Fresh Fish 8/FreshFishVol8-CD2.bin/bbs/util/macsnd_dt-1.7.lha/MacSND_dt/Source/Class.c

C/C++ Source or Header | 1994-12-15 | 8KB | 403 lines

/*
**    MacSND DataType
**
**    Written by Olaf `Olsen' Barthel <[e-mail]>
**        Public domain
**
** :ts=4
*/

#include "Global.h"

    // Maximum supported replay rate, as per the "Amiga Hardware Reference Manual"

#define MAX_SAMPLE_RATE 28867

    // The minimum sample rate we will allow when scaling a sound down

#define MIN_SAMPLE_RATE 5563

    // How many bytes to read in one piece

#define MIN_FRAME_RATE    (2048 * 8)

    /* ConvertSample(const UBYTE *Src,BYTE *Dst,LONG NumSamples,const LONG Skip):
     *
     *    Convert the native Macintosh format sample data into plain
     *    signed 8 bits/sample Amiga data
     */

STATIC VOID __regargs
ConvertSample(const UBYTE *Src,BYTE *Dst,LONG NumSamples,const LONG Skip)
{
    LONG    SkipCount;
    UBYTE    Value;

        // Make sure that the first sample is converted

    SkipCount = 1;

        // Convert all the samples if possible

    while(NumSamples-- > 0)
    {
            // It's easy to convert a Macintosh sample :^)

        Value = *(Src++) ^ 0x80;

            // Store this sample value?

        if(--SkipCount < 1)
        {
                // Keep this sample

            *Dst++ = (BYTE)Value;

                // Skip the next samples if necessary

            SkipCount = Skip;
        }
    }
}

    /* GetSND(Object *object,struct TagItem *Tags,struct ClassBase *ClassBase):
     *
     *    Convert a Macintosh "snd " resource into a DataTypes object
     */

STATIC BOOL __regargs
GetSND(Object *object,struct TagItem *Tags,struct ClassBase *ClassBase)
{
    struct VoiceHeader    *VoiceHeader    = NULL;
    BPTR                 File            = NULL;
    LONG                 Error            = 0;
    STRPTR                 Title            = (STRPTR)GetTagData(DTA_Name,NULL,Tags);
    BOOL                 Result         = FALSE;

        // Get the basic data

    GetDTAttrs(object,
        SDTA_VoiceHeader,    &VoiceHeader,
        DTA_Handle,         &File,
    TAG_DONE);

        // Do we have everything we need?

    if(File && VoiceHeader && Title)
    {
        BPTR FileHandle;

            // Open the file

        if(FileHandle = Open(Title,MODE_OLDFILE))
        {
            struct SoundDataHeader    Header;
            BOOL                    GotIt = FALSE;

                // Add some cache

            SetVBuf(FileHandle,NULL,BUF_FULL,4096);

                // Read the MacBinary header if possible

            if(ReadMacBinaryHeader(FileHandle,&Error,SysBase,DOSBase))
            {
                    // If it's a MacBinary format file, read the rest

                if(ScanResource(FileHandle,&Header,&Error,SysBase,DOSBase))
                    GotIt = TRUE;
            }

                // So it's not a MacBinary format file

            if(!GotIt)
            {
                    // Return to the beginning of the file

                if(Seek(FileHandle,0,OFFSET_BEGINNING) != -1)
                {
                        // Look for "snd " resources

                    if(ScanResource(FileHandle,&Header,&Error,SysBase,DOSBase))
                        GotIt = TRUE;
                }
            }

                // Did we get anything?

            if(GotIt)
            {
                BYTE    *Sample = NULL;
                UBYTE    *Source;
                ULONG     Memory;
                LONG     Rate,Size,Skip,Frame;

                    // Fill in the basic data

                Rate    = Header . SampleRate;
                Size    = Header . SampleSize;
                Skip    = 1;

                    // Don't waste too much memory for reading

                if(Header . SampleSize < MIN_FRAME_RATE)
                    Frame = Header . SampleSize;
                else
                    Frame = MIN_FRAME_RATE;

                    // sound.datatype v40 no longer requires
                    // the entire sample to reside in chip memory

                if(SuperClassBase -> lib_Version > 39)
                    Memory = MEMF_ANY;
                else
                    Memory = MEMF_CHIP;

                    // Scale the sound down if the Amiga sound hardware
                    // would be unable to handle the replay rate

                while(Size > 0 && Rate > MIN_SAMPLE_RATE && Rate > MAX_SAMPLE_RATE)
                {
                    Size    /= 2;
                    Rate    /= 2;
                    Skip    *= 2;
                }

                    // Allocate the read buffer

                if(Source = AllocVec(Frame,MEMF_ANY))
                {
                        // Try to allocate memory for the sample data

                    while(!(Sample = AllocVec(Size,Memory | MEMF_CLEAR)) && Size > 0 && Rate > MIN_SAMPLE_RATE)
                    {
                            // Scale it down if necessary

                        Size    /= 2;
                        Rate    /= 2;
                        Skip    *= 2;
                    }

                        // Did we get anything?

                    if(!Sample)
                        Error = ERROR_NO_FREE_STORE;
                }
                else
                    Error = ERROR_NO_FREE_STORE;

                    // Did we get what we wanted?

                if(Sample && !Error)
                {
                    BYTE    *Dst    = Sample;
                    LONG     Total    = Header . SampleSize,
                             Needed;

                        // Read the source data

                    while(!Error && Total > 0)
                    {
                        if(Frame > Total)
                            Needed = Total;
                        else
                            Needed = Frame;

                        if(Read(FileHandle,Source,Needed) == Needed)
                        {
                                // Convert the source data

                            ConvertSample(Source,Dst,Needed,Skip);

                            Total    -= Needed;
                            Dst     += Needed;
                        }
                        else
                            Error = IoErr();
                    }

                        // No read error so far?

                    if(!Error)
                    {
                        BYTE    Smallest,Largest;
                        LONG    i;

                            // Initialize the voice header

                        memset(VoiceHeader,0,sizeof(struct VoiceHeader));

                        VoiceHeader -> vh_OneShotHiSamples    = Size;
                        VoiceHeader -> vh_SamplesPerSec     = Rate;
                        VoiceHeader -> vh_Octaves            = 1;
                        VoiceHeader -> vh_Compression        = CMP_NONE;
                        VoiceHeader -> vh_Volume            = 64;

                            // Look for the smallest and the largest
                            // sample value

                        Smallest    = 127;
                        Largest     = -128;
                        Dst         = Sample;

                        for(i = 0 ; i < Size ; i++)
                        {
                            if(Dst[i] < Smallest)
                                Smallest = Dst[i];

                            if(Dst[i] > Largest)
                                Largest = Dst[i];
                        }

                            // Does it use the full range?

                        if(Smallest > -128 || Largest < 127)
                        {
                            BYTE    Table[256],*Index;
                            WORD    j;

                                // Point it into the middle

                            Index = &Table[128];

                                // Scale the negative values
                                // to use the full dynamic
                                // amplitude range

                            for(j = Smallest ; j < 0 ; j++)
                                Index[j] = (-128 * j) / Smallest;

                                // Cut off anything below the
                                // smallest value

                            for(j = -128 ; j < Smallest ; j++)
                                Index[j] = -128;

                            Index[0] = 0;

                                // Scale the positive values
                                // to use the full dynamic
                                // amplitude range

                            for(j = 1 ; j <= Largest ; j++)
                                Index[j] = (127 * j) / Largest;

                                // Cut off anything above the
                                // largest value

                            for(j = Largest + 1 ; j < 256 ; j++)
                                Index[j] = 127;

                                // Make the data use the full range

                            Dst = Sample;

                            for(i = 0 ; i < Size ; i++)
                                Dst[i] = Index[Dst[i]];
                        }

                            // Fill in the remaining information

                        SetDTAttrs(object,NULL,NULL,
                            DTA_ObjName,        Title,
                            SDTA_Sample,        Sample,
                            SDTA_SampleLength,    VoiceHeader -> vh_OneShotHiSamples,
                            SDTA_Period,        (ULONG)(SysBase -> ex_EClockFrequency * 5) / (ULONG)VoiceHeader -> vh_SamplesPerSec,
                            SDTA_Volume,        64,
                            SDTA_Cycles,        1,
                        TAG_DONE);

                            // Successful conversion

                        Result = TRUE;
                    }
                }

                    // No success?

                if(Error)
                    Result = FALSE;

                    // Clean up...

                if(Source)
                    FreeVec(Source);

                if(Sample && !Result)
                    FreeVec(Sample);
            }
            else
                Error = ERROR_OBJECT_NOT_FOUND;

            Close(FileHandle);
        }
        else
            Error = IoErr();
    }
    else
        Error = ERROR_OBJECT_NOT_FOUND;

        // Set the error code

    if(Error)
        SetIoErr(Error);

    return(Result);
}

    /* RealClassDispatch():
     *
     *    The class dispatcher routine.
     */

STATIC Object * __stdargs
RealClassDispatch(Class *class,Object *object,Msg msg)
{
    struct ClassBase    *ClassBase = (struct ClassBase *)class -> cl_UserData;
    Object                *Result;

        // What message is it?

    switch(msg -> MethodID)
    {
            // Create a new instance

        case OM_NEW:

            if(Result = (Object *)DoSuperMethodA(class,object,msg))
            {
                if(!GetSND(Result,((struct opSet *)msg) -> ops_AttrList,ClassBase))
                {
                    CoerceMethod(class,Result,OM_DISPOSE);

                    Result = NULL;
                }
            }

            break;

            // Let the superclass handle the rest

        default:

            Result = (Object *)DoSuperMethodA(class,object,msg);

            break;
    }

    return(Result);
}

    /* ClassDispatch():
     *
     *    The frontend to the real class dispatcher routine.
     */

Object * __saveds __asm
ClassDispatch(register __a0 Class *class,register __a2 Object *object,register __a1 Msg msg)
{
    LONG Success;

    return((Object *)StackCall(&Success,8192,3,(LONG (* __stdargs)(...))RealClassDispatch,class,object,msg));
}