1 /*- 2 * Copyright (c) 1996 Peter Wemm <peter@freebsd.org> 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 */ 25 26 #if defined(LIBC_RCS) && !defined(lint) 27 static char rcsid[] = "$Id$"; 28 #endif /* LIBC_RCS and not lint */ 29 30 #include <stdio.h> 31 #include <stdlib.h> 32 33 #if __STDC__ 34 #include <stdarg.h> 35 #else 36 #include <varargs.h> 37 #endif 38 39 #define CHUNK_SPARE 128 /* how much spare to allocate to avoid realloc calls */ 40 41 struct bufcookie { 42 char *base; /* start of buffer */ 43 int size; 44 int left; 45 }; 46 47 static int 48 writehook(cookie, buf, len) 49 void *cookie; 50 char *buf; 51 int len; 52 { 53 struct bufcookie *h = (struct bufcookie *)cookie; 54 55 if (len == 0) 56 return 0; 57 58 if (len > h->left) { 59 /* grow malloc region */ 60 h->left = h->left + len + CHUNK_SPARE; 61 h->size = h->size + len + CHUNK_SPARE; 62 h->base = realloc(h->base, h->size); 63 if (h->base == NULL) 64 return (-1); 65 } 66 /* "write" it */ 67 (void)memcpy(h->base + h->size - h->left, buf, len); 68 h->left -= len; 69 return (0); 70 } 71 72 73 int 74 vasprintf(str, fmt, ap) 75 char **str; 76 const char *fmt; 77 va_list ap; 78 { 79 int ret; 80 FILE *f; 81 struct bufcookie h; 82 83 h.base = malloc(CHUNK_SPARE); 84 if (h.base == NULL) 85 return (-1); 86 h.size = CHUNK_SPARE; 87 h.left = CHUNK_SPARE; 88 89 f = funopen(&h, NULL, writehook, NULL, NULL); 90 if (f == NULL) { 91 free(h.base); 92 return (-1); 93 } 94 ret = vfprintf(f, fmt, ap); 95 fclose(f); 96 if (ret < 0) { 97 free(h.base); 98 return (-1); 99 } 100 if (h.base == NULL) /* failed to realloc in writehook */ 101 return (-1); 102 103 h.base[h.size - h.left] = '\0'; 104 *str = realloc(h.base, h.size - h.left + 1); 105 if (*str == NULL) /* failed to realloc it to actual size */ 106 return -1; 107 return (ret); 108 } 109