在 zig 中读取 wav 标题时出现问题，找到不相关的值

Question

我试图在我的程序中读取 wav 文件（与媒体播放器一起使用的 wav 文件）的标头， 但我只找到无效值（采样率、通道数等）

pub const WavObject = struct {
    riff_identifier: *[4]u8, // Chunk identifier: "RIFF"
    riff_chunk_size: u32, // Chunk size (file size - 8 bytes)
    riff_format: *[4]u8, // Format identifier: "WAVE"
    fmt_identifier: *[4]u8, // Format subchunk identifier: "fmt "
    fmt_subchunk_size: u32, // Subchunk size (16 for PCM)
    fmt_audio_format: u16, // Audio format (1 for PCM)
    fmt_num_channels: u16, // Number of channels (1 for mono, 2 for stereo)
    fmt_sample_rate: u32, // Sample rate (samples per second)
    fmt_byte_rate: u32, // Byte rate (sample rate * block size)
    fmt_block_size: u16, // Block size (channels * bits per sample  8)
    fmt_bits_per_sample: u16, //Bits per sample (8 or 16)
    data_identifier: *[4]u8, // Data subchunk identifier: "data"
    data_size: u32, // Data subchunk size (size of the raw audio data)

    
    pub fn deserializeHeader(wavBytes: []u8, allocator: std.mem.Allocator) !*WavObject {
        var wavObj = try allocator.create(WavObject);
        if (wavBytes.len < 44) return error.InvalidWav;

        const riffChunku32: u32 = undefined;
        const subChunkSize: u32 = undefined;
        const audioFormat: u16 = undefined;
        const numChannels: u16 = undefined;
        const sampleRate: u32 = undefined;
        const byteRate: u32 = undefined;
        const blockSize: u16 = undefined;
        const bitsPerSample: u16 = undefined;
        const dataSize: u32 = undefined;

        // Parse individual fields from the wavBytes array
        std.mem.writeInt(u32, wavBytes[4..8], riffChunku32, .little);
        std.mem.writeInt(u32, wavBytes[16..20], subChunkSize, .little);
        std.mem.writeInt(u16, wavBytes[20..22], audioFormat, .little);
        std.mem.writeInt(u16, wavBytes[22..24], numChannels, .little);
        std.mem.writeInt(u32, wavBytes[24..28], sampleRate, .little);
        std.mem.writeInt(u32, wavBytes[28..32], byteRate, .little);
        std.mem.writeInt(u16, wavBytes[32..34], blockSize, .little);
        std.mem.writeInt(u16, wavBytes[34..36], bitsPerSample, .little);
        std.mem.writeInt(u32, wavBytes[40..44], dataSize, .little);

        wavObj.riff_identifier = wavBytes[0..4];
        wavObj.riff_chunk_size = riffChunku32;
        wavObj.riff_format = wavBytes[8..12];
        wavObj.fmt_identifier = wavBytes[12..16];
        wavObj.fmt_subchunk_size = subChunkSize;
        wavObj.fmt_audio_format = audioFormat;
        wavObj.fmt_num_channels = numChannels;
        wavObj.fmt_sample_rate = sampleRate;
        wavObj.fmt_byte_rate = byteRate;
        wavObj.fmt_block_size = blockSize;
        wavObj.fmt_bits_per_sample = bitsPerSample;
        wavObj.data_identifier = wavBytes[36..40];
        wavObj.data_size = dataSize;
        return wavObj;
    }
    // test code 
    test "basic play wav" {
    const start = std.time.microTimestamp();
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    const allocator = gpa.allocator();
    // reads header and prints values
    const buffer = try allocator.alloc(u8, 2048 * 100000);
    const file = try std.fs.cwd().openFile("./samples/hip_hop_kick.wav", .{ .mode = std.fs.File.OpenMode.read_only });
    const reader = file.reader();
    _ = try reader.read(buffer);
    const wavObj = try wav.WavObject.deserializeHeader(buffer[0..44], allocator);
    wavObj.PrintHeader();
    std.debug.print("{d}", .{buffer[0..44]});
    const end = std.time.microTimestamp();

    std.debug.print("time {d} \n", .{end - start});
}

Answer 1

    // Parse individual fields from the wavBytes array
   std.mem.writeInt(u32, wavBytes[4..8], riffChunku32, .little);
   ...

您正在使用

writeInt

，它写入内存，而不是读取内存。尝试使用

readInt

。

如果将

wavBytes

更改为

[]const u8

，输入

deserializeHeader

，您将收到编译器错误，突出显示您的错误。