Andrew's git - gitweb.git/blob

   1/**
   2 * Copyright 2013, GitHub, Inc
   3 * Copyright 2009-2013, Daniel Lemire, Cliff Moon,
   4 *      David McIntosh, Robert Becho, Google Inc. and Veronika Zenz
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version 2
   9 * of the License, or (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
  18 */
  19#include "git-compat-util.h"
  20#include "ewok.h"
  21#include "strbuf.h"
  22
  23int ewah_serialize_native(struct ewah_bitmap *self, int fd)
  24{
  25        uint32_t write32;
  26        size_t to_write = self->buffer_size * 8;
  27
  28        /* 32 bit -- bit size for the map */
  29        write32 = (uint32_t)self->bit_size;
  30        if (write(fd, &write32, 4) != 4)
  31                return -1;
  32
  33        /** 32 bit -- number of compressed 64-bit words */
  34        write32 = (uint32_t)self->buffer_size;
  35        if (write(fd, &write32, 4) != 4)
  36                return -1;
  37
  38        if (write(fd, self->buffer, to_write) != to_write)
  39                return -1;
  40
  41        /** 32 bit -- position for the RLW */
  42        write32 = self->rlw - self->buffer;
  43        if (write(fd, &write32, 4) != 4)
  44                return -1;
  45
  46        return (3 * 4) + to_write;
  47}
  48
  49int ewah_serialize_to(struct ewah_bitmap *self,
  50                      int (*write_fun)(void *, const void *, size_t),
  51                      void *data)
  52{
  53        size_t i;
  54        eword_t dump[2048];
  55        const size_t words_per_dump = sizeof(dump) / sizeof(eword_t);
  56        uint32_t bitsize, word_count, rlw_pos;
  57
  58        const eword_t *buffer;
  59        size_t words_left;
  60
  61        /* 32 bit -- bit size for the map */
  62        bitsize =  htonl((uint32_t)self->bit_size);
  63        if (write_fun(data, &bitsize, 4) != 4)
  64                return -1;
  65
  66        /** 32 bit -- number of compressed 64-bit words */
  67        word_count =  htonl((uint32_t)self->buffer_size);
  68        if (write_fun(data, &word_count, 4) != 4)
  69                return -1;
  70
  71        /** 64 bit x N -- compressed words */
  72        buffer = self->buffer;
  73        words_left = self->buffer_size;
  74
  75        while (words_left >= words_per_dump) {
  76                for (i = 0; i < words_per_dump; ++i, ++buffer)
  77                        dump[i] = htonll(*buffer);
  78
  79                if (write_fun(data, dump, sizeof(dump)) != sizeof(dump))
  80                        return -1;
  81
  82                words_left -= words_per_dump;
  83        }
  84
  85        if (words_left) {
  86                for (i = 0; i < words_left; ++i, ++buffer)
  87                        dump[i] = htonll(*buffer);
  88
  89                if (write_fun(data, dump, words_left * 8) != words_left * 8)
  90                        return -1;
  91        }
  92
  93        /** 32 bit -- position for the RLW */
  94        rlw_pos = (uint8_t*)self->rlw - (uint8_t *)self->buffer;
  95        rlw_pos = htonl(rlw_pos / sizeof(eword_t));
  96
  97        if (write_fun(data, &rlw_pos, 4) != 4)
  98                return -1;
  99
 100        return (3 * 4) + (self->buffer_size * 8);
 101}
 102
 103static int write_strbuf(void *user_data, const void *data, size_t len)
 104{
 105        struct strbuf *sb = user_data;
 106        strbuf_add(sb, data, len);
 107        return len;
 108}
 109
 110int ewah_serialize_strbuf(struct ewah_bitmap *self, struct strbuf *sb)
 111{
 112        return ewah_serialize_to(self, write_strbuf, sb);
 113}
 114
 115ssize_t ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len)
 116{
 117        const uint8_t *ptr = map;
 118        size_t data_len;
 119        size_t i;
 120
 121        if (len < sizeof(uint32_t))
 122                return error("corrupt ewah bitmap: eof before bit size");
 123        self->bit_size = get_be32(ptr);
 124        ptr += sizeof(uint32_t);
 125        len -= sizeof(uint32_t);
 126
 127        if (len < sizeof(uint32_t))
 128                return error("corrupt ewah bitmap: eof before length");
 129        self->buffer_size = self->alloc_size = get_be32(ptr);
 130        ptr += sizeof(uint32_t);
 131        len -= sizeof(uint32_t);
 132
 133        REALLOC_ARRAY(self->buffer, self->alloc_size);
 134
 135        /*
 136         * Copy the raw data for the bitmap as a whole chunk;
 137         * if we're in a little-endian platform, we'll perform
 138         * the endianness conversion in a separate pass to ensure
 139         * we're loading 8-byte aligned words.
 140         */
 141        data_len = st_mult(self->buffer_size, sizeof(eword_t));
 142        if (len < data_len)
 143                return error("corrupt ewah bitmap: eof in data "
 144                             "(%"PRIuMAX" bytes short)",
 145                             (uintmax_t)(data_len - len));
 146        memcpy(self->buffer, ptr, data_len);
 147        ptr += data_len;
 148        len -= data_len;
 149
 150        for (i = 0; i < self->buffer_size; ++i)
 151                self->buffer[i] = ntohll(self->buffer[i]);
 152
 153        if (len < sizeof(uint32_t))
 154                return error("corrupt ewah bitmap: eof before rlw");
 155        self->rlw = self->buffer + get_be32(ptr);
 156        ptr += sizeof(uint32_t);
 157        len -= sizeof(uint32_t);
 158
 159        return ptr - (const uint8_t *)map;
 160}