1 #include "substdio.h"

     2 #include "byte.h"

     3 #include "error.h"

     4 

     5 static int oneread(op,fd,buf,len)

     6 register int (*op)();

     7 register int fd;

     8 register char *buf;

     9 register int len;

    10 {

    11   register int r;

    12 

    13   for (;;) {

    14     r = op(fd,buf,len);

    15     if (r == -1) if (errno == error_intr) continue;

    16     return r;

    17   }

    18 }

    19 

    20 static int getthis(s,buf,len)

    21 register substdio *s;

    22 register char *buf;

    23 register int len;

    24 {

    25   register int r;

    26   register int q;

    27  

    28   r = s->p;

    29   q = r - len;

    30   if (q > 0) { r = len; s->p = q; } else s->p = 0;

    31   byte_copy(buf,r,s->x + s->n);

    32   s->n += r;

    33   return r;

    34 }

    35 

    36 int substdio_feed(s)

    37 register substdio *s;

    38 {

    39   register int r;

    40   register int q;

    41 

    42   if (s->p) return s->p;

    43   q = s->n;

    44   r = oneread(s->op,s->fd,s->x,q);

    45   if (r <= 0) return r;

    46   s->p = r;

    47   q -= r;

    48   s->n = q;

    49   if (q > 0) /* damn, gotta shift */ byte_copyr(s->x + q,r,s->x);

    50   return r;

    51 }

    52 

    53 int substdio_bget(s,buf,len)

    54 register substdio *s;

    55 register char *buf;

    56 register int len;

    57 {

    58   register int r;

    59  

    60   if (s->p > 0) return getthis(s,buf,len);

    61   r = s->n; if (r <= len) return oneread(s->op,s->fd,buf,r);

    62   r = substdio_feed(s); if (r <= 0) return r;

    63   return getthis(s,buf,len);

    64 }

    65 

    66 int substdio_get(s,buf,len)

    67 register substdio *s;

    68 register char *buf;

    69 register int len;

    70 {

    71   register int r;

    72  

    73   if (s->p > 0) return getthis(s,buf,len);

    74   if (s->n <= len) return oneread(s->op,s->fd,buf,len);

    75   r = substdio_feed(s); if (r <= 0) return r;

    76   return getthis(s,buf,len);

    77 }

    78 

    79 char *substdio_peek(s)

    80 register substdio *s;

    81 {

    82   return s->x + s->n;

    83 }

    84 

    85 void substdio_seek(s,len)

    86 register substdio *s;

    87 register int len;

    88 {

    89   s->n += len;

    90   s->p -= len;

    91 }