rustdoc/html/render/search_index/
encode.rs1pub(crate) fn write_signed_vlqhex_to_string(n: i32, string: &mut String) {
2 let (sign, magnitude): (bool, u32) =
3 if n >= 0 { (false, n.try_into().unwrap()) } else { (true, (-n).try_into().unwrap()) };
4 let value: u32 = (magnitude << 1) | (if sign { 1 } else { 0 });
6 let mut shift: u32 = 28;
18 let mut mask: u32 = 0xF0_00_00_00;
19 while shift < 32 {
21 let hexit = (value & mask) >> shift;
22 if hexit != 0 || shift == 0 {
23 break;
24 }
25 shift = shift.wrapping_sub(4);
26 mask >>= 4;
27 }
28 while shift < 32 {
30 let hexit = (value & mask) >> shift;
31 let hex = char::try_from(if shift == 0 { '`' } else { '@' } as u32 + hexit).unwrap();
32 string.push(hex);
33 shift = shift.wrapping_sub(4);
34 mask >>= 4;
35 }
36}
37
38pub fn read_signed_vlqhex_from_string(string: &[u8]) -> Option<(i32, usize)> {
39 let mut n = 0i32;
40 let mut i = 0;
41 while let Some(&c) = string.get(i) {
42 i += 1;
43 n = (n << 4) | i32::from(c & 0xF);
44 if c >= 96 {
45 let (sign, magnitude) = (n & 1, n >> 1);
47 let value = if sign == 0 { 1 } else { -1 } * magnitude;
48 return Some((value, i));
49 }
50 }
51 None
52}
53
54pub fn write_postings_to_string(postings: &[Vec<u32>], buf: &mut Vec<u8>) {
55 for list in postings {
56 if list.is_empty() {
57 buf.push(0);
58 continue;
59 }
60 let len_before = buf.len();
61 stringdex::internals::encode::write_bitmap_to_bytes(&list, &mut *buf).unwrap();
62 let len_after = buf.len();
63 if len_after - len_before > 1 + (4 * list.len()) && list.len() < 0x3a {
64 buf.truncate(len_before);
65 buf.push(list.len() as u8);
66 for &item in list {
67 buf.push(item as u8);
68 buf.push((item >> 8) as u8);
69 buf.push((item >> 16) as u8);
70 buf.push((item >> 24) as u8);
71 }
72 }
73 }
74}
75
76pub fn read_postings_from_string(postings: &mut Vec<Vec<u32>>, mut buf: &[u8]) {
77 use stringdex::internals::decode::RoaringBitmap;
78 while let Some(&c) = buf.get(0) {
79 if c < 0x3a {
80 buf = &buf[1..];
81 let mut slot = Vec::new();
82 for _ in 0..c {
83 slot.push(
84 (buf[0] as u32)
85 | ((buf[1] as u32) << 8)
86 | ((buf[2] as u32) << 16)
87 | ((buf[3] as u32) << 24),
88 );
89 buf = &buf[4..];
90 }
91 postings.push(slot);
92 } else {
93 let (bitmap, consumed_bytes_len) =
94 RoaringBitmap::from_bytes(buf).unwrap_or_else(|| (RoaringBitmap::default(), 0));
95 assert_ne!(consumed_bytes_len, 0);
96 postings.push(bitmap.to_vec());
97 buf = &buf[consumed_bytes_len..];
98 }
99 }
100}