/// @file

#ifndef U3_RETRIEVE_H
#define U3_RETRIEVE_H

#include "c3/c3.h"
#include "allocate.h"
#include "error.h"
#include "gmp.h"
#include "types.h"

    /** u3r_*: read without ever crashing.
    **/

      /* u3r_cell(): factor (a) as a cell (b c).
      */
        inline c3_o
        u3r_cell(u3_noun a, u3_noun* b, u3_noun* c)
        {
          u3a_cell* cel_u;

          u3_assert(u3_none != a);

          if ( c3y == u3a_is_cell(a) ) {
            cel_u = u3a_to_ptr(a);
            if ( b ) *b = cel_u->hed;
            if ( c ) *c = cel_u->tel;
            return c3y;
          }
          else {
            return c3n;
          }
        }

      /* u3r_trel(): factor (a) as a trel (b c d).
      */
        inline c3_o
        u3r_trel(u3_noun a, u3_noun *b, u3_noun *c, u3_noun *d)
        {
          u3_noun guf;

          if ( (c3y == u3r_cell(a, b, &guf)) &&
               (c3y == u3r_cell(guf, c, d)) ) {
            return c3y;
          }
          else {
            return c3n;
          }
        }

      /* u3r_qual(): factor (a) as a qual (b c d e).
      */
        inline c3_o
        u3r_qual(u3_noun  a,
                 u3_noun* b,
                 u3_noun* c,
                 u3_noun* d,
                 u3_noun* e)
        {
          u3_noun guf;

          if ( (c3y == u3r_cell(a, b, &guf)) &&
               (c3y == u3r_trel(guf, c, d, e)) ) {
            return c3y;
          }
          else return c3n;
        }

      /* u3r_quil(): factor (a) as a quil (b c d e f).
      */
        inline c3_o
        u3r_quil(u3_noun  a,
                 u3_noun* b,
                 u3_noun* c,
                 u3_noun* d,
                 u3_noun* e,
                 u3_noun* f)
        {
          u3_noun guf;

          if ( (c3y == u3r_cell(a, b, &guf)) &&
               (c3y == u3r_qual(guf, c, d, e, f)) ) {
            return c3y;
          }
          else return c3n;
        }

      /* u3r_hext(): factor (a) as a hext (b c d e f g)
      */
        inline c3_o
        u3r_hext(u3_noun  a,
                 u3_noun* b,
                 u3_noun* c,
                 u3_noun* d,
                 u3_noun* e,
                 u3_noun* f,
                 u3_noun* g)
        {
          u3_noun guf;

          if ( (c3y == u3r_cell(a, b, &guf)) &&
               (c3y == u3r_quil(guf, c, d, e, f, g)) ) {
            return c3y;
          }
          else return c3n;
        }

      /* u3r_at(): fragment `a` of `b`, or u3_none.
      */
        u3_weak
        u3r_at(u3_atom a, u3_weak b);

      /* u3r_mean():
      **
      **   Attempt to deconstruct `a` by axis, noun pairs; 0 terminates.
      **   Axes must be sorted in tree order.
      */
        c3_o
        u3r_vmean(u3_noun a, va_list ap);
        c3_o
        u3r_mean(u3_noun a, ...);

      /* u3r_mug_both(): Join two mugs.
      */
        c3_l
        u3r_mug_both(c3_w lef_w, c3_w rit_w);

      /* u3r_mug_bytes(): Compute the mug of `buf`, `len`, LSW first.
      */
        c3_l
        u3r_mug_bytes(const c3_y *buf_y,
                      c3_w        len_w);

      /* u3r_mug_c(): Compute the mug of `a`, LSB first.
      */
        c3_l
        u3r_mug_c(const c3_c *a_c);

      /* u3r_mug_cell(): Compute the mug of the cell `[hed tel]`.
      */
        c3_l
        u3r_mug_cell(u3_noun hed,
                     u3_noun tel);

      /* u3r_mug_chub(): Compute the mug of `num`, LSW first.
      */
        c3_l
        u3r_mug_chub(c3_d num_d);

      /* u3r_mug_words(): 31-bit nonzero MurmurHash3 on raw words.
      */
        c3_l
        u3r_mug_words(const c3_w* key_w, c3_w len_w);

      /* u3r_mug(): statefully mug a noun with 31-bit murmur3.
      */
        c3_l
        u3r_mug(u3_noun veb);

      /* u3r_fing():
      **
      **   Yes iff (a) and (b) are the same copy of the same noun.
      **   (Ie, by pointer equality - u3r_sing with false negatives.)
      */
        c3_o
        u3r_fing(u3_noun a,
                 u3_noun b);

      /* u3r_fing_cell():
      **
      **   Yes iff `[p q]` and `b` are the same copy of the same noun.
      */
        c3_o
        u3r_fing_cell(u3_noun p,
                      u3_noun q,
                      u3_noun b);

      /* u3r_fing_mixt():
      **
      **   Yes iff `[p q]` and `b` are the same copy of the same noun.
      */
        c3_o
        u3r_fing_mixt(const c3_c* p_c,
                      u3_noun     q,
                      u3_noun     b);

      /* u3r_fing_trel():
      **
      **   Yes iff `[p q r]` and `b` are the same copy of the same noun.
      */
        c3_o
        u3r_fing_trel(u3_noun p,
                      u3_noun q,
                      u3_noun r,
                      u3_noun b);

      /* u3r_fing_qual():
      **
      **   Yes iff `[p q r s]` and `b` are the same copy of the same noun.
      */
        c3_o
        u3r_fing_qual(u3_noun p,
                      u3_noun q,
                      u3_noun r,
                      u3_noun s,
                      u3_noun b);

      /* u3r_sing(): noun value equality.
      **
      **   Unifies noun pointers on inner roads.
      */
        c3_o
        u3r_sing(u3_noun a, u3_noun b);

      /* u3r_sing_c(): cord/C-string value equivalence.
      */
        c3_o
        u3r_sing_c(const c3_c* a_c,
                   u3_noun     b);

      /* u3r_sing_cell():
      **
      **   Yes iff `[p q]` and `b` are the same noun.
      */
        c3_o
        u3r_sing_cell(u3_noun p,
                      u3_noun q,
                      u3_noun b);

      /* u3r_sing_mixt():
      **
      **   Yes iff `[p q]` and `b` are the same noun.
      */
        c3_o
        u3r_sing_mixt(const c3_c* p_c,
                      u3_noun     q,
                      u3_noun     b);

      /* u3r_sing_trel():
      **
      **   Yes iff `[p q r]` and `b` are the same noun.
      */
        c3_o
        u3r_sing_trel(u3_noun p,
                      u3_noun q,
                      u3_noun r,
                      u3_noun b);

      /* u3r_sing_qual():
      **
      **   Yes iff `[p q r s]` and `b` are the same noun.
      */
        c3_o
        u3r_sing_qual(u3_noun p,
                      u3_noun q,
                      u3_noun r,
                      u3_noun s,
                      u3_noun b);

      /* u3r_nord():
      **
      **   Return 0, 1 or 2 if `a` is below, equal to, or above `b`.
      */
        u3_atom
        u3r_nord(u3_noun a,
                 u3_noun b);

      /* u3r_mold():
      **
      **   Divide `a` as a mold `[b.[p q] c]`.
      */
        c3_o
        u3r_mold(u3_noun  a,
                 u3_noun* b,
                 u3_noun* c);

      /* u3r_bite(): retrieve/default $bloq and $step from $bite.
      */
        c3_o
        u3r_bite(u3_noun bite, u3_atom* bloq, u3_atom *step);

      /* u3r_p():
      **
      **   & [0] if [a] is of the form [b *c].
      */
        c3_o
        u3r_p(u3_noun  a,
              u3_noun  b,
              u3_noun* c);

      /* u3r_bush():
      **
      **   Factor [a] as a bush [b.[p q] c].
      */
        c3_o
        u3r_bush(u3_noun  a,
                 u3_noun* b,
                 u3_noun* c);

      /* u3r_pq():
      **
      **   & [0] if [a] is of the form [b *c d].
      */
        c3_o
        u3r_pq(u3_noun  a,
               u3_noun  b,
               u3_noun* c,
               u3_noun* d);

      /* u3r_pqr():
      **
      **   & [0] if [a] is of the form [b *c *d *e].
      */
        c3_o
        u3r_pqr(u3_noun  a,
                u3_noun  b,
                u3_noun* c,
                u3_noun* d,
                u3_noun* e);

      /* u3r_pqrs():
      **
      **   & [0] if [a] is of the form [b *c *d *e *f].
      */
        c3_o
        u3r_pqrs(u3_noun  a,
                 u3_noun  b,
                 u3_noun* c,
                 u3_noun* d,
                 u3_noun* e,
                 u3_noun* f);

      /* u3r_met():
      **
      **   Return the size of (b) in bits, rounded up to
      **   (1 << a_y).
      **
      **   For example, (a_y == 3) returns the size in bytes.
      **   NB: (a_y) must be < 37.
      */
        c3_w
        u3r_met(c3_y    a_y,
                u3_atom b);

      /* u3r_bit():
      **
      **   Return bit (a_w) of (b).
      */
        c3_b
        u3r_bit(c3_w    a_w,
                u3_atom b);

      /* u3r_byte():
      **
      **   Return byte (a_w) of (b).
      */
        c3_y
        u3r_byte(c3_w    a_w,
                 u3_atom b);

      /* u3r_bytes():
      **
      **   Copy bytes (a_w) through (a_w + b_w - 1) from (d) to (c).
      */
        void
        u3r_bytes(c3_w    a_w,
                  c3_w    b_w,
                  c3_y*   c_y,
                  u3_atom d);

      /* u3r_bytes_fit():
      **
      **   Copy (len_w) bytes of (a) into (buf_y) if it fits, returning overage.
      */
        c3_w
        u3r_bytes_fit(c3_w    len_w,
                      c3_y*   buf_y,
                      u3_atom a);

      /* u3r_bytes_alloc():
      **
      **  Copy (len_w) bytes starting at (a_w) from (b) into a fresh allocation.
      */
        c3_y*
        u3r_bytes_alloc(c3_w    a_w,
                        c3_w    len_w,
                        u3_atom b);

      /* u3r_bytes_all():
      **
      **  Allocate and return a new byte array with all the bytes of (a),
      **  storing the length in (len_w).
      */
        c3_y*
        u3r_bytes_all(c3_w*   len_w,
                      u3_atom a);

      /* u3r_chop_bits():
      **
      **   XOR `wid_d` bits from`src_w` at `bif_g` to `dst_w` at `bif_g`
      **
      **   NB: [dst_w] must have space for [bit_g + wid_d] bits
      */
        void
        u3r_chop_bits(c3_g  bif_g,
                      c3_d  wid_d,
                      c3_g  bit_g,
                      c3_w* dst_w,
                const c3_w* src_w);

      /* u3r_chop_words():
      **
      **   Into the bloq space of `met`, from position `fum` for a
      **   span of `wid`, to position `tou`, XOR from `src_w`
      **   into `dst_w`.
      **
      **   NB: [dst_w] must have space for [tou_w + wid_w] bloqs
      */
        void
        u3r_chop_words(c3_g  met_g,
                       c3_w  fum_w,
                       c3_w  wid_w,
                       c3_w  tou_w,
                       c3_w* dst_w,
                       c3_w  len_w,
                 const c3_w* src_w);

      /* u3r_chop():
      **
      **   Into the bloq space of `met`, from position `fum` for a
      **   span of `wid`, to position `tou`, XOR from atom `src`
      **   into `dst_w`.
      **
      **   NB: [dst_w] must have space for [tou_w + wid_w] bloqs
      */
        void
        u3r_chop(c3_g  met_g,
                 c3_w  fum_w,
                 c3_w  wid_w,
                 c3_w  tou_w,
                 c3_w* dst_w,
                 u3_atom src);

      /* u3r_mp():
      **
      **   Copy (b) into (a_mp).
      */
        void
        u3r_mp(mpz_t   a_mp,
               u3_atom b);

      /* u3r_short():
      **
      **   Return short (a_w) of (b).
      */
        c3_s
        u3r_short(c3_w  a_w,
                  u3_atom b);

      /* u3r_word():
      **
      **   Return word (a_w) of (b).
      */
        c3_w
        u3r_word(c3_w    a_w,
                 u3_atom b);


      /* u3r_word_fit():
      **
      **   Fill (out_w) with (a) if it fits, returning success.
      */
        c3_t
        u3r_word_fit(c3_w*   out_w,
                     u3_atom a);

      /* u3r_chub():
      **
      **   Return double-word (a_w) of (b).
      */
        c3_d
        u3r_chub(c3_w    a_w,
                 u3_atom b);

      /* u3r_words():
      **
      **  Copy words (a_w) through (a_w + b_w - 1) from (d) to (c).
      */
        void
        u3r_words(c3_w    a_w,
                  c3_w    b_w,
                  c3_w*   c_w,
                  u3_atom d);

      /* u3r_chubs():
      **
      **  Copy double-words (a_w) through (a_w + b_w - 1) from (d) to (c).
      */
        void
        u3r_chubs(c3_w    a_w,
                  c3_w    b_w,
                  c3_d*   c_d,
                  u3_atom d);

      /* u3r_safe_byte(): validate and retrieve byte.
      */
        c3_o
        u3r_safe_byte(u3_noun dat, c3_y* out_y);

      /* u3r_safe_word(): validate and retrieve word.
      */
        c3_o
        u3r_safe_word(u3_noun dat, c3_w* out_w);

      /* u3r_safe_chub(): validate and retrieve chub.
      */
        c3_o
        u3r_safe_chub(u3_noun dat, c3_d* out_d);

      /* u3r_string(): `a`, a text atom, as malloced C string.
      */
        c3_c*
        u3r_string(u3_atom a);

      /* u3r_tape(): `a`, a list of bytes, as malloced C string.
      */
        c3_y*
        u3r_tape(u3_noun a);

      /* u3r_skip():
      **
      **  Extract a constant from a formula, ignoring
      **  safe/static hints, doing no computation.
      */
        u3_weak
        u3r_skip(u3_noun fol);

      /* u3r_safe():
      **
      **  Returns yes if the formula won't crash
      **  and has no hints, returning constant result
      **  if possible
      */
      c3_o
      u3r_safe(u3_noun fol, u3_weak* out);

#endif /* ifndef U3_RETRIEVE_H */