mpv/stream.h

#define STREAM_BUFFER_SIZE 2048

#define STREAMTYPE_FILE 0
#define STREAMTYPE_VCD  1
#define STREAMTYPE_STREAM 2    // same as FILE but no seeking (for stdin)

#define VCD_SECTOR_SIZE 2352
#define VCD_SECTOR_OFFS 24
#define VCD_SECTOR_DATA 2324

int vcd_seek_to_track(int fd,int track);
void vcd_read_toc(int fd);

#ifdef VCD_CACHE
void vcd_cache_init(int s);
#endif

typedef struct {
  int fd;
  long pos;
  int eof;
  int type; // 0=file 1=VCD
  unsigned int buf_pos,buf_len;
  long start_pos,end_pos;
  unsigned char buffer[STREAM_BUFFER_SIZE>VCD_SECTOR_SIZE?STREAM_BUFFER_SIZE:VCD_SECTOR_SIZE];
} stream_t;

int stream_fill_buffer(stream_t *s);
int stream_seek_long(stream_t *s,unsigned int pos);

inline static int stream_read_char(stream_t *s){
  return (s->buf_pos<s->buf_len)?s->buffer[s->buf_pos++]:
    (stream_fill_buffer(s)?s->buffer[s->buf_pos++]:-256);
//  if(s->buf_pos<s->buf_len) return s->buffer[s->buf_pos++];
//  stream_fill_buffer(s);
//  if(s->buf_pos<s->buf_len) return s->buffer[s->buf_pos++];
//  return 0; // EOF
}

inline static unsigned int stream_read_word(stream_t *s){
  int x,y;
  x=stream_read_char(s);
  y=stream_read_char(s);
  return (x<<8)|y;
}

inline static unsigned int stream_read_dword(stream_t *s){
  unsigned int y;
  y=stream_read_char(s);
  y=(y<<8)|stream_read_char(s);
  y=(y<<8)|stream_read_char(s);
  y=(y<<8)|stream_read_char(s);
  return y;
}

inline static unsigned int stream_read_word_le(stream_t *s){
  int x,y;
  x=stream_read_char(s);
  y=stream_read_char(s);
  return (y<<8)|x;
}

inline static unsigned int stream_read_dword_le(stream_t *s){
  unsigned int y;
  y=stream_read_char(s);
  y|=stream_read_char(s)<<8;
  y|=stream_read_char(s)<<16;
  y|=stream_read_char(s)<<24;
  return y;
}

inline static void stream_read(stream_t *s,char* mem,int len){
  while(len>0){
    int x;
    x=s->buf_len-s->buf_pos;
    if(x==0){
      if(!stream_fill_buffer(s)) return; // EOF
      x=s->buf_len-s->buf_pos;
    }
    if(s->buf_pos>s->buf_len) printf("stream_read: WARNING! s->buf_pos>s->buf_len\n");
    if(x>len) x=len;
    memcpy(mem,&s->buffer[s->buf_pos],x);
    s->buf_pos+=x; mem+=x; len-=x;
  }
}

inline static int stream_eof(stream_t *s){
  return s->eof;
}

inline static int stream_tell(stream_t *s){
  return s->pos+s->buf_pos-s->buf_len;
}

inline static int stream_seek(stream_t *s,unsigned int pos){

//  if(verbose>=3) printf("seek to 0x%X\n",pos);

  if(pos<s->pos){
    int x=pos-(s->pos-s->buf_len);
    if(x>=0){
      s->buf_pos=x;
//      putchar('*');fflush(stdout);
      return 1;
    }
  }
  
  return stream_seek_long(s,pos);
}

inline static void stream_skip(stream_t *s,int len){
  if(len<0 || (len>2*STREAM_BUFFER_SIZE && s->type!=STREAMTYPE_STREAM)){
    // negative or big skip!
    stream_seek(s,stream_tell(s)+len);
    return;
  }
  while(len>0){
    int x=s->buf_len-s->buf_pos;
    if(x==0){
      if(!stream_fill_buffer(s)) return; // EOF
      x=s->buf_len-s->buf_pos;
    }
    if(x>len) x=len;
    //memcpy(mem,&s->buf[s->buf_pos],x);
    s->buf_pos+=x; len-=x;
  }
}

void stream_reset(stream_t *s);
stream_t* new_stream(int fd,int type);
void free_stream(stream_t *s);