1 files changed, 117 insertions, 0 deletions
diff --git a/dba_write.c b/dba_write.c
new file mode 100644
index 00000000..9746d575
--- /dev/null
+++ b/dba_write.c
@@ -0,0 +1,117 @@
+/*	$Id$ */
+/*
+ * Copyright (c) 2016 Ingo Schwarze <schwarze@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Low-level functions for serializing allocation-based data to disk.
+ * The interface is defined in "dba_write.h".
+ */
+#include <assert.h>
+#include <endian.h>
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#include "dba_write.h"
+
+static FILE	*ofp;
+
+
+int
+dba_open(const char *fname)
+{
+	ofp = fopen(fname, "w");
+	return ofp == NULL ? -1 : 0;
+}
+
+int
+dba_close(void)
+{
+	return fclose(ofp) == EOF ? -1 : 0;
+}
+
+int32_t
+dba_tell(void)
+{
+	long		 pos;
+
+	if ((pos = ftell(ofp)) == -1)
+		err(1, "ftell");
+	if (pos >= INT32_MAX) {
+		errno = EOVERFLOW;
+		err(1, "ftell = %ld", pos);
+	}
+	return pos;
+}
+
+void
+dba_seek(int32_t pos)
+{
+	if (fseek(ofp, pos, SEEK_SET) == -1)
+		err(1, "fseek(%d)", pos);
+}
+
+int32_t
+dba_align(void)
+{
+	int32_t		 pos;
+
+	pos = dba_tell();
+	while (pos & 3) {
+		dba_char_write('\0');
+		pos++;
+	}
+	return pos;
+}
+
+int32_t
+dba_skip(int32_t nmemb, int32_t sz)
+{
+	const int32_t	 out[5] = {0, 0, 0, 0, 0};
+	int32_t		 i, pos;
+
+	assert(sz >= 0);
+	assert(nmemb > 0);
+	assert(nmemb <= 5);
+	pos = dba_tell();
+	for (i = 0; i < sz; i++)
+		if (nmemb - fwrite(&out, sizeof(out[0]), nmemb, ofp))
+			err(1, "fwrite");
+	return pos;
+}
+
+void
+dba_char_write(int c)
+{
+	if (putc(c, ofp) == EOF)
+		err(1, "fputc");
+}
+
+void
+dba_str_write(const char *str)
+{
+	if (fputs(str, ofp) == EOF)
+		err(1, "fputs");
+	dba_char_write('\0');
+}
+
+void
+dba_int_write(int32_t i)
+{
+	i = htobe32(i);
+	if (fwrite(&i, sizeof(i), 1, ofp) != 1)
+		err(1, "fwrite");
+}