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Annotation of 43BSD/ingres/source/gutil/freebuf.c, revision 1.1.1.1

1.1       root        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: }

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