/* Byte code fragment construction functions */
typedef struct frag Frag;
struct frag {
unsigned char *start;
ptrdiff_t len;
ptrdiff_t size;
ptrdiff_t align;
};
/* Initialize a fragment: 'alignment' sets the natural alignment of
* the fragment. After any emit or fetch function is called, the
* fragment is filled to the next multiple of 'alignment'.
*/
void iz_frag(Frag *, ptrdiff_t alignmnet);
void clr_frag(Frag *);
/* Generate byte offset you need to add to p so that
* it is an exact multiple of size (which is a power of 2).
*/
#define align_o(p, size) (((size) - 1) & -(ptrdiff_t)(p))
/* Align frag to next multiple of n */
void align_frag(Frag *f, ptrdiff_t n);
/* Append data to a fragment: return byte offset to data.
* These do two alignments: one before and one after the emit. Before,
* it fills the fragment until its size is a multiple of the size of
* the emitted data. After the emit, it fills the fragment until its
* size is a multiple of the natural alignment specified in iz_frag.
*/
ptrdiff_t emitb_noalign(Frag *f, char c);
ptrdiff_t emitb(Frag *f, char c);
ptrdiff_t emith(Frag *f, short n);
ptrdiff_t emiti(Frag *f, int n);
ptrdiff_t emitd(Frag *f, double d);
ptrdiff_t emitp(Frag *f, void *p);
ptrdiff_t emits(Frag *f, unsigned char *s, int len);
ptrdiff_t emit_branch(Frag *f, ptrdiff_t target);
void fixup_branch(Frag *f, ptrdiff_t pos);
void frag_link(Frag *f, ptrdiff_t chain);
/* Access data in a fragment */
#define fragc(f, ofst) (*((f)->start + (ofst)))
#define fragh(f, ofst) (*(short *)((f)->start + (ofst)))
#define fragi(f, ofst) (*(int *)((f)->start + (ofst)))
#define fragd(f, ofst) (*(double *)((f)->start + (ofst)))
#define fragp(f, ofst) (*(void **)((f)->start + (ofst)))
/* Fetch an datum from a fragment and advance the "PC" */
int fetchi(Frag *f, ptrdiff_t *pc);
short fetchh(Frag *f, ptrdiff_t *pc);
void *fetchp(Frag *f, ptrdiff_t *pc);
void fin_code(Frag *f);
