Read a varint (LEB128-encoded u64) from a byte slice. Returns `(value, bytes_consumed)`.
(data: &[u8])
| 58 | /// |
| 59 | /// Returns `(value, bytes_consumed)`. |
| 60 | fn read_varint(data: &[u8]) -> Result<(u64, usize), CodecError> { |
| 61 | let mut value: u64 = 0; |
| 62 | let mut shift: u32 = 0; |
| 63 | |
| 64 | for (i, &byte) in data.iter().enumerate() { |
| 65 | if shift >= 70 { |
| 66 | return Err(CodecError::Corrupt { |
| 67 | detail: "varint too long (>10 bytes)".into(), |
| 68 | }); |
| 69 | } |
| 70 | |
| 71 | value |= ((byte & 0x7F) as u64) << shift; |
| 72 | shift += 7; |
| 73 | |
| 74 | if byte & 0x80 == 0 { |
| 75 | return Ok((value, i + 1)); |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | Err(CodecError::Truncated { |
| 80 | expected: data.len() + 1, |
| 81 | actual: data.len(), |
| 82 | }) |
| 83 | } |
| 84 | |
| 85 | // --------------------------------------------------------------------------- |
| 86 | // Public encode / decode API |