Errors

snappy.zig returns typed, structured errors from the canonical error sets:

pub const Error = error{
    CorruptStream,
    TruncatedInput,
    OutputBufferTooSmall,
    ResourceLimitExceeded,
    InvalidChunkLength,
    UnknownChunkType,
    ChecksumMismatch,
    InvalidMagic,
    InvalidVarint,
    OutOfMemory,
    InputTooLarge,
};

pub const StreamError = Error || std.Io.Writer.Error || std.Io.Reader.Error;

---

Error Descriptions

Error	Description
CorruptStream	Input data is malformed or violates the Snappy format specification (e.g. invalid tag or illegal copy offset).
TruncatedInput	Input data ended prematurely before all expected bytes or instructions were read.
OutputBufferTooSmall	Caller-provided output buffer has insufficient capacity.
ResourceLimitExceeded	Decompressed content exceeds caller-configured maxOutputSize limit (decompression bomb protection).
InvalidChunkLength	Chunk length in framed stream exceeds 65,536 bytes or is less than header minimums.
UnknownChunkType	Unrecognized unskippable chunk type (0x02..0x7f) encountered in framed stream.
ChecksumMismatch	32-bit masked CRC-32C checksum does not match decoded chunk data.
InvalidMagic	Stream does not start with the mandatory Snappy stream identifier (0xff 0x06 0x00 0x00 sNaPpY).
InvalidVarint	Little-endian varint encoding is unterminated or overflows 32 bits.
OutOfMemory	System allocator failed to allocate memory.
InputTooLarge	Input size exceeds format limits ($2^{32} - 1$ bytes).

---

Idiomatic Error Handling Pattern

const std = @import("std");
const snappy = @import("snappy");

pub fn processInput(allocator: std.mem.Allocator, data: []const u8) !void {
    const uncompressed = snappy.decompress(allocator, data) catch |err| switch (err) {
        error.InvalidMagic => {
            std.debug.print("Not a valid Snappy framed stream\n", .{});
            return;
        },
        error.ChecksumMismatch => {
            std.debug.print("Data integrity check failed: corrupt payload\n", .{});
            return;
        },
        error.CorruptStream, error.TruncatedInput, error.InvalidVarint => {
            std.debug.print("Malformed Snappy data\n", .{});
            return;
        },
        error.ResourceLimitExceeded => {
            std.debug.print("Decompressed payload exceeded safety limit\n", .{});
            return;
        },
        error.OutOfMemory => return err,
        else => {
            std.debug.print("Decompression error: {}\n", .{err});
            return err;
        },
    };
    defer allocator.free(uncompressed);
}