mie: implement caching and emitting string data

mie/ctx.c

@@ -43,6 +43,7 @@ struct mie_ctx *mie_ctx_create(void)
 	out->ctx_false = MIE_CONST(mie_ctx_get_int(out, 0, 1));
 
 	out->ctx_sel_cache = b_hashmap_create(free, free);
+	out->ctx_string_cache = b_hashmap_create(free, free);
 
 	return out;
 }
@@ -214,3 +215,38 @@ struct mie_value *mie_ctx_get_selector(struct mie_ctx *ctx, const char *sel)
 
 	return MIE_VALUE(sel_value);
 }
+
+struct mie_value *mie_ctx_get_string(struct mie_ctx *ctx, const char *s)
+{
+	b_hashmap_key key = {
+		.key_data = s,
+		.key_size = strlen(s),
+	};
+
+	const b_hashmap_value *cache_entry
+		= b_hashmap_get(ctx->ctx_string_cache, &key);
+
+	if (cache_entry) {
+		return cache_entry->value_data;
+	}
+
+	struct mie_const *string_value = malloc(sizeof *string_value);
+	if (!string_value) {
+		return NULL;
+	}
+
+	mie_value_init(&string_value->c_base, MIE_VALUE_CONST);
+	string_value->c_type = mie_ctx_get_type(ctx, MIE_TYPE_STR);
+	string_value->c_v.v_str = b_strdup(s);
+
+	key.key_data = string_value->c_v.v_str;
+
+	b_hashmap_value hashmap_value = {
+		.value_data = string_value,
+		.value_size = sizeof *string_value,
+	};
+
+	b_hashmap_put(ctx->ctx_string_cache, &key, &hashmap_value);
+
+	return MIE_VALUE(string_value);
+}