Minimal bindings for the libsndfile library.

libsndfile.cs

using System;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using System.Runtime.InteropServices;
using System.Security;
using System.Text;

namespace SndFile
{
    [SuppressUnmanagedCodeSecurity]
    [SuppressMessage("ReSharper", "InconsistentNaming")]
    [SuppressMessage("ReSharper", "IdentifierTypo")]
    [SuppressMessage("ReSharper", "MemberCanBePrivate.Global")]
    public static class libsndfile
    {
        private const string LIBRARY = "sndfile";

        public delegate sf_count_t sf_vio_get_filelen(IntPtr user);

        public delegate sf_count_t sf_vio_seek(sf_count_t offset, SeekOrigin whence, IntPtr user);

        public delegate sf_count_t sf_vio_read(IntPtr ptr, sf_count_t count, IntPtr user);

        public delegate sf_count_t sf_vio_write(IntPtr ptr, sf_count_t count, IntPtr user);

        public delegate sf_count_t sf_vio_tell(IntPtr user);

        [StructLayout(LayoutKind.Sequential)]
        public struct sf_count_t
        {
            private readonly UIntPtr value;

            public sf_count_t(int value)
            {
                if (value < 0)
                    throw new ArgumentOutOfRangeException(nameof(value), "Size must be 0 or greater.");
                this.value = new UIntPtr((uint) value);
            }

            public sf_count_t(long value)
            {
                if (value < 0)
                    throw new ArgumentOutOfRangeException(nameof(value), "Size must be 0 or greater.");
                this.value = new UIntPtr((ulong) value);
            }

            [CLSCompliant(false)]
            public sf_count_t(uint value)
            {
                this.value = new UIntPtr(value);
            }

            [CLSCompliant(false)]
            public sf_count_t(ulong value)
            {
                this.value = new UIntPtr(value);
            }

            public long Value => Convert.ToInt64(value.ToUInt64());
        }

        public struct SF_VIRTUAL_IO
        {
            sf_vio_get_filelen get_filelen;
            sf_vio_seek seek;
            sf_vio_read read;
            sf_vio_write write;
            sf_vio_tell tell;
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct SF_INFO
        {
            public readonly sf_count_t frames;
            public readonly int samplerate;
            public readonly int channels;
            public readonly int format;
            public readonly int sections;
            public readonly int seekable;
        }

        /// <summary>
        /// Opaque type used as a handle to a native audio stream.
        /// </summary>
        [StructLayout(LayoutKind.Sequential)]
        public struct SNDFILE
        {
            /// <summary>
            /// The native handle, used to enforce pointer size for the structure to use without ref
            /// </summary>
            private readonly IntPtr handle;
        }

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        private static extern SNDFILE sf_open(byte[] path, FileAccess mode, out SF_INFO info); // TODO: Mode

        public static SNDFILE sf_open(string path, FileAccess mode, out SF_INFO info)
        {
            var bytes = Encoding.UTF8.GetBytes(path);
            return sf_open(bytes, mode, out info);
        }

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern SNDFILE sf_open_virtual(SF_VIRTUAL_IO io, FileAccess mode, out SF_INFO info, IntPtr user);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool sf_format_check(ref SF_INFO info);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_seek(SNDFILE sndfile, sf_count_t frames, SeekOrigin whence);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern SF_ERROR sf_error(SNDFILE sndfile); // TODO: Error Code

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern int sf_close(SNDFILE sndfile);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl, EntryPoint = "sf_strerror")]
        private static extern IntPtr sf_strerror_ptr(SNDFILE sndfile);

        public static string sf_strerror(SNDFILE sndfile) => Marshal.PtrToStringUTF8(sf_strerror_ptr(sndfile));

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl, EntryPoint = "sf_error_number")]
        private static extern IntPtr sf_error_number_ptr(int error);

        public static string sf_error_number(SF_ERROR error) =>
            Marshal.PtrToStringUTF8(sf_error_number_ptr((int) error));

        public static string sf_error_number(int error) => Marshal.PtrToStringUTF8(sf_error_number_ptr(error));

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern void sf_write_sync(SNDFILE sndfile);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_read_short(SNDFILE sndfile, IntPtr ptr, sf_count_t items);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_read_int(SNDFILE sndfile, IntPtr ptr, sf_count_t items);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_read_float(SNDFILE sndfile, IntPtr ptr, sf_count_t items);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_read_double(SNDFILE sndfile, IntPtr ptr, sf_count_t items);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_readf_short(SNDFILE sndfile, IntPtr ptr, sf_count_t frames);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_readf_int(SNDFILE sndfile, IntPtr ptr, sf_count_t frames);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_readf_float(SNDFILE sndfile, IntPtr ptr, sf_count_t frames);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_readf_double(SNDFILE sndfile, IntPtr ptr, sf_count_t frames);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_write_short(SNDFILE sndfile, IntPtr ptr, sf_count_t items);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_write_int(SNDFILE sndfile, IntPtr ptr, sf_count_t items);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_write_float(SNDFILE sndfile, IntPtr ptr, sf_count_t items);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_write_double(SNDFILE sndfile, IntPtr ptr, sf_count_t items);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_writef_short(SNDFILE sndfile, IntPtr ptr, sf_count_t frames);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_writef_int(SNDFILE sndfile, IntPtr ptr, sf_count_t frames);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_writef_float(SNDFILE sndfile, IntPtr ptr, sf_count_t frames);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_writef_double(SNDFILE sndfile, IntPtr ptr, sf_count_t frames);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_read_raw(SNDFILE sndfile, IntPtr ptr, sf_count_t bytes);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern sf_count_t sf_write_raw(SNDFILE sndfile, IntPtr ptr, sf_count_t bytes);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl, EntryPoint = "sf_get_string")]
        private static extern IntPtr sf_get_string_ptr(SNDFILE sndfile, int type);

        public static string sf_get_string(SNDFILE sndfile, int type) =>
            Marshal.PtrToStringUTF8(sf_get_string_ptr(sndfile, type));

        public static string sf_get_string(SNDFILE sndfile, SF_STR type) =>
            Marshal.PtrToStringUTF8(sf_get_string_ptr(sndfile, (int) type));

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl, EntryPoint = "sf_set_string")]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool sf_set_string_ptr(SNDFILE file, int type, byte[] str);

        public static bool sf_set_string(SNDFILE file, int type, string str)
        {
            var bytes = Encoding.UTF8.GetBytes(str);
            return sf_set_string_ptr(file, type, bytes);
        }

        public static bool sf_set_string(SNDFILE file, SF_STR type, string str) => sf_set_string(file, (int) type, str);

        [DllImport(LIBRARY, CallingConvention = CallingConvention.Cdecl)]
        public static extern int sf_command(SNDFILE sndfile, int cmd, IntPtr data, int datasize);

        public enum SFC_COMMAND
        {
            SFC_GET_LIB_VERSION = 0x1000,
            SFC_GET_LOG_INFO = 0x1001,
            SFC_GET_CURRENT_SF_INFO = 0x1002,

            SFC_GET_NORM_DOUBLE = 0x1010,
            SFC_GET_NORM_FLOAT = 0x1011,
            SFC_SET_NORM_DOUBLE = 0x1012,
            SFC_SET_NORM_FLOAT = 0x1013,
            SFC_SET_SCALE_FLOAT_INT_READ = 0x1014,
            SFC_SET_SCALE_INT_FLOAT_WRITE = 0x1015,

            SFC_GET_SIMPLE_FORMAT_COUNT = 0x1020,
            SFC_GET_SIMPLE_FORMAT = 0x1021,

            SFC_GET_FORMAT_INFO = 0x1028,

            SFC_GET_FORMAT_MAJOR_COUNT = 0x1030,
            SFC_GET_FORMAT_MAJOR = 0x1031,
            SFC_GET_FORMAT_SUBTYPE_COUNT = 0x1032,
            SFC_GET_FORMAT_SUBTYPE = 0x1033,

            SFC_CALC_SIGNAL_MAX = 0x1040,
            SFC_CALC_NORM_SIGNAL_MAX = 0x1041,
            SFC_CALC_MAX_ALL_CHANNELS = 0x1042,
            SFC_CALC_NORM_MAX_ALL_CHANNELS = 0x1043,
            SFC_GET_SIGNAL_MAX = 0x1044,
            SFC_GET_MAX_ALL_CHANNELS = 0x1045,

            SFC_SET_ADD_PEAK_CHUNK = 0x1050,

            SFC_UPDATE_HEADER_NOW = 0x1060,
            SFC_SET_UPDATE_HEADER_AUTO = 0x1061,

            SFC_FILE_TRUNCATE = 0x1080,

            SFC_SET_RAW_START_OFFSET = 0x1090,

            SFC_SET_DITHER_ON_WRITE = 0x10A0,
            SFC_SET_DITHER_ON_READ = 0x10A1,

            SFC_GET_DITHER_INFO_COUNT = 0x10A2,
            SFC_GET_DITHER_INFO = 0x10A3,

            SFC_GET_EMBED_FILE_INFO = 0x10B0,

            SFC_SET_CLIPPING = 0x10C0,
            SFC_GET_CLIPPING = 0x10C1,

            SFC_GET_CUE_COUNT = 0x10CD,
            SFC_GET_CUE = 0x10CE,
            SFC_SET_CUE = 0x10CF,

            SFC_GET_INSTRUMENT = 0x10D0,
            SFC_SET_INSTRUMENT = 0x10D1,

            SFC_GET_LOOP_INFO = 0x10E0,

            SFC_GET_BROADCAST_INFO = 0x10F0,
            SFC_SET_BROADCAST_INFO = 0x10F1,

            SFC_GET_CHANNEL_MAP_INFO = 0x1100,
            SFC_SET_CHANNEL_MAP_INFO = 0x1101,

            SFC_RAW_DATA_NEEDS_ENDSWAP = 0x1110,

            /* Support for Wavex Ambisonics Format */
            SFC_WAVEX_SET_AMBISONIC = 0x1200,
            SFC_WAVEX_GET_AMBISONIC = 0x1201,

            /*
            ** RF64 files can be set so that on-close, writable files that have less
            ** than 4GB of data in them are converted to RIFF/WAV, as per EBU
            ** recommendations.
            */
            SFC_RF64_AUTO_DOWNGRADE = 0x1210,

            SFC_SET_VBR_ENCODING_QUALITY = 0x1300,
            SFC_SET_COMPRESSION_LEVEL = 0x1301,

            /* Cart Chunk support */
            SFC_SET_CART_INFO = 0x1400,
            SFC_GET_CART_INFO = 0x1401,

            /* Opus files original samplerate metadata */
            SFC_SET_ORIGINAL_SAMPLERATE = 0x1500,
            SFC_GET_ORIGINAL_SAMPLERATE = 0x1501,

            /* Following commands for testing only. */
            SFC_TEST_IEEE_FLOAT_REPLACE = 0x6001,

            /*
            ** These SFC_SET_ADD_* values are deprecated and will disappear at some
            ** time in the future. They are guaranteed to be here up to and
            ** including version 1.0.8 to avoid breakage of existing software.
            ** They currently do nothing and will continue to do nothing.
            */
            SFC_SET_ADD_HEADER_PAD_CHUNK = 0x1051,

            SFC_SET_ADD_DITHER_ON_WRITE = 0x1070,
            SFC_SET_ADD_DITHER_ON_READ = 0x1071
        }

        public enum SF_STR
        {
            SF_STR_TITLE,
            SF_STR_COPYRIGHT,
            SF_STR_SOFTWARE,
            SF_STR_ARTIST,
            SF_STR_COMMENT,
            SF_STR_DATE,
            SF_STR_ALBUM,
            SF_STR_LICENSE,
            SF_STR_TRACKNUMBER,
            SF_STR_GENRE
        }

        public enum SF_ERROR
        {
            SF_ERR_NO_ERROR = 0,
            SF_ERR_UNRECOGNISED_FORMAT = 1,
            SF_ERR_SYSTEM = 2,
            SF_ERR_MALFORMED_FILE = 3,
            SF_ERR_UNSUPPORTED_ENCODING = 4
        }

        public enum SF_FORMAT
        {
            /* Major formats. */
            SF_FORMAT_WAV = 0x010000, /* Microsoft WAV format (little endian). */
            SF_FORMAT_AIFF = 0x020000, /* Apple/SGI AIFF format (big endian). */
            SF_FORMAT_AU = 0x030000, /* Sun/NeXT AU format (big endian). */
            SF_FORMAT_RAW = 0x040000, /* RAW PCM data. */
            SF_FORMAT_PAF = 0x050000, /* Ensoniq PARIS file format. */
            SF_FORMAT_SVX = 0x060000, /* Amiga IFF / SVX8 / SV16 format. */
            SF_FORMAT_NIST = 0x070000, /* Sphere NIST format. */
            SF_FORMAT_VOC = 0x080000, /* VOC files. */
            SF_FORMAT_IRCAM = 0x0A0000, /* Berkeley/IRCAM/CARL */
            SF_FORMAT_W64 = 0x0B0000, /* Sonic Foundry's 64 bit RIFF/WAV */
            SF_FORMAT_MAT4 = 0x0C0000, /* Matlab (tm) V4.2 / GNU Octave 2.0 */
            SF_FORMAT_MAT5 = 0x0D0000, /* Matlab (tm) V5.0 / GNU Octave 2.1 */
            SF_FORMAT_PVF = 0x0E0000, /* Portable Voice Format */
            SF_FORMAT_XI = 0x0F0000, /* Fasttracker 2 Extended Instrument */
            SF_FORMAT_HTK = 0x100000, /* HMM Tool Kit format */
            SF_FORMAT_SDS = 0x110000, /* Midi Sample Dump Standard */
            SF_FORMAT_AVR = 0x120000, /* Audio Visual Research */
            SF_FORMAT_WAVEX = 0x130000, /* MS WAVE with WAVEFORMATEX */
            SF_FORMAT_SD2 = 0x160000, /* Sound Designer 2 */
            SF_FORMAT_FLAC = 0x170000, /* FLAC lossless file format */
            SF_FORMAT_CAF = 0x180000, /* Core Audio File format */
            SF_FORMAT_WVE = 0x190000, /* Psion WVE format */
            SF_FORMAT_OGG = 0x200000, /* Xiph OGG container */
            SF_FORMAT_MPC2K = 0x210000, /* Akai MPC 2000 sampler */
            SF_FORMAT_RF64 = 0x220000, /* RF64 WAV file */

            /* Subtypes from here on. */

            SF_FORMAT_PCM_S8 = 0x0001, /* Signed 8 bit data */
            SF_FORMAT_PCM_16 = 0x0002, /* Signed 16 bit data */
            SF_FORMAT_PCM_24 = 0x0003, /* Signed 24 bit data */
            SF_FORMAT_PCM_32 = 0x0004, /* Signed 32 bit data */

            SF_FORMAT_PCM_U8 = 0x0005, /* Unsigned 8 bit data (WAV and RAW only) */

            SF_FORMAT_FLOAT = 0x0006, /* 32 bit float data */
            SF_FORMAT_DOUBLE = 0x0007, /* 64 bit float data */

            SF_FORMAT_ULAW = 0x0010, /* U-Law encoded. */
            SF_FORMAT_ALAW = 0x0011, /* A-Law encoded. */
            SF_FORMAT_IMA_ADPCM = 0x0012, /* IMA ADPCM. */
            SF_FORMAT_MS_ADPCM = 0x0013, /* Microsoft ADPCM. */

            SF_FORMAT_GSM610 = 0x0020, /* GSM 6.10 encoding. */
            SF_FORMAT_VOX_ADPCM = 0x0021, /* Oki Dialogic ADPCM encoding. */

            SF_FORMAT_G721_32 = 0x0030, /* 32kbs G721 ADPCM encoding. */
            SF_FORMAT_G723_24 = 0x0031, /* 24kbs G723 ADPCM encoding. */
            SF_FORMAT_G723_40 = 0x0032, /* 40kbs G723 ADPCM encoding. */

            SF_FORMAT_DWVW_12 = 0x0040, /* 12 bit Delta Width Variable Word encoding. */
            SF_FORMAT_DWVW_16 = 0x0041, /* 16 bit Delta Width Variable Word encoding. */
            SF_FORMAT_DWVW_24 = 0x0042, /* 24 bit Delta Width Variable Word encoding. */
            SF_FORMAT_DWVW_N = 0x0043, /* N bit Delta Width Variable Word encoding. */

            SF_FORMAT_DPCM_8 = 0x0050, /* 8 bit differential PCM (XI only) */
            SF_FORMAT_DPCM_16 = 0x0051, /* 16 bit differential PCM (XI only) */

            SF_FORMAT_VORBIS = 0x0060, /* Xiph Vorbis encoding. */

            /* Endian-ness options. */

            SF_ENDIAN_FILE = 0x00000000, /* Default file endian-ness. */
            SF_ENDIAN_LITTLE = 0x10000000, /* Force little endian-ness. */
            SF_ENDIAN_BIG = 0x20000000, /* Force big endian-ness. */
            SF_ENDIAN_CPU = 0x30000000, /* Force CPU endian-ness. */

            SF_FORMAT_SUBMASK = 0x0000FFFF,
            SF_FORMAT_TYPEMASK = 0x0FFF0000,
            SF_FORMAT_ENDMASK = 0x30000000
        }
    }
}