ruby--ruby/transcode_data.h

typedef unsigned char base_element;

typedef struct byte_lookup {
    const base_element *base;
    const struct byte_lookup *const *info;
} BYTE_LOOKUP;

#ifdef TRANSCODE_DATA
/* data file needs to treat this as a pointer, to remove warnings */
#define PType (const BYTE_LOOKUP *)
#else
/* in code, this is treated as just an integer */
#define PType (int)
#endif

#define NOMAP   (PType 0x01)   /* single byte direct map */
#define ONEbt   (0x02)   /* one byte payload */
#define TWObt   (0x03)   /* two bytes payload */
#define THREEbt (0x05)   /* three bytes payload */
#define FOURbt  (0x06)   /* four bytes payload, UTF-8 only, macros start at getBT0 */
#define ILLEGAL (PType 0x07)   /* illegal byte sequence */
#define UNDEF   (PType 0x09)   /* legal but undefined */
#define ZERObt  (PType 0x0A)   /* zero bytes of payload, i.e. remove */

#define o1(b1)          ((const BYTE_LOOKUP *)((((unsigned char)(b1))<<8)|ONEbt))
#define o2(b1,b2)       ((const BYTE_LOOKUP *)((((unsigned char)(b1))<<8)|(((unsigned char)(b2))<<16)|TWObt))
#define o3(b1,b2,b3)    ((const BYTE_LOOKUP *)((((unsigned char)(b1))<<8)|(((unsigned char)(b2))<<16)|(((unsigned char)(b3))<<24)|THREEbt))
#define o4(b0,b1,b2,b3) ((const BYTE_LOOKUP *)((((unsigned char)(b1))<< 8)|(((unsigned char)(b2))<<16)|(((unsigned char)(b3))<<24)|((((unsigned char)(b0))&0x07)<<5)|FOURbt))

#define getBT1(a)      (((a)>> 8)&0xFF)
#define getBT2(a)      (((a)>>16)&0xFF)
#define getBT3(a)      (((a)>>24)&0xFF)
#define getBT0(a)      ((((a)>> 5)&0x07)|0xF0)   /* for UTF-8 only!!! */

/* do we need these??? maybe not, can be done with simple tables */
#define ONETRAIL       /* legal but undefined if one more trailing UTF-8 */
#define TWOTRAIL       /* legal but undefined if two more trailing UTF-8 */
#define THREETRAIL     /* legal but undefined if three more trailing UTF-8 */