// Emacs style mode select   -*- C -*-
//-----------------------------------------------------------------------------
//
// Copyright(C) 2009 Simon Howard
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
// 02111-1307, USA.
//
// DESCRIPTION:
//    Reading of MIDI files.
//
//-----------------------------------------------------------------------------

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#ifndef TEST
#include "doomdef.h"
#include "doomtype.h"
#else
typedef enum {false, true} dboolean;
typedef unsigned char byte;
#define PACKEDATTR __attribute__((packed))
#endif
#include "lprintf.h"
#include "midifile.h"

#define HEADER_CHUNK_ID "MThd"
#define TRACK_CHUNK_ID  "MTrk"
#define MAX_BUFFER_SIZE 0x10000





#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifndef ntohl
#ifdef WORDS_BIGENDIAN
#define ntohl
#define ntohs
#else // WORDS_BIGENDIAN

#define ntohl(x) \
        (/*(long int)*/((((unsigned long int)(x) & 0x000000ffU) << 24) | \
                             (((unsigned long int)(x) & 0x0000ff00U) <<  8) | \
                             (((unsigned long int)(x) & 0x00ff0000U) >>  8) | \
                             (((unsigned long int)(x) & 0xff000000U) >> 24)))

#define ntohs(x) \
        (/*(short int)*/((((unsigned short int)(x) & 0x00ff) << 8) | \
                              (((unsigned short int)(x) & 0xff00) >> 8)))
#endif // WORDS_BIGENDIAN
#endif // ntohl


#ifdef _MSC_VER
#pragma pack(push, 1)
#endif

typedef struct
{
    byte chunk_id[4];
    unsigned int chunk_size;
} PACKEDATTR chunk_header_t;

typedef struct
{
    chunk_header_t chunk_header;
    unsigned short format_type;
    unsigned short num_tracks;
    unsigned short time_division;
} PACKEDATTR midi_header_t;

#ifdef _MSC_VER
#pragma pack(pop)
#endif

typedef struct
{
    // Length in bytes:

    unsigned int data_len;

    // Events in this track:

    midi_event_t *events;
    unsigned int num_events;
    unsigned int num_event_mem; // NSM track size of structure
} midi_track_t;

struct midi_track_iter_s
{
    midi_track_t *track;
    unsigned int position;
};

struct midi_file_s
{
    midi_header_t header;

    // All tracks in this file:
    midi_track_t *tracks;
    unsigned int num_tracks;

    // Data buffer used to store data read for SysEx or meta events:
    byte *buffer;
    unsigned int buffer_size;
};



// Check the header of a chunk:

static dboolean CheckChunkHeader(chunk_header_t *chunk,
                                const char *expected_id)
{
    dboolean result;

    result = (memcmp((char *) chunk->chunk_id, expected_id, 4) == 0);

    if (!result)
    {
        lprintf (LO_WARN, "CheckChunkHeader: Expected '%s' chunk header, "
                        "got '%c%c%c%c'\n",
                        expected_id,
                        chunk->chunk_id[0], chunk->chunk_id[1],
                        chunk->chunk_id[2], chunk->chunk_id[3]);
    }

    return result;
}

// Read a single byte.  Returns false on error.

static dboolean ReadByte(byte *result, midimem_t *mf)
{
    if (mf->pos >= mf->len)
    {
        lprintf (LO_WARN, "ReadByte: Unexpected end of file\n");
        return false;
    }

    *result = mf->data[mf->pos++];
    return true;
}

static dboolean ReadMultipleBytes (void *dest, size_t len, midimem_t *mf)
{
  byte *cdest = (byte *) dest;
  unsigned i;
  for (i = 0; i < len; i++)
  {
    if (!ReadByte (cdest + i, mf))
    {
      lprintf (LO_WARN, "ReadMultipleBytes: Unexpected end of file\n");
      return false;
    }
  }
  return true;
}

// Read a variable-length value.

static dboolean ReadVariableLength(unsigned int *result, midimem_t *mf)
{
    int i;
    byte b;

    *result = 0;

    for (i=0; i<4; ++i)
    {
        if (!ReadByte(&b, mf))
        {
            lprintf (LO_WARN, "ReadVariableLength: Error while reading "
                            "variable-length value\n");
            return false;
        }

        // Insert the bottom seven bits from this byte.

        *result <<= 7;
        *result |= b & 0x7f;

        // If the top bit is not set, this is the end.

        if ((b & 0x80) == 0)
        {
            return true;
        }
    }

    lprintf (LO_WARN, "ReadVariableLength: Variable-length value too "
                    "long: maximum of four bytes\n");
    return false;
}

// Read a byte sequence into the data buffer.

static void *ReadByteSequence(unsigned int num_bytes, midimem_t *mf)
{
    unsigned int i;
    byte *result;

    // events can be length 0.  malloc(0) is not portable (can return NULL)
    if (!num_bytes)
      return Z_Malloc (4);

    // Allocate a buffer:

    result = (byte*)Z_Malloc(num_bytes);

    if (result == NULL)
    {
        lprintf (LO_WARN, "ReadByteSequence: Failed to allocate buffer %u bytes\n", num_bytes);
        return NULL;
    }

    // Read the data:

    for (i=0; i<num_bytes; ++i)
    {
        if (!ReadByte(&result[i], mf))
        {
            lprintf (LO_WARN, "ReadByteSequence: Error while reading byte %u\n", i);
            Z_Free(result);
            return NULL;
        }
    }

    return result;
}

// Read a MIDI channel event.
// two_param indicates that the event type takes two parameters
// (three byte) otherwise it is single parameter (two byte)

static dboolean ReadChannelEvent(midi_event_t *event,
                                byte event_type, dboolean two_param,
                                midimem_t *mf)
{
    byte b;

    // Set basics:

    event->event_type = (midi_event_type_t)(event_type & 0xf0);
    event->data.channel.channel = event_type & 0x0f;

    // Read parameters:

    if (!ReadByte(&b, mf))
    {
        lprintf (LO_WARN, "ReadChannelEvent: Error while reading channel "
                        "event parameters\n");
        return false;
    }

    event->data.channel.param1 = b;

    // Second parameter:

    if (two_param)
    {
        if (!ReadByte(&b, mf))
        {
            lprintf (LO_WARN, "ReadChannelEvent: Error while reading channel "
                            "event parameters\n");
            return false;
        }

        event->data.channel.param2 = b;
    }

    return true;
}

// Read sysex event:

static dboolean ReadSysExEvent(midi_event_t *event, int event_type,
                               midimem_t *mf)
{
    event->event_type = (midi_event_type_t)event_type;

    if (!ReadVariableLength(&event->data.sysex.length, mf))
    {
        lprintf (LO_WARN, "ReadSysExEvent: Failed to read length of "
                                        "SysEx block\n");
        return false;
    }

    // Read the byte sequence:

    event->data.sysex.data = (byte*)ReadByteSequence(event->data.sysex.length, mf);

    if (event->data.sysex.data == NULL)
    {
        lprintf (LO_WARN, "ReadSysExEvent: Failed while reading SysEx event\n");
        return false;
    }

    return true;
}

// Read meta event:

static dboolean ReadMetaEvent(midi_event_t *event, midimem_t *mf)
{
    byte b;

    event->event_type = MIDI_EVENT_META;

    // Read meta event type:

    if (!ReadByte(&b, mf))
    {
        lprintf (LO_WARN, "ReadMetaEvent: Failed to read meta event type\n");
        return false;
    }

    event->data.meta.type = b;

    // Read length of meta event data:

    if (!ReadVariableLength(&event->data.meta.length, mf))
    {
        lprintf (LO_WARN, "ReadMetaEvent: Failed to read length of "
                                        "MetaEvent block\n");
        return false;
    }

    // Read the byte sequence:

    event->data.meta.data = (byte*)ReadByteSequence(event->data.meta.length, mf);

    if (event->data.meta.data == NULL)
    {
        lprintf (LO_WARN, "ReadMetaEvent: Failed while reading MetaEvent\n");
        return false;
    }

    return true;
}

static dboolean ReadEvent(midi_event_t *event, unsigned int *last_event_type,
                          midimem_t *mf)
{
    byte event_type;

    if (!ReadVariableLength(&event->delta_time, mf))
    {
        lprintf (LO_WARN, "ReadEvent: Failed to read event timestamp\n");
        return false;
    }

    if (!ReadByte(&event_type, mf))
    {
        lprintf (LO_WARN, "ReadEvent: Failed to read event type\n");
        return false;
    }

    // All event types have their top bit set.  Therefore, if
    // the top bit is not set, it is because we are using the "same
    // as previous event type" shortcut to save a byte.  Skip back
    // a byte so that we read this byte again.

    if ((event_type & 0x80) == 0)
    {
        event_type = *last_event_type;
        mf->pos--;
    }
    else
    {
        *last_event_type = event_type;
    }

    // Check event type:

    switch (event_type & 0xf0)
    {
        // Two parameter channel events:

        case MIDI_EVENT_NOTE_OFF:
        case MIDI_EVENT_NOTE_ON:
        case MIDI_EVENT_AFTERTOUCH:
        case MIDI_EVENT_CONTROLLER:
        case MIDI_EVENT_PITCH_BEND:
            return ReadChannelEvent(event, event_type, true, mf);

        // Single parameter channel events:

        case MIDI_EVENT_PROGRAM_CHANGE:
        case MIDI_EVENT_CHAN_AFTERTOUCH:
            return ReadChannelEvent(event, event_type, false, mf);

        default:
            break;
    }

    // Specific value?

    switch (event_type)
    {
        case MIDI_EVENT_SYSEX:
        case MIDI_EVENT_SYSEX_SPLIT:
            return ReadSysExEvent(event, event_type, mf);

        case MIDI_EVENT_META:
            return ReadMetaEvent(event, mf);

        default:
            break;
    }

    lprintf (LO_WARN, "ReadEvent: Unknown MIDI event type: 0x%x\n", event_type);
    return false;
}

// Free an event:

static void FreeEvent(midi_event_t *event)
{
    // Some event types have dynamically allocated buffers assigned
    // to them that must be freed.

    switch (event->event_type)
    {
        case MIDI_EVENT_SYSEX:
        case MIDI_EVENT_SYSEX_SPLIT:
            Z_Free(event->data.sysex.data);
            break;

        case MIDI_EVENT_META:
            Z_Free(event->data.meta.data);
            break;

        default:
            // Nothing to do.
            break;
    }
}

// Read and check the track chunk header

static dboolean ReadTrackHeader(midi_track_t *track, midimem_t *mf)
{
    size_t records_read;
    chunk_header_t chunk_header;

    records_read = ReadMultipleBytes(&chunk_header, sizeof(chunk_header_t), mf);

    if (records_read < 1)
    {
        return false;
    }

    if (!CheckChunkHeader(&chunk_header, TRACK_CHUNK_ID))
    {
        return false;
    }

    track->data_len = ntohl(chunk_header.chunk_size);

    return true;
}

static dboolean ReadTrack(midi_track_t *track, midimem_t *mf)
{
    midi_event_t *new_events = NULL;
    midi_event_t *event;
    unsigned int last_event_type;

    track->num_events = 0;
    track->events = NULL;
    track->num_event_mem = 0; // NSM

    // Read the header:

    if (!ReadTrackHeader(track, mf))
    {
        return false;
    }

    // Then the events:

    last_event_type = 0;

    for (;;)
    {
        // Resize the track slightly larger to hold another event:
        /*
        new_events = Z_Realloc(track->events,
                             sizeof(midi_event_t) * (track->num_events + 1));
        */
        if (track->num_events == track->num_event_mem)
        { // depending on the state of the heap and the malloc implementation, realloc()
          // one more event at a time can be VERY slow.  10sec+ in MSVC
          track->num_event_mem += 100;
          new_events = (midi_event_t*)Z_Realloc (track->events, sizeof (midi_event_t) * track->num_event_mem);
        }

        if (new_events == NULL)
        {
            return false;
        }

        track->events = new_events;

        // Read the next event:

        event = &track->events[track->num_events];
        if (!ReadEvent(event, &last_event_type, mf))
        {
            return false;
        }

        ++track->num_events;

        // End of track?

        if (event->event_type == MIDI_EVENT_META
         && event->data.meta.type == MIDI_META_END_OF_TRACK)
        {
            break;
        }
    }

    return true;
}

// Free a track:

static void FreeTrack(midi_track_t *track)
{
    unsigned i;

    for (i=0; i<track->num_events; ++i)
    {
        FreeEvent(&track->events[i]);
    }

    Z_Free(track->events);
}

static dboolean ReadAllTracks(midi_file_t *file, midimem_t *mf)
{
    unsigned int i;

    // Allocate list of tracks and read each track:

    file->tracks = (midi_track_t*)Z_Malloc(sizeof(midi_track_t) * file->num_tracks);

    if (file->tracks == NULL)
    {
        return false;
    }

    memset(file->tracks, 0, sizeof(midi_track_t) * file->num_tracks);

    // Read each track:

    for (i=0; i<file->num_tracks; ++i)
    {
        if (!ReadTrack(&file->tracks[i], mf))
        {
            return false;
        }
    }

    return true;
}

// Read and check the header chunk.

static dboolean ReadFileHeader(midi_file_t *file, midimem_t *mf)
{
    size_t records_read;
    unsigned int format_type;

    records_read = ReadMultipleBytes (&file->header, sizeof(midi_header_t), mf);

    if (records_read < 1)
    {
        return false;
    }

    if (!CheckChunkHeader(&file->header.chunk_header, HEADER_CHUNK_ID)
     || ntohl(file->header.chunk_header.chunk_size) != 6)
    {
        lprintf (LO_WARN, "ReadFileHeader: Invalid MIDI chunk header! "
                        "chunk_size=%ld\n",
                        ntohl(file->header.chunk_header.chunk_size));
        return false;
    }

    format_type = ntohs(file->header.format_type);
    file->num_tracks = ntohs(file->header.num_tracks);

    if ((format_type != 0 && format_type != 1)
     || file->num_tracks < 1)
    {
        lprintf (LO_WARN, "ReadFileHeader: Only type 0/1 "
                                         "MIDI files supported!\n");
        return false;
    }
    // NSM
    file->header.time_division = ntohs (file->header.time_division);


    return true;
}

void MIDI_FreeFile(midi_file_t *file)
{
    unsigned i;

    if (file->tracks != NULL)
    {
        for (i=0; i<file->num_tracks; ++i)
        {
            FreeTrack(&file->tracks[i]);
        }

        Z_Free(file->tracks);
    }

    Z_Free(file);
}

midi_file_t *MIDI_LoadFile (midimem_t *mf)
{
    midi_file_t *file;

    file = (midi_file_t*)Z_Malloc(sizeof(midi_file_t));

    if (file == NULL)
    {
        return NULL;
    }

    file->tracks = NULL;
    file->num_tracks = 0;
    file->buffer = NULL;
    file->buffer_size = 0;

    // Read MIDI file header

    if (!ReadFileHeader(file, mf))
    {
        MIDI_FreeFile(file);
        return NULL;
    }

    // Read all tracks:

    if (!ReadAllTracks(file, mf))
    {
        MIDI_FreeFile(file);
        return NULL;
    }

    return file;
}

// Get the number of tracks in a MIDI file.

unsigned int MIDI_NumTracks(const midi_file_t *file)
{
    return file->num_tracks;
}

// Start iterating over the events in a track.

midi_track_iter_t *MIDI_IterateTrack(const midi_file_t *file, unsigned int track)
{
    midi_track_iter_t *iter;

    assert(track < file->num_tracks);

    iter = (midi_track_iter_t*)Z_Malloc(sizeof(*iter));
    iter->track = &file->tracks[track];
    iter->position = 0;

    return iter;
}

void MIDI_FreeIterator(midi_track_iter_t *iter)
{
    Z_Free(iter);
}

// Get the time until the next MIDI event in a track.

unsigned int MIDI_GetDeltaTime(midi_track_iter_t *iter)
{
    if (iter->position < iter->track->num_events)
    {
        midi_event_t *next_event;

        next_event = &iter->track->events[iter->position];

        return next_event->delta_time;
    }
    else
    {
        return 0;
    }
}

// Get a pointer to the next MIDI event.

int MIDI_GetNextEvent(midi_track_iter_t *iter, midi_event_t **event)
{
    if (iter->position < iter->track->num_events)
    {
        *event = &iter->track->events[iter->position];
        ++iter->position;

        return 1;
    }
    else
    {
        return 0;
    }
}

unsigned int MIDI_GetFileTimeDivision(const midi_file_t *file)
{
    return file->header.time_division;
}

void MIDI_RestartIterator(midi_track_iter_t *iter)
{
    iter->position = 0;
}



static void MIDI_PrintFlatListDBG (const midi_event_t **evs)
{
  const midi_event_t *event;

  while (1)
  {
    event = *evs++;

    if (event->delta_time > 0)
      printf("Delay: %i ticks\n", event->delta_time);


    switch (event->event_type)
    {
      case MIDI_EVENT_NOTE_OFF:
        printf ("MIDI_EVENT_NOTE_OFF\n");break;
      case MIDI_EVENT_NOTE_ON:
        printf ("MIDI_EVENT_NOTE_ON\n");break;
      case MIDI_EVENT_AFTERTOUCH:
        printf ("MIDI_EVENT_AFTERTOUCH\n");break;
      case MIDI_EVENT_CONTROLLER:
        printf ("MIDI_EVENT_CONTROLLER\n");break;
      case MIDI_EVENT_PROGRAM_CHANGE:
        printf ("MIDI_EVENT_PROGRAM_CHANGE\n");break;
      case MIDI_EVENT_CHAN_AFTERTOUCH:
        printf ("MIDI_EVENT_CHAN_AFTERTOUCH\n");break;
      case MIDI_EVENT_PITCH_BEND:
        printf ("MIDI_EVENT_PITCH_BEND\n");break;
      case MIDI_EVENT_SYSEX:
        printf ("MIDI_EVENT_SYSEX\n");break;
      case MIDI_EVENT_SYSEX_SPLIT:
        printf ("MIDI_EVENT_SYSEX_SPLIT\n");break;
      case MIDI_EVENT_META:
        printf ("MIDI_EVENT_META\n");break;

      default:
        printf ("(unknown)\n");break;
    }
    switch(event->event_type)
    {
            case MIDI_EVENT_NOTE_OFF:
            case MIDI_EVENT_NOTE_ON:
            case MIDI_EVENT_AFTERTOUCH:
            case MIDI_EVENT_CONTROLLER:
            case MIDI_EVENT_PROGRAM_CHANGE:
            case MIDI_EVENT_CHAN_AFTERTOUCH:
            case MIDI_EVENT_PITCH_BEND:
                printf("\tChannel: %i\n", event->data.channel.channel);
                printf("\tParameter 1: %i\n", event->data.channel.param1);
                printf("\tParameter 2: %i\n", event->data.channel.param2);
                break;

            case MIDI_EVENT_SYSEX:
            case MIDI_EVENT_SYSEX_SPLIT:
                printf("\tLength: %i\n", event->data.sysex.length);
                break;

            case MIDI_EVENT_META:
                printf("\tMeta type: %i\n", event->data.meta.type);
                printf("\tLength: %i\n", event->data.meta.length);
                break;
    }
    if (event->event_type == MIDI_EVENT_META &&
        event->data.meta.type == MIDI_META_END_OF_TRACK)
    {
      printf ("gotta go!\n");
      return;
    }
  }
}






// NSM: an alternate iterator tool.

midi_event_t **MIDI_GenerateFlatList (midi_file_t *file)
{
  int totalevents = 0;
  unsigned i, delta;
  int nextrk;

  int totaldelta = 0;

  int *trackpos = (int*)Z_Calloc (file->num_tracks, sizeof (int));
  int *tracktime = (int*)Z_Calloc (file->num_tracks, sizeof (int));
  int trackactive = file->num_tracks;

  midi_event_t **ret;
  midi_event_t **epos;

  for (i = 0; i < file->num_tracks; i++)
    totalevents += file->tracks[i].num_events;

  ret = (midi_event_t**)Z_Malloc (totalevents * sizeof (midi_event_t **));

  epos = ret;

  while (trackactive)
  {
    delta = 0x10000000;
    nextrk = -1;
    for (i = 0; i < file->num_tracks; i++)
    {
      if (trackpos[i] != -1 && file->tracks[i].events[trackpos[i]].delta_time - tracktime[i] < delta)
      {
        delta = file->tracks[i].events[trackpos[i]].delta_time - tracktime[i];
        nextrk = i;
      }
    }
    if (nextrk == -1) // unexpected EOF (not every track got end track)
      break;

    *epos = file->tracks[nextrk].events + trackpos[nextrk];

    for (i = 0; i < file->num_tracks; i++)
    {
      if (i == (unsigned) nextrk)
      {
        tracktime[i] = 0;
        trackpos[i]++;
      }
      else
        tracktime[i] += delta;
    }
    // yes, this clobbers the original timecodes
    epos[0]->delta_time = delta;
    totaldelta += delta;

    if (epos[0]->event_type == MIDI_EVENT_META
      && epos[0]->data.meta.type == MIDI_META_END_OF_TRACK)
    { // change end of track into no op
      trackactive--;
      trackpos[nextrk] = -1;
      epos[0]->data.meta.type = MIDI_META_TEXT;
    }
    else if ((unsigned) trackpos[nextrk] == file->tracks[nextrk].num_events)
    {
      lprintf (LO_WARN, "MIDI_GenerateFlatList: Unexpected end of track\n");
      Z_Free (trackpos);
      Z_Free (tracktime);
      Z_Free (ret);
      return NULL;
    }
    epos++;
  }

  if (trackactive)
  { // unexpected EOF
    lprintf (LO_WARN, "MIDI_GenerateFlatList: Unexpected end of midi file\n");
    Z_Free (trackpos);
    Z_Free (tracktime);
    Z_Free (ret);
    return NULL;
  }

  // last end of track event is preserved though
  epos[-1]->data.meta.type = MIDI_META_END_OF_TRACK;

  Z_Free (trackpos);
  Z_Free (tracktime);

  if (totaldelta < 100)
  {
    lprintf (LO_WARN, "MIDI_GeneratFlatList: very short file %i\n", totaldelta);
    Z_Free (ret);
    return NULL;
  }


  //MIDI_PrintFlatListDBG (ret);

  return ret;
}



void MIDI_DestroyFlatList (midi_event_t **evs)
{
  Z_Free (evs);
}



// NSM: timing assist functions
// they compute samples per midi clock, where midi clock is the units
// that the time deltas are in, and samples is an arbitrary unit of which
// "sndrate" of them occur per second


static double compute_spmc_normal (unsigned mpq, unsigned tempo, unsigned sndrate)
{ // returns samples per midi clock

  // inputs: mpq (midi clocks per quarternote, from header)
  // tempo (from tempo event, in microseconds per quarternote)
  // sndrate (sound sample rate in hz)

  // samples   quarternote     microsec    samples    second
  // ------- = ----------- * ----------- * ------- * --------
  // midiclk     midiclk     quarternote   second    microsec

  // return  =  (1 / mpq)  *    tempo    * sndrate * (1 / 1000000)

  return (double) tempo / 1000000 * sndrate / mpq;

}

static double compute_spmc_smpte (unsigned smpte_fps, unsigned mpf, unsigned sndrate)
{ // returns samples per midi clock

  // inputs: smpte_fps (24, 25, 29, 30)
  // mpf (midi clocks per frame, 0-255)
  // sndrate (sound sample rate in hz)

  // tempo is ignored here

  // samples     frame      seconds    samples
  // ------- = --------- * --------- * -------
  // midiclk    midiclk      frame     second

  // return  = (1 / mpf) * (1 / fps) * sndrate


  double fps; // actual frames per second
  switch (smpte_fps)
  {
    case 24:
    case 25:
    case 30:
      fps = smpte_fps;
      break;
    case 29:
      // i hate NTSC, i really do
      fps = smpte_fps * 1000.0 / 1001.0;
      break;
    default:
      lprintf (LO_WARN, "MIDI_spmc: Unexpected SMPTE timestamp %i\n", smpte_fps);
      // assume
      fps = 30.0;
      break;
  }

  return (double) sndrate / fps / mpf;

}

// if event is NULL, compute with default starting tempo (120BPM)

double MIDI_spmc (const midi_file_t *file, const midi_event_t *ev, unsigned sndrate)
{
  int smpte_fps;
  unsigned tempo;
  unsigned headerval = MIDI_GetFileTimeDivision (file);

  if (headerval & 0x8000) // SMPTE
  { // i don't really have any files to test this on...
    smpte_fps = -(short) headerval >> 8;
    return compute_spmc_smpte (smpte_fps, headerval & 0xff, sndrate);
  }

  // normal timing
  tempo = 500000; // default 120BPM
  if (ev)
  {
    if (ev->event_type == MIDI_EVENT_META)
    {
      if (ev->data.meta.length == 3)
      {
        tempo = (unsigned) ev->data.meta.data[0] << 16 |
                (unsigned) ev->data.meta.data[1] << 8 |
                (unsigned) ev->data.meta.data[2];
      }
      else
        lprintf (LO_WARN, "MIDI_spmc: wrong length tempo meta message in midi file\n");
    }
    else
      lprintf (LO_WARN, "MIDI_spmc: passed non-meta event\n");
  }

  return compute_spmc_normal (headerval, tempo, sndrate);
}

#ifdef TEST

static char *MIDI_EventTypeToString(midi_event_type_t event_type)
{
    switch (event_type)
    {
        case MIDI_EVENT_NOTE_OFF:
            return "MIDI_EVENT_NOTE_OFF";
        case MIDI_EVENT_NOTE_ON:
            return "MIDI_EVENT_NOTE_ON";
        case MIDI_EVENT_AFTERTOUCH:
            return "MIDI_EVENT_AFTERTOUCH";
        case MIDI_EVENT_CONTROLLER:
            return "MIDI_EVENT_CONTROLLER";
        case MIDI_EVENT_PROGRAM_CHANGE:
            return "MIDI_EVENT_PROGRAM_CHANGE";
        case MIDI_EVENT_CHAN_AFTERTOUCH:
            return "MIDI_EVENT_CHAN_AFTERTOUCH";
        case MIDI_EVENT_PITCH_BEND:
            return "MIDI_EVENT_PITCH_BEND";
        case MIDI_EVENT_SYSEX:
            return "MIDI_EVENT_SYSEX";
        case MIDI_EVENT_SYSEX_SPLIT:
            return "MIDI_EVENT_SYSEX_SPLIT";
        case MIDI_EVENT_META:
            return "MIDI_EVENT_META";

        default:
            return "(unknown)";
    }
}

void PrintTrack (midi_track_t *track)
{
    midi_event_t *event;
    unsigned int i;

    for (i=0; i<track->num_events; ++i)
    {
        event = &track->events[i];

        if (event->delta_time > 0)
        {
            printf("Delay: %i ticks\n", event->delta_time);
        }

        printf("Event type: %s (%i)\n",
               MIDI_EventTypeToString(event->event_type),
               event->event_type);

        switch(event->event_type)
        {
            case MIDI_EVENT_NOTE_OFF:
            case MIDI_EVENT_NOTE_ON:
            case MIDI_EVENT_AFTERTOUCH:
            case MIDI_EVENT_CONTROLLER:
            case MIDI_EVENT_PROGRAM_CHANGE:
            case MIDI_EVENT_CHAN_AFTERTOUCH:
            case MIDI_EVENT_PITCH_BEND:
                printf("\tChannel: %i\n", event->data.channel.channel);
                printf("\tParameter 1: %i\n", event->data.channel.param1);
                printf("\tParameter 2: %i\n", event->data.channel.param2);
                break;

            case MIDI_EVENT_SYSEX:
            case MIDI_EVENT_SYSEX_SPLIT:
                printf("\tLength: %i\n", event->data.sysex.length);
                break;

            case MIDI_EVENT_META:
                printf("\tMeta type: %i\n", event->data.meta.type);
                printf("\tLength: %i\n", event->data.meta.length);
                break;
        }
    }
}

int main(int argc, char *argv[])
{
    FILE *f;
    midimem_t mf;
    midi_file_t *file;
    unsigned int i;

    if (argc < 2)
    {
        printf("Usage: %s <filename>\n", argv[0]);
        exit(1);
    }
    f = fopen (argv[1], "rb");
    if (!f)
    {
        fprintf(stderr, "Failed to open %s\n", argv[1]);
        exit(1);
    }
    fseek (f, 0, SEEK_END);
    mf.len = ftell (f);
    mf.pos = 0;
    rewind (f);
    mf.data = Z_Malloc (mf.len);
    fread (mf.data, 1, mf.len, f);
    fclose (f);

    file = MIDI_LoadFile (&mf);

    if (file == NULL)
    {
        fprintf(stderr, "Failed to open %s\n", argv[1]);
        exit(1);
    }

    for (i=0; i<file->num_tracks; ++i)
    {
        printf("\n== Track %i ==\n\n", i);

        PrintTrack(&file->tracks[i]);
    }

    return 0;
}

#endif
