Spec conformance: zstd.zig implements the Zstandard 1.6.0 specification natively in Zig - every algorithm, frame element, and default table in this document follows that version.

Errors

ZstdError

The main error set for zstd operations, re-exported as zstd.ZstdError:

pub const ZstdError = error{
    Corruption,
    ChecksumWrong,
    DictionaryCorrupted,
    DictionaryWrong,
    ParameterOutOfBound,
    TableLogTooLarge,
    MaxSymbolValueTooLarge,
    MaxSymbolValueTooSmall,
    StageWrong,
    InitMissing,
    MemoryAllocation,
    WorkspaceTooSmall,
    DstSizeTooSmall,
    SrcSizeWrong,
    DstBufferNull,
    NoForwardProgressDestFull,
    NoForwardProgressInputEmpty,
    FrameIndexTooLarge,
    PrefixUnknown,
    VersionUnsupported,
    FrameParameterUnsupported,
    WindowTooLarge,
    UnsupportedFeature,
    InvalidMagic,
    InvalidFrameHeader,
    InvalidBlock,
    InvalidBlockSize,
    InvalidDictionary,
    InvalidFseTable,
    InvalidHuffmanTable,
    InvalidSequence,
    InvalidOffset,
    ContentSizeMismatch,
    AllocationFailure,
    GenericError,
    OutOfMemory,
};

Helper:

pub fn errorToString(err: ZstdError) []const u8
// e.g. error.ChecksumWrong -> "checksum_wrong"

Exposed as zstd.errorToString. It is a free function rather than a member of ZstdError, which is an error set and cannot carry methods. Use it when the name goes into a log or a message that crosses a boundary; use @errorName for Zig-idiomatic output inside your own code.

Common Errors

Error	Cause
PrefixUnknown	Data doesn't start with zstd magic (0xFD2FB528)
Corruption	Data is corrupted
SrcSizeWrong	Source buffer too short / truncated
DstSizeTooSmall	Destination buffer too small
OutOfMemory	Memory allocation failed
ChecksumWrong	Frame XXH64 checksum mismatch
InvalidDictionary	Dictionary bytes invalid
ContentSizeMismatch	Decoded size differs from header contentSize
WindowTooLarge	Window log exceeds limit

Handling Example (examples/error_handling.zig)

const good = try zstd.compress(allocator, "valid data");
defer allocator.free(good);

var bad = try allocator.dupe(u8, good);
defer allocator.free(bad);
bad[0] ^= 0xFF;

const result = zstd.decompress(allocator, bad);
if (result) |data| {
    defer allocator.free(data);
    return error.TestFailed;
} else |err| {
      std.debug.print("Correctly caught: {s} ({s})\n", .{ @errorName(err), zstd.errorToString(err) });
}

const truncated = good[0 .. good.len / 2];
const r2 = zstd.decompress(allocator, truncated); // -> error.SrcSizeWrong

var small: [2]u8 = undefined;
const r3 = zstd.decompressInto(allocator, &small, good); // -> error.DstSizeTooSmall