diff options
Diffstat (limited to 'third_party/git/ewah/ewah_io.c')
| -rw-r--r-- | third_party/git/ewah/ewah_io.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/third_party/git/ewah/ewah_io.c b/third_party/git/ewah/ewah_io.c new file mode 100644 index 0000000000..9035ee65ea --- /dev/null +++ b/third_party/git/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; +} |