xref: /inferno-os/libkern/vsmprint.c (revision 46439007cf417cbd9ac8049bb4122c890097a0fa)
1 /*
2  * The authors of this software are Rob Pike and Ken Thompson.
3  *              Copyright (c) 2002 by Lucent Technologies.
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose without fee is hereby granted, provided that this entire notice
6  * is included in all copies of any software which is or includes a copy
7  * or modification of this software and in all copies of the supporting
8  * documentation for such software.
9  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
10  * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
11  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
12  * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
13  */
14 #include "lib9.h"
15 #include "fmtdef.h"
16 
17 static int
18 fmtStrFlush(Fmt *f)
19 {
20 	char *s;
21 	int n;
22 
23 	n = (int)f->farg;
24 	n += 256;
25 	f->farg = (void*)n;
26 	s = f->start;
27 	f->start = realloc(s, n);
28 	if(f->start == nil){
29 		free(s);
30 		f->to = nil;
31 		f->stop = nil;
32 		return 0;
33 	}
34 	f->to = (char*)f->start + ((char*)f->to - s);
35 	f->stop = (char*)f->start + n - 1;
36 	return 1;
37 }
38 
39 int
40 fmtstrinit(Fmt *f)
41 {
42 	int n;
43 
44 	f->runes = 0;
45 	n = 32;
46 	f->start = malloc(n);
47 	if(f->start == nil)
48 		return -1;
49 	f->to = f->start;
50 	f->stop = (char*)f->start + n - 1;
51 	f->flush = fmtStrFlush;
52 	f->farg = (void*)n;
53 	f->nfmt = 0;
54 	return 0;
55 }
56 
57 /*
58  * print into an allocated string buffer
59  */
60 char*
61 vsmprint(char *fmt, va_list args)
62 {
63 	Fmt f;
64 	int n;
65 
66 	if(fmtstrinit(&f) < 0)
67 		return nil;
68 	f.args = args;
69 	n = dofmt(&f, fmt);
70 	if(n < 0)
71 		return nil;
72 	*(char*)f.to = '\0';
73 	return f.start;
74 }
75