wedb_standalone 0.1.1

单机网络服务底座：RESP 协议帧、AOF 逻辑层与节点服务编排（对标 Garnet libs/server 单机半区）
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164

//! 位图管理底层算法与工具函数
//! 对标 Garnet `libs/server/Resp/Bitmap/BitmapManager.cs`

pub struct BitmapManager;

/// 最大位图载荷字节数（512MB）
pub const MAX_BITMAP_PAYLOAD_BYTES: usize = 512 * 1024 * 1024;

/// 最大合法位偏移（(512MB * 8) - 1）
pub const MAX_OFFSET_FOR_BITMAP_LENGTH: i64 = (MAX_BITMAP_PAYLOAD_BYTES as i64 * 8) - 1;

impl BitmapManager {
  /// libs/server/Resp/Bitmap/BitmapManager.cs:IsValidBitOffset
  #[inline(always)]
  pub const fn is_valid_bit_offset(offset: i64) -> bool {
    offset >= 0 && offset <= MAX_OFFSET_FOR_BITMAP_LENGTH
  }

  /// libs/server/Resp/Bitmap/BitmapManager.cs:TryValidateLengthInBytes
  #[inline(always)]
  pub const fn try_validate_length_in_bytes(offset: i64) -> Option<usize> {
    if !Self::is_valid_bit_offset(offset) {
      return None;
    }
    Some(((offset >> 3) + 1) as usize)
  }

  /// libs/server/Resp/Bitmap/BitmapManager.cs:TryValidateBitfieldOffset
  #[inline]
  pub fn try_validate_bitfield_offset(
    offset: i64,
    bit_count: u8,
    multiply_offset: bool,
  ) -> Option<(i64, i64)> {
    if bit_count == 0 {
      return None;
    }

    let normalized_offset = if multiply_offset {
      offset.checked_mul(bit_count as i64)?
    } else {
      offset
    };

    if normalized_offset < 0 {
      return None;
    }

    let end_offset = normalized_offset.checked_add(bit_count as i64 - 1)?;

    if Self::is_valid_bit_offset(end_offset) {
      Some((normalized_offset, end_offset))
    } else {
      None
    }
  }

  /// libs/server/Resp/Bitmap/BitmapManager.cs:TryValidateBitPosOffsets
  #[inline]
  pub fn try_validate_bit_pos_offsets(
    start_offset: i64,
    end_offset: i64,
    offset_type: u8,
    has_start_offset: bool,
    has_end_offset: bool,
  ) -> bool {
    let max_offset = if offset_type == 0x1 {
      MAX_OFFSET_FOR_BITMAP_LENGTH
    } else {
      MAX_BITMAP_PAYLOAD_BYTES as i64 - 1
    };

    if has_start_offset && !(start_offset >= -max_offset && start_offset <= max_offset) {
      return true;
    }

    if has_end_offset && !(end_offset >= -max_offset && end_offset <= max_offset) {
      return true;
    }

    false
  }

  /// libs/server/Resp/Bitmap/BitmapManager.cs:NormalizeBitCountOffsets
  #[inline]
  pub fn normalize_bit_count_offsets(
    start_offset: &mut i64,
    end_offset: &mut i64,
    offset_type: u8,
  ) {
    let max_offset = if offset_type == 0x1 {
      MAX_OFFSET_FOR_BITMAP_LENGTH
    } else {
      MAX_BITMAP_PAYLOAD_BYTES as i64 - 1
    };

    if *start_offset < -max_offset {
      *start_offset = -max_offset;
    } else if *start_offset > max_offset {
      *start_offset = max_offset;
    }

    if *end_offset < -max_offset {
      *end_offset = -max_offset;
    } else if *end_offset > max_offset {
      *end_offset = max_offset;
    }
  }

  /// libs/server/Resp/Bitmap/BitmapManager.cs:LengthInBytes
  #[inline]
  pub const fn length_in_bytes(offset: i64) -> Option<usize> {
    Self::try_validate_length_in_bytes(offset)
  }

  /// libs/server/Resp/Bitmap/BitmapManager.cs:IsLargeEnough
  #[inline]
  pub fn is_large_enough(vlen: usize, offset: i64) -> bool {
    match Self::length_in_bytes(offset) {
      Some(len) => len <= vlen,
      None => false,
    }
  }

  /// libs/server/Resp/Bitmap/BitmapManager.cs:NewBlockAllocLength
  #[inline]
  pub fn new_block_alloc_length(value_len: usize, offset: i64) -> usize {
    let length_in_bytes = Self::length_in_bytes(offset).unwrap_or(0);
    value_len.max(length_in_bytes)
  }

  /// libs/server/Resp/Bitmap/BitmapManager.cs:UpdateBitmap
  #[inline]
  pub fn update_bitmap(value: &mut [u8], offset: i64, set: u8) -> u8 {
    let byte_index = (offset >> 3) as usize;
    let bit_index = 7 - (offset & 7) as u32;

    let byte_val = value[byte_index];
    let old_val = (byte_val >> bit_index) & 1;

    if set == 1 {
      value[byte_index] |= 1 << bit_index;
    } else {
      value[byte_index] &= !(1 << bit_index);
    }
    old_val
  }

  /// libs/server/Resp/Bitmap/BitmapManager.cs:ProcessNegativeOffset
  #[inline(always)]
  pub const fn process_negative_offset(offset: i64, val_len: i64) -> i64 {
    if val_len <= 0 {
      0
    } else {
      (offset % val_len) + val_len
    }
  }

  /// libs/server/Resp/Bitmap/BitmapManager.cs:reverse
  #[inline(always)]
  pub const fn reverse(n: u8) -> u8 {
    n.reverse_bits()
  }
}