optionals.c

(75 lines)
   1 // Optional types
   2 
   3 #include <math.h>
   4 
   5 #include "datatypes.h"
   6 #include "metamethods.h"
   7 #include "nums.h"
   8 #include "optionals.h"
   9 #include "text.h"
  10 #include "util.h"
  11 
  12 public
  13 PUREFUNC bool is_none(const void *obj, const TypeInfo_t *non_optional_type) {
  14     if (non_optional_type->metamethods.is_none) return non_optional_type->metamethods.is_none(obj, non_optional_type);
  15 
  16     const bool *has_value = (const bool *)(obj + non_optional_type->size);
  17     return !(*has_value);
  18 }
  19 
  20 PUREFUNC public uint64_t Optional$hash(const void *obj, const TypeInfo_t *type) {
  21     return is_none(obj, type->OptionalInfo.type) ? 0 : generic_hash(obj, type->OptionalInfo.type);
  22 }
  23 
  24 PUREFUNC public int32_t Optional$compare(const void *x, const void *y, const TypeInfo_t *type) {
  25     if (x == y) return 0;
  26     bool x_is_null = is_none(x, type->OptionalInfo.type);
  27     bool y_is_null = is_none(y, type->OptionalInfo.type);
  28     if (x_is_null && y_is_null) return 0;
  29     else if (x_is_null != y_is_null) return (int32_t)y_is_null - (int32_t)x_is_null;
  30     else return generic_compare(x, y, type->OptionalInfo.type);
  31 }
  32 
  33 PUREFUNC public bool Optional$equal(const void *x, const void *y, const TypeInfo_t *type) {
  34     if (x == y) return true;
  35 
  36     bool x_is_null = is_none(x, type->OptionalInfo.type);
  37     bool y_is_null = is_none(y, type->OptionalInfo.type);
  38     if (x_is_null && y_is_null) return true;
  39     else if (x_is_null != y_is_null) return false;
  40     else return generic_equal(x, y, type->OptionalInfo.type);
  41 }
  42 
  43 public
  44 Text_t Optional$as_text(const void *obj, bool colorize, const TypeInfo_t *type) {
  45     if (!obj) return Text$concat(generic_as_text(obj, colorize, type->OptionalInfo.type), Text("?"));
  46 
  47     if (is_none(obj, type->OptionalInfo.type)) return colorize ? Text("\x1b[31mnone\x1b[m") : Text("none");
  48     return generic_as_text(obj, colorize, type->OptionalInfo.type);
  49 }
  50 
  51 public
  52 void Optional$serialize(const void *obj, FILE *out, Table_t *pointers, const TypeInfo_t *type) {
  53     bool has_value = !is_none(obj, type->OptionalInfo.type);
  54     assert(fputc((int)has_value, out) != EOF);
  55     if (has_value) _serialize(obj, out, pointers, type->OptionalInfo.type);
  56 }
  57 
  58 public
  59 void Optional$deserialize(FILE *in, void *outval, List_t *pointers, const TypeInfo_t *type) {
  60     bool has_value = (bool)fgetc(in);
  61     const TypeInfo_t *nonnull = type->OptionalInfo.type;
  62     if (has_value) {
  63         memset(outval, 0, (size_t)type->size);
  64         _deserialize(in, outval, pointers, nonnull);
  65     } else {
  66         if (nonnull->tag == TextInfo) *(Text_t *)outval = NONE_TEXT;
  67         else if (nonnull->tag == ListInfo) *(List_t *)outval = NONE_LIST;
  68         else if (nonnull->tag == TableInfo) *(Table_t *)outval = NONE_TABLE;
  69         else if (nonnull == &Num$info) *(double *)outval = (double)NAN;
  70         else if (nonnull == &Num32$info) *(float *)outval = (float)NAN;
  71         else if (nonnull->tag == StructInfo || (nonnull->tag == OpaqueInfo && type->size > nonnull->size))
  72             memset(outval + type->size, -1, (size_t)(type->size - nonnull->size));
  73         else memset(outval, 0, (size_t)type->size);
  74     }
  75 }