mirror of https://github.com/tstack/lnav
You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
31 lines
1.2 KiB
C
31 lines
1.2 KiB
C
static inline __m256i
|
|
enc_translate (const __m256i in)
|
|
{
|
|
// A lookup table containing the absolute offsets for all ranges:
|
|
const __m256i lut = _mm256_setr_epi8(
|
|
65, 71, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -19, -16, 0, 0,
|
|
65, 71, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -19, -16, 0, 0);
|
|
|
|
// Translate values 0..63 to the Base64 alphabet. There are five sets:
|
|
// # From To Abs Index Characters
|
|
// 0 [0..25] [65..90] +65 0 ABCDEFGHIJKLMNOPQRSTUVWXYZ
|
|
// 1 [26..51] [97..122] +71 1 abcdefghijklmnopqrstuvwxyz
|
|
// 2 [52..61] [48..57] -4 [2..11] 0123456789
|
|
// 3 [62] [43] -19 12 +
|
|
// 4 [63] [47] -16 13 /
|
|
|
|
// Create LUT indices from the input. The index for range #0 is right,
|
|
// others are 1 less than expected:
|
|
__m256i indices = _mm256_subs_epu8(in, _mm256_set1_epi8(51));
|
|
|
|
// mask is 0xFF (-1) for range #[1..4] and 0x00 for range #0:
|
|
const __m256i mask = _mm256_cmpgt_epi8(in, _mm256_set1_epi8(25));
|
|
|
|
// Subtract -1, so add 1 to indices for range #[1..4]. All indices are
|
|
// now correct:
|
|
indices = _mm256_sub_epi8(indices, mask);
|
|
|
|
// Add offsets to input values:
|
|
return _mm256_add_epi8(in, _mm256_shuffle_epi8(lut, indices));
|
|
}
|