/* Send function, takes a Perl value and should write the binary encoded
 * format into the given fustr. */
typedef void (*fupg_send_fn)(pTHX_ SV *, fustr *, void *);

/* Receive function, takes a binary string and should return a Perl value.
 * libpq guarantees that the given buffer is aligned to MAXIMUM_ALIGNOF.
 * For fixed-length types, the recv function is only called after verifying
 * that the input buffer has the correct length. */
typedef SV *(*fupg_recv_fn)(pTHX_ const char *, int, void *);

typedef struct {
    Oid oid;
    int len;
    const char *name;
    fupg_send_fn send;
    fupg_recv_fn recv;
} fupg_type;



#define RECVFN(name) static SV *fupg_recv_##name(pTHX_ const char *buf, int buflen __attribute__((unused)), void *data __attribute__((unused)))

RECVFN(textfmt) {
    return newSVpvn_utf8(buf, buflen, 1);
}

RECVFN(bool) {
    return *buf ? &PL_sv_yes : &PL_sv_no;
}

RECVFN(int2) {
    return newSViv((I16)__builtin_bswap16(*((U16 *)buf)));
}

RECVFN(int4) {
    return newSViv((I32)__builtin_bswap32(*((U32 *)buf)));
}

RECVFN(int8) {
    return newSViv((I64)__builtin_bswap64(*((U64 *)buf)));
}

#undef RECVFN



#define R(name) fupg_recv_##name

/* Sorted by oid to support binary search.
 * (XXX: hash lookup might be faster, but requires codegen) */
static const fupg_type fupg_types[] = {
    {  0, 0, NULL,   NULL, R(textfmt) }, /* Invalid Oid, abused for text format */
    { 16, 1, "bool", NULL, R(bool)    },
    { 20, 8, "int8", NULL, R(int8)    },
    { 21, 2, "int2", NULL, R(int2)    },
    { 23, 4, "int4", NULL, R(int4)    },
};
/* TODO: A LOT MORE TYPES */

#undef R

#define FUPG_TYPES (sizeof(fupg_types) / sizeof(fupg_type))


static const fupg_type *fupg_type_lookup(Oid oid) {
    int i, b = 0, e = FUPG_TYPES-1;
    while (b <= e) {
        i = b + (e - b)/2;
        if (fupg_types[i].oid == oid) return fupg_types+i;
        if (fupg_types[i].oid < oid) b = i+1;
        else e = i-1;
    }
    return NULL;
}