Tech Arsenal 1/Tech Arsenal (Arsenal Computer).ISO/tek-01/wtek0693.zip/ECKEL.ZIP/MULTIMED.CPP

C/C++ Source or Header | 1992-07-15 | 5KB | 197 lines

//: MULTIMED.CPP -- MultiMedia class implementation.
//. This uses the high-level MCI string interface, but
//. can be changed to use lower-level interfaces without
//. changing the rest of the code in the project.
#include <stdlib.h>
#include <string.h>
#include <strstream.h>
#include <windows.h>
#include "multimed.h"
#include <mmsystem.h>

CD cd;  // single global instance

// Error checking MCI interface function:
static char* mci_command(char* cmd) {
  const size = 200;
  static char returnbuf[size];  // for mci return message
  int error = mciSendString(cmd, returnbuf, size, NULL);
  // Return string is in returnbuf.
  if(error) {
    MessageBox(NULL, cmd, "MCI command causing error", MB_OK);
    char errbuf[size];
    if(mciGetErrorString(error, errbuf, size))
    MessageBox(NULL, errbuf, "MCI error", MB_OK);
    else
    MessageBox(NULL, "Unknown error", "MCI error", MB_OK);
  }
  return returnbuf;
}

int CD::open() {
  if(!cd_open) {
    char * isthere = mci_command("capability cdaudio can play");
    if(strcmp("true", isthere) == 0) present = 1;  // disk available
    if(!present) return 0;
    mci_command("open cdaudio shareable");
    mci_command("set cdaudio time format tmsf");
    maxtracks = atoi(mci_command("status cdaudio number of tracks"));
    length = new songlength[maxtracks];
    for(int i = 1; i <= maxtracks; i++) {
    ostrstream commandstr(command, sz);
    commandstr << "status cdaudio length track " << i << '\0';
    length[i-1].minutes = atoi(strtok(mci_command(command), ":"));
    length[i-1].seconds = atoi(strtok(NULL, ":"));
    }
    cd_open = 1;
  }
  return 1;
}

void CD::play() {
  open();
  if(!present) return;
  state = normal;
  ostrstream commandstr(command, sz);
  // Note format: track:minutes:seconds:frames
  commandstr << "play cdaudio from " <<
    track << ":" << minute << ":"<<
    second << ":00" << '\0';
  mci_command(command);
}

CD::CD(when w) : state(normal), cd_open(0), maxtracks(0),
     length(0), track(1), minute(0), second(0), present(0) {
  if(w == open_now) open();
}

CD::~CD() {
  if(cd_open) mci_command("close cdaudio");
  delete []length; // dynamically allocated buffer
}

void CD::stop() {
  if(!cd_open) open();
  if(!present) return;
  mci_command("stop cdaudio");
  track = 1; minute = second = 0;
  state = normal;
}

void CD::forward_track() {
  if(++track > maxtracks) track = maxtracks;
  minute = second = 0;
  play();
}

void CD::backward_track() {
  if(--track < 1) track = 1;
  minute = second = 0;
  play();
}

void CD::update_position() {
  // Change internal data to reflect current CD position
  if(!present) return;
  track = atoi(strtok(mci_command("status cdaudio position"), ":"));
  minute = atoi(strtok(NULL, ":"));
  second = atoi(strtok(NULL, ":"));
}

void CD::rewind() {
  // Rewind:
  open();
  if(!present) return;
  update_position();
  state = frewind;
}

void CD::rewind_step() {
  if(--second < 0) {
    if(--minute < 0) {
      if(--track < 1)  {
    track = 1;
    minute = second = 0;
      } else {
    minute = length[track - 1].minutes;
    second = length[track - 1].seconds;
      }
    } else {
      second = 59;
    }
  }
}

void CD::fast_forward() {
  // Fast-forward:
  open();
  if(!present) return;
  update_position();
  state = fforward;
}

void CD::fforward_step() {
  if(minute == length[track-1].minutes) {
    if(++second >= length[track-1].seconds)
      if(++track > maxtracks) {
    track = maxtracks;
    minute = length[track-1].minutes;
    second = length[track-1].seconds;
      } else {
    minute = second = 0;
      }
    return;
  }
  // Here, we aren't at the track's minute length
  if(++second >= 60) {
    minute++;
    second = 0;
  }
}

////////// SoundPlayer Method Implementations ////////////

void SoundPlayer::play(char * file) {
  sndPlaySound(file, SND_ASYNC);
}

SoundRecorder::SoundRecorder() : audio_used(0), recording(0) {
  // You must have the empty sound file tmp.wav
  // in the current directory
  mci_command("open tmp.wav type waveaudio");
  mci_command("cue tmp.wav input");
  mci_command("delete tmp.wav from 0");
}

SoundRecorder::~SoundRecorder() {
  stop_recording();
  mci_command("close tmp.wav");
}

void SoundRecorder::start_recording() {
  char *ready = mci_command("status tmp.wav ready");
  if(strcmp(ready, "true") != 0) {
    MessageBox(NULL, ready, "tmp.wav not ready", MB_OK);
    return;
  }
  if(audio_used) {
      mci_command("delete tmp.wav from 0");
  }
  mci_command("record tmp.wav from 0");
  audio_used = recording = 1;
}

void SoundRecorder::stop_recording() {
  if(recording) {
    mci_command("stop tmp.wav");
    recording = 0;
  }
}

void SoundRecorder::save(char * file) {
  stop_recording();
  ostrstream commandstr(command, sz);
  commandstr << "save tmp.wav " << file << '\0';
  mci_command(command);
}