annotate create.cpp @ 398:443c2939e84b api-inversion

off_t in ABI structures is a bad thing.

Why?  Because its size depends on the compile-time environment.  It was
OK, ish, when the only off_t was at the end of the struct, because then
we only stomped on uninitialized bits of memory; it is terrible when
there is more than one off_t kind of field.  Use uint64_t for those
fields instead.

#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

*/

extern "C" {
  adb_t *audiodb_create(const char *path, unsigned datasize, unsigned ntracks, unsigned datadim) {
    int fd;
    adb_header_t *header = 0;
    off_t databytes, auxbytes;
    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) {
      goto error;
    }
    if (acquire_lock(fd, true)) {
      goto error;
    }

    header = (adb_header_t *) malloc(sizeof(adb_header_t));
    if(!header) {
      goto error;
    }
    
    // Initialize header
    header->magic = O2_MAGIC;
    header->version = O2_FORMAT_VERSION;
    header->numFiles = 0;
    header->dim = 0;
    header->flags = 0;
    header->headerSize = O2_HEADERSIZE;
    header->length = 0;
    header->fileTableOffset = ALIGN_PAGE_UP(O2_HEADERSIZE);
    header->trackTableOffset = ALIGN_PAGE_UP(header->fileTableOffset + O2_FILETABLE_ENTRY_SIZE*ntracks);
    header->dataOffset = ALIGN_PAGE_UP(header->trackTableOffset + O2_TRACKTABLE_ENTRY_SIZE*ntracks);
    
    databytes = ((off_t) datasize) * 1024 * 1024;
    auxbytes = databytes / datadim;

    /* FIXME: what's going on here?  There are two distinct
       preprocessor constants (O2_LSH_N_POINT_BITS, LSH_N_POINT_BITS);
       a third is presumably some default
       (O2_DEFAULT_LSH_N_POINT_BITS), and then there's this magic 28
       bits.  Should this really be part of the flags structure at
       all?  Putting it elsewhere will of course break backwards
       compatibility, unless 14 is the only value that's been used
       anywhere... */
    
    // 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
    
    header->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){
      header->timesTableOffset = ALIGN_PAGE_UP(header->dataOffset + databytes);
      header->powerTableOffset = ALIGN_PAGE_UP(header->timesTableOffset + 2*auxbytes);
      header->l2normTableOffset = ALIGN_PAGE_UP(header->powerTableOffset + auxbytes);
      header->dbSize = ALIGN_PAGE_UP(header->l2normTableOffset + auxbytes);
    } else { // Create LARGE_ADB, features and powers kept on filesystem 
      header->flags |= O2_FLAG_LARGE_ADB;
      header->timesTableOffset = ALIGN_PAGE_UP(header->dataOffset + O2_FILETABLE_ENTRY_SIZE*ntracks);
      header->powerTableOffset = ALIGN_PAGE_UP(header->timesTableOffset + O2_FILETABLE_ENTRY_SIZE*ntracks);
      header->l2normTableOffset = ALIGN_PAGE_UP(header->powerTableOffset + O2_FILETABLE_ENTRY_SIZE*ntracks);
      header->dbSize = header->l2normTableOffset;
    } 
    
    if (write(fd, header, O2_HEADERSIZE) != O2_HEADERSIZE) {
      goto error;
    }
    
    // go to the location corresponding to the last byte
    if (lseek (fd, header->dbSize - 1, SEEK_SET) == -1) {
      goto error;
    }

    // write a dummy byte at the last location
    if (write (fd, "", 1) != 1) {
      goto error;
    }

    free(header);
    return audiodb_open(path, O_RDWR);

  error:
    if(header) {
      free(header);
    }
    return NULL;
  }
}