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bdz.search_u32: search directly

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Motiejus Jakštys 2022-03-06 18:18:35 +02:00 committed by Motiejus Jakštys
parent c6a133d175
commit 24d984d712
1 changed files with 10 additions and 8 deletions
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18
src/bdz.zig
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@ -7,8 +7,10 @@ pub fn search(packed_mphf: []const u8, key: []const u8) u32 {
return @as(u32, bdz_search_packed(packed_mphf.ptr, key.ptr, len)); return @as(u32, bdz_search_packed(packed_mphf.ptr, key.ptr, len));
} }
const u32len = 5;
pub fn search_u32(packed_mphf: []const u8, key: u32) u32 { pub fn search_u32(packed_mphf: []const u8, key: u32) u32 {
return search(packed_mphf, unzero(key)[0..]); return @as(u32, bdz_search_packed(packed_mphf.ptr, &unzero(key), u32len));
} }
// encode a u32 to 5 bytes so no bytes is a '\0'. // encode a u32 to 5 bytes so no bytes is a '\0'.
@ -17,12 +19,12 @@ pub fn search_u32(packed_mphf: []const u8, key: u32) u32 {
// packing would accept zero bytes. For now we will be doing a dance of not // packing would accept zero bytes. For now we will be doing a dance of not
// passing zero bytes. // passing zero bytes.
pub fn unzero(x: u32) [5]u8 { pub fn unzero(x: u32) [5]u8 {
const one: u8 = 0b10000000; const bit: u8 = 0b10000000;
var buf: [5]u8 = undefined; var buf: [u32len]u8 = undefined;
buf[0] = @truncate(u8, (x & 0b11111110_00000000_00000000_00000000) >> 25) | one; buf[0] = @truncate(u8, (x & 0b11111110_00000000_00000000_00000000) >> 25) | bit;
buf[1] = @truncate(u8, (x & 0b00000001_11111100_00000000_00000000) >> 18) | one; buf[1] = @truncate(u8, (x & 0b00000001_11111100_00000000_00000000) >> 18) | bit;
buf[2] = @truncate(u8, (x & 0b00000000_00000011_11110000_00000000) >> 12) | one; buf[2] = @truncate(u8, (x & 0b00000000_00000011_11110000_00000000) >> 12) | bit;
buf[3] = @truncate(u8, (x & 0b00000000_00000000_00001111_11000000) >> 6) | one; buf[3] = @truncate(u8, (x & 0b00000000_00000000_00001111_11000000) >> 6) | bit;
buf[4] = @truncate(u8, (x & 0b00000000_00000000_00000000_00111111) >> 0) | one; buf[4] = @truncate(u8, (x & 0b00000000_00000000_00000000_00111111) >> 0) | bit;
return buf; return buf;
} }