git

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/**
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 * Copyright 2013, GitHub, Inc
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 * Copyright 2009-2013, Daniel Lemire, Cliff Moon,
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 *	David McIntosh, Robert Becho, Google Inc. and Veronika Zenz
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 *
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 * This program is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU General Public License
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 * as published by the Free Software Foundation; either version 2
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 * of the License, or (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, see <http://www.gnu.org/licenses/>.
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 */
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#include "git-compat-util.h"
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#include "ewok.h"
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#include "strbuf.h"
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int ewah_serialize_to(struct ewah_bitmap *self,
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		      int (*write_fun)(void *, const void *, size_t),
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		      void *data)
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{
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	size_t i;
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	eword_t dump[2048];
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	const size_t words_per_dump = sizeof(dump) / sizeof(eword_t);
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	uint32_t bitsize, word_count, rlw_pos;
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	const eword_t *buffer;
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	size_t words_left;
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	/* 32 bit -- bit size for the map */
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	bitsize =  htonl((uint32_t)self->bit_size);
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	if (write_fun(data, &bitsize, 4) != 4)
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		return -1;
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	/** 32 bit -- number of compressed 64-bit words */
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	word_count =  htonl((uint32_t)self->buffer_size);
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	if (write_fun(data, &word_count, 4) != 4)
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		return -1;
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	/** 64 bit x N -- compressed words */
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	buffer = self->buffer;
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	words_left = self->buffer_size;
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	while (words_left >= words_per_dump) {
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		for (i = 0; i < words_per_dump; ++i, ++buffer)
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			dump[i] = htonll(*buffer);
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		if (write_fun(data, dump, sizeof(dump)) != sizeof(dump))
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			return -1;
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		words_left -= words_per_dump;
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	}
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	if (words_left) {
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		for (i = 0; i < words_left; ++i, ++buffer)
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			dump[i] = htonll(*buffer);
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		if (write_fun(data, dump, words_left * 8) != words_left * 8)
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			return -1;
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	}
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	/** 32 bit -- position for the RLW */
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	rlw_pos = (uint8_t*)self->rlw - (uint8_t *)self->buffer;
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	rlw_pos = htonl(rlw_pos / sizeof(eword_t));
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	if (write_fun(data, &rlw_pos, 4) != 4)
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		return -1;
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	return (3 * 4) + (self->buffer_size * 8);
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}
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static int write_strbuf(void *user_data, const void *data, size_t len)
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{
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	struct strbuf *sb = user_data;
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	strbuf_add(sb, data, len);
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	return len;
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}
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int ewah_serialize_strbuf(struct ewah_bitmap *self, struct strbuf *sb)
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{
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	return ewah_serialize_to(self, write_strbuf, sb);
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}
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ssize_t ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len)
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{
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	const uint8_t *ptr = map;
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	size_t data_len;
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	size_t i;
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	if (len < sizeof(uint32_t))
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		return error("corrupt ewah bitmap: eof before bit size");
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	self->bit_size = get_be32(ptr);
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	ptr += sizeof(uint32_t);
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	len -= sizeof(uint32_t);
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	if (len < sizeof(uint32_t))
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		return error("corrupt ewah bitmap: eof before length");
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	self->buffer_size = self->alloc_size = get_be32(ptr);
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	ptr += sizeof(uint32_t);
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	len -= sizeof(uint32_t);
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	REALLOC_ARRAY(self->buffer, self->alloc_size);
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	/*
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	 * Copy the raw data for the bitmap as a whole chunk;
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	 * if we're in a little-endian platform, we'll perform
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	 * the endianness conversion in a separate pass to ensure
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	 * we're loading 8-byte aligned words.
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	 */
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	data_len = st_mult(self->buffer_size, sizeof(eword_t));
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	if (len < data_len)
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		return error("corrupt ewah bitmap: eof in data "
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			     "(%"PRIuMAX" bytes short)",
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			     (uintmax_t)(data_len - len));
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	memcpy(self->buffer, ptr, data_len);
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	ptr += data_len;
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	len -= data_len;
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	for (i = 0; i < self->buffer_size; ++i)
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		self->buffer[i] = ntohll(self->buffer[i]);
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	if (len < sizeof(uint32_t))
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		return error("corrupt ewah bitmap: eof before rlw");
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	self->rlw = self->buffer + get_be32(ptr);
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	ptr += sizeof(uint32_t);
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	len -= sizeof(uint32_t);
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	return ptr - (const uint8_t *)map;
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}
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