ewah/ewah_io.c

   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
  23 int 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
  49 int 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
 103 static 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
 110 int ewah_serialize_strbuf(struct ewah_bitmap *self, struct strbuf *sb)
 111 {
 112         return ewah_serialize_to(self, write_strbuf, sb);
 113 }
 114
 115 ssize_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 }