4.3BSD - /usr/ingres/source/gutil/freebuf.c

   1: # include   <sccs.h>
   2: 
   3: SCCSID(@(#)freebuf.c	8.1	12/31/84)
   4: 
   5: /*
   6: **  FREEBUF.C -- more routines for LIFO dynamic buffer allocation [need.c]
   7: **
   8: **	These routines allow the deallocation of a need() type buffer,
   9: **	and also using the same buffer for various SERIALIZED purposes
  10: **	by marking the end of one, beginning of the next.
  11: **
  12: **	Defines:
  13: **		freebuf()
  14: **		markbuf()
  15: **		seterr()
  16: */
  17: 
  18: 
  19: 
  20: 
  21: 
  22: 
  23: /* structure that the routines use to allocate space */
  24: struct nodbuffer
  25: {
  26:     int     nleft;      /* bytes left */
  27:     int     err_num;    /* error code on overflow */
  28:     int     (*err_func)();  /* error function on overflow */
  29:     char        *xfree;     /* next free byte */
  30:     char        buffer [1]; /*beginning of buffer area */
  31: };
  32: 
  33: /*
  34: **  MARKBUF -- Mark a place in the buffer to deallocate to
  35: **
  36: **	Parameters:
  37: **		bf -- buffer
  38: **
  39: **	Returns:
  40: **		int >= 0 marking place in buffer (should be used in calling
  41: **			freebuf())
  42: **
  43: **	Side Effects:
  44: **		none
  45: */
  46: 
  47: markbuf(bf)
  48: struct nodbuffer    *bf;
  49: {
  50:     register struct nodbuffer   *buf;
  51: 
  52:     buf = bf;
  53:     return (buf->nleft);
  54: }
  55: /*
  56: **  FREEBUF -- frees part of a buffer
  57: **
  58: **	Parameters:
  59: **		bf -- buffer
  60: **		bytes -- a previous return from markbuf().
  61: **
  62: **	Returns:
  63: **		none
  64: **
  65: **	Side Effects:
  66: **		none
  67: */
  68: 
  69: freebuf(bf, bytes)
  70: struct nodbuffer    *bf;
  71: int         bytes;
  72: {
  73:     register struct nodbuffer   *buf;
  74:     register int            i;
  75: 
  76:     buf = bf;
  77:     i = bytes - buf->nleft;
  78:     if (i < 0)
  79:         syserr("freebuf %d, %d", i, bytes);
  80:     buf->xfree -= i;
  81:     buf->nleft += i;
  82: }
  83: /*
  84: **  SETERR -- change the error info for a buffer
  85: **
  86: **	Parameters:
  87: **		bf -- buffer
  88: **		errnum -- new overflow error code
  89: **		err_func -- new error handler
  90: **
  91: **	Returns:
  92: **		none
  93: **
  94: **	Side Effects:
  95: **		adjusts buffer structure
  96: */
  97: 
  98: seterr(bf, errnum, err_func)
  99: struct nodbuffer    *bf;
 100: int         errnum;
 101: int         (*err_func)();
 102: {
 103:     register struct nodbuffer   *buf;
 104:     register int            (*erf)();
 105: 
 106:     buf = bf;
 107:     erf = err_func;
 108:     buf->err_num = errnum;
 109:     bf->err_func = erf;
 110: }

Defined functions

Defined struct's