cSvn-UI for SVN Repositories

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdlib.h>
#include <stdio.h>
#include <sys/sysinfo.h>
#include <sys/types.h>
#include <stdint.h>
#include <dirent.h>
#include <sys/stat.h> /* chmod(2)    */
#include <sys/file.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <limits.h>
#include <string.h>   /* strdup(3)   */
#include <libgen.h>   /* basename(3) */
#include <ctype.h>    /* tolower(3)  */
#include <errno.h>
#include <time.h>
#include <sys/time.h>
#include <pwd.h>
#include <grp.h>
#include <stdarg.h>
#include <unistd.h>

#include <defs.h>
#include <cscm/bcf.h>

#include <dlist.h>
#include <strbuf.h>
#include <repolist.h>
#include <wrapper.h>


#define RLIST_ERRMSG_SIZE 4096

void rlist_error( const char *fmt, ... )
{
  va_list arg_ptr;
  char  buf[RLIST_ERRMSG_SIZE];
  char  msg[RLIST_ERRMSG_SIZE];
  char *format = "%s: %s\n";

  va_start( arg_ptr, fmt );

  vsnprintf( msg, RLIST_ERRMSG_SIZE, (const void *)fmt, arg_ptr );

  va_end( arg_ptr ); /* Reset variable arguments. */

  snprintf( buf, RLIST_ERRMSG_SIZE, format, "rlist", msg );

  (void)write( STDERR_FILENO, buf, strlen( buf ) );

  exit( 1 );
}

rlist_errfunc rlist_fatal = rlist_error;


struct dlist *config = NULL;

static void *bcf = NULL;

static size_t read_bcf( void )
{
  int fd;
  struct stat st;
  void *addr;

  fd = shm_open( CSVN_SHM_BCF, O_RDONLY, S_IRUSR | S_IWUSR );
  if( fd == -1 )
  {
    rlist_fatal( "Canot open SHM/%s data", "csvn.bcf" );
    return 0;
  }
  if( !fstat( fd, (struct stat *)&st ) )
  {
    addr = mmap( NULL, (size_t)st.st_size, PROT_READ, MAP_SHARED, fd, 0 );
    if( addr != MAP_FAILED )
    {
      bcf = malloc( (size_t)st.st_size );
      if( !bcf )
      {
        (void)munmap( addr, (size_t)st.st_size );
        rlist_fatal( "Canot allocate memory for SHM/%s data", "csvn.bcf" );
        return 0;
      }
      memcpy( bcf, addr, (size_t)st.st_size );
      (void)munmap( addr, (size_t)st.st_size );
      return (size_t)st.st_size;
    }
    else
    {
      rlist_fatal( "Canot mmap SHM/%s data", "csvn.bcf" );
      return 0;
    }
  }
  else
  {
    rlist_fatal( "Canot stat SHM/%s data", "csvn.bcf" );
    return 0;
  }
}


static void check_bcf_ident( const void *bf, size_t size )
{
  Bcf32_fhdr *fhdr = (Bcf32_fhdr *)bf;

  if( !fhdr )
    rlist_fatal( "Invalid address of SHM/%s data", "csvn.bcf" );

  if( (size_t)fhdr->b_fsize != size )
    rlist_fatal( "Binary Config SHM/%s: invalid size", "csvn.bcf" );
  if( memcmp( fhdr->b_ident, BCFMAG, (size_t)SZBCFMAG ) )
    rlist_fatal( "Binary Config SHM/%s: invalid MAGIC number", "csvn.bcf" );
  if( fhdr->b_ident[BI_CLASS] != BCF_CLASS_32 )
    rlist_fatal( "Binary Config SHM/%s: invalid objects class", "csvn.bcf" );
#if __BYTE_ORDER == __LITTLE_ENDIAN
  if( fhdr->b_ident[BI_DATA] != BCF_DATA_LSB )
    rlist_fatal( "Binary Config SHM/%s: invalid byte-order", "csvn.bcf" );
#else
  if( fhdr->b_ident[BI_DATA] != BCF_DATA_MSB )
    rlist_fatal( "Binary Config SHM/%s: invalid byte-order", "csvn.bcf" );
#endif
  if( fhdr->b_ident[BI_VERSION] != BV_CURRENT )
    rlist_fatal( "Binary Config SHM/%s: invalid version", "csvn.bcf" );
}


/***************************************************************
  Print config file functions:
 */
static void __print_global_variable( void *data, void *user_data )
{
  struct variable *variable = (struct variable *)data;
  struct strbuf   *sb   = (struct strbuf *)user_data;

  if( !variable || !sb ) return;

  switch( variable->type )
  {
    case DT_NUMERICAL:
      strbuf_addf( sb, "  %s = %d;\n", variable->name, variable->_v.val );
      break;
    case DT_PATH:
      strbuf_addf( sb, "  %s = '%s';\n", variable->name, variable->_v.vptr );
      break;
    case DT_STRING:
      strbuf_addf( sb, "  %s = \"%s\";\n", variable->name, variable->_v.vptr );
      break;
    default:
      break;
  }
}

static void print_global_variables( struct strbuf *sb, struct dlist *list )
{
  if( list ) { dlist_foreach( list, __print_global_variable, (void *)sb ); }
}

static void __print_repo_variable( void *data, void *user_data )
{
  struct variable *variable = (struct variable *)data;
  struct strbuf   *sb   = (struct strbuf *)user_data;

  if( !variable || !sb ) return;

  switch( variable->type )
  {
    case DT_NUMERICAL:
      strbuf_addf( sb, "    %s = %d;\n", variable->name, variable->_v.val );
      break;
    case DT_PATH:
      strbuf_addf( sb, "    %s = '%s';\n", variable->name, variable->_v.vptr );
      break;
    case DT_STRING:
      strbuf_addf( sb, "    %s = \"%s\";\n", variable->name, variable->_v.vptr );
      break;
    default:
      break;
  }
}

static void print_repo_variables( struct strbuf *sb, struct dlist *list )
{
  if( list ) { dlist_foreach( list, __print_repo_variable, (void *)sb ); }
}

static void __print_repo( void *data, void *user_data )
{
  struct repo   *repo = (struct repo *)data;
  struct strbuf *sb   = (struct strbuf *)user_data;

  if( !repo || !sb ) return;

  strbuf_addf( sb, "  repo '%s' {\n", repo->path );
  if( repo->list )
  {
    print_repo_variables( sb, repo->list );
  }
  strbuf_addf( sb, "  }\n\n" );
}

static void print_repos( struct strbuf *sb, struct dlist *list )
{
  if( list ) { dlist_foreach( list, __print_repo, (void *)sb ); }
}

static void __print_section( void *data, void *user_data )
{
  struct section *section = (struct section *)data;
  struct strbuf  *sb      = (struct strbuf *)user_data;

  if( !section || !sb ) return;

  if( section->list )
  {
    if( section->type == ST_REPOS )
    {
      strbuf_addf( sb, "section \"%s\" {\n\n", section->name );
      print_repos( sb, section->list );
      strbuf_addf( sb, "}\n\n" );
    }
    else if( section->type == ST_GLOBAL )
    {
      strbuf_addf( sb, "section \".global\" {\n" );
      print_global_variables( sb, section->list );
      strbuf_addf( sb, "}\n\n" );
    }
  }
}

void print_config( struct strbuf *sb, struct dlist *list )
{
  strbuf_addf( sb, "<pre><code class='language-C'>\n" );
  strbuf_addf( sb, "/*******************************************************\n" );
  strbuf_addf( sb, "  Global variables are propagate into repo sections but\n" );
  strbuf_addf( sb, "  their values overrides by correspond repo variables.\n" );
  strbuf_addf( sb, " */\n\n" );
  if( list ) { dlist_foreach( list, __print_section, (void *)sb ); }
  strbuf_addf( sb, "</code></pre>\n" );
}
/*
  End of print config file functions.
 ***************************************************************/


/**************************
  lookup variable in repo:
 */
static int __compare_variables_by_name( const void *a, const void *b )
{
  struct variable *va = (struct variable *)a;
  struct variable *vb = (struct variable *)b;

  if( !va || !vb ) return -1;

  return strcmp( (const char *)va->name, (const char *)vb->name );
}

struct variable *lookup( struct repo *repo, struct variable *variable )
{
  struct dlist *found = NULL;

  if( !repo || !repo->list ) return NULL;

  found = dlist_find_data( repo->list, __compare_variables_by_name, (const void *)variable );
  if( found )
    return (struct variable *)(found->data);
  return NULL;
}

struct variable *lookup_global( struct section *section, struct variable *variable )
{
  struct dlist *found = NULL;

  if( !section || !section->list ) return NULL;

  found = dlist_find_data( section->list, __compare_variables_by_name, (const void *)variable );
  if( found )
    return (struct variable *)(found->data);
  return NULL;
}

/**************
  lookup repo:
 */
struct repo *lookup_repo( struct dlist *config, const char *path )
{
  struct dlist *list = NULL;

  if( !config || !path ) return NULL;

  list = config;
  while( list )
  {
    struct section *section = (struct section *)list->data;

    if( section->type == ST_REPOS )
    {
      struct dlist *rlist = section->list;
      while( rlist )
      {
        struct repo *repo = (struct repo *)rlist->data;
        if( !strcmp( (const char *)repo->path, path ) )
          return repo;
        rlist = dlist_next( rlist );
      }
    }
    list = dlist_next( list );
  }

  return NULL;
}

/*****************
  lookup section:
 */
struct section *lookup_section( struct dlist *config, const char *name )
{
  struct dlist *list = NULL;

  if( !config || !name ) return NULL;

  list = config;
  while( list )
  {
    struct section *section = (struct section *)list->data;

    if( section && section->type == ST_REPOS && !strcmp( (const char *)section->name, name ) )
        return section;

    list = dlist_next( list );
  }

  return NULL;
}

/************************
  lookup global section:
 */
struct section *lookup_global_section( struct dlist *config )
{
  struct dlist *list = NULL;

  if( !config ) return NULL;

  list = config;
  while( list )
  {
    struct section *section = (struct section *)list->data;

    if( section && section->type == ST_GLOBAL )
        return section;

    list = dlist_next( list );
  }

  return NULL;
}

/******************
  repolist length:
 */
int repolist_length( struct dlist *config )
{
  struct dlist *list = NULL;
  int length = 0;

  if( !config ) return length;

  list = config;
  while( list )
  {
    struct section *section = (struct section *)list->data;

    if( section->type == ST_REPOS )
    {
      struct dlist *rlist = section->list;
      while( rlist )
      {
        ++length;
        rlist = dlist_next( rlist );
      }
    }
    list = dlist_next( list );
  }

  return length;
}

/***************
  repolist nth:
 */
struct repo *repolist_nth( struct dlist *config, int n )
{
  struct dlist *list = NULL;
  int length = 0;

  if( !config || n < 0 ) return NULL;

  list = config;
  while( list )
  {
    struct section *section = (struct section *)list->data;

    if( section->type == ST_REPOS )
    {
      struct dlist *rlist = section->list;
      while( rlist )
      {
        if( length == n )
        {
          struct repo *repo = (struct repo *)rlist->data;
          return repo;
        }
        ++length;
        rlist = dlist_next( rlist );
      }
    }
    list = dlist_next( list );
  }

  return NULL;
}

/**************************
  repo position in config:
 */
int repo_position( struct dlist *config, struct repo *repo )
{
  struct dlist *list = NULL;
  int position = -1;

  if( !config || !repo ) return position;

  position = 0;

  list = config;
  while( list )
  {
    struct section *section = (struct section *)list->data;

    if( section->type == ST_REPOS )
    {
      struct dlist *rlist = section->list;
      while( rlist )
      {
        if( (struct repo *)rlist->data == repo )
        {
          return position;
        }
        ++position;
        rlist = dlist_next( rlist );
      }
    }
    list = dlist_next( list );
  }

  return -1;
}


/**************************************
  parent section node of repolist nth:
 */
struct dlist *parent_section_node_repolist_nth( struct dlist *config, int n )
{
  struct dlist *list = NULL;
  int length = 0;

  if( !config || n < 0 ) return NULL;

  list = config;
  while( list )
  {
    struct section *section = (struct section *)list->data;

    if( section->type == ST_REPOS )
    {
      struct dlist *rlist = section->list;
      while( rlist )
      {
        if( length == n )
        {
          return list;
        }
        ++length;
        rlist = dlist_next( rlist );
      }
    }
    list = dlist_next( list );
  }

  return NULL;
}

/************************************
  parent rlist node of repolist nth:
 */
struct dlist *parent_rlist_node_repolist_nth( struct dlist *config, int n )
{
  struct dlist *list = NULL;
  int length = 0;

  if( !config || n < 0 ) return NULL;

  list = config;
  while( list )
  {
    struct section *section = (struct section *)list->data;

    if( section->type == ST_REPOS )
    {
      struct dlist *rlist = section->list;
      while( rlist )
      {
        if( length == n )
        {
          return rlist;
        }
        ++length;
        rlist = dlist_next( rlist );
      }
    }
    list = dlist_next( list );
  }

  return NULL;
}



/**********************************************
  Provide all global variables into each repo
  if that variable is not present in the repo:
 */
static void __provide_foreach_data( void *data, void *user_data )
{
  struct variable *variable = (struct variable *)data;
  struct repo     *repo     = (struct repo *)user_data;

  if( !repo || !variable ) return;

  if( !lookup( repo, variable ) )
  {
    struct variable *var = (struct variable *)xmalloc( sizeof(struct variable) );
    memcpy( (void *)var, (void *)variable, sizeof(struct variable) );
    repo->list = dlist_append( repo->list, (void *)var );
  }
}

static void __provide_foreach_repos( void *data, void *user_data )
{
  struct section *global = (struct section *)user_data;

  if( !global || !global->list ) return;

  dlist_foreach( global->list, __provide_foreach_data, data );
}

static void __provide_foreach_sections( void *data, void *user_data )
{
  struct section *section = (struct section *)data;
  if( !section || section->type == ST_GLOBAL || !section->list ) return;

  dlist_foreach( section->list, __provide_foreach_repos, user_data );
}

static void provide_global_data( struct dlist *tree, struct section *global )
{
  if( tree ) { dlist_foreach( tree, __provide_foreach_sections, (void *)global ); }
}
/*
 **********************************************/

/**********************************************
  Free REPO list functions:
 */
static void __free_variable( void *data, void *user_data )
{
  struct variable *variable = (struct variable *)data;
  if( variable ) free( variable );
}

static void free_variables( struct dlist *list )
{
  if( list ) { dlist_free( list, __free_variable ); }
}

static void __free_repo( void *data, void *user_data )
{
  struct repo *repo = (struct repo *)data;
  if( !repo ) return;
  if( repo->list ) { free_variables( repo->list ); }
  free( repo );
}

static void free_repos( struct dlist *list )
{
  if( list ) { dlist_free( list, __free_repo ); }
}

static void __free_section( void *data, void *user_data )
{
  struct section *section = (struct section *)data;
  if( !section ) return;

  if( section->list )
  {
    if( section->type == ST_GLOBAL )
      free_variables( section->list );
    else if( section->type == ST_REPOS )
      free_repos( section->list );
  }
  free( section );
}

static void free_repolist( struct dlist *list )
{
  if( list ) { dlist_free( list, __free_section ); }
}
/*
 **********************************************/

void free_config( void )
{
  free_repolist( config ); config = NULL;
  if( bcf ) { free( bcf ); bcf = NULL; }
}

static struct dlist *read_repolist( const void *bf )
{
  struct dlist  *tree = NULL;
  Bcf32_fhdr    *fhdr = NULL;
  unsigned char *ftab, *stab;

  ftab = (unsigned char *)bf;
  fhdr = (Bcf32_fhdr *)ftab;

  if( !fhdr )
    return tree;

  stab = (unsigned char *)(ftab + (int)fhdr->b_stoff);

#if __DEBUG__ == 1
  fprintf( stderr, "BCF: header's size in bytes: %d\n",  fhdr->b_hsize );
  fprintf( stderr, "BCF: Whole BCF file size in bytes: %d\n",  fhdr->b_fsize );
  fprintf( stderr, "BCF: section header table’s file offset in bytes: %d\n",  fhdr->b_shoff );
  fprintf( stderr, "BCF: section header's size in bytes: %d\n",  fhdr->b_shentsize );
  fprintf( stderr, "BCF: number of entries in section headers table: %d\n",  fhdr->b_shnum );
  fprintf( stderr, "BCF: repository header table’s file offset in bytes: %d\n",  fhdr->b_rhoff );
  fprintf( stderr, "BCF: repository header's size in bytes: %d\n",  fhdr->b_rhentsize );
  fprintf( stderr, "BCF: number of entries in repository headers table: %d\n",  fhdr->b_rhnum );
  fprintf( stderr, "BCF: data entries table’s file offset in bytes: %d\n",  fhdr->b_dtoff );
  fprintf( stderr, "BCF: data entry's size in bytes: %d\n",  fhdr->b_dtentsize );
  fprintf( stderr, "BCF: number of entries in data entries table: %d\n",  fhdr->b_dtnum );
  fprintf( stderr, "BCF: string table’s file offset in bytes: %d\n\n",  fhdr->b_stoff );
#endif

  {
    Bcf32_shdr *shdr = NULL;
    int s = 0;

    struct section *global = NULL;

    shdr = (Bcf32_shdr *)((unsigned char *)bf + (int)fhdr->b_shoff);

    while( s < fhdr->b_shnum )
    {
#if __DEBUG__ == 1
      fprintf( stderr, "SECTION: s_name: %s\n",  shdr->s_name );
      fprintf( stderr, "SECTION: s_type: %d\n",  shdr->s_type );
      fprintf( stderr, "SECTION: s_shdr (offset in string table): %d\n",  shdr->s_shdr );
      fprintf( stderr, "SECTION: s_sdata (file offset to data): %d\n",  shdr->s_sdata );
      fprintf( stderr, "SECTION: s_dnum (number of data entries): %d\n",  shdr->s_dnum );
      fprintf( stderr, "SECTION: name: \"%s\"\n\n",  stab + (int)shdr->s_shdr );
#endif

      if( shdr->s_type == ST_GLOBAL )
      {
        Bcf32_dntr *dntr = NULL;
        int d = 0;

        struct section *sec = NULL;
        sec = (struct section *)xmalloc( sizeof(struct section) );
        sec->type = ST_GLOBAL;
        sec->name = (unsigned char *)(stab + (int)shdr->s_shdr); /*do not allocate, all in bcf */
        tree = dlist_append( tree, (void *)sec );
        global = sec;

        dntr = (Bcf32_dntr *)(ftab + (int)shdr->s_sdata);

        while( d < shdr->s_dnum )
        {
#if __DEBUG__ == 1
          fprintf( stderr, "DATA: d_name: %s\n",  stab + (int)dntr->d_name );
#endif

          switch( dntr->d_type )
          {
            case DT_NUMERICAL:
#if __DEBUG__ == 1
              fprintf( stderr, "DATA: _v.d_value: %d\n\n",  dntr->_v.d_value );
#endif
              {
                struct variable *var = NULL;
                var = (struct variable *)xmalloc( sizeof(struct variable) );
                var->type = DT_NUMERICAL;
                var->name = (unsigned char *)(stab + (int)dntr->d_name); /*do not allocate, all in bcf */
                var->_v.val = (int)dntr->_v.d_value;
                sec->list = dlist_append( sec->list, (void *)var );
              }
              break;
            case DT_PATH:
#if __DEBUG__ == 1
              fprintf( stderr, "DATA: _v.d_valptr (path): '%s';\n\n", stab + (int)dntr->_v.d_valptr );
#endif
              {
                struct variable *var = NULL;
                var = (struct variable *)xmalloc( sizeof(struct variable) );
                var->type = DT_PATH;
                var->name = (unsigned char *)(stab + (int)dntr->d_name); /*do not allocate, all in bcf */
                var->_v.vptr = (unsigned char *)(stab + (int)dntr->_v.d_valptr);
                sec->list = dlist_append( sec->list, (void *)var );
              }
              break;
            case DT_STRING:
#if __DEBUG__ == 1
              fprintf( stderr, "DATA: _v.d_valptr (string): \"%s\";\n\n", stab + (int)dntr->_v.d_valptr );
#endif
              {
                struct variable *var = NULL;
                var = (struct variable *)xmalloc( sizeof(struct variable) );
                var->type = DT_STRING;
                var->name = (unsigned char *)(stab + (int)dntr->d_name); /*do not allocate, all in bcf */
                var->_v.vptr = (unsigned char *)(stab + (int)dntr->_v.d_valptr);
                sec->list = dlist_append( sec->list, (void *)var );
              }
              break;
            default:
              break;
          }

          ++d;
          ++dntr;

        } /* End of while( global data ) */

      }
      else if( shdr->s_type == ST_REPOS )
      {
        Bcf32_rhdr *rhdr = NULL;
        int r = 0;

        struct section *sec = NULL;
        sec = (struct section *)xmalloc( sizeof(struct section) );
        sec->type = ST_REPOS;
        sec->name = (unsigned char *)(stab + (int)shdr->s_shdr); /*do not allocate, all in bcf */
        tree = dlist_append( tree, (void *)sec );

        rhdr = (Bcf32_rhdr *)(ftab + (int)shdr->s_sdata);

        while( r < shdr->s_dnum )
        {
          int d = 0;
          Bcf32_dntr *dntr = NULL;

          struct repo *repo = NULL;
          repo = (struct repo *)xmalloc( sizeof(struct repo) );
          repo->path = (unsigned char *)(stab + (int)rhdr->r_rhdr); /*do not allocate, all in bcf */
          sec->list = dlist_append( sec->list, (void *)repo );

#if __DEBUG__ == 1
          fprintf( stderr, "REPO: path: %s\n",  stab + (int)rhdr->r_rhdr );
#endif
          dntr = (Bcf32_dntr *)(ftab + (int)rhdr->r_rdata);

          while( d < rhdr->r_dnum )
          {
#if __DEBUG__ == 1
            fprintf( stderr, "REPO's DATA: d_name: %s\n",  stab + (int)dntr->d_name );
#endif
            switch( dntr->d_type )
            {
              case DT_NUMERICAL:
#if __DEBUG__ == 1
                fprintf( stderr, "REPO's DATA: _v.d_value: %d\n\n",  dntr->_v.d_value );
#endif
                {
                  struct variable *var = NULL;
                  var = (struct variable *)xmalloc( sizeof(struct variable) );
                  var->type = DT_NUMERICAL;
                  var->name = (unsigned char *)(stab + (int)dntr->d_name); /*do not allocate, all in bcf */
                  var->_v.val = (int)dntr->_v.d_value;
                  repo->list = dlist_append( repo->list, (void *)var );
                }
                break;
              case DT_PATH:
#if __DEBUG__ == 1
                fprintf( stderr, "REPO's DATA: _v.d_valptr (path): '%s';\n\n", stab + (int)dntr->_v.d_valptr );
#endif
                {
                  struct variable *var = NULL;
                  var = (struct variable *)xmalloc( sizeof(struct variable) );
                  var->type = DT_PATH;
                  var->name = (unsigned char *)(stab + (int)dntr->d_name); /*do not allocate, all in bcf */
                  var->_v.vptr = (unsigned char *)(stab + (int)dntr->_v.d_valptr);
                  repo->list = dlist_append( repo->list, (void *)var );
                }
                break;
              case DT_STRING:
#if __DEBUG__ == 1
                fprintf( stderr, "REPO's DATA: _v.d_valptr (string): \"%s\";\n\n", stab + (int)dntr->_v.d_valptr );
#endif
                {
                  struct variable *var = NULL;
                  var = (struct variable *)xmalloc( sizeof(struct variable) );
                  var->type = DT_STRING;
                  var->name = (unsigned char *)(stab + (int)dntr->d_name); /*do not allocate, all in bcf */
                  var->_v.vptr = (unsigned char *)(stab + (int)dntr->_v.d_valptr);
                  repo->list = dlist_append( repo->list, (void *)var );
                }
                break;
              default:
                break;
            }

            ++d;
            ++dntr;

          } /* End of while( repo data ) */

          ++r;
          ++rhdr;

        } /* End of while( repos ) */

#if __DEBUG__ == 1
        fprintf( stderr, "\n" );
#endif
      }
      else
      {
        rlist_fatal( "Invalid section in the SHM/%s data", "csvn.bcf" );
#if __DEBUG__ == 1
        fprintf( stderr, "SECTION: empty\n" );
#endif
      }

      ++s;
      ++shdr;

    } /* End of while( sections ) */

    if( global )
      provide_global_data( tree, global );
  }

  return tree;
}


struct dlist *read_config( void )
{
  size_t  bsize = 0;

  if( (bsize = read_bcf()) )
  {
    check_bcf_ident( bcf, bsize ); /* fatal on error */
    return read_repolist( bcf );
  }

  return NULL;
}