String buffer API

2 files changed, 347 insertions, 0 deletions

diff --git a/sys/kern/subr_sbuf.c b/sys/kern/subr_sbuf.c
new file mode 100644
index 000000000000..9e537a8fbf1a
--- /dev/null
+++ b/sys/kern/subr_sbuf.c
@@ -0,0 +1,271 @@
+/*-
+ * Copyright (c) 2000 Poul-Henning Kamp and Dag-Erling Coïdan Smørgrav
+ * All rights reserved.
+ *
+ * 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
+ *    in this position and unchanged.
+ * 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
+ *
+ *      $FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/sbuf.h>
+#include <sys/systm.h>
+
+#include <machine/stdarg.h>
+
+MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers");
+
+#ifdef INVARIANTS
+static void
+assert_sbuf_integrity(struct sbuf *s)
+{
+	KASSERT(s != NULL,
+	    (__FUNCTION__ " called with a NULL sbuf pointer"));
+	KASSERT(s->s_buf != NULL,
+	    (__FUNCTION__ " called with unitialized or corrupt sbuf"));
+	KASSERT(s->s_len < s->s_size,
+	    ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
+}
+
+static void
+assert_sbuf_state(struct sbuf *s, int state)
+{
+	KASSERT((s->s_flags & SBUF_FINISHED) == state,
+	    (__FUNCTION__ " called with %sfinished or corrupt sbuf",
+	    (state ? "un" : "")));
+}
+#else
+#define assert_sbuf_integrity(s) do { } while (0)
+#define assert_sbuf_state(s, i)	 do { } while (0)
+#endif
+
+/*
+ * Initialize an sbuf.
+ * If buf is non-NULL, it points to a static or already-allocated string
+ * big enough to hold at least length characters.
+ */
+int
+sbuf_new(struct sbuf *s, char *buf, size_t length, int flags)
+{
+	KASSERT(flags == 0,
+	    (__FUNCTION__ " called with non-zero flags"));
+	KASSERT(s != NULL,
+	    (__FUNCTION__ " called with a NULL sbuf pointer"));
+
+	bzero(s, sizeof *s);
+	s->s_size = length;
+	if (buf) {
+		s->s_buf = buf;
+		return (0);
+	}
+	s->s_buf = malloc(s->s_size, M_SBUF, M_WAITOK);
+	if (s->s_buf == NULL)
+		return (-1);
+	SBUF_SETFLAG(s, SBUF_DYNAMIC);
+	return (0);
+}
+
+/*
+ * Set the sbuf's position to an arbitrary value
+ */
+int
+sbuf_setpos(struct sbuf *s, size_t pos)
+{
+	assert_sbuf_integrity(s);
+	assert_sbuf_state(s, 0);
+	
+	KASSERT(pos >= 0,
+	    ("attempt to seek to a negative position (%d)", pos));
+	KASSERT(pos < s->s_size,
+	    ("attempt to seek past end of sbuf (%d >= %d)", pos, s->s_size));
+	       
+	if (pos < 0 || pos > s->s_len)
+		return (-1);
+	s->s_len = pos;
+	return (0);
+}
+
+/*
+ * Append a string to an sbuf.
+ */
+int
+sbuf_cat(struct sbuf *s, char *str)
+{
+	assert_sbuf_integrity(s);
+	assert_sbuf_state(s, 0);
+	
+	if (SBUF_HASOVERFLOWED(s))
+		return (-1);
+	
+	while (*str && SBUF_HASROOM(s))
+		s->s_buf[s->s_len++] = *str++;
+	if (*str) {
+		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
+		return (-1);
+	}
+	return (0);
+}
+
+/*
+ * Copy a string into an sbuf.
+ */
+int
+sbuf_cpy(struct sbuf *s, char *str)
+{
+	assert_sbuf_integrity(s);
+	assert_sbuf_state(s, 0);
+	
+	s->s_len = 0;
+	return (sbuf_cat(s, str));
+}
+
+/*
+ * PCHAR function for sbuf_printf()
+ */
+static void
+_sbuf_pchar(int c, void *v)
+{
+	struct sbuf *s = (struct sbuf *)v;
+
+	assert_sbuf_integrity(s);
+	assert_sbuf_state(s, 0);
+	
+	if (SBUF_HASOVERFLOWED(s))
+		return;
+	if (SBUF_HASROOM(s))
+		s->s_buf[s->s_len++] = c;
+	else
+		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
+}
+
+/*
+ * Format the given arguments and append the resulting string to an sbuf.
+ */
+int
+sbuf_printf(struct sbuf *s, char *fmt, ...)
+{
+	va_list ap;
+	size_t len;
+
+	assert_sbuf_integrity(s);
+	assert_sbuf_state(s, 0);
+	
+	KASSERT(fmt != NULL,
+	    (__FUNCTION__ " called with a NULL format string"));
+	
+	if (SBUF_HASOVERFLOWED(s))
+		return (-1);
+
+	va_start(ap, fmt);
+	len = kvprintf(fmt, _sbuf_pchar, s, 10, ap);
+	va_end(ap);
+
+	KASSERT(s->s_len < s->s_size,
+	    ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
+
+	if (SBUF_HASOVERFLOWED(s))
+		return (-1);
+	return (0);
+}
+
+/*
+ * Append a character to an sbuf.
+ */
+int
+sbuf_putc(struct sbuf *s, int c)
+{
+	assert_sbuf_integrity(s);
+	assert_sbuf_state(s, 0);
+	
+	if (SBUF_HASOVERFLOWED(s))
+		return (-1);
+	
+	if (!SBUF_HASROOM(s)) {
+		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
+		return (-1);
+	}
+	s->s_buf[s->s_len++] = c;
+	return (0);
+}
+
+/*
+ * Finish off an sbuf.
+ */
+int
+sbuf_finish(struct sbuf *s)
+{
+	assert_sbuf_integrity(s);
+	assert_sbuf_state(s, 0);
+	
+	if (SBUF_HASOVERFLOWED(s))
+		return (-1);
+	
+	s->s_buf[s->s_len++] = '\0';
+	SBUF_SETFLAG(s, SBUF_FINISHED);
+	return (0);
+}
+
+/*
+ * Return a pointer to the sbuf data.
+ */
+char *
+sbuf_data(struct sbuf *s)
+{
+	assert_sbuf_integrity(s);
+	assert_sbuf_state(s, SBUF_FINISHED);
+	
+	if (SBUF_HASOVERFLOWED(s))
+		return (NULL);
+	return s->s_buf;
+}
+
+/*
+ * Return the length of the sbuf data.
+ */
+size_t
+sbuf_len(struct sbuf *s)
+{
+	assert_sbuf_integrity(s);
+	assert_sbuf_state(s, SBUF_FINISHED);
+	
+	if (SBUF_HASOVERFLOWED(s))
+		return (0);
+	return s->s_len;
+}
+
+/*
+ * Clear an sbuf, free its buffer if necessary.
+ */
+void
+sbuf_delete(struct sbuf *s)
+{
+	assert_sbuf_integrity(s);
+	/* don't care if it's finished or not */
+	
+	if (SBUF_ISDYNAMIC(s))
+		free(s->s_buf, M_SBUF);
+	bzero(s, sizeof *s);
+}
diff --git a/sys/sys/sbuf.h b/sys/sys/sbuf.h
new file mode 100644
index 000000000000..5995ec1c32b4
--- /dev/null
+++ b/sys/sys/sbuf.h
@@ -0,0 +1,76 @@
+/*-
+ * Copyright (c) 2000 Poul-Henning Kamp and Dag-Erling Coïdan Smørgrav
+ * All rights reserved.
+ *
+ * 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
+ *    in this position and unchanged.
+ * 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
+ *
+ *      $FreeBSD$
+ */
+
+#ifndef _SYS_SBUF_H_
+#define _SYS_SBUF_H_
+
+/*
+ * Structure definition
+ */
+struct sbuf {
+	char		*s_buf;		/* storage buffer */
+	struct sbuf	*s_next;        /* next in chain */
+	size_t		 s_size;	/* size of storage buffer */
+	size_t		 s_len;		/* current length of string */
+#define SBUF_AUTOEXTEND	0x00000001	/* automatically extend buffer */
+#define SBUF_DYNAMIC	0x00010000	/* s_buf must be freed */
+#define SBUF_FINISHED	0x00020000	/* set by sbuf_finish() */
+#define SBUF_OVERFLOWED	0x00040000	/* sbuf overflowed */
+	int		 s_flags;	/* flags */
+};
+
+/*
+ * Predicates
+ */
+#define SBUF_ISDYNAMIC(s)	((s)->s_flags & SBUF_DYNAMIC)
+#define SBUF_ISFINISHED(s)	((s)->s_flags & SBUF_FINISHED)
+#define SBUF_HASOVERFLOWED(s)	((s)->s_flags & SBUF_OVERFLOWED)
+#define SBUF_HASROOM(s)		((s)->s_len < (s)->s_size - 1)
+
+/*
+ * Other macros
+ */
+#define SBUF_SETFLAG(s, f)	do { (s)->s_flags |= (f); } while (0)
+
+/*
+ * API functions
+ */
+int	 sbuf_new(struct sbuf *s, char *buf, size_t length, int flags);
+int	 sbuf_setpos(struct sbuf *s, size_t pos);
+int	 sbuf_cat(struct sbuf *s, char *str);
+int	 sbuf_cpy(struct sbuf *s, char *str);
+int	 sbuf_printf(struct sbuf *s, char *fmt, ...);
+int	 sbuf_putc(struct sbuf *s, int c);
+int	 sbuf_finish(struct sbuf *s);
+char    *sbuf_data(struct sbuf *s);
+size_t	 sbuf_len(struct sbuf *s);
+void	 sbuf_delete(struct sbuf *s);
+
+#endif