kitedb 0.2.2

High-performance embedded graph database
Documentation 
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
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336

//! Compression utilities for snapshot sections
//!
//! Supports multiple compression algorithms with automatic detection.
//! Ported from src/util/compression.ts

use crate::error::{RayError, Result};
use flate2::read::{DeflateDecoder, GzDecoder};
use flate2::write::{DeflateEncoder, GzEncoder};
use flate2::Compression;
use std::io::{Read, Write};

// ============================================================================
// Compression Types
// ============================================================================

/// Compression algorithm identifier
/// Stored in section entry's compression field (u32)
#[repr(u32)]
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum CompressionType {
  /// No compression
  #[default]
  None = 0,
  /// Zstandard compression (default)
  Zstd = 1,
  /// Gzip compression
  Gzip = 2,
  /// Raw deflate compression
  Deflate = 3,
}

impl CompressionType {
  /// Create from u32 value
  pub fn from_u32(v: u32) -> Option<Self> {
    match v {
      0 => Some(Self::None),
      1 => Some(Self::Zstd),
      2 => Some(Self::Gzip),
      3 => Some(Self::Deflate),
      _ => None,
    }
  }

  /// Get display name
  pub fn name(&self) -> &'static str {
    match self {
      Self::None => "none",
      Self::Zstd => "zstd",
      Self::Gzip => "gzip",
      Self::Deflate => "deflate",
    }
  }
}

/// Compression options for snapshot building
#[derive(Debug, Clone)]
pub struct CompressionOptions {
  /// Enable compression (default: false for backwards compatibility)
  pub enabled: bool,
  /// Compression algorithm to use (default: ZSTD)
  pub compression_type: CompressionType,
  /// Minimum section size to compress (default: 64 bytes)
  pub min_size: usize,
  /// Compression level (zstd: 1-22, gzip/deflate: 0-9)
  pub level: i32,
}

impl Default for CompressionOptions {
  fn default() -> Self {
    Self {
      enabled: false,
      compression_type: CompressionType::Zstd,
      min_size: 64,
      level: 3,
    }
  }
}

// ============================================================================
// Compression Functions
// ============================================================================

/// Compress data using the specified algorithm
pub fn compress(data: &[u8], compression_type: CompressionType, level: i32) -> Result<Vec<u8>> {
  match compression_type {
    CompressionType::None => Ok(data.to_vec()),

    CompressionType::Zstd => zstd_encode(data, level),

    CompressionType::Gzip => {
      let level = level.clamp(0, 9) as u32;
      let mut encoder = GzEncoder::new(Vec::new(), Compression::new(level));
      encoder
        .write_all(data)
        .map_err(|e| RayError::Compression(e.to_string()))?;
      encoder
        .finish()
        .map_err(|e| RayError::Compression(e.to_string()))
    }

    CompressionType::Deflate => {
      let level = level.clamp(0, 9) as u32;
      let mut encoder = DeflateEncoder::new(Vec::new(), Compression::new(level));
      encoder
        .write_all(data)
        .map_err(|e| RayError::Compression(e.to_string()))?;
      encoder
        .finish()
        .map_err(|e| RayError::Compression(e.to_string()))
    }
  }
}

/// Decompress data using the specified algorithm
pub fn decompress(data: &[u8], compression_type: CompressionType) -> Result<Vec<u8>> {
  match compression_type {
    CompressionType::None => Ok(data.to_vec()),

    CompressionType::Zstd => zstd_decode(data),

    CompressionType::Gzip => {
      let mut decoder = GzDecoder::new(data);
      let mut out = Vec::new();
      decoder
        .read_to_end(&mut out)
        .map_err(|e| RayError::Compression(e.to_string()))?;
      Ok(out)
    }

    CompressionType::Deflate => {
      let mut decoder = DeflateDecoder::new(data);
      let mut out = Vec::new();
      decoder
        .read_to_end(&mut out)
        .map_err(|e| RayError::Compression(e.to_string()))?;
      Ok(out)
    }
  }
}

/// Decompress data with known uncompressed size (more efficient allocation)
pub fn decompress_with_size(
  data: &[u8],
  compression_type: CompressionType,
  uncompressed_size: usize,
) -> Result<Vec<u8>> {
  match compression_type {
    CompressionType::None => Ok(data.to_vec()),

    CompressionType::Zstd => zstd_decode_with_size(data, uncompressed_size),

    CompressionType::Gzip => {
      let mut out = Vec::with_capacity(uncompressed_size);
      let mut decoder = GzDecoder::new(data);
      decoder
        .read_to_end(&mut out)
        .map_err(|e| RayError::Compression(e.to_string()))?;
      Ok(out)
    }

    CompressionType::Deflate => {
      let mut out = Vec::with_capacity(uncompressed_size);
      let mut decoder = DeflateDecoder::new(data);
      decoder
        .read_to_end(&mut out)
        .map_err(|e| RayError::Compression(e.to_string()))?;
      Ok(out)
    }
  }
}

/// Determine if compression is beneficial for the given data
///
/// Only compresses if:
/// 1. Data size >= minSize
/// 2. Compressed size < original size
pub fn maybe_compress(data: &[u8], options: &CompressionOptions) -> (Vec<u8>, CompressionType) {
  if !options.enabled {
    return (data.to_vec(), CompressionType::None);
  }

  if data.len() < options.min_size {
    return (data.to_vec(), CompressionType::None);
  }

  match compress(data, options.compression_type, options.level) {
    Ok(compressed) if compressed.len() < data.len() => (compressed, options.compression_type),
    _ => (data.to_vec(), CompressionType::None),
  }
}

// ========================================================================
// Zstd helpers (native only)
// ========================================================================

#[cfg(not(target_arch = "wasm32"))]
fn zstd_encode(data: &[u8], level: i32) -> Result<Vec<u8>> {
  zstd::encode_all(data, level).map_err(|e| RayError::Compression(e.to_string()))
}

#[cfg(target_arch = "wasm32")]
fn zstd_encode(_data: &[u8], _level: i32) -> Result<Vec<u8>> {
  Err(RayError::Compression(
    "zstd compression is not supported on wasm targets".to_string(),
  ))
}

#[cfg(not(target_arch = "wasm32"))]
fn zstd_decode(data: &[u8]) -> Result<Vec<u8>> {
  zstd::decode_all(data).map_err(|e| RayError::Compression(e.to_string()))
}

#[cfg(target_arch = "wasm32")]
fn zstd_decode(_data: &[u8]) -> Result<Vec<u8>> {
  Err(RayError::Compression(
    "zstd decompression is not supported on wasm targets".to_string(),
  ))
}

#[cfg(not(target_arch = "wasm32"))]
fn zstd_decode_with_size(data: &[u8], uncompressed_size: usize) -> Result<Vec<u8>> {
  let mut out = Vec::with_capacity(uncompressed_size);
  let mut decoder = zstd::Decoder::new(data).map_err(|e| RayError::Compression(e.to_string()))?;
  decoder
    .read_to_end(&mut out)
    .map_err(|e| RayError::Compression(e.to_string()))?;
  Ok(out)
}

#[cfg(target_arch = "wasm32")]
fn zstd_decode_with_size(_data: &[u8], _uncompressed_size: usize) -> Result<Vec<u8>> {
  Err(RayError::Compression(
    "zstd decompression is not supported on wasm targets".to_string(),
  ))
}

/// Check if a compression type value is valid
pub fn is_valid_compression_type(value: u32) -> bool {
  CompressionType::from_u32(value).is_some()
}

#[cfg(test)]
mod tests {
  use super::*;

  #[test]
  fn test_compression_none() {
    let data = b"hello world";
    let compressed = compress(data, CompressionType::None, 0).unwrap();
    assert_eq!(compressed, data);
    let decompressed = decompress(&compressed, CompressionType::None).unwrap();
    assert_eq!(decompressed, data);
  }

  #[test]
  fn test_compression_zstd() {
    let data = b"hello world hello world hello world";
    let compressed = compress(data, CompressionType::Zstd, 3).unwrap();
    assert!(compressed.len() < data.len());
    let decompressed = decompress(&compressed, CompressionType::Zstd).unwrap();
    assert_eq!(decompressed, data);
  }

  #[test]
  fn test_compression_gzip() {
    let data = b"hello world hello world hello world";
    let compressed = compress(data, CompressionType::Gzip, 6).unwrap();
    let decompressed = decompress(&compressed, CompressionType::Gzip).unwrap();
    assert_eq!(decompressed, data);
  }

  #[test]
  fn test_compression_deflate() {
    let data = b"hello world hello world hello world";
    let compressed = compress(data, CompressionType::Deflate, 6).unwrap();
    let decompressed = decompress(&compressed, CompressionType::Deflate).unwrap();
    assert_eq!(decompressed, data);
  }

  #[test]
  fn test_maybe_compress_too_small() {
    let data = b"small";
    let options = CompressionOptions {
      enabled: true,
      min_size: 100,
      ..Default::default()
    };
    let (result, compression_type) = maybe_compress(data, &options);
    assert_eq!(compression_type, CompressionType::None);
    assert_eq!(result, data);
  }

  #[test]
  fn test_maybe_compress_disabled() {
    let data = b"hello world hello world hello world";
    let options = CompressionOptions {
      enabled: false,
      ..Default::default()
    };
    let (result, compression_type) = maybe_compress(data, &options);
    assert_eq!(compression_type, CompressionType::None);
    assert_eq!(result, data);
  }

  #[test]
  fn test_maybe_compress_compressible() {
    let data = vec![b'a'; 1000]; // Highly compressible
    let options = CompressionOptions {
      enabled: true,
      compression_type: CompressionType::Zstd,
      min_size: 64,
      level: 3,
    };
    let (result, compression_type) = maybe_compress(&data, &options);
    assert_eq!(compression_type, CompressionType::Zstd);
    assert!(result.len() < data.len());
  }

  #[test]
  fn test_decompress_with_size() {
    let data = vec![b'x'; 10000];
    let compressed = compress(&data, CompressionType::Zstd, 3).unwrap();
    let decompressed =
      decompress_with_size(&compressed, CompressionType::Zstd, data.len()).unwrap();
    assert_eq!(decompressed, data);
  }

  #[test]
  fn test_compression_type_from_u32() {
    assert_eq!(CompressionType::from_u32(0), Some(CompressionType::None));
    assert_eq!(CompressionType::from_u32(1), Some(CompressionType::Zstd));
    assert_eq!(CompressionType::from_u32(2), Some(CompressionType::Gzip));
    assert_eq!(CompressionType::from_u32(3), Some(CompressionType::Deflate));
    assert_eq!(CompressionType::from_u32(4), None);
  }
}