FNam2PDB.c

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/************************************************************************/
/**

   \file       FNam2PDB.c
   
   \version    V1.2
   \date       07.07.14
   \brief      Extract a PDB code from a filename
   
   \copyright  (c) Dr. Andrew C. R. Martin 1995
   \author     Dr. Andrew C. R. Martin
   \par
               Institute of Structural & Molecular Biology,
               University College London,
               Gower Street,
               London.
               WC1E 6BT.
   \par
               andrew@bioinf.org.uk
               andrew.martin@ucl.ac.uk
               
**************************************************************************

   This code is NOT IN THE PUBLIC DOMAIN, but it may be copied
   according to the conditions laid out in the accompanying file
   COPYING.DOC.

   The code may be modified as required, but any modifications must be
   documented so that the person responsible can be identified.

   The code may not be sold commercially or included as part of a 
   commercial product except as described in the file COPYING.DOC.

**************************************************************************

   Description:
   ============


**************************************************************************

   Usage:
   ======

**************************************************************************

   Revision History:
   =================
-  V1.0  24.07.95 Original
-  V1.1  26.07.95 Fixed a NULL to '\0'
-  V1.2  07.07.14 Use bl prefix for functions By: CTP

*************************************************************************/
/* Doxygen
   -------
   #GROUP    Handling PDB Data
   #SUBGROUP File IO
   #FUNCTION  blFNam2PDB()
   Attempts to extract a PDB code from a filename
*/
/************************************************************************/
/* Includes
*/
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include "macros.h"

/************************************************************************/
/* Defines and macros
*/

/************************************************************************/
/* Globals
*/

/************************************************************************/
/* Prototypes
*/

/************************************************************************/
/*>char *blFNam2PDB(char *filename)
   --------------------------------
*//**

   \param[in]     *filename    A PDB filename containing a PDB code
   \return                     The PDB code (lower case)
                               NULL if memory allocation fails
                               XXXX if filename blank or NULL or if
                               unable to find PDB code
                               
   This routine attempts to convert a filename stem to a PDB code.

   All the following inputs should produce the same output
   of 1fbj:


      $A:[PDB]PDB1FBJ.ENT
      C:\P1FBJ.PDB
      /pdb/p1fbj.pdb
      /pdb/pdb1fbj.pdb
      1fbj.pdb
      1fbjL

   The routine first removes characters from the start of the filename up
   to the last : ] / or \. It then searches for the following possible
   patterns (where N is a digit and X is an alphanumeric)


      pdbNXXX
      pNXXX
      NXXX
      XXXX.pdb
      XXXX.ent

   This should cover just about any filename which includes a legal PDB
   code.

-  24.07.95 Original    By: ACRM
-  26.07.95 Corrected a NULL to '\0'
-  07.07.14 Use bl prefix for functions By: CTP
*/
char *blFNam2PDB(char *filename)
{
   int         length,
               pos;
   char        *temp = NULL,
               *p,
               *start;
   static char pdbcode[8];
   
   /* Check real string given                                           */
   if(filename != NULL)
   {
      /* Check length not zero                                          */
      if((length = strlen(filename))!=0)
      {
         /* Make a temporary copy of the string                         */
         if((temp = (char *)malloc((length+1)*sizeof(char)))==NULL)
            return(NULL);
         strcpy(temp,filename);

         /* Downcase the copy                                           */
         LOWER(temp);

         /* Step from the end of string to char after any : ] / or \    */
         start = temp;
         for(pos=length-1; pos>=0; pos--)
         {
            if((temp[pos] == ':') ||
               (temp[pos] == ']') ||
               (temp[pos] == '/') ||
               (temp[pos] == '\\'))
            {
               start = temp+pos+1;
               break;
            }
         }

         /* Search for `pdb' followed by a digit & 3 alphanumerics      */
         p=start;
         for(;;)
         {
            if((p=strstr(p,"pdb"))!=NULL)
            {
               if(isdigit(p[3]) && 
                  isalnum(p[4]) &&
                  isalnum(p[5]) &&
                  isalnum(p[6]))
               {
                  p[7] = '\0';
                  strcpy(pdbcode, p+3);
                  free(temp);
                  return(pdbcode);
               }
               else
               {
                  p++;
               }
            }
            else
            {
               break;
            }
         }

         /* Search for `p' followed by a digit & 3 alphanumerics        */
         p=start;
         for(;;)
         {
            if((p=strstr(p,"p"))!=NULL)
            {
               if(isdigit(p[3]) &&
                  isalnum(p[4]) &&
                  isalnum(p[5]) &&
                  isalnum(p[6]))
               {
                  p[7] = '\0';
                  strcpy(pdbcode, p+3);
                  free(temp);
                  return(pdbcode);
               }
               else
               {
                  p++;
               }
            }
            else
            {
               break;
            }
         }

         /* Search for digit followed by 3 alphanumerics                */
         for(p=start; *p!='\0'; p++)
         {
            if(isdigit(p[0]) && 
               isalnum(p[1]) &&
               isalnum(p[2]) &&
               isalnum(p[3]))
            {
               p[4] = '\0';
               strcpy(pdbcode, p);
               free(temp);
               return(pdbcode);
            }
         }

         /* Search for 4 characters before .pdb                         */
         if((p=strstr(start,".pdb"))!=NULL)
         {
            p -= 4;
            if(p>=start)
            {
               p[4] = '\0';
               strcpy(pdbcode, p);
               free(temp);
               return(pdbcode);
            }
         }
         
         /* Search for 4 characters before .ent                         */
         if((p=strstr(start,".ent"))!=NULL)
         {
            p -= 4;
            if(p>=start)
            {
               p[4] = '\0'; 
               strcpy(pdbcode, p);
               free(temp);
               return(pdbcode);
            }
         }
         
         /* Give up!                                                    */
         strcpy(pdbcode,"XXXX");
         free(temp);
         return(pdbcode);
      }
   }

   strcpy(pdbcode,"XXXX");
   return(pdbcode);
}