1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- G N A T . P E R F E C T _ H A S H _ G E N E R A T O R S --
9 -- Copyright (C) 2002-2007, AdaCore --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 with Ada.Exceptions; use Ada.Exceptions;
35 with Ada.IO_Exceptions; use Ada.IO_Exceptions;
37 with GNAT.Heap_Sort_A; use GNAT.Heap_Sort_A;
38 with GNAT.OS_Lib; use GNAT.OS_Lib;
41 package body GNAT.Perfect_Hash_Generators is
43 -- We are using the algorithm of J. Czech as described in Zbigniew J.
44 -- Czech, George Havas, and Bohdan S. Majewski ``An Optimal Algorithm for
45 -- Generating Minimal Perfect Hash Functions'', Information Processing
46 -- Letters, 43(1992) pp.257-264, Oct.1992
48 -- This minimal perfect hash function generator is based on random graphs
49 -- and produces a hash function of the form:
51 -- h (w) = (g (f1 (w)) + g (f2 (w))) mod m
53 -- where f1 and f2 are functions that map strings into integers, and g is a
54 -- function that maps integers into [0, m-1]. h can be order preserving.
55 -- For instance, let W = {w_0, ..., w_i, ...,
56 -- w_m-1}, h can be defined such that h (w_i) = i.
58 -- This algorithm defines two possible constructions of f1 and f2. Method
59 -- b) stores the hash function in less memory space at the expense of
62 -- a) fk (w) = sum (for i in 1 .. length (w)) (Tk (i, w (i))) mod n
64 -- size (Tk) = max (for w in W) (length (w)) * size (used char set)
66 -- b) fk (w) = sum (for i in 1 .. length (w)) (Tk (i) * w (i)) mod n
68 -- size (Tk) = max (for w in W) (length (w)) but the table lookups are
69 -- replaced by multiplications.
71 -- where Tk values are randomly generated. n is defined later on but the
72 -- algorithm recommends to use a value a little bit greater than 2m. Note
73 -- that for large values of m, the main memory space requirements comes
74 -- from the memory space for storing function g (>= 2m entries).
76 -- Random graphs are frequently used to solve difficult problems that do
77 -- not have polynomial solutions. This algorithm is based on a weighted
78 -- undirected graph. It comprises two steps: mapping and assigment.
80 -- In the mapping step, a graph G = (V, E) is constructed, where = {0, 1,
81 -- ..., n-1} and E = {(for w in W) (f1 (w), f2 (w))}. In order for the
82 -- assignment step to be successful, G has to be acyclic. To have a high
83 -- probability of generating an acyclic graph, n >= 2m. If it is not
84 -- acyclic, Tk have to be regenerated.
86 -- In the assignment step, the algorithm builds function g. As is acyclic,
87 -- there is a vertex v1 with only one neighbor v2. Let w_i be the word such
88 -- that v1 = f1 (w_i) and v2 = f2 (w_i). Let g (v1) = 0 by construction and
89 -- g (v2) = (i - g (v1)) mod n (or to be general, (h (i) - g (v1) mod n).
90 -- If word w_j is such that v2 = f1 (w_j) and v3 = f2 (w_j), g (v3) = (j -
91 -- g (v2)) mod (or to be general, (h (j) - g (v2)) mod n). If w_i has no
92 -- neighbor, then another vertex is selected. The algorithm traverses G to
93 -- assign values to all the vertices. It cannot assign a value to an
94 -- already assigned vertex as G is acyclic.
96 subtype Word_Id is Integer;
97 subtype Key_Id is Integer;
98 subtype Vertex_Id is Integer;
99 subtype Edge_Id is Integer;
100 subtype Table_Id is Integer;
102 No_Vertex : constant Vertex_Id := -1;
103 No_Edge : constant Edge_Id := -1;
104 No_Table : constant Table_Id := -1;
106 Max_Word_Length : constant := 32;
107 subtype Word_Type is String (1 .. Max_Word_Length);
108 Null_Word : constant Word_Type := (others => ASCII.NUL);
109 -- Store keyword in a word. Note that the length of word is limited to 32
112 type Key_Type is record
115 -- A key corresponds to an edge in the algorithm graph
117 type Vertex_Type is record
121 -- A vertex can be involved in several edges. First and Last are the bounds
122 -- of an array of edges stored in a global edge table.
124 type Edge_Type is record
129 -- An edge is a peer of vertices. In the algorithm, a key is associated to
132 package WT is new GNAT.Table (Word_Type, Word_Id, 0, 32, 32);
133 package IT is new GNAT.Table (Integer, Integer, 0, 32, 32);
134 -- The two main tables. IT is used to store several tables of components
135 -- containing only integers.
137 function Image (Int : Integer; W : Natural := 0) return String;
138 function Image (Str : String; W : Natural := 0) return String;
139 -- Return a string which includes string Str or integer Int preceded by
140 -- leading spaces if required by width W.
142 Output : File_Descriptor renames GNAT.OS_Lib.Standout;
145 EOL : constant Character := ASCII.LF;
147 Max : constant := 78;
149 Line : String (1 .. Max);
150 -- Use this line to provide buffered IO
152 procedure Add (C : Character);
153 procedure Add (S : String);
154 -- Add a character or a string in Line and update Last
157 (F : File_Descriptor;
165 -- Write string S into file F as a element of an array of one or two
166 -- dimensions. Fk (resp. Lk and Ck) indicates the first (resp last and
167 -- current) index in the k-th dimension. If F1 = L1 the array is considered
168 -- as a one dimension array. This dimension is described by F2 and L2. This
169 -- routine takes care of all the parenthesis, spaces and commas needed to
170 -- format correctly the array. Moreover, the array is well indented and is
171 -- wrapped to fit in a 80 col line. When the line is full, the routine
172 -- writes it into file F. When the array is completed, the routine adds
173 -- semi-colon and writes the line into file F.
175 procedure New_Line (File : File_Descriptor);
176 -- Simulate Ada.Text_IO.New_Line with GNAT.OS_Lib
178 procedure Put (File : File_Descriptor; Str : String);
179 -- Simulate Ada.Text_IO.Put with GNAT.OS_Lib
181 procedure Put_Used_Char_Set (File : File_Descriptor; Title : String);
182 -- Output a title and a used character set
184 procedure Put_Int_Vector
185 (File : File_Descriptor;
189 -- Output a title and a vector
191 procedure Put_Int_Matrix
192 (File : File_Descriptor;
197 -- Output a title and a matrix. When the matrix has only one non-empty
198 -- dimension (Len_2 = 0), output a vector.
200 procedure Put_Edges (File : File_Descriptor; Title : String);
201 -- Output a title and an edge table
203 procedure Put_Initial_Keys (File : File_Descriptor; Title : String);
204 -- Output a title and a key table
206 procedure Put_Reduced_Keys (File : File_Descriptor; Title : String);
207 -- Output a title and a key table
209 procedure Put_Vertex_Table (File : File_Descriptor; Title : String);
210 -- Output a title and a vertex table
212 ----------------------------------
213 -- Character Position Selection --
214 ----------------------------------
216 -- We reduce the maximum key size by selecting representative positions
217 -- in these keys. We build a matrix with one word per line. We fill the
218 -- remaining space of a line with ASCII.NUL. The heuristic selects the
219 -- position that induces the minimum number of collisions. If there are
220 -- collisions, select another position on the reduced key set responsible
221 -- of the collisions. Apply the heuristic until there is no more collision.
223 procedure Apply_Position_Selection;
224 -- Apply Position selection and build the reduced key table
226 procedure Parse_Position_Selection (Argument : String);
227 -- Parse Argument and compute the position set. Argument is list of
228 -- substrings separated by commas. Each substring represents a position
229 -- or a range of positions (like x-y).
231 procedure Select_Character_Set;
232 -- Define an optimized used character set like Character'Pos in order not
233 -- to allocate tables of 256 entries.
235 procedure Select_Char_Position;
236 -- Find a min char position set in order to reduce the max key length. The
237 -- heuristic selects the position that induces the minimum number of
238 -- collisions. If there are collisions, select another position on the
239 -- reduced key set responsible of the collisions. Apply the heuristic until
240 -- there is no collision.
242 -----------------------------
243 -- Random Graph Generation --
244 -----------------------------
246 procedure Random (Seed : in out Natural);
247 -- Simulate Ada.Discrete_Numerics.Random
249 procedure Generate_Mapping_Table
253 Seed : in out Natural);
254 -- Random generation of the tables below. T is already allocated
256 procedure Generate_Mapping_Tables
258 Seed : in out Natural);
259 -- Generate the mapping tables T1 and T2. They are used to define fk (w) =
260 -- sum (for i in 1 .. length (w)) (Tk (i, w (i))) mod n. Keys, NK and Chars
261 -- are used to compute the matrix size.
263 ---------------------------
264 -- Algorithm Computation --
265 ---------------------------
267 procedure Compute_Edges_And_Vertices (Opt : Optimization);
268 -- Compute the edge and vertex tables. These are empty when a self loop is
269 -- detected (f1 (w) = f2 (w)). The edge table is sorted by X value and then
270 -- Y value. Keys is the key table and NK the number of keys. Chars is the
271 -- set of characters really used in Keys. NV is the number of vertices
272 -- recommended by the algorithm. T1 and T2 are the mapping tables needed to
273 -- compute f1 (w) and f2 (w).
275 function Acyclic return Boolean;
276 -- Return True when the graph is acyclic. Vertices is the current vertex
277 -- table and Edges the current edge table.
279 procedure Assign_Values_To_Vertices;
280 -- Execute the assignment step of the algorithm. Keys is the current key
281 -- table. Vertices and Edges represent the random graph. G is the result of
282 -- the assignment step such that:
283 -- h (w) = (g (f1 (w)) + g (f2 (w))) mod m
288 Opt : Optimization) return Natural;
289 -- For an optimization of CPU_Time return
290 -- fk (w) = sum (for i in 1 .. length (w)) (Tk (i, w (i))) mod n
291 -- For an optimization of Memory_Space return
292 -- fk (w) = sum (for i in 1 .. length (w)) (Tk (i) * w (i)) mod n
295 -------------------------------
296 -- Internal Table Management --
297 -------------------------------
299 function Allocate (N : Natural; S : Natural := 1) return Table_Id;
300 -- Allocate N * S ints from IT table
302 procedure Free_Tmp_Tables;
303 -- Deallocate the tables used by the algorithm (but not the keys table)
309 Keys : Table_Id := No_Table;
311 -- NK : Number of Keys
313 function Initial (K : Key_Id) return Word_Id;
314 pragma Inline (Initial);
316 function Reduced (K : Key_Id) return Word_Id;
317 pragma Inline (Reduced);
319 function Get_Key (N : Key_Id) return Key_Type;
320 procedure Set_Key (N : Key_Id; Item : Key_Type);
321 -- Get or Set Nth element of Keys table
327 Char_Pos_Set : Table_Id := No_Table;
328 Char_Pos_Set_Len : Natural;
329 -- Character Selected Position Set
331 function Get_Char_Pos (P : Natural) return Natural;
332 procedure Set_Char_Pos (P : Natural; Item : Natural);
333 -- Get or Set the string position of the Pth selected character
339 Used_Char_Set : Table_Id := No_Table;
340 Used_Char_Set_Len : Natural;
341 -- Used Character Set : Define a new character mapping. When all the
342 -- characters are not present in the keys, in order to reduce the size
343 -- of some tables, we redefine the character mapping.
345 function Get_Used_Char (C : Character) return Natural;
346 procedure Set_Used_Char (C : Character; Item : Natural);
352 T1 : Table_Id := No_Table;
353 T2 : Table_Id := No_Table;
356 -- T1 : Values table to compute F1
357 -- T2 : Values table to compute F2
359 function Get_Table (T : Integer; X, Y : Natural) return Natural;
360 procedure Set_Table (T : Integer; X, Y : Natural; Item : Natural);
366 G : Table_Id := No_Table;
368 -- Values table to compute G
370 NT : Natural := Default_Tries;
371 -- Number of tries running the algorithm before raising an error
373 function Get_Graph (N : Natural) return Integer;
374 procedure Set_Graph (N : Natural; Item : Integer);
375 -- Get or Set Nth element of graph
381 Edge_Size : constant := 3;
382 Edges : Table_Id := No_Table;
384 -- Edges : Edge table of the random graph G
386 function Get_Edges (F : Natural) return Edge_Type;
387 procedure Set_Edges (F : Natural; Item : Edge_Type);
393 Vertex_Size : constant := 2;
395 Vertices : Table_Id := No_Table;
396 -- Vertex table of the random graph G
399 -- Number of Vertices
401 function Get_Vertices (F : Natural) return Vertex_Type;
402 procedure Set_Vertices (F : Natural; Item : Vertex_Type);
403 -- Comments needed ???
406 -- Ratio between Keys and Vertices (parameter of Czech's algorithm)
409 -- Optimization mode (memory vs CPU)
411 Max_Key_Len : Natural := 0;
412 Min_Key_Len : Natural := Max_Word_Length;
413 -- Maximum and minimum of all the word length
418 function Type_Size (L : Natural) return Natural;
419 -- Given the last L of an unsigned integer type T, return its size
425 function Acyclic return Boolean is
426 Marks : array (0 .. NV - 1) of Vertex_Id := (others => No_Vertex);
428 function Traverse (Edge : Edge_Id; Mark : Vertex_Id) return Boolean;
429 -- Propagate Mark from X to Y. X is already marked. Mark Y and propagate
430 -- it to the edges of Y except the one representing the same key. Return
431 -- False when Y is marked with Mark.
437 function Traverse (Edge : Edge_Id; Mark : Vertex_Id) return Boolean is
438 E : constant Edge_Type := Get_Edges (Edge);
439 K : constant Key_Id := E.Key;
440 Y : constant Vertex_Id := E.Y;
441 M : constant Vertex_Id := Marks (E.Y);
448 elsif M = No_Vertex then
450 V := Get_Vertices (Y);
452 for J in V.First .. V.Last loop
454 -- Do not propagate to the edge representing the same key
456 if Get_Edges (J).Key /= K
457 and then not Traverse (J, Mark)
469 -- Start of processing for Acyclic
472 -- Edges valid range is
474 for J in 1 .. Edges_Len - 1 loop
476 Edge := Get_Edges (J);
478 -- Mark X of E when it has not been already done
480 if Marks (Edge.X) = No_Vertex then
481 Marks (Edge.X) := Edge.X;
484 -- Traverse E when this has not already been done
486 if Marks (Edge.Y) = No_Vertex
487 and then not Traverse (J, Edge.X)
500 procedure Add (C : Character) is
502 Line (Last + 1) := C;
510 procedure Add (S : String) is
511 Len : constant Natural := S'Length;
513 Line (Last + 1 .. Last + Len) := S;
521 function Allocate (N : Natural; S : Natural := 1) return Table_Id is
522 L : constant Integer := IT.Last;
524 IT.Set_Last (L + N * S);
528 ------------------------------
529 -- Apply_Position_Selection --
530 ------------------------------
532 procedure Apply_Position_Selection is
534 WT.Set_Last (2 * NK);
535 for J in 0 .. NK - 1 loop
537 I_Word : constant Word_Type := WT.Table (Initial (J));
538 R_Word : Word_Type := Null_Word;
539 Index : Natural := I_Word'First - 1;
542 -- Select the characters of Word included in the position
545 for C in 0 .. Char_Pos_Set_Len - 1 loop
546 exit when I_Word (Get_Char_Pos (C)) = ASCII.NUL;
548 R_Word (Index) := I_Word (Get_Char_Pos (C));
551 -- Build the new table with the reduced word
553 WT.Table (Reduced (J)) := R_Word;
554 Set_Key (J, (Edge => No_Edge));
557 end Apply_Position_Selection;
559 -------------------------------
560 -- Assign_Values_To_Vertices --
561 -------------------------------
563 procedure Assign_Values_To_Vertices is
566 procedure Assign (X : Vertex_Id);
567 -- Execute assignment on X's neighbors except the vertex that we are
568 -- coming from which is already assigned.
574 procedure Assign (X : Vertex_Id) is
576 V : constant Vertex_Type := Get_Vertices (X);
579 for J in V.First .. V.Last loop
582 if Get_Graph (E.Y) = -1 then
583 Set_Graph (E.Y, (E.Key - Get_Graph (X)) mod NK);
589 -- Start of processing for Assign_Values_To_Vertices
592 -- Value -1 denotes an unitialized value as it is supposed to
593 -- be in the range 0 .. NK.
597 G := Allocate (G_Len, 1);
600 for J in 0 .. G_Len - 1 loop
604 for K in 0 .. NK - 1 loop
605 X := Get_Edges (Get_Key (K).Edge).X;
607 if Get_Graph (X) = -1 then
613 for J in 0 .. G_Len - 1 loop
614 if Get_Graph (J) = -1 then
620 Put_Int_Vector (Output, "Assign Values To Vertices", G, G_Len);
622 end Assign_Values_To_Vertices;
628 procedure Compute (Position : String := Default_Position) is
629 Success : Boolean := False;
632 NV := Natural (K2V * Float (NK));
634 Keys := Allocate (NK);
637 Put_Initial_Keys (Output, "Initial Key Table");
640 if Position'Length /= 0 then
641 Parse_Position_Selection (Position);
643 Select_Char_Position;
648 (Output, "Char Position Set", Char_Pos_Set, Char_Pos_Set_Len);
651 Apply_Position_Selection;
654 Put_Reduced_Keys (Output, "Reduced Keys Table");
657 Select_Character_Set;
660 Put_Used_Char_Set (Output, "Character Position Table");
663 -- Perform Czech's algorithm
665 for J in 1 .. NT loop
666 Generate_Mapping_Tables (Opt, S);
667 Compute_Edges_And_Vertices (Opt);
669 -- When graph is not empty (no self-loop from previous operation) and
672 if 0 < Edges_Len and then Acyclic then
679 raise Too_Many_Tries;
682 Assign_Values_To_Vertices;
685 --------------------------------
686 -- Compute_Edges_And_Vertices --
687 --------------------------------
689 procedure Compute_Edges_And_Vertices (Opt : Optimization) is
694 Vertex : Vertex_Type;
695 Not_Acyclic : Boolean := False;
697 procedure Move (From : Natural; To : Natural);
698 function Lt (L, R : Natural) return Boolean;
699 -- Subprograms needed for GNAT.Heap_Sort_A
705 function Lt (L, R : Natural) return Boolean is
706 EL : constant Edge_Type := Get_Edges (L);
707 ER : constant Edge_Type := Get_Edges (R);
709 return EL.X < ER.X or else (EL.X = ER.X and then EL.Y < ER.Y);
716 procedure Move (From : Natural; To : Natural) is
718 Set_Edges (To, Get_Edges (From));
721 -- Start of processing for Compute_Edges_And_Vertices
724 -- We store edges from 1 to 2 * NK and leave zero alone in order to use
727 Edges_Len := 2 * NK + 1;
729 if Edges = No_Table then
730 Edges := Allocate (Edges_Len, Edge_Size);
733 if Vertices = No_Table then
734 Vertices := Allocate (NV, Vertex_Size);
737 for J in 0 .. NV - 1 loop
738 Set_Vertices (J, (No_Vertex, No_Vertex - 1));
741 -- For each w, X = f1 (w) and Y = f2 (w)
743 for J in 0 .. NK - 1 loop
748 X := Sum (WT.Table (Reduced (J)), T1, Opt);
749 Y := Sum (WT.Table (Reduced (J)), T2, Opt);
751 -- Discard T1 and T2 as soon as we discover a self loop
758 -- We store (X, Y) and (Y, X) to ease assignment step
760 Set_Edges (2 * J + 1, (X, Y, J));
761 Set_Edges (2 * J + 2, (Y, X, J));
764 -- Return an empty graph when self loop detected
771 Put_Edges (Output, "Unsorted Edge Table");
772 Put_Int_Matrix (Output, "Function Table 1", T1,
774 Put_Int_Matrix (Output, "Function Table 2", T2,
778 -- Enforce consistency between edges and keys. Construct Vertices and
779 -- compute the list of neighbors of a vertex First .. Last as Edges
780 -- is sorted by X and then Y. To compute the neighbor list, sort the
785 Move'Unrestricted_Access,
786 Lt'Unrestricted_Access);
789 Put_Edges (Output, "Sorted Edge Table");
790 Put_Int_Matrix (Output, "Function Table 1", T1,
792 Put_Int_Matrix (Output, "Function Table 2", T2,
796 -- Edges valid range is 1 .. 2 * NK
798 for E in 1 .. Edges_Len - 1 loop
799 Edge := Get_Edges (E);
800 Key := Get_Key (Edge.Key);
802 if Key.Edge = No_Edge then
804 Set_Key (Edge.Key, Key);
807 Vertex := Get_Vertices (Edge.X);
809 if Vertex.First = No_Edge then
814 Set_Vertices (Edge.X, Vertex);
818 Put_Reduced_Keys (Output, "Key Table");
819 Put_Edges (Output, "Edge Table");
820 Put_Vertex_Table (Output, "Vertex Table");
823 end Compute_Edges_And_Vertices;
831 Item_Size : out Natural;
832 Length_1 : out Natural;
833 Length_2 : out Natural)
837 when Character_Position =>
839 Length_1 := Char_Pos_Set_Len;
842 when Used_Character_Set =>
847 when Function_Table_1
848 | Function_Table_2 =>
849 Item_Size := Type_Size (NV);
854 Item_Size := Type_Size (NK);
864 procedure Finalize is
873 Min_Key_Len := Max_Word_Length;
876 ---------------------
877 -- Free_Tmp_Tables --
878 ---------------------
880 procedure Free_Tmp_Tables is
886 Char_Pos_Set := No_Table;
887 Char_Pos_Set_Len := 0;
889 Used_Char_Set := No_Table;
890 Used_Char_Set_Len := 0;
904 Vertices := No_Table;
908 ----------------------------
909 -- Generate_Mapping_Table --
910 ----------------------------
912 procedure Generate_Mapping_Table
916 Seed : in out Natural)
919 for J in 0 .. L1 - 1 loop
920 for K in 0 .. L2 - 1 loop
922 Set_Table (Tab, J, K, Seed mod NV);
925 end Generate_Mapping_Table;
927 -----------------------------
928 -- Generate_Mapping_Tables --
929 -----------------------------
931 procedure Generate_Mapping_Tables
933 Seed : in out Natural)
936 -- If T1 and T2 are already allocated no need to do it twice. Reuse them
937 -- as their size has not changed.
939 if T1 = No_Table and then T2 = No_Table then
941 Used_Char_Last : Natural := 0;
945 if Opt = CPU_Time then
946 for P in reverse Character'Range loop
947 Used_Char := Get_Used_Char (P);
948 if Used_Char /= 0 then
949 Used_Char_Last := Used_Char;
955 T1_Len := Char_Pos_Set_Len;
956 T2_Len := Used_Char_Last + 1;
957 T1 := Allocate (T1_Len * T2_Len);
958 T2 := Allocate (T1_Len * T2_Len);
962 Generate_Mapping_Table (T1, T1_Len, T2_Len, Seed);
963 Generate_Mapping_Table (T2, T1_Len, T2_Len, Seed);
966 Put_Used_Char_Set (Output, "Used Character Set");
967 Put_Int_Matrix (Output, "Function Table 1", T1,
969 Put_Int_Matrix (Output, "Function Table 2", T2,
972 end Generate_Mapping_Tables;
978 function Get_Char_Pos (P : Natural) return Natural is
979 N : constant Natural := Char_Pos_Set + P;
988 function Get_Edges (F : Natural) return Edge_Type is
989 N : constant Natural := Edges + (F * Edge_Size);
993 E.Y := IT.Table (N + 1);
994 E.Key := IT.Table (N + 2);
1002 function Get_Graph (N : Natural) return Integer is
1004 return IT.Table (G + N);
1011 function Get_Key (N : Key_Id) return Key_Type is
1014 K.Edge := IT.Table (Keys + N);
1022 function Get_Table (T : Integer; X, Y : Natural) return Natural is
1023 N : constant Natural := T + (Y * T1_Len) + X;
1025 return IT.Table (N);
1032 function Get_Used_Char (C : Character) return Natural is
1033 N : constant Natural := Used_Char_Set + Character'Pos (C);
1035 return IT.Table (N);
1042 function Get_Vertices (F : Natural) return Vertex_Type is
1043 N : constant Natural := Vertices + (F * Vertex_Size);
1046 V.First := IT.Table (N);
1047 V.Last := IT.Table (N + 1);
1055 function Image (Int : Integer; W : Natural := 0) return String is
1056 B : String (1 .. 32);
1059 procedure Img (V : Natural);
1060 -- Compute image of V into B, starting at B (L), incrementing L
1066 procedure Img (V : Natural) is
1073 B (L) := Character'Val ((V mod 10) + Character'Pos ('0'));
1076 -- Start of processing for Image
1087 return Image (B (1 .. L), W);
1094 function Image (Str : String; W : Natural := 0) return String is
1095 Len : constant Natural := Str'Length;
1096 Max : Natural := Len;
1104 Buf : String (1 .. Max) := (1 .. Max => ' ');
1107 for J in 0 .. Len - 1 loop
1108 Buf (Max - Len + 1 + J) := Str (Str'First + J);
1119 function Initial (K : Key_Id) return Word_Id is
1128 procedure Initialize
1130 K_To_V : Float := Default_K_To_V;
1131 Optim : Optimization := CPU_Time;
1132 Tries : Positive := Default_Tries)
1135 -- Free previous tables (the settings may have changed between two runs)
1139 if K_To_V <= 2.0 then
1140 Put (Output, "K to V ratio cannot be lower than 2.0");
1142 raise Program_Error;
1155 procedure Insert (Value : String) is
1156 Word : Word_Type := Null_Word;
1157 Len : constant Natural := Value'Length;
1160 Word (1 .. Len) := Value (Value'First .. Value'First + Len - 1);
1162 WT.Table (NK) := Word;
1164 NV := Natural (Float (NK) * K2V);
1166 -- Do not accept a value of K2V too close to 2.0 such that once rounded
1167 -- up, NV = 2 * NK because the algorithm would not converge.
1169 if NV <= 2 * NK then
1173 if Max_Key_Len < Len then
1177 if Len < Min_Key_Len then
1186 procedure New_Line (File : File_Descriptor) is
1188 if Write (File, EOL'Address, 1) /= 1 then
1189 raise Program_Error;
1193 ------------------------------
1194 -- Parse_Position_Selection --
1195 ------------------------------
1197 procedure Parse_Position_Selection (Argument : String) is
1198 N : Natural := Argument'First;
1199 L : constant Natural := Argument'Last;
1200 M : constant Natural := Max_Key_Len;
1202 T : array (1 .. M) of Boolean := (others => False);
1204 function Parse_Index return Natural;
1205 -- Parse argument starting at index N to find an index
1211 function Parse_Index return Natural is
1212 C : Character := Argument (N);
1221 if C not in '0' .. '9' then
1223 (Program_Error'Identity, "cannot read position argument");
1226 while C in '0' .. '9' loop
1227 V := V * 10 + (Character'Pos (C) - Character'Pos ('0'));
1236 -- Start of processing for Parse_Position_Selection
1239 -- Empty specification means all the positions
1242 Char_Pos_Set_Len := M;
1243 Char_Pos_Set := Allocate (Char_Pos_Set_Len);
1245 for C in 0 .. Char_Pos_Set_Len - 1 loop
1246 Set_Char_Pos (C, C + 1);
1252 First, Last : Natural;
1255 First := Parse_Index;
1260 if N <= L and then Argument (N) = '-' then
1262 Last := Parse_Index;
1265 -- Include the positions in the selection
1267 for J in First .. Last loop
1274 if Argument (N) /= ',' then
1276 (Program_Error'Identity, "cannot read position argument");
1282 -- Compute position selection length
1285 for J in T'Range loop
1291 -- Fill position selection
1293 Char_Pos_Set_Len := N;
1294 Char_Pos_Set := Allocate (Char_Pos_Set_Len);
1297 for J in T'Range loop
1299 Set_Char_Pos (N, J);
1304 end Parse_Position_Selection;
1310 procedure Produce (Pkg_Name : String := Default_Pkg_Name) is
1311 File : File_Descriptor;
1314 -- For call to Close
1316 function Array_Img (N, T, R1 : String; R2 : String := "") return String;
1317 -- Return string "N : constant array (R1[, R2]) of T;"
1319 function Range_Img (F, L : Natural; T : String := "") return String;
1320 -- Return string "[T range ]F .. L"
1322 function Type_Img (L : Natural) return String;
1323 -- Return the larger unsigned type T such that T'Last < L
1331 R2 : String := "") return String
1337 Add (" : constant array (");
1348 return Line (1 .. Last);
1355 function Range_Img (F, L : Natural; T : String := "") return String is
1356 FI : constant String := Image (F);
1357 FL : constant Natural := FI'Length;
1358 LI : constant String := Image (L);
1359 LL : constant Natural := LI'Length;
1360 TL : constant Natural := T'Length;
1361 RI : String (1 .. TL + 7 + FL + 4 + LL);
1366 RI (Len + 1 .. Len + TL) := T;
1368 RI (Len + 1 .. Len + 7) := " range ";
1372 RI (Len + 1 .. Len + FL) := FI;
1374 RI (Len + 1 .. Len + 4) := " .. ";
1376 RI (Len + 1 .. Len + LL) := LI;
1378 return RI (1 .. Len);
1385 function Type_Img (L : Natural) return String is
1386 S : constant String := Image (Type_Size (L));
1387 U : String := "Unsigned_ ";
1391 for J in S'Range loop
1403 PLen : constant Natural := Pkg_Name'Length;
1404 FName : String (1 .. PLen + 4);
1406 -- Start of processing for Produce
1409 FName (1 .. PLen) := Pkg_Name;
1410 for J in 1 .. PLen loop
1411 if FName (J) in 'A' .. 'Z' then
1412 FName (J) := Character'Val (Character'Pos (FName (J))
1413 - Character'Pos ('A')
1414 + Character'Pos ('a'));
1416 elsif FName (J) = '.' then
1421 FName (PLen + 1 .. PLen + 4) := ".ads";
1423 File := Create_File (FName, Binary);
1425 Put (File, "package ");
1426 Put (File, Pkg_Name);
1429 Put (File, " function Hash (S : String) return Natural;");
1432 Put (File, Pkg_Name);
1435 Close (File, Status);
1441 FName (PLen + 4) := 'b';
1443 File := Create_File (FName, Binary);
1445 Put (File, "with Interfaces; use Interfaces;");
1448 Put (File, "package body ");
1449 Put (File, Pkg_Name);
1454 if Opt = CPU_Time then
1455 Put (File, Array_Img ("C", Type_Img (256), "Character"));
1458 F := Character'Pos (Character'First);
1459 L := Character'Pos (Character'Last);
1461 for J in Character'Range loop
1462 P := Get_Used_Char (J);
1463 Put (File, Image (P), 1, 0, 1, F, L, Character'Pos (J));
1470 L := Char_Pos_Set_Len - 1;
1472 Put (File, Array_Img ("P", "Natural", Range_Img (F, L)));
1475 for J in F .. L loop
1476 Put (File, Image (Get_Char_Pos (J)), 1, 0, 1, F, L, J);
1481 if Opt = CPU_Time then
1484 Array_Img ("T1", Type_Img (NV),
1485 Range_Img (0, T1_Len - 1),
1486 Range_Img (0, T2_Len - 1, Type_Img (256))),
1487 T1, T1_Len, T2_Len);
1492 Array_Img ("T1", Type_Img (NV),
1493 Range_Img (0, T1_Len - 1)),
1499 if Opt = CPU_Time then
1502 Array_Img ("T2", Type_Img (NV),
1503 Range_Img (0, T1_Len - 1),
1504 Range_Img (0, T2_Len - 1, Type_Img (256))),
1505 T2, T1_Len, T2_Len);
1510 Array_Img ("T2", Type_Img (NV),
1511 Range_Img (0, T1_Len - 1)),
1519 Array_Img ("G", Type_Img (NK),
1520 Range_Img (0, G_Len - 1)),
1524 Put (File, " function Hash (S : String) return Natural is");
1526 Put (File, " F : constant Natural := S'First - 1;");
1528 Put (File, " L : constant Natural := S'Length;");
1530 Put (File, " F1, F2 : Natural := 0;");
1533 Put (File, " J : ");
1535 if Opt = CPU_Time then
1536 Put (File, Type_Img (256));
1538 Put (File, "Natural");
1544 Put (File, " begin");
1546 Put (File, " for K in P'Range loop");
1548 Put (File, " exit when L < P (K);");
1550 Put (File, " J := ");
1552 if Opt = CPU_Time then
1555 Put (File, "Character'Pos");
1558 Put (File, " (S (P (K) + F));");
1561 Put (File, " F1 := (F1 + Natural (T1 (K");
1563 if Opt = CPU_Time then
1569 if Opt = Memory_Space then
1573 Put (File, ") mod ");
1574 Put (File, Image (NV));
1578 Put (File, " F2 := (F2 + Natural (T2 (K");
1580 if Opt = CPU_Time then
1586 if Opt = Memory_Space then
1590 Put (File, ") mod ");
1591 Put (File, Image (NV));
1595 Put (File, " end loop;");
1599 " return (Natural (G (F1)) + Natural (G (F2))) mod ");
1601 Put (File, Image (NK));
1604 Put (File, " end Hash;");
1608 Put (File, Pkg_Name);
1611 Close (File, Status);
1622 procedure Put (File : File_Descriptor; Str : String) is
1623 Len : constant Natural := Str'Length;
1625 if Write (File, Str'Address, Len) /= Len then
1626 raise Program_Error;
1635 (F : File_Descriptor;
1644 Len : constant Natural := S'Length;
1647 -- Write current line, followed by LF
1655 Put (F, Line (1 .. Last));
1660 -- Start of processing for Put
1663 if C1 = F1 and then C2 = F2 then
1667 if Last + Len + 3 > Max then
1672 Line (Last + 1 .. Last + 5) := " ";
1676 if C1 = F1 and then C2 = F2 then
1700 Line (Last + 1 .. Last + Len) := S;
1729 procedure Put_Edges (File : File_Descriptor; Title : String) is
1731 F1 : constant Natural := 1;
1732 L1 : constant Natural := Edges_Len - 1;
1733 M : constant Natural := Max / 5;
1739 -- Edges valid range is 1 .. Edge_Len - 1
1741 for J in F1 .. L1 loop
1743 Put (File, Image (J, M), F1, L1, J, 1, 4, 1);
1744 Put (File, Image (E.X, M), F1, L1, J, 1, 4, 2);
1745 Put (File, Image (E.Y, M), F1, L1, J, 1, 4, 3);
1746 Put (File, Image (E.Key, M), F1, L1, J, 1, 4, 4);
1750 ----------------------
1751 -- Put_Initial_Keys --
1752 ----------------------
1754 procedure Put_Initial_Keys (File : File_Descriptor; Title : String) is
1755 F1 : constant Natural := 0;
1756 L1 : constant Natural := NK - 1;
1757 M : constant Natural := Max / 5;
1764 for J in F1 .. L1 loop
1766 Put (File, Image (J, M), F1, L1, J, 1, 3, 1);
1767 Put (File, Image (K.Edge, M), F1, L1, J, 1, 3, 2);
1768 Put (File, WT.Table (Initial (J)), F1, L1, J, 1, 3, 3);
1770 end Put_Initial_Keys;
1772 --------------------
1773 -- Put_Int_Matrix --
1774 --------------------
1776 procedure Put_Int_Matrix
1777 (File : File_Descriptor;
1783 F1 : constant Integer := 0;
1784 L1 : constant Integer := Len_1 - 1;
1785 F2 : constant Integer := 0;
1786 L2 : constant Integer := Len_2 - 1;
1794 for J in F1 .. L1 loop
1795 Ix := IT.Table (Table + J);
1796 Put (File, Image (Ix), 1, 0, 1, F1, L1, J);
1800 for J in F1 .. L1 loop
1801 for K in F2 .. L2 loop
1802 Ix := IT.Table (Table + J + K * Len_1);
1803 Put (File, Image (Ix), F1, L1, J, F2, L2, K);
1809 --------------------
1810 -- Put_Int_Vector --
1811 --------------------
1813 procedure Put_Int_Vector
1814 (File : File_Descriptor;
1819 F2 : constant Natural := 0;
1820 L2 : constant Natural := Length - 1;
1826 for J in F2 .. L2 loop
1827 Put (File, Image (IT.Table (Vector + J)), 1, 0, 1, F2, L2, J);
1831 ----------------------
1832 -- Put_Reduced_Keys --
1833 ----------------------
1835 procedure Put_Reduced_Keys (File : File_Descriptor; Title : String) is
1836 F1 : constant Natural := 0;
1837 L1 : constant Natural := NK - 1;
1838 M : constant Natural := Max / 5;
1845 for J in F1 .. L1 loop
1847 Put (File, Image (J, M), F1, L1, J, 1, 3, 1);
1848 Put (File, Image (K.Edge, M), F1, L1, J, 1, 3, 2);
1849 Put (File, WT.Table (Reduced (J)), F1, L1, J, 1, 3, 3);
1851 end Put_Reduced_Keys;
1853 -----------------------
1854 -- Put_Used_Char_Set --
1855 -----------------------
1857 procedure Put_Used_Char_Set (File : File_Descriptor; Title : String) is
1858 F : constant Natural := Character'Pos (Character'First);
1859 L : constant Natural := Character'Pos (Character'Last);
1865 for J in Character'Range loop
1867 (File, Image (Get_Used_Char (J)), 1, 0, 1, F, L, Character'Pos (J));
1869 end Put_Used_Char_Set;
1871 ----------------------
1872 -- Put_Vertex_Table --
1873 ----------------------
1875 procedure Put_Vertex_Table (File : File_Descriptor; Title : String) is
1876 F1 : constant Natural := 0;
1877 L1 : constant Natural := NV - 1;
1878 M : constant Natural := Max / 4;
1885 for J in F1 .. L1 loop
1886 V := Get_Vertices (J);
1887 Put (File, Image (J, M), F1, L1, J, 1, 3, 1);
1888 Put (File, Image (V.First, M), F1, L1, J, 1, 3, 2);
1889 Put (File, Image (V.Last, M), F1, L1, J, 1, 3, 3);
1891 end Put_Vertex_Table;
1897 procedure Random (Seed : in out Natural) is
1899 -- Park & Miller Standard Minimal using Schrage's algorithm to avoid
1900 -- overflow: Xn+1 = 16807 * Xn mod (2 ** 31 - 1)
1907 R := Seed mod 127773;
1909 X := 16807 * R - 2836 * Q;
1912 Seed := X + 2147483647;
1922 function Reduced (K : Key_Id) return Word_Id is
1927 --------------------------
1928 -- Select_Char_Position --
1929 --------------------------
1931 procedure Select_Char_Position is
1933 type Vertex_Table_Type is array (Natural range <>) of Vertex_Type;
1935 procedure Build_Identical_Keys_Sets
1936 (Table : in out Vertex_Table_Type;
1937 Last : in out Natural;
1939 -- Build a list of keys subsets that are identical with the current
1940 -- position selection plus Pos. Once this routine is called, reduced
1941 -- words are sorted by subsets and each item (First, Last) in Sets
1942 -- defines the range of identical keys.
1943 -- Need comment saying exactly what Last is ???
1945 function Count_Different_Keys
1946 (Table : Vertex_Table_Type;
1948 Pos : Natural) return Natural;
1949 -- For each subset in Sets, count the number of different keys if we add
1950 -- Pos to the current position selection.
1952 Sel_Position : IT.Table_Type (1 .. Max_Key_Len);
1953 Last_Sel_Pos : Natural := 0;
1954 Max_Sel_Pos : Natural := 0;
1956 -------------------------------
1957 -- Build_Identical_Keys_Sets --
1958 -------------------------------
1960 procedure Build_Identical_Keys_Sets
1961 (Table : in out Vertex_Table_Type;
1962 Last : in out Natural;
1965 S : constant Vertex_Table_Type := Table (Table'First .. Last);
1966 C : constant Natural := Pos;
1967 -- Shortcuts (why are these not renames ???)
1971 -- First and last words of a subset
1974 -- GNAT.Heap_Sort assumes that the first array index is 1. Offset
1975 -- defines the translation to operate.
1977 function Lt (L, R : Natural) return Boolean;
1978 procedure Move (From : Natural; To : Natural);
1979 -- Subprograms needed by GNAT.Heap_Sort_A
1985 function Lt (L, R : Natural) return Boolean is
1986 C : constant Natural := Pos;
1992 Left := Reduced (0) - 1;
1993 Right := Offset + R;
1996 Right := Reduced (0) - 1;
1999 Right := Offset + R;
2002 return WT.Table (Left)(C) < WT.Table (Right)(C);
2009 procedure Move (From : Natural; To : Natural) is
2010 Target, Source : Natural;
2014 Source := Reduced (0) - 1;
2015 Target := Offset + To;
2017 Source := Offset + From;
2018 Target := Reduced (0) - 1;
2020 Source := Offset + From;
2021 Target := Offset + To;
2024 WT.Table (Target) := WT.Table (Source);
2027 -- Start of processing for Build_Identical_Key_Sets
2032 -- For each subset in S, extract the new subsets we have by adding C
2033 -- in the position selection.
2035 for J in S'Range loop
2036 if S (J).First = S (J).Last then
2040 Table (Last) := (F, L);
2043 Offset := Reduced (S (J).First) - 1;
2045 (S (J).Last - S (J).First + 1,
2046 Move'Unrestricted_Access,
2047 Lt'Unrestricted_Access);
2051 for N in S (J).First .. S (J).Last loop
2053 -- For the last item, close the last subset
2055 if N = S (J).Last then
2057 Table (Last) := (F, N);
2059 -- Two contiguous words are identical when they have the
2060 -- same Cth character.
2062 elsif WT.Table (Reduced (N))(C) =
2063 WT.Table (Reduced (N + 1))(C)
2067 -- Find a new subset of identical keys. Store the current
2068 -- one and create a new subset.
2072 Table (Last) := (F, L);
2079 end Build_Identical_Keys_Sets;
2081 --------------------------
2082 -- Count_Different_Keys --
2083 --------------------------
2085 function Count_Different_Keys
2086 (Table : Vertex_Table_Type;
2088 Pos : Natural) return Natural
2090 N : array (Character) of Natural;
2095 -- For each subset, count the number of words that are still
2096 -- different when we include Pos in the position selection. Only
2097 -- focus on this position as the other positions already produce
2100 for S in 1 .. Last loop
2102 -- Count the occurrences of the different characters
2105 for K in Table (S).First .. Table (S).Last loop
2106 C := WT.Table (Reduced (K))(Pos);
2110 -- Update the number of different keys. Each character used
2111 -- denotes a different key.
2113 for J in N'Range loop
2121 end Count_Different_Keys;
2123 -- Start of processing for Select_Char_Position
2126 -- Initialize the reduced words set
2128 WT.Set_Last (2 * NK);
2129 for K in 0 .. NK - 1 loop
2130 WT.Table (Reduced (K)) := WT.Table (Initial (K));
2134 Differences : Natural;
2135 Max_Differences : Natural := 0;
2136 Old_Differences : Natural;
2137 Max_Diff_Sel_Pos : Natural := 0; -- init to kill warning
2138 Max_Diff_Sel_Pos_Idx : Natural := 0; -- init to kill warning
2139 Same_Keys_Sets_Table : Vertex_Table_Type (1 .. NK);
2140 Same_Keys_Sets_Last : Natural := 1;
2143 for C in Sel_Position'Range loop
2144 Sel_Position (C) := C;
2147 Same_Keys_Sets_Table (1) := (0, NK - 1);
2150 -- Preserve maximum number of different keys and check later on
2151 -- that this value is strictly incrementing. Otherwise, it means
2152 -- that two keys are stricly identical.
2154 Old_Differences := Max_Differences;
2156 -- The first position should not exceed the minimum key length.
2157 -- Otherwise, we may end up with an empty word once reduced.
2159 if Last_Sel_Pos = 0 then
2160 Max_Sel_Pos := Min_Key_Len;
2162 Max_Sel_Pos := Max_Key_Len;
2165 -- Find which position increases more the number of differences
2167 for J in Last_Sel_Pos + 1 .. Max_Sel_Pos loop
2168 Differences := Count_Different_Keys
2169 (Same_Keys_Sets_Table,
2170 Same_Keys_Sets_Last,
2175 "Selecting position" & Sel_Position (J)'Img &
2176 " results in" & Differences'Img &
2181 if Differences > Max_Differences then
2182 Max_Differences := Differences;
2183 Max_Diff_Sel_Pos := Sel_Position (J);
2184 Max_Diff_Sel_Pos_Idx := J;
2188 if Old_Differences = Max_Differences then
2190 (Program_Error'Identity, "some keys are identical");
2193 -- Insert selected position and sort Sel_Position table
2195 Last_Sel_Pos := Last_Sel_Pos + 1;
2196 Sel_Position (Last_Sel_Pos + 1 .. Max_Diff_Sel_Pos_Idx) :=
2197 Sel_Position (Last_Sel_Pos .. Max_Diff_Sel_Pos_Idx - 1);
2198 Sel_Position (Last_Sel_Pos) := Max_Diff_Sel_Pos;
2200 for P in 1 .. Last_Sel_Pos - 1 loop
2201 if Max_Diff_Sel_Pos < Sel_Position (P) then
2202 Sel_Position (P + 1 .. Last_Sel_Pos) :=
2203 Sel_Position (P .. Last_Sel_Pos - 1);
2204 Sel_Position (P) := Max_Diff_Sel_Pos;
2209 exit when Max_Differences = NK;
2211 Build_Identical_Keys_Sets
2212 (Same_Keys_Sets_Table,
2213 Same_Keys_Sets_Last,
2218 "Selecting position" & Max_Diff_Sel_Pos'Img &
2219 " results in" & Max_Differences'Img &
2224 for J in 1 .. Same_Keys_Sets_Last loop
2226 Same_Keys_Sets_Table (J).First ..
2227 Same_Keys_Sets_Table (J).Last
2229 Put (Output, WT.Table (Reduced (K)));
2239 Char_Pos_Set_Len := Last_Sel_Pos;
2240 Char_Pos_Set := Allocate (Char_Pos_Set_Len);
2242 for C in 1 .. Last_Sel_Pos loop
2243 Set_Char_Pos (C - 1, Sel_Position (C));
2245 end Select_Char_Position;
2247 --------------------------
2248 -- Select_Character_Set --
2249 --------------------------
2251 procedure Select_Character_Set is
2252 Last : Natural := 0;
2253 Used : array (Character) of Boolean := (others => False);
2257 for J in 0 .. NK - 1 loop
2258 for K in 0 .. Char_Pos_Set_Len - 1 loop
2259 Char := WT.Table (Initial (J))(Get_Char_Pos (K));
2260 exit when Char = ASCII.NUL;
2261 Used (Char) := True;
2265 Used_Char_Set_Len := 256;
2266 Used_Char_Set := Allocate (Used_Char_Set_Len);
2268 for J in Used'Range loop
2270 Set_Used_Char (J, Last);
2273 Set_Used_Char (J, 0);
2276 end Select_Character_Set;
2282 procedure Set_Char_Pos (P : Natural; Item : Natural) is
2283 N : constant Natural := Char_Pos_Set + P;
2285 IT.Table (N) := Item;
2292 procedure Set_Edges (F : Natural; Item : Edge_Type) is
2293 N : constant Natural := Edges + (F * Edge_Size);
2295 IT.Table (N) := Item.X;
2296 IT.Table (N + 1) := Item.Y;
2297 IT.Table (N + 2) := Item.Key;
2304 procedure Set_Graph (N : Natural; Item : Integer) is
2306 IT.Table (G + N) := Item;
2313 procedure Set_Key (N : Key_Id; Item : Key_Type) is
2315 IT.Table (Keys + N) := Item.Edge;
2322 procedure Set_Table (T : Integer; X, Y : Natural; Item : Natural) is
2323 N : constant Natural := T + ((Y * T1_Len) + X);
2325 IT.Table (N) := Item;
2332 procedure Set_Used_Char (C : Character; Item : Natural) is
2333 N : constant Natural := Used_Char_Set + Character'Pos (C);
2335 IT.Table (N) := Item;
2342 procedure Set_Vertices (F : Natural; Item : Vertex_Type) is
2343 N : constant Natural := Vertices + (F * Vertex_Size);
2345 IT.Table (N) := Item.First;
2346 IT.Table (N + 1) := Item.Last;
2356 Opt : Optimization) return Natural
2362 if Opt = CPU_Time then
2363 for J in 0 .. T1_Len - 1 loop
2364 exit when Word (J + 1) = ASCII.NUL;
2365 R := Get_Table (Table, J, Get_Used_Char (Word (J + 1)));
2366 S := (S + R) mod NV;
2370 for J in 0 .. T1_Len - 1 loop
2371 exit when Word (J + 1) = ASCII.NUL;
2372 R := Get_Table (Table, J, 0);
2373 S := (S + R * Character'Pos (Word (J + 1))) mod NV;
2384 function Type_Size (L : Natural) return Natural is
2388 elsif L <= 2 ** 16 then
2402 K : Natural := 0) return Natural
2406 when Character_Position =>
2407 return Get_Char_Pos (J);
2409 when Used_Character_Set =>
2410 return Get_Used_Char (Character'Val (J));
2412 when Function_Table_1 =>
2413 return Get_Table (T1, J, K);
2415 when Function_Table_2 =>
2416 return Get_Table (T2, J, K);
2419 return Get_Graph (J);
2424 end GNAT.Perfect_Hash_Generators;