diff options
Diffstat (limited to 'libmailutils/string/vasnprintf.c')
-rw-r--r-- | libmailutils/string/vasnprintf.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/libmailutils/string/vasnprintf.c b/libmailutils/string/vasnprintf.c new file mode 100644 index 000000000..0f4350edb --- /dev/null +++ b/libmailutils/string/vasnprintf.c @@ -0,0 +1,87 @@ +/* GNU Mailutils -- a suite of utilities for electronic mail + Copyright (C) 2009, 2010 Free Software Foundation, Inc. + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General + Public License along with this library; if not, write to the + Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, + Boston, MA 02110-1301 USA */ + +#if HAVE_CONFIG_H +# include <config.h> +#endif + +#include <stdlib.h> +#include <stdarg.h> +#include <stdio.h> +#include <errno.h> +#include <string.h> + +#include <mailutils/io.h> + +int +mu_vasnprintf (char **pbuf, size_t *psize, const char *fmt, va_list ap) +{ + char *buf = *pbuf; + size_t buflen = *psize; + int rc = 0; + + if (!buf) + { + if (buflen == 0) + buflen = 512; /* Initial allocation */ + + buf = calloc (1, buflen); + if (buf == NULL) + return ENOMEM; + } + + for (;;) + { + ssize_t n = vsnprintf (buf, buflen, fmt, ap); + if (n < 0 || n >= buflen || !memchr (buf, '\0', n + 1)) + { + char *newbuf; + size_t newlen = buflen * 2; + if (newlen < buflen) + { + rc = ENOMEM; + break; + } + newbuf = realloc (buf, newlen); + if (newbuf == NULL) + { + rc = ENOMEM; + break; + } + buflen = newlen; + buf = newbuf; + } + else + break; + } + + if (rc) + { + if (!*pbuf) + { + /* We made first allocation, now free it */ + free (buf); + buf = NULL; + buflen = 0; + } + } + + *pbuf = buf; + *psize = buflen; + return rc; +} |