1: /* $Header$ */
   2: 
   3: /*
   4:  * Author: Peter J. Nicklin
   5:  */
   6: 
   7: /*
   8:  * openpdb() opens a database named by name located in a directory with
   9:  * name path and associates a database stream with it. Returns a pointer
  10:  * which identifies the database stream in subsequent operations. A null
  11:  * pointer is returned if the database cannot be accessed or is already
  12:  * open for writing or appending. When writing or appending, a temporary
  13:  * file with name name_temp is created in the same directory as the database.
  14:  */
  15: #include <stdio.h>
  16: #include "null.h"
  17: #include "path.h"
  18: #include "pdb.h"
  19: #include "system.h"
  20: #include "yesno.h"
  21: 
  22: extern int errno;
  23: extern int sys_nerr;
  24: extern char *sys_errlist[];
  25: 
  26: char PDBERR[PDBERRSIZE];        /* database error message buffer */
  27: 
  28: PDB *
  29: openpdb(name, path, mode)
  30:     char *name;         /* database name */
  31:     char *path;         /* directory pathname to database */
  32:     register char *mode;        /* mode of access */
  33: {
  34:     char *malloc();         /* memory allocator */
  35:     char *pathcat();        /* pathname concatenation */
  36:     char *sprintf();        /* print output to string */
  37:     char *strcat();         /* string concatenation */
  38:     char *strcpy();         /* string copy */
  39:     char *strncpy();        /* string copy n characters */
  40:     char tname[15];         /* temporary database name */
  41:     FILE *fopen();          /* open file */
  42:     PDB *pdbp;          /* database stream */
  43: 
  44:     if ((pdbp = (PDB *) malloc(sizeof(PDB))) == NULL)
  45:         {
  46:         sprintf(PDBERR, "out of memory");
  47:         return(NULL);
  48:         }
  49:     pathcat(pdbp->path, path, name);
  50:     if (mode[0]=='r' && mode[1]=='\0')
  51:         {
  52:         if ((pdbp->fp = fopen(pdbp->path, mode)) == NULL)
  53:             {
  54:             if (errno < sys_nerr)
  55:                 {
  56:                 sprintf(PDBERR, "%s: %s", pdbp->path,
  57:                     sys_errlist[errno]);
  58:                 }
  59:             else    {
  60:                 sprintf(PDBERR, "can't open %s", pdbp->path);
  61:                 }
  62:             free((char *) pdbp);
  63:             return(NULL);
  64:             }
  65:         }
  66:     else if (mode[0]=='w' || mode[0]=='a' || (mode[0]=='r' && mode[1]=='w'))
  67:         {
  68:         strncpy(tname, name, 8);
  69:         tname[8] = '\0';
  70:         strcat(tname, "_temp");
  71:         pathcat(pdbp->tpath, path, tname);
  72:         if (FILEXIST(pdbp->tpath))
  73:             {
  74:             sprintf(PDBERR,"%s temporarily unavailable",pdbp->path);
  75:             free((char *) pdbp);
  76:             return(NULL);
  77:             }
  78:         if ((pdbp->fp = fopen(pdbp->path, mode)) == NULL)
  79:             {
  80:             if (errno < sys_nerr)
  81:                 {
  82:                 sprintf(PDBERR, "%s: %s", pdbp->path,
  83:                     sys_errlist[errno]);
  84:                 }
  85:             else    {
  86:                 sprintf(PDBERR, "can't open %s", pdbp->path);
  87:                 }
  88:             free((char *) pdbp);
  89:             return(NULL);
  90:             }
  91:         if ((pdbp->tfp = fopen(pdbp->tpath, "w")) == NULL)
  92:             {
  93:             if (errno < sys_nerr)
  94:                 {
  95:                 sprintf(PDBERR, "%s: %s", pdbp->path,
  96:                     sys_errlist[errno]);
  97:                 }
  98:             else    {
  99:                 sprintf(PDBERR, "can't open %s", pdbp->path);
 100:                 }
 101:             fclose(pdbp->fp);
 102:             free((char *) pdbp);
 103:             return(NULL);
 104:             }
 105:         if (mode[0]=='w' || mode[0]=='a')
 106:             fclose(pdbp->tfp);
 107:         }
 108:     else    {
 109:         sprintf(PDBERR, "bad mode %s opening %s", mode, pdbp->path);
 110:         free((char *) pdbp);
 111:         return(NULL);
 112:         }
 113:     pdbp->flag &= ~(_PACCESS|_PSTAT);
 114:     switch (*mode)
 115:         {
 116:         case 'r':
 117:             pdbp->flag |= _PREAD;
 118:             if (mode[1] != 'w')
 119:                 break;
 120:         case 'w':
 121:             pdbp->flag |= _PWRITE;
 122:             break;
 123:         case 'a':
 124:             pdbp->flag |= _PAPPEND | _PEOF;
 125:             break;
 126:         }
 127:     strcpy(pdbp->root, path);
 128:     *pdbp->perr = '\0';
 129:     return(pdbp);
 130: }

Defined functions

openpdb defined in line 28; never used

Defined variables

PDBERR defined in line 26; used 9 times
Last modified: 1985-07-03
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