/*

File: EatClosedCaptionSCC.c

Abstract: Code to read and parse a Scenarist Closed Caption (SCC)

          file into a QuickTime Movie 

Version: 1.0

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*/

#include "EatClosedCaptionSCC.h"

#ifdef MIN

    #undef MIN

#endif

#define MIN(x,y) ((x) < (y) ? (x) : (y))

#ifdef MAX

    #undef MAX

#endif

#define MAX(x,y) ((x) > (y) ? (x) : (y))

#pragma mark- Declarations

// Utility Routines

ComponentResult ParseByte(const char *string, UInt8 *byte, Boolean hex);

#pragma mark-

#pragma mark- Scenarist Closed Caption Functions

// Initialization routine that sets up globals

ComponentResult ScenaristClosedCaptionParserInit(EatClosedCaptionGlobals store)

{

    EatScenaristClosedCaptionGlobals globals = NULL;

    ComponentResult err = noErr;

    store->parserGlobals = globals = (EatScenaristClosedCaptionGlobals)NewPtrClear(sizeof(EatScenaristClosedCaptionGlobalsRecord));

    require_action(store->parserGlobals, bail, err = memFullErr);

    globals->ccGlobals = store;

    globals->firstSampleDecoded = false;

    globals->firstSampleMediaTime = -1;

    globals->timeCodeDef.flags = 0;

    globals->timeCodeDef.fTimeScale = 30000;

    globals->timeCodeDef.frameDuration = 1001;

    globals->timeCodeDef.numFrames = 30;

    globals->sampleDesc = (SampleDescriptionHandle)NewHandleClear(sizeof(SampleDescription));

    require_action(globals->sampleDesc, bail, err = memFullErr);

    globals->sampleData = NewHandle(0);

    require_action(globals->sampleData, bail, err = memFullErr);

    // Compile our regular expressions

    require_action(regcomp(&globals->lineRegEx, kSCCLineRegEx, REG_EXTENDED | REG_NEWLINE) == 0, bail, err = memFullErr);

    require_action(regcomp(&globals->emptyRegEx, kSCCEmptyRegEx, REG_EXTENDED | REG_NEWLINE) == 0, bail, err = memFullErr);

    require_action(regcomp(&globals->headerRegEx, kSCCHeaderRegEx, REG_EXTENDED | REG_NEWLINE) == 0, bail, err = memFullErr);

    require_action(regcomp(&globals->sampleRegEx, kSCCSampleRegEx, REG_EXTENDED | REG_NEWLINE) == 0, bail, err = memFullErr);

    // Allocate enough space to hold the maximum number of regmatch_t entries that any of our regular expressions might generate

    globals->regExMatches = (regmatch_t*)calloc(1 + MAX(1, MAX(MAX(globals->lineRegEx.re_nsub, globals->emptyRegEx.re_nsub),

                                        MAX(globals->headerRegEx.re_nsub, globals->sampleRegEx.re_nsub))), sizeof(regmatch_t));

    require_action(globals->regExMatches, bail, err = memFullErr);

bail:

    // Clean up

    if (err != noErr)

        ScenaristClosedCaptionParserTerminate(store);

    return err;

}

// Clean-up routine

void ScenaristClosedCaptionParserTerminate(EatClosedCaptionGlobals store)

{

    if (store)

    {

        EatScenaristClosedCaptionGlobals globals = (EatScenaristClosedCaptionGlobals)store->parserGlobals;

        // Clean up

        if (globals)

        {

            DisposeHandle((Handle)globals->sampleDesc);

            DisposeHandle(globals->sampleData);

            regfree(&globals->lineRegEx);

            regfree(&globals->emptyRegEx);

            regfree(&globals->headerRegEx);

            regfree(&globals->sampleRegEx);

            free(globals->regExMatches);

            DisposePtr(store->parserGlobals); store->parserGlobals = NULL;

        }

        if (store->editingClosedCaption)

        {

            EndMediaEdits(store->closedCaptionMedia);

            store->editingClosedCaption = false;

        }

        if (store->editingTimeCode)

        {

            EndMediaEdits(store->timeCodeMedia);

            store->editingTimeCode = false;

        }

    }

}

ComponentResult ScenaristClosedCaptionParserDoParse(EatClosedCaptionGlobals store, TimeValue atTime, TimeValue *durationAdded)

{

    EatScenaristClosedCaptionGlobals globals = (EatScenaristClosedCaptionGlobals)store->parserGlobals;

    ComponentResult err = noErr;

    Boolean openedForRead = false;

    int reResult = 0;

    long dataSize = 0, dataOffset = 0;

    long bufferSize = 0, bufferUsed = 0, bufferOffset = 0;

    Ptr buffer = NULL;

    Boolean headerParsed = false;

    // Prepare for reading

    require_noerr(err = DataHOpenForRead(store->dataHandler), bail);

    openedForRead = true;

    // Get the data size

    require_noerr(err = DataHGetFileSize(store->dataHandler, &dataSize), bail);

    // Allocate a buffer to read into

    bufferSize = 512;

    buffer = malloc(bufferSize);

    require_action(buffer, bail, err = memFullErr);

    // Parse the data

    while (dataOffset < dataSize)

    {

        // Some useful bookkeeping

        long bufferAvailable = bufferSize - bufferUsed;

        long dataAvailable = dataSize - dataOffset;

        long bytesToRead = 0;

        // See if we need to increase our buffer size

        if (bufferAvailable <= 0)

        {

            Ptr newBuffer = NULL;

            bufferSize *= 2;

            newBuffer = realloc(buffer, bufferSize);

            require_action(newBuffer, bail, err = memFullErr);

            buffer = newBuffer;

            bufferAvailable = bufferSize - bufferUsed;

        }

        // Read some data

        bytesToRead = MIN(bufferAvailable, dataAvailable);

        require_noerr(err = DataHScheduleData(store->dataHandler, buffer + bufferUsed, dataOffset, bytesToRead, 0, NULL, NULL), bail);

        bufferUsed += bytesToRead;

        bufferAvailable -= bytesToRead;

        dataOffset += bytesToRead;

        dataAvailable -= bytesToRead;

        // See if there's enough data to read in one or more lines of caption data

        globals->regExMatches[0].rm_so = bufferOffset;

        globals->regExMatches[0].rm_eo = bufferUsed;

        while (regexec(&globals->lineRegEx, buffer, globals->lineRegEx.re_nsub + 1, globals->regExMatches, REG_NOTEOL | REG_STARTEND) == 0)

        {

            globals->lastMatchString = buffer;

            bufferOffset = globals->regExMatches[0].rm_eo + 1;

            // regexec can't seem to get around cr/lf pairs, so we have to skip the cr if present

            if (bufferOffset < bufferSize && *(char*)(buffer + bufferOffset) == '\r')

                ++bufferOffset;

            // Read past the header line if we haven't already done so

            if (!headerParsed)

            {

                require_action((reResult = regexec(&globals->headerRegEx, buffer, globals->headerRegEx.re_nsub + 1, globals->regExMatches, REG_STARTEND)) == 0, bail, err = paramErr);

                globals->lastMatchString = buffer;

                // Found a valid header

                headerParsed = true;

            }

            else

            {

                // Skip empty lines and decode caption lines

                regoff_t lineStart = globals->regExMatches[0].rm_so;

                regoff_t lineEnd = globals->regExMatches[0].rm_eo;

                if ((reResult = regexec(&globals->emptyRegEx, buffer, globals->emptyRegEx.re_nsub + 1, globals->regExMatches, REG_STARTEND)) == REG_NOMATCH ||

                    (globals->regExMatches[0].rm_so != lineStart || globals->regExMatches[0].rm_eo != lineEnd))

                {

                    globals->lastMatchString = buffer;

                    globals->regExMatches[0].rm_so = lineStart;

                    globals->regExMatches[0].rm_eo = lineEnd;

                    reResult = regexec(&globals->sampleRegEx, buffer, globals->sampleRegEx.re_nsub + 1, globals->regExMatches, REG_STARTEND);

                    globals->lastMatchString = buffer;

                    require_action(reResult == 0, bail, err = paramErr);

                    // Found a valid line of sample data... decode it

                    require_noerr(err = ScenaristClosedCaptionParserDecodeSample(store), bail);

                }

            }

            globals->regExMatches[0].rm_so = bufferOffset;

            globals->regExMatches[0].rm_eo = bufferUsed;

        }

        bufferUsed = bufferUsed - bufferOffset;

        if (bufferUsed)

            memmove(buffer, buffer + bufferOffset, bufferUsed);

        bufferOffset = 0;

        bufferAvailable = bufferSize - bufferUsed;

    }

    // Make sure we used it all up

    if (dataSize != dataOffset || bufferUsed > 0)

        require_noerr(err = paramErr, bail);

    // Write out the last sample and the timecode

    if (err == noErr && globals->firstSampleDecoded)

    {

        require_noerr(err = ScenaristClosedCaptionParserAddSample(store, -1, true), bail);

        require_noerr(err = ScenaristClosedCaptionParserAddTimeCode(store), bail);

    }

bail:

    // Done reading

    if (openedForRead)

        DataHCloseForRead(store->dataHandler);

    // Clean up

    free(buffer);

    return err;

}

// Decode a caption read from the source data ref

ComponentResult ScenaristClosedCaptionParserDecodeSample(EatClosedCaptionGlobals store)

{

    EatScenaristClosedCaptionGlobals globals = (EatScenaristClosedCaptionGlobals)store->parserGlobals;

    // The need for error checking in this function is minimal, as we would not have made it this far without a regular

    //  expression match, whick already validates the data string

    ComponentResult err = noErr;

    size_t atomHeaderSize = sizeof(long) + sizeof(OSType);

    // Timecode

    {

        TimeCodeRecord newSampleTimeCode = { 0 };

        // The entire file must be either drop frame or non-drop frame... no mix and match

        if (!globals->firstSampleDecoded && globals->lastMatchString[globals->regExMatches[kSCCSampleMatchTCDropFrame].rm_so] == ';')

            globals->timeCodeDef.flags |= tcDropFrame;

        else

            require_action((globals->timeCodeDef.flags & tcDropFrame == tcDropFrame) == (globals->lastMatchString[globals->regExMatches[kSCCSampleMatchTCDropFrame].rm_so] == ';'), bail, err = paramErr);

        // Parse all of the timecode fields

        ParseByte(globals->lastMatchString + globals->regExMatches[kSCCSampleMatchTCHours].rm_so, &newSampleTimeCode.t.hours, false);

        ParseByte(globals->lastMatchString + globals->regExMatches[kSCCSampleMatchTCMinutes].rm_so, &newSampleTimeCode.t.minutes, false);

        ParseByte(globals->lastMatchString + globals->regExMatches[kSCCSampleMatchTCSeconds].rm_so, &newSampleTimeCode.t.seconds, false);

        ParseByte(globals->lastMatchString + globals->regExMatches[kSCCSampleMatchTCFrames].rm_so, &newSampleTimeCode.t.frames, false);

        if (globals->firstSampleDecoded)

        {

            // Once we've decoded more than one sample, we can calculate the duration of the previous sample

            long prevSampleFrameNumber = 0, sampleFrameNumber = 0, sampleSize = 0;

            require_noerr(err = TCTimeCodeToFrameNumber(GetMediaHandler(store->timeCodeMedia), &globals->timeCodeDef, &globals->sampleTimeCode, &prevSampleFrameNumber), bail);

            require_noerr(err = TCTimeCodeToFrameNumber(GetMediaHandler(store->timeCodeMedia), &globals->timeCodeDef, &newSampleTimeCode, &sampleFrameNumber), bail);

            sampleSize = GetHandleSize(globals->sampleData) - atomHeaderSize;

            if (sampleSize > (sampleFrameNumber - prevSampleFrameNumber) * 2)

            {

                // Timecode of current sample overlaps previous sample

                require_noerr(err = paramErr, bail);

            }

            // Add the previous sample using the duration we calculated above

            require_noerr(err = ScenaristClosedCaptionParserAddSample(store, (sampleFrameNumber - prevSampleFrameNumber) * 1001, false), bail);

        }

        else

        {

            // Save off the first timecode that was encountered

            globals->firstSampleTimeCode = newSampleTimeCode;

        }

        // Save off the current timecode for use in calculating the duration of this sample next time around

        globals->sampleTimeCode = newSampleTimeCode;

    }

    // Closed caption

    {

        const char *sampleString = NULL;

        UInt8 *sampleData = NULL;

        size_t ndx = 0;

        // The sample data string is made up of exactly one substring corresponding to the regular expression match "kSCCSampleMatchLastSampleData" and

        //  zero or more substrings corresponding to the regular expression match "kSCCSampleSecondLastSampleData".  Each of these matches represents

        //  two bytes of sample data, so we can calculate the necessary size of our sample buffer

        size_t sampleStringLength = globals->regExMatches[kSCCSampleMatchAllSampleData].rm_eo - globals->regExMatches[kSCCSampleMatchAllSampleData].rm_so;

        size_t lastMatchLength = globals->regExMatches[kSCCSampleMatchLastSampleData].rm_eo - globals->regExMatches[kSCCSampleMatchLastSampleData].rm_so;

        size_t otherMatchLength = globals->regExMatches[kSCCSampleMatchSecondLastSampleData].rm_eo - globals->regExMatches[kSCCSampleMatchSecondLastSampleData].rm_so;

        size_t numSampleBytes =  2 * (1 + ((sampleStringLength - lastMatchLength) / (otherMatchLength ? otherMatchLength : 1)));

        // Make the sample data handle big enough to hold all of the data plus an atom header

        SetHandleSize(globals->sampleData, atomHeaderSize + numSampleBytes);

        sampleString = globals->lastMatchString + globals->regExMatches[kSCCSampleMatchAllSampleData].rm_so;

        HLock(globals->sampleData);

        sampleData = (UInt8*)*globals->sampleData;

        // Write out the size of the atom

        *(long*)sampleData = EndianS32_NtoB(atomHeaderSize + numSampleBytes);

        sampleData += sizeof(long);

        // Write out the atom type

        *(OSType*)sampleData = EndianU32_NtoB('cdat');

        sampleData += sizeof(OSType);

        // Parse and write the sample data

        for (ndx = 0; ndx < numSampleBytes / 2; ndx++)

        {

            ParseByte(sampleString, (UInt8*)sampleData, true);

            ParseByte(sampleString + 2, (UInt8*)sampleData + 1, true);

            sampleString += otherMatchLength;

            sampleData += 2;

        }

        HUnlock(globals->sampleData);

    }

    // We've decoded a sample

    globals->firstSampleDecoded = true;

bail:   

    return err;

}

// Add a decoded sample to the Movie

ComponentResult ScenaristClosedCaptionParserAddSample(EatClosedCaptionGlobals store, TimeValue duration, Boolean lastSample)

{

    EatScenaristClosedCaptionGlobals globals = (EatScenaristClosedCaptionGlobals)store->parserGlobals;

    ComponentResult err = noErr;

    TimeRecord sampleDuration = { 0 };

    // Setup on the first call

    if (!store->editingClosedCaption)

    {

        require_noerr(err = BeginMediaEdits(store->closedCaptionMedia), bail);

        store->editingClosedCaption = true;

        (*globals->sampleDesc)->descSize = GetHandleSize((Handle)globals->sampleDesc);

        (*globals->sampleDesc)->dataFormat = 'c608';

        (*globals->sampleDesc)->resvd1 = 0;

        (*globals->sampleDesc)->resvd2 = 0;

    }

    // Add the caption sample to the media

    sampleDuration.base = NULL;

    sampleDuration.scale = 30000;

    sampleDuration.value.lo = duration >= 0 ? duration : GetHandleSize(globals->sampleData) / 2 * 1001;

    ConvertTimeScale(&sampleDuration, GetMediaTimeScale(store->closedCaptionMedia));

    HLock(globals->sampleData);

    require_noerr(err = AddMediaSample2(store->closedCaptionMedia, (UInt8*)*(globals->sampleData), GetHandleSize(globals->sampleData), sampleDuration.value.lo, 0,

                                        globals->sampleDesc, 1, 0, globals->firstSampleMediaTime < 0 ? &globals->firstSampleMediaTime : NULL), bail);

    HUnlock(globals->sampleData);

    // Teardown on last call

    if (lastSample)

    {

        TimeRecord  captionTrackStart = { 0 };

        TimeValue   captionInsertDuration = 0;

        require_noerr(err = EndMediaEdits(store->closedCaptionMedia), bail);

        store->editingClosedCaption = false;

        // Insert the media into the track

        captionInsertDuration = GetMediaDuration(store->closedCaptionMedia) - globals->firstSampleMediaTime;

        if (captionInsertDuration > 0)

            require_noerr(err = InsertMediaIntoTrack(store->closedCaptionTrack, captionTrackStart.value.lo, globals->firstSampleMediaTime, captionInsertDuration, fixed1), bail);

    }

bail:

    if (err)

    {

        if (store->editingClosedCaption)

        {

            EndMediaEdits(store->closedCaptionMedia);

            store->editingClosedCaption = false;

        }

    }

    return err;

}

// Add timecode to the Movie

ComponentResult ScenaristClosedCaptionParserAddTimeCode(EatClosedCaptionGlobals store)

{

    EatScenaristClosedCaptionGlobals globals = (EatScenaristClosedCaptionGlobals)store->parserGlobals;

    ComponentResult err = noErr;

    TimeCodeDescriptionHandle timeCodeDesc = NULL;

    if (store->timeCodeTrack)

    {

        long firstFrameNumber = 0;

        long sampleFrameNumber = 0;

        long sampleFrames = 0;

        TimeValue64 duration = 0;

        long sampleData = 0;

        require_noerr(err = BeginMediaEdits(store->timeCodeMedia), bail);

        // Use the saved timecode values from the first and last captions (adding the duration of the last sample as well)

        TCTimeCodeToFrameNumber(GetMediaHandler(store->timeCodeMedia), &globals->timeCodeDef, &globals->firstSampleTimeCode, &firstFrameNumber);

        TCTimeCodeToFrameNumber(GetMediaHandler(store->timeCodeMedia), &globals->timeCodeDef, &globals->sampleTimeCode, &sampleFrameNumber);

        sampleFrames = GetHandleSize(globals->sampleData) / 2;

        duration = (sampleFrameNumber - firstFrameNumber + sampleFrames) * 1001;

        timeCodeDesc = (TimeCodeDescriptionHandle)NewHandleClear(sizeof(TimeCodeDescription));

        HLock((Handle)timeCodeDesc);

        (*timeCodeDesc)->descSize = GetHandleSize((Handle)timeCodeDesc);

        (*timeCodeDesc)->dataFormat = TimeCodeMediaType;

        (*timeCodeDesc)->timeCodeDef = globals->timeCodeDef;

        sampleData = EndianS32_NtoB(firstFrameNumber);

        require_noerr(err = AddMediaSample2(store->timeCodeMedia, (UInt8*)&sampleData, sizeof(sampleData), duration, 0,

                                            (SampleDescriptionHandle)timeCodeDesc, 1, 0, NULL), bail);

        HUnlock((Handle)timeCodeDesc);

        // Teardown

        {

            TimeRecord  timeCodeTrackStart = { 0 };

            TimeValue   timeCodeInsertDuration = GetMediaDuration(store->timeCodeMedia);

            // End editing and add media to the track

            timeCodeTrackStart.value.lo = 0;

            timeCodeTrackStart.scale = GetMediaTimeScale(store->timeCodeMedia);

            timeCodeTrackStart.base = NULL;

            require_noerr(err = EndMediaEdits(store->timeCodeMedia), bail);

            if (timeCodeInsertDuration > 0)

                require_noerr(err = InsertMediaIntoTrack(store->timeCodeTrack, timeCodeTrackStart.value.lo, 0, timeCodeInsertDuration, fixed1), bail);

        }

    }

bail:

    if (timeCodeDesc);

        DisposeHandle((Handle)timeCodeDesc);

    return err;

}

// Utility routine for parsing numerical strings

ComponentResult ParseByte(const char *string, UInt8 *byte, Boolean hex)

{

    ComponentResult err = paramErr;

    char chars[2];

    if (sscanf(string, "%2c", chars) == 1)

    {

        chars[0] = (char)tolower(chars[0]);

        chars[1] = (char)tolower(chars[1]);

        if (((chars[0] >= '0' && chars[0] <= '9') || (hex && (chars[0] >= 'a' && chars[0] <= 'f'))) &&

            ((chars[1] >= '0' && chars[1] <= '9') || (hex && (chars[1] >= 'a' && chars[1] <= 'f'))))

        {

            *byte = 0;

            if (chars[0] >= '0' && chars[0] <= '9')

                *byte = (chars[0] - '0') * (hex ? 16 : 10);

            else if (chars[0] >= 'a' && chars[0] <= 'f')

                *byte = (chars[0] - 'a' + 10) * 16;

            if (chars[1] >= '0' && chars[1] <= '9')

                *byte += (chars[1] - '0');

            else if (chars[1] >= 'a' && chars[1] <= 'f')

                *byte += (chars[1] - 'a' + 10);

            err = noErr;

        }

    }

    return err;

}