view create.cpp @ 385:4e68f7d4d524 api-inversion

Invert audiodb_create() / audioDB::create().

(This was straightforward, because audioDB::create() doesn't depend on
having any kind of state or reading it from disk, except of course for
the locks.  New global functions acquire_lock() and divest_lock() [silly
name, I know], to be used both within audioDB::get_lock() and
audioDB::release_lock() and within (inverted) API functions directly.
Eventually the audioDB:: versions will be able to go away entirely)

#include "audioDB.h"
extern "C" {
#include "audioDB_API.h"
}
/* Make a new database.

IF size(featuredata) < O2_LARGE_ADB_SIZE 
   The database consists of:

   * a header (see dbTableHeader struct definition);
   * keyTable: list of keys of tracks;
   * trackTable: Maps implicit feature index to a feature vector
     matrix (sizes of tracks)
   * featureTable: Lots of doubles;
   * timesTable: (start,end) time points for each feature vector;
   * powerTable: associated power for each feature vector;
   * l2normTable: squared l2norms for each feature vector.
   
ELSE the database consists of:
   
   * a header (see dbTableHeader struct definition);
   * keyTable: list of keys of tracks
   * trackTable: sizes of tracks
   * featureTable: list of feature file names
   * timesTable: list of times file names
   * powerTable: list of power file names

*/

int acquire_lock(int, bool);

extern "C" {
  adb_t *audiodb_create(const char *path, unsigned datasize, unsigned ntracks, unsigned datadim) {
    int fd;
    if(datasize == 0) {
      datasize = O2_DEFAULT_DATASIZE;
    }
    if(ntracks == 0) {
      ntracks = O2_DEFAULT_NTRACKS;
    }
    if(datadim == 0) {
      datadim = O2_DEFAULT_DATADIM;
    }

    if ((fd = open(path, O_RDWR|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH)) < 0) {
      return NULL;
    }
    if (acquire_lock(fd, true)) {
      return NULL;
    }
    dbTableHeaderT *dbH = new dbTableHeaderT();
    
    // Initialize header
    dbH->magic = O2_MAGIC;
    dbH->version = O2_FORMAT_VERSION;
    dbH->numFiles = 0;
    dbH->dim = 0;
    dbH->flags = 0;
    dbH->headerSize = O2_HEADERSIZE;
    dbH->length = 0;
    dbH->fileTableOffset = ALIGN_PAGE_UP(O2_HEADERSIZE);
    dbH->trackTableOffset = ALIGN_PAGE_UP(dbH->fileTableOffset + O2_FILETABLE_ENTRY_SIZE*ntracks);
    dbH->dataOffset = ALIGN_PAGE_UP(dbH->trackTableOffset + O2_TRACKTABLE_ENTRY_SIZE*ntracks);
    
    off_t databytes = ((off_t) datasize) * 1024 * 1024;
    off_t auxbytes = databytes / datadim;
    
    // For backward-compatibility, Record the point-encoding parameter for LSH indexing in the adb header
    // If this value is 0 then it will be set to 14
    
#if O2_LSH_N_POINT_BITS > 15
#error "AudioDB Compile ERROR: consistency check of O2_LSH_POINT_BITS failed (>15)"
#endif
    
    dbH->flags |= LSH_N_POINT_BITS << 28;
    
    // If database will fit in a single file the vectors are copied into the AudioDB instance
    // Else all the vectors are left on the FileSystem and we use the dataOffset as storage
    // for the location of the features, powers and times files (assuming that arbitrary keys are used for the fileTable)
    if(ntracks<O2_LARGE_ADB_NTRACKS && datasize<O2_LARGE_ADB_SIZE){
      dbH->timesTableOffset = ALIGN_PAGE_UP(dbH->dataOffset + databytes);
      dbH->powerTableOffset = ALIGN_PAGE_UP(dbH->timesTableOffset + 2*auxbytes);
      dbH->l2normTableOffset = ALIGN_PAGE_UP(dbH->powerTableOffset + auxbytes);
      dbH->dbSize = ALIGN_PAGE_UP(dbH->l2normTableOffset + auxbytes);
    } else { // Create LARGE_ADB, features and powers kept on filesystem 
      dbH->flags |= O2_FLAG_LARGE_ADB;
      dbH->timesTableOffset = ALIGN_PAGE_UP(dbH->dataOffset + O2_FILETABLE_ENTRY_SIZE*ntracks);
      dbH->powerTableOffset = ALIGN_PAGE_UP(dbH->timesTableOffset + O2_FILETABLE_ENTRY_SIZE*ntracks);
      dbH->l2normTableOffset = ALIGN_PAGE_UP(dbH->powerTableOffset + O2_FILETABLE_ENTRY_SIZE*ntracks);
      dbH->dbSize = dbH->l2normTableOffset;
    } 
    
    write(fd, dbH, O2_HEADERSIZE);
    
    // go to the location corresponding to the last byte
    if (lseek (fd, dbH->dbSize - 1, SEEK_SET) == -1)
      return NULL;
    
    // write a dummy byte at the last location
    if (write (fd, "", 1) != 1)
      return NULL;
    
    return audiodb_open(path);
  }
}