src/st-byte-array.c

   1 /*
   2  * st-byte-array.c
   3  *
   4  * Copyright (c) 2008 Vincent Geddes
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23 */
  24
  25 #include "st-byte-array.h"
  26 #include "st-object.h"
  27 #include "st-utils.h"
  28 #include "st-descriptor.h"
  29
  30 #include <string.h>
  31
  32 static st_oop
  33 allocate_arrayed (st_space *space,
  34                   st_oop    class,
  35                   st_smi    size)
  36 {
  37     st_uint size_oops;
  38     st_oop  array;
  39
  40     st_assert (size >= 0);
  41
  42     /* add 1 byte for NULL terminator. Allows toll-free bridging with C string function */
  43     size_oops = ST_ROUNDED_UP_OOPS (size + 1);
  44
  45     array = st_space_allocate_object (space, class, ST_SIZE_OOPS (struct st_byte_array) + size_oops);
  46     ST_ARRAYED_OBJECT (array)->size = st_smi_new (size);
  47
  48     memset (st_byte_array_bytes (array), 0, ST_OOPS_TO_BYTES (size_oops));
  49
  50     return array;
  51 }
  52
  53 bool
  54 st_byte_array_equal (st_oop object, st_oop other)
  55 {
  56     st_smi size, size_other;
  57
  58     if (st_object_class (other) != st_byte_array_class &&
  59         st_object_class (other) != st_string_class &&
  60         st_object_class (other) != st_symbol_class)
  61         return false;
  62
  63     size = st_smi_value (ST_ARRAYED_OBJECT (object)->size);
  64     size_other = st_smi_value (ST_ARRAYED_OBJECT (other)->size);
  65
  66     if (size != size_other)
  67         return false;
  68
  69     return memcmp (st_byte_array_bytes (object), st_byte_array_bytes (other), size) == 0;
  70 }
  71
  72 st_uint
  73 st_byte_array_hash (st_oop object)
  74 {
  75     const signed char *p = (signed char *) st_byte_array_bytes (object);
  76     st_uint h = *p;
  77
  78     long size = st_smi_value (ST_ARRAYED_OBJECT (object)->size);
  79
  80     if (size == 0 || !h)
  81         return h;
  82
  83     for (st_smi i = 1; i < size; i++) {
  84         h = (h << 5) - h + *(p + i);
  85     }
  86
  87     return h;
  88 }
  89
  90 static st_oop
  91 byte_array_copy (st_oop object)
  92 {
  93     st_oop copy;
  94     st_smi size;
  95
  96     size = st_smi_value (ST_ARRAYED_OBJECT (object)->size);
  97
  98     copy = allocate_arrayed (memory->moving_space, st_object_class (object), size);
  99
 100     memcpy (st_byte_array_bytes (copy),
 101             st_byte_array_bytes (object),
 102             size);
 103
 104     return copy;
 105 }
 106
 107 static st_uint
 108 byte_array_size (st_oop object)
 109 {
 110     st_uint size;
 111
 112     size = st_smi_value (st_arrayed_object_size (object));
 113     return ST_SIZE_OOPS (struct st_arrayed_object) + ST_ROUNDED_UP_OOPS (size + 1);
 114 }
 115
 116 static void
 117 byte_array_contents (st_oop object, struct contents *contents)
 118 {
 119     contents->oops = NULL;
 120     contents->size = 0;
 121 }
 122
 123 st_descriptor *
 124 st_byte_array_descriptor (void)
 125 {
 126     static st_descriptor __descriptor =
 127         { .allocate         = NULL,
 128           .allocate_arrayed = allocate_arrayed,
 129           .copy             = byte_array_copy,
 130           .size             = byte_array_size,
 131           .contents         = byte_array_contents,
 132         };
 133
 134     return & __descriptor;
 135 }