1 files changed, 142 insertions, 0 deletions
diff --git a/lib/libc/stdio/vasprintf.c b/lib/libc/stdio/vasprintf.c
new file mode 100644
index 0000000..7b75b2c
--- /dev/null
+++ b/lib/libc/stdio/vasprintf.c
@@ -0,0 +1,142 @@
+/*-
+ * Copyright (c) 1996  Peter Wemm <peter@freebsd.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if defined(LIBC_RCS) && !defined(lint)
+static char rcsid[] = "$Id: vasprintf.c,v 1.6 1997/07/06 07:54:56 peter Exp $";
+#endif /* LIBC_RCS and not lint */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#if __STDC__
+#include <stdarg.h>
+#else
+#include <varargs.h>
+#endif
+
+#define CHUNK_SPARE 128 /* how much spare to allocate to avoid realloc calls */
+
+struct bufcookie {
+	char	*base;	/* start of buffer */
+	size_t	size;
+	size_t	left;
+};
+
+static int 	writehook __P((void *cookie, const char *, int));
+
+static int
+writehook(cookie, buf, len)
+	void *cookie;
+	const char *buf;
+	int   len;
+{
+	struct bufcookie *h = (struct bufcookie *)cookie;
+	char *newbuf;
+
+	if (len == 0)
+		return 0;
+
+	if (len > h->left) {
+		/* grow malloc region */
+ 		/*
+		 * XXX this is linearly expanded, which is slow for obscenely
+		 * large strings.
+		 */
+		h->left = h->left + len + CHUNK_SPARE;
+		h->size = h->size + len + CHUNK_SPARE;
+		newbuf = realloc(h->base, h->size);
+		if (newbuf == NULL) {
+			free(h->base);
+			h->base = NULL;
+			return (-1);
+		} else
+			h->base = newbuf;
+	}
+	/* "write" it */
+	(void)memcpy(h->base + h->size - h->left, buf, (size_t)len);
+	h->left -= len;
+	return (len);
+}
+
+
+int
+vasprintf(str, fmt, ap)
+	char **str;
+	const char *fmt;
+	va_list ap;
+{
+	int ret;
+	FILE *f;
+	struct bufcookie h;
+
+	h.base = malloc(CHUNK_SPARE);
+	if (h.base == NULL)
+		return (-1);
+	h.size = CHUNK_SPARE;
+	h.left = CHUNK_SPARE;
+
+	f = funopen(&h, NULL, writehook, NULL, NULL);
+	if (f == NULL) {
+		free(h.base);
+		return (-1);
+	}
+	ret = vfprintf(f, fmt, ap);
+	fclose(f);
+
+	/*
+	 * clean up the wreckage. Did writehook fail or did something else
+	 * in stdio explode perhaps?
+	 */
+	if (h.base == NULL)	/* realloc failed in writehook */
+		return (-1);
+	if (ret < 0) {		/* something else? */
+		free(h.base);
+		return (-1);
+	}
+
+	/*
+	 * At this point, we have a non-null terminated string in a
+	 * buffer.  There may not be enough room to null-terminate it
+	 * (h.left == 0) - if realloc failes to expand it, it's fatal.
+	 * If we were merely trying to shrink the buffer, a realloc failure
+	 * is not [yet] fatal. Note that when realloc returns NULL,
+	 * the original buffer is left allocated and valid.
+	 */
+	if (h.left == 1)	/* exact fit, do not realloc */
+		*str = h.base;
+	else {
+		*str = realloc(h.base, (size_t)(h.size - h.left + 1));
+		if (*str == NULL) {
+			/* failed to expand? - fatal */
+			if (h.left == 0) {
+				free(h.base);
+				return (-1);
+			}
+			*str = h.base;	/* use oversize original buffer */
+		}
+	}
+	(*str)[h.size - h.left] = '\0';
+	return (ret);
+}