initial commit: wip

tag.c

@@ -0,0 +1,134 @@
+#include "tag.h"
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+struct private {
+    char *name;
+    union {
+        long value_as_int;
+        double value_as_float;
+        char *value_as_string;
+    };
+};
+
+static const char *
+tag_name(const struct tag *tag)
+{
+    const struct private *priv = tag->private;
+    return priv->name;
+}
+
+static void
+destroy_int_and_float(struct tag *tag)
+{
+    struct private *priv = tag->private;
+    free(priv->name);
+    free(priv);
+    free(tag);
+}
+
+static void
+destroy_string(struct tag *tag)
+{
+    struct private *priv = tag->private;
+    free(priv->value_as_string);
+    destroy_int_and_float(tag);
+}
+
+static const char *
+value_int(const struct tag *tag)
+{
+    static char as_string[128];
+    const struct private *priv = tag->private;
+
+    snprintf(as_string, sizeof(as_string), "%ld", priv->value_as_int);
+    return as_string;
+}
+
+static const char *
+value_float(const struct tag *tag)
+{
+    static char as_string[128];
+    const struct private *priv = tag->private;
+
+    snprintf(as_string, sizeof(as_string), "%.2f", priv->value_as_float);
+    return as_string;
+}
+
+static const char *
+value_string(const struct tag *tag)
+{
+    const struct private *priv = tag->private;
+    return priv->value_as_string;
+}
+
+struct tag *
+tag_new_int(const char *name, long value)
+{
+    struct private *priv = malloc(sizeof(*priv));
+    priv->name = strdup(name);
+    priv->value_as_int = value;
+
+    struct tag *tag = malloc(sizeof(*tag));
+    tag->private = priv;
+    tag->destroy = &destroy_int_and_float;
+    tag->name = &tag_name;
+    tag->value = &value_int;
+    return tag;
+}
+
+struct tag *
+tag_new_float(const char *name, double value)
+{
+    struct private *priv = malloc(sizeof(*priv));
+    priv->name = strdup(name);
+    priv->value_as_float = value;
+
+    struct tag *tag = malloc(sizeof(*tag));
+    tag->private = priv;
+    tag->destroy = &destroy_int_and_float;
+    tag->name = &tag_name;
+    tag->value = &value_float;
+    return tag;
+}
+
+struct tag *
+tag_new_string(const char *name, const char *value)
+{
+    struct private *priv = malloc(sizeof(*priv));
+    priv->name = strdup(name);
+    priv->value_as_string = strdup(value);
+
+    struct tag *tag = malloc(sizeof(*tag));
+    tag->private = priv;
+    tag->destroy = &destroy_string;
+    tag->name = &tag_name;
+    tag->value = &value_string;
+    return tag;
+}
+
+const struct tag *
+tag_for_name(const struct tag_set *set, const char *name)
+{
+    if (set == NULL)
+        return NULL;
+
+    for (size_t i = 0; i < set->count; i++) {
+        const struct tag *tag = set->tags[i];
+        if (strcmp(tag->name(tag), name) == 0)
+            return tag;
+    }
+
+    return NULL;
+}
+
+void
+tag_set_destroy(struct tag_set *set)
+{
+    for (size_t i = 0; i < set->count; i++)
+        set->tags[i]->destroy(set->tags[i]);
+
+    set->tags = NULL;
+    set->count = 0;
+}