qubit_codec/transcode/
transcode_contract_error.rs

1// =============================================================================
2//    Copyright (c) 2026 Haixing Hu.
3//
4//    SPDX-License-Identifier: Apache-2.0
5//
6//    Licensed under the Apache License, Version 2.0.
7// =============================================================================
8use thiserror::Error;
9
10/// Error reported when a transcoder returns inconsistent progress.
11///
12/// This error represents a broken [`crate::Transcoder`] implementation rather
13/// than malformed input data. Buffered drivers call
14/// [`crate::TranscodeProgress::validate`] before trusting progress counters for
15/// unchecked buffer cursor movement.
16#[derive(Clone, Copy, Debug, Eq, Error, Hash, PartialEq)]
17pub enum TranscodeContractError {
18    /// The transcoder consumed more input units than the caller supplied.
19    #[error(
20        "transcoder consumed {read} units but only {available} were available"
21    )]
22    OverRead {
23        /// Input units reported as consumed.
24        read: usize,
25        /// Input units available to the transcode call.
26        available: usize,
27    },
28
29    /// The transcoder wrote more output units than the caller supplied.
30    #[error(
31        "transcoder wrote {written} units but only {available} output slots were available"
32    )]
33    OverWritten {
34        /// Output units reported as written.
35        written: usize,
36        /// Output slots available to the transcode call.
37        available: usize,
38    },
39
40    /// Progress could not be represented as an absolute index.
41    #[error(
42        "transcoder progress overflow: index {index} plus advanced {advanced}"
43    )]
44    ProgressIndexOverflow {
45        /// Absolute index supplied to the transcode call.
46        index: usize,
47        /// Relative progress reported by the transcoder.
48        advanced: usize,
49    },
50
51    /// A status reported an index that does not match relative progress.
52    #[error("transcoder reported status index {reported}, expected {expected}")]
53    StatusIndexMismatch {
54        /// Index reported by the status.
55        reported: usize,
56        /// Index implied by the progress counter.
57        expected: usize,
58    },
59
60    /// A status requested input or output that is already available.
61    #[error(
62        "transcoder reported required {required} with available {available}"
63    )]
64    SatisfiedNeed {
65        /// Required units reported by the status.
66        required: usize,
67        /// Available units reported by the status.
68        available: usize,
69    },
70}
qubit_codec/transcode/transcode_contract_error.rs

qubit_codec/transcode/
transcode_contract_error.rs
