mrbgems/mruby-hash-ext/src/hash-ext.c

   1 /*
   2 ** hash.c - Hash class
   3 **
   4 ** See Copyright Notice in mruby.h
   5 */
   6
   7 #include <mruby.h>
   8 #include <mruby/array.h>
   9 #include <mruby/hash.h>
  10
  11 /*
  12  * call-seq:
  13  *   hsh.values_at(key, ...)   -> array
  14  *
  15  * Return an array containing the values associated with the given keys.
  16  * Also see <code>Hash.select</code>.
  17  *
  18  *   h = { "cat" => "feline", "dog" => "canine", "cow" => "bovine" }
  19  *   h.values_at("cow", "cat")  #=> ["bovine", "feline"]
  20  */
  21
  22 static mrb_value
  23 hash_values_at(mrb_state *mrb, mrb_value hash)
  24 {
  25   const mrb_value *argv;
  26   mrb_value result;
  27   mrb_int argc, i;
  28   int ai;
  29
  30   mrb_get_args(mrb, "*", &argv, &argc);
  31   result = mrb_ary_new_capa(mrb, argc);
  32   if (argc == 0) return result;
  33   ai = mrb_gc_arena_save(mrb);
  34   for (i = 0; i < argc; i++) {
  35     mrb_ary_push(mrb, result, mrb_hash_get(mrb, hash, argv[i]));
  36     mrb_gc_arena_restore(mrb, ai);
  37   }
  38   return result;
  39 }
  40
  41 /*
  42  *  call-seq:
  43  *     hsh.slice(*keys) -> a_hash
  44  *
  45  *  Returns a hash containing only the given keys and their values.
  46  *
  47  *     h = { a: 100, b: 200, c: 300 }
  48  *     h.slice(:a)           #=> {:a=>100}
  49  *     h.slice(:b, :c, :d)   #=> {:b=>200, :c=>300}
  50  */
  51 static mrb_value
  52 hash_slice(mrb_state *mrb, mrb_value hash)
  53 {
  54   const mrb_value *argv;
  55   mrb_value result;
  56   mrb_int argc, i;
  57
  58   mrb_get_args(mrb, "*", &argv, &argc);
  59   result = mrb_hash_new_capa(mrb, argc);
  60   if (argc == 0) return result; /* empty hash */
  61   for (i = 0; i < argc; i++) {
  62     mrb_value key = argv[i];
  63     mrb_value val;
  64
  65     val = mrb_hash_fetch(mrb, hash, key, mrb_undef_value());
  66     if (!mrb_undef_p(val)) {
  67       mrb_hash_set(mrb, result, key, val);
  68     }
  69   }
  70   return result;
  71 }
  72
  73 /*
  74  *  call-seq:
  75  *     hsh.except(*keys) -> a_hash
  76  *
  77  *  Returns a hash excluding the given keys and their values.
  78  *
  79  *     h = { a: 100, b: 200, c: 300 }
  80  *     h.except(:a)          #=> {:b=>200, :c=>300}
  81  *     h.except(:b, :c, :d)  #=> {:a=>100}
  82  */
  83 static mrb_value
  84 hash_except(mrb_state *mrb, mrb_value hash)
  85 {
  86   const mrb_value *argv;
  87   mrb_value result;
  88   mrb_int argc, i;
  89
  90   mrb_get_args(mrb, "*", &argv, &argc);
  91   result = mrb_hash_dup(mrb, hash);
  92   for (i = 0; i < argc; i++) {
  93     mrb_hash_delete_key(mrb, result, argv[i]);
  94   }
  95   return result;
  96 }
  97
  98 void
  99 mrb_mruby_hash_ext_gem_init(mrb_state *mrb)
 100 {
 101   struct RClass *h;
 102
 103   h = mrb->hash_class;
 104   mrb_define_method(mrb, h, "values_at", hash_values_at, MRB_ARGS_ANY());
 105   mrb_define_method(mrb, h, "slice",     hash_slice, MRB_ARGS_ANY());
 106   mrb_define_method(mrb, h, "except",    hash_except, MRB_ARGS_ANY());
 107 }