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PDP-10 Archives
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SRI_NIC_PERM_FS_1_19910112
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kccdist/lib/stdio/sopen.c
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/*
* SOPEN - string open
*
* Copyright (C) 1986 by Ian Macky, SRI International
*/
#include "stdio.h"
FILE *sopen(s, flags, max_size)
char *s, *flags;
int max_size;
{
char *malloc();
int c, local_flags = 0;
FILE *f;
switch (c = *flags++) {
case 'r': local_flags |= _SIOF_READ; break;
case 'w': local_flags |= _SIOF_WRITE; break;
default: return NULL;
}
/*
* flags of "w+" mean auto-expanding string
*/
if ((local_flags & _SIOF_WRITE) && ((c = *flags) == '+'))
local_flags |= _SIOF_GROWBUF;
if (!(f = _makeFILE())) return NULL; /* get a FILE descriptor */
/*
* if they want us to allocate the string space, then check
* the size arg and do it
*/
if (!s) {
if (max_size <= 0 || !(s = malloc(max_size))) {
_freeFILE(f);
return NULL;
} else f->siopbuf = s;
} else f->siopbuf = 0;
/*
* now stuff it!
*/
f->siocp = s - 1; /* one before, for pre-inc load */
f->siolbuf = f->siocnt = max_size; /* length of buffer */
f->sioflgs |= local_flags | _SIOF_STR | _SIOF_BUF;
f->siofd = -1; /* Ensure no FD there */
f->siocheck = _SIOF_OPEN; /* validate block */
return f;
}