class: added functions for looking up fields and methods

Signed-off-by: Vegard Nossum <[email protected]>

include/cafebabe/class.h

@@ -67,4 +67,11 @@ int cafebabe_class_constant_get_utf8(struct cafebabe_class *c, uint16_t i,
 int cafebabe_class_constant_get_class(struct cafebabe_class *c, uint16_t i,
 	struct cafebabe_constant_info_class **r);
 
+int cafebabe_class_get_field(struct cafebabe_class *c,
+	const char *name, const char *descriptor,
+	struct cafebabe_field_info **r);
+int cafebabe_class_get_method(struct cafebabe_class *c,
+	const char *name, const char *descriptor,
+	struct cafebabe_method_info **r);
+
 #endif

include/cafebabe/constant_pool.h

@@ -117,4 +117,7 @@ int cafebabe_constant_pool_init(struct cafebabe_constant_pool *cp,
 	struct cafebabe_stream *s);
 void cafebabe_constant_pool_deinit(struct cafebabe_constant_pool *cp);
 
+int cafebabe_constant_info_utf8_compare(
+	const struct cafebabe_constant_info_utf8 *s1, const char *s2);
+
 #endif

src/cafebabe/class.c

@@ -223,3 +223,77 @@ cafebabe_class_constant_get_class(struct cafebabe_class *c, uint16_t i,
 	*r = &pool->class;
 	return 0;
 }
+
+int
+cafebabe_class_get_field(struct cafebabe_class *c,
+	const char *name, const char *descriptor,
+	struct cafebabe_field_info **r)
+{
+	for (uint16_t i = 0; i < c->fields_count; ++i) {
+		struct cafebabe_constant_info_utf8 *field_name;
+		if (cafebabe_class_constant_get_utf8(c,
+			c->fields[i].name_index, &field_name))
+		{
+			return 1;
+		}
+
+		if (cafebabe_constant_info_utf8_compare(field_name, name))
+			continue;
+
+		struct cafebabe_constant_info_utf8 *field_descriptor;
+		if (cafebabe_class_constant_get_utf8(c,
+			c->fields[i].descriptor_index, &field_descriptor))
+		{
+			return 1;
+		}
+
+		if (cafebabe_constant_info_utf8_compare(
+			field_descriptor, descriptor))
+		{
+			continue;
+		}
+
+		*r = &c->fields[i];
+		return 0;
+	}
+
+	/* Not found */
+	return 1;
+}
+
+int
+cafebabe_class_get_method(struct cafebabe_class *c,
+	const char *name, const char *descriptor,
+	struct cafebabe_method_info **r)
+{
+	for (uint16_t i = 0; i < c->methods_count; ++i) {
+		struct cafebabe_constant_info_utf8 *method_name;
+		if (cafebabe_class_constant_get_utf8(c,
+			c->methods[i].name_index, &method_name))
+		{
+			return 1;
+		}
+
+		if (cafebabe_constant_info_utf8_compare(method_name, name))
+			continue;
+
+		struct cafebabe_constant_info_utf8 *method_descriptor;
+		if (cafebabe_class_constant_get_utf8(c,
+			c->methods[i].descriptor_index, &method_descriptor))
+		{
+			return 1;
+		}
+
+		if (cafebabe_constant_info_utf8_compare(
+			method_descriptor, descriptor))
+		{
+			continue;
+		}
+
+		*r = &c->methods[i];
+		return 0;
+	}
+
+	/* Not found */
+	return 1;
+}

src/cafebabe/constant_pool.c

@@ -20,6 +20,7 @@
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include "cafebabe/constant_pool.h"
 #include "cafebabe/stream.h"
@@ -347,3 +348,10 @@ cafebabe_constant_pool_deinit(struct cafebabe_constant_pool *cp)
 		break;
 	}
 }
+
+int
+cafebabe_constant_info_utf8_compare(
+	const struct cafebabe_constant_info_utf8 *s1, const char *s2)
+{
+	return strncmp((const char *) s1->bytes, s2, s1->length);
+}

src/dump.c

@@ -145,6 +145,13 @@ main(int argc, char *argv[])
 			method_name->length, method_name->bytes);
 	}
 
+	struct cafebabe_method_info *main_method;
+	if (!cafebabe_class_get_method(&class,
+		"main", "([Ljava/lang/String;)V", &main_method))
+	{
+		printf("class has main method\n");
+	}
+
 	cafebabe_class_deinit(&class);
 	cafebabe_stream_close(&stream);