1 files changed, 134 insertions, 0 deletions
diff --git a/ewah/ewah_io.c b/ewah/ewah_io.c
new file mode 100644
index 0000000..9035ee6
--- /dev/null
+++ b/ewah/ewah_io.c
@@ -0,0 +1,134 @@
+/**
+ * Copyright 2013, GitHub, Inc
+ * Copyright 2009-2013, Daniel Lemire, Cliff Moon,
+ *	David McIntosh, Robert Becho, Google Inc. and Veronika Zenz
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#include "git-compat-util.h"
+#include "ewok.h"
+#include "strbuf.h"
+
+int ewah_serialize_to(struct ewah_bitmap *self,
+		      int (*write_fun)(void *, const void *, size_t),
+		      void *data)
+{
+	size_t i;
+	eword_t dump[2048];
+	const size_t words_per_dump = sizeof(dump) / sizeof(eword_t);
+	uint32_t bitsize, word_count, rlw_pos;
+
+	const eword_t *buffer;
+	size_t words_left;
+
+	/* 32 bit -- bit size for the map */
+	bitsize =  htonl((uint32_t)self->bit_size);
+	if (write_fun(data, &bitsize, 4) != 4)
+		return -1;
+
+	/** 32 bit -- number of compressed 64-bit words */
+	word_count =  htonl((uint32_t)self->buffer_size);
+	if (write_fun(data, &word_count, 4) != 4)
+		return -1;
+
+	/** 64 bit x N -- compressed words */
+	buffer = self->buffer;
+	words_left = self->buffer_size;
+
+	while (words_left >= words_per_dump) {
+		for (i = 0; i < words_per_dump; ++i, ++buffer)
+			dump[i] = htonll(*buffer);
+
+		if (write_fun(data, dump, sizeof(dump)) != sizeof(dump))
+			return -1;
+
+		words_left -= words_per_dump;
+	}
+
+	if (words_left) {
+		for (i = 0; i < words_left; ++i, ++buffer)
+			dump[i] = htonll(*buffer);
+
+		if (write_fun(data, dump, words_left * 8) != words_left * 8)
+			return -1;
+	}
+
+	/** 32 bit -- position for the RLW */
+	rlw_pos = (uint8_t*)self->rlw - (uint8_t *)self->buffer;
+	rlw_pos = htonl(rlw_pos / sizeof(eword_t));
+
+	if (write_fun(data, &rlw_pos, 4) != 4)
+		return -1;
+
+	return (3 * 4) + (self->buffer_size * 8);
+}
+
+static int write_strbuf(void *user_data, const void *data, size_t len)
+{
+	struct strbuf *sb = user_data;
+	strbuf_add(sb, data, len);
+	return len;
+}
+
+int ewah_serialize_strbuf(struct ewah_bitmap *self, struct strbuf *sb)
+{
+	return ewah_serialize_to(self, write_strbuf, sb);
+}
+
+ssize_t ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len)
+{
+	const uint8_t *ptr = map;
+	size_t data_len;
+	size_t i;
+
+	if (len < sizeof(uint32_t))
+		return error("corrupt ewah bitmap: eof before bit size");
+	self->bit_size = get_be32(ptr);
+	ptr += sizeof(uint32_t);
+	len -= sizeof(uint32_t);
+
+	if (len < sizeof(uint32_t))
+		return error("corrupt ewah bitmap: eof before length");
+	self->buffer_size = self->alloc_size = get_be32(ptr);
+	ptr += sizeof(uint32_t);
+	len -= sizeof(uint32_t);
+
+	REALLOC_ARRAY(self->buffer, self->alloc_size);
+
+	/*
+	 * Copy the raw data for the bitmap as a whole chunk;
+	 * if we're in a little-endian platform, we'll perform
+	 * the endianness conversion in a separate pass to ensure
+	 * we're loading 8-byte aligned words.
+	 */
+	data_len = st_mult(self->buffer_size, sizeof(eword_t));
+	if (len < data_len)
+		return error("corrupt ewah bitmap: eof in data "
+			     "(%"PRIuMAX" bytes short)",
+			     (uintmax_t)(data_len - len));
+	memcpy(self->buffer, ptr, data_len);
+	ptr += data_len;
+	len -= data_len;
+
+	for (i = 0; i < self->buffer_size; ++i)
+		self->buffer[i] = ntohll(self->buffer[i]);
+
+	if (len < sizeof(uint32_t))
+		return error("corrupt ewah bitmap: eof before rlw");
+	self->rlw = self->buffer + get_be32(ptr);
+	ptr += sizeof(uint32_t);
+	len -= sizeof(uint32_t);
+
+	return ptr - (const uint8_t *)map;
+}