 010 011 010 110 011 010 000 = 0
// 10..=99 011 011 011 110 011 010 001 = 1
// 100..=999 011 100 000 110 011 010 010 = 2
// 1000..=9999 011 100 000 111 011 011 011 = 3
// 10000..=99999 011 100 000 111 100 100 100 = 4
return (((x + C1) & (x + C2)) ^ ((x + C3) & (x + C4))) >> 17;
}