Swizzletastic

gistfile1.txt

#include <objc/runtime.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "SwizzleMyNizzleProtocol.h"

void SwizzleMethod(Class _class, SEL sel, IMP imp, const char *prefix) {
	if (_class == nil)
		return;
	
	Method method = class_getInstanceMethod(_class, sel);
	if (method == nil)
		return;
	
	const char *name = sel_getName(sel);
	const char *type = method_getTypeEncoding(method);
	
	if (prefix != NULL) {
		size_t namelen = strlen(name);
		size_t fixlen = strlen(prefix);
		
		char newname[fixlen + namelen + 1];
		memcpy(newname, prefix, fixlen);
		memcpy(newname + fixlen, name, namelen + 1);
		
		if (!class_addMethod(_class, sel_registerName(newname), method_getImplementation(method), type)) 
			printf("Error: failed to rename1");
		
	}
	
	
	unsigned int count;
	Method *methods = class_copyMethodList(_class, &count);
	for (unsigned int index = 0; index < count; index++)
		if (methods[index] == method)
			goto found;
	
	if (imp != NULL)
		if (!class_addMethod(_class, sel, imp, type))
			printf("Error: failed to rename2");
	goto done;
	
found:
	if (imp != NULL)
		method_setImplementation(method, imp);
	
done:
	free(methods);
}