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struct _category_t {const char *name; // 1struct _class_t *cls; // 2 const struct _method_list_t *instance_methods; // 3 const struct _method_list_t *class_methods; // 4 const struct _protocol_list_t *protocols; // 5 const struct _prop_list_t *properties; // 6 }; 

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@interface Sark : NSObject
- (void)speak;
@end @interface Sark (GayExtention) - (void)burst; @end 

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$ clang -rewrite-objc sark.m

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static struct _category_t _OBJC_$_CATEGORY_Sark_$_GayExtention __attribute__ ((used, section ("__DATA,__objc_const"))) =
{"Sark",0, // &OBJC_CLASS_$_Sark, (const struct _method_list_t *)&_OBJC_$_CATEGORY_INSTANCE_METHODS_Sark_$_GayExtention, 0, 0, 0, }; 

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static struct _category_t *L_OBJC_LABEL_CATEGORY_$ [1] __attribute__((used, section ("__DATA, __objc_catlist,regular,no_dead_strip")))= {&_OBJC_$_CATEGORY_Sark_$_GayExtention,
};

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#define GETSECT(name, type, sectname)                                   \type *name(const header_info *hi, size_t *outCount) \ { \ unsigned long byteCount = 0; \ type *data = (type *) \ getsectiondata(hi->mhdr, SEG_DATA, sectname, &byteCount); \ *outCount = byteCount / sizeof(type); \ return data; \ } // ... // GETSECT(_getObjc2CategoryList, category_t *, "__objc_catlist"); 

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// Process this category.
// First, register the category with its target class.
// Then, rebuild the class's method lists (etc) if
// the class is realized.
BOOL classExists = NO;
if (cat->instanceMethods || cat->protocols || cat->instanceProperties) { addUnattachedCategoryForClass(cat, cls, hi); if (isRealized(cls)) { remethodizeClass(cls); classExists = YES; } } if (cat->classMethods || cat->protocols ) { addUnattachedCategoryForClass(cat, cls->isa, hi); if (isRealized(cls->isa)) { remethodizeClass(cls->isa); } } 

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static void
attachCategoryMethods(class_t *cls, category_list *cats,BOOL *inoutVtablesAffected)
{if (!cats) return;if (PrintReplacedMethods) printReplacements(cls, cats); BOOL isMeta = isMetaClass(cls); method_list_t **mlists = (method_list_t **) _malloc_internal(cats->count * sizeof(*mlists)); // Count backwards through cats to get newest categories first int mcount = 0; int i = cats->count; BOOL fromBundle = NO; while (i--) { method_list_t *mlist = cat_method_list(cats->list[i].cat, isMeta); if (mlist) { mlists[mcount++] = mlist; fromBundle |= cats->list[i].fromBundle; } } attachMethodLists(cls, mlists, mcount, NO, fromBundle, inoutVtablesAffected); _free_internal(mlists); }