aiger.h

/***************************************************************************
Copyright (c) 2006 - 2018, Armin Biere, Johannes Kepler University.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to
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IN THE SOFTWARE.
***************************************************************************/

/*------------------------------------------------------------------------*/
/* This file contains the API of the 'AIGER' library, which is a reader and
 * writer for the AIGER AIG format.  The code of the library 
 * consists of 'aiger.c' and 'aiger.h'.  It is independent of 'simpaig.c'
 * and 'simpaig.h'.
 * library.
 */
#ifndef aiger_h_INCLUDED
#define aiger_h_INCLUDED

#include <stdio.h>

/*------------------------------------------------------------------------*/

#define AIGER_VERSION "1.9"

/*------------------------------------------------------------------------*/

#ifdef __cplusplus
extern "C" {
#endif

typedef struct aiger aiger;
typedef struct aiger_and aiger_and;
typedef struct aiger_symbol aiger_symbol;

/*------------------------------------------------------------------------*/
/* AIG references are represented as unsigned integers and are called
 * literals.  The least significant bit is the sign.  The index of a literal
 * can be obtained by dividing the literal by two.  Only positive indices
 * are allowed, which leaves 0 for the boolean constant FALSE.  The boolean
 * constant TRUE is encoded as the unsigned number 1 accordingly.
 */
#define aiger_false 0
#define aiger_true 1

#define aiger_is_constant(l) \
  ((l) == aiger_false || ((l) == aiger_true))

#define aiger_sign(l) \
  (((unsigned)(l))&1)

#define aiger_strip(l) \
  (((unsigned)(l))&~1)

#define aiger_not(l) \
  (((unsigned)(l))^1)

/*------------------------------------------------------------------------*/
/* Each literal is associated to a variable having an unsigned index.  The
 * variable index is obtained by deviding the literal index by two, which is
 * the same as removing the sign bit.
 */
#define aiger_var2lit(i) \
  (((unsigned)(i)) << 1)

#define aiger_lit2var(l) \
  (((unsigned)(l)) >> 1)

/*------------------------------------------------------------------------*/
/* Callback functions for client memory management.  The 'free' wrapper will
 * get as last argument the size of the memory as it was allocated.
 */
typedef void *(*aiger_malloc) (void *mem_mgr, size_t);
typedef void (*aiger_free) (void *mem_mgr, void *ptr, size_t);

/*------------------------------------------------------------------------*/
/* Callback function for client character stream reading.  It returns an
 * ASCII character or EOF.  Thus is has the same semantics as the standard
 * library 'getc'.   See 'aiger_read_generic' for more details.
 */
typedef int (*aiger_get) (void *client_state);

/*------------------------------------------------------------------------*/
/* Callback function for client character stream writing.  The return value
 * is EOF iff writing failed and otherwise the character 'ch' casted to an
 * unsigned char.  It has therefore the same semantics as 'fputc' and 'putc'
 * from the standard library.
 */
typedef int (*aiger_put) (char ch, void *client_state);

/*------------------------------------------------------------------------*/

enum aiger_mode
{
  aiger_binary_mode = 0,
  aiger_ascii_mode = 1,
  aiger_stripped_mode = 2,	/* can be ORed with one of the previous */
};

typedef enum aiger_mode aiger_mode;

/*------------------------------------------------------------------------*/

struct aiger_and
{
  unsigned lhs;			/* as literal [2..2*maxvar], even */
  unsigned rhs0;		/* as literal [0..2*maxvar+1] */
  unsigned rhs1;		/* as literal [0..2*maxvar+1] */
};

/*------------------------------------------------------------------------*/

struct aiger_symbol
{
  unsigned lit;			/* as literal [0..2*maxvar+1] */
  unsigned next, reset;		/* used only for latches */
  unsigned size, * lits;	/* used only for justice */
  char *name;
};

/*------------------------------------------------------------------------*/
/* This is the externally visible state of the library.  The format is
 * almost the same as the ASCII file format.  The first part is exactly as
 * in the header 'M I L O A' and optional 'B C J F' after the format identifier
 * string.
 */
struct aiger
{
  /* variable not literal index, e.g. maxlit = 2*maxvar + 1 
   */
  unsigned maxvar;

  unsigned num_inputs;
  unsigned num_latches;
  unsigned num_outputs;
  unsigned num_ands;
  unsigned num_bad;
  unsigned num_constraints;
  unsigned num_justice;
  unsigned num_fairness;

  aiger_symbol *inputs;		/* [0..num_inputs[ */
  aiger_symbol *latches;	/* [0..num_latches[ */
  aiger_symbol *outputs;	/* [0..num_outputs[ */
  aiger_symbol *bad;		/* [0..num_bad[ */
  aiger_symbol *constraints;	/* [0..num_constraints[ */
  aiger_symbol *justice;	/* [0..num_justice[ */
  aiger_symbol *fairness;	/* [0..num_fairness[ */

  aiger_and *ands;		/* [0..num_ands[ */

  char **comments;		/* zero terminated */
};

/*------------------------------------------------------------------------*/
/* Version and CVS identifier.
 */
const char *aiger_id (void);  	     /* not working after moving to 'git' */
const char *aiger_version (void);

/*------------------------------------------------------------------------*/
/* You need to initialize the library first.  This generic initialization
 * function uses standard 'malloc' and 'free' from the standard library for
 * memory management.
 */
aiger *aiger_init (void);

/*------------------------------------------------------------------------*/
/* Same as previous initialization function except that a memory manager
 * from the client is used for memory allocation.  See the 'aiger_malloc'
 * and 'aiger_free' definitions above.
 */
aiger *aiger_init_mem (void *mem_mgr, aiger_malloc, aiger_free);

/*------------------------------------------------------------------------*/
/* Reset and delete the library.
 */
void aiger_reset (aiger *);

/*------------------------------------------------------------------------*/
/* Treat the literal 'lit' as input, output, latch, bad, constraint,
 * justice of fairness respectively.  The
 * literal of latches and inputs can not be signed nor a constant (< 2).
 * You can not register latches nor inputs multiple times.  An input can not
 * be a latch.  The last argument is the symbolic name if non zero.
 * The same literal can of course be used for multiple outputs.
 */
void aiger_add_input (aiger *, unsigned lit, const char *);
void aiger_add_latch (aiger *, unsigned lit, unsigned next, const char *);
void aiger_add_output (aiger *, unsigned lit, const char *);
void aiger_add_bad (aiger *, unsigned lit, const char *);
void aiger_add_constraint (aiger *, unsigned lit, const char *);
void aiger_add_justice (aiger *, unsigned size, unsigned *, const char *);
void aiger_add_fairness (aiger *, unsigned lit, const char *);

/*------------------------------------------------------------------------*/
/* Add a reset value to the latch 'lit'.  The 'lit' has to be a previously
 * added latch and 'reset' is either '0', '1' or equal to 'lit', the latter
 * means undefined.
 */
void aiger_add_reset (aiger *, unsigned lit, unsigned reset);

/*------------------------------------------------------------------------*/
/* Register an unsigned AND with AIGER.  The arguments are signed literals
 * as discussed above, e.g. the least significant bit stores the sign and
 * the remaining bit the variable index.  The 'lhs' has to be unsigned
 * (even).  It identifies the AND and can only be registered once.  After
 * registration an AND can be accessed through 'ands[aiger_lit2idx (lhs)]'.
 */
void aiger_add_and (aiger *, unsigned lhs, unsigned rhs0, unsigned rhs1);

/*------------------------------------------------------------------------*/
/* Add a line of comments.  The comment may not contain a new line character.
 */
void aiger_add_comment (aiger *, const char *comment_line);

/*------------------------------------------------------------------------*/
/* This checks the consistency for debugging and testing purposes.  In
 * particular, it is checked that all 'next' literals of latches, all
 * outputs, and all right hand sides of ANDs are defined, where defined
 * means that the corresponding literal is a constant 0 or 1, or defined as
 * an input, a latch, or AND gate.  Furthermore the definitions of ANDs are
 * checked to be non cyclic.  If a check fails a corresponding error message
 * is returned.
 */
const char *aiger_check (aiger *);

/*------------------------------------------------------------------------*/
/* These are the writer functions for AIGER.  They return zero on failure.
 * The assumptions on 'aiger_put' are the same as with 'fputc' from the
 * standard library (see the 'aiger_put' definition above).  Note, that
 * writing in binary mode triggers 'aig_reencode' and thus destroys the
 * original literal association and may even delete AND nodes.  See
 * 'aiger_reencode' for more details.
 */
int aiger_write_to_file (aiger *, aiger_mode, FILE *);
int aiger_write_to_string (aiger *, aiger_mode, char *str, size_t len);
int aiger_write_generic (aiger *, aiger_mode, void *state, aiger_put);

/*------------------------------------------------------------------------*/
/* The following function allows to write to a file.  The write mode is
 * determined from the suffix in the file name.  The mode used is ASCII for
 * a '.aag' suffix and binary mode otherwise.  In addition a '.gz' suffix can
 * be added which requests the file to written by piping it through 'gzip'.
 * This feature assumes that the 'gzip' program is in your path and can be
 * executed through 'popen'.  The return value is non zero on success.
 */
int aiger_open_and_write_to_file (aiger *, const char *file_name);

/*------------------------------------------------------------------------*/
/* The binary format reencodes all indices.  After normalization the input
 * indices come first followed by the latch and then the AND indices.  In
 * addition the indices will be topologically sorted to respect the
 * child/parent relation, e.g. child indices will always be smaller than
 * their parent indices.   This function can directly be called by the
 * client.  As a side effect, ANDs that are not in any cone of a next state
 * function nor in any cone of an output function are discarded.  The new
 * indices of ANDs start immediately after all input and latch indices.  The
 * data structures are updated accordingly including 'maxvar'.  The client
 * data within ANDs is reset to zero.
 */
int aiger_is_reencoded (aiger *);
void aiger_reencode (aiger *);

/*------------------------------------------------------------------------*/
/* This function computes the cone of influence (coi). The coi contains
 * those literals that may have an influence to one of the outputs.   A
 * variable 'v' is in the coi if the array returned as result is non zero at
 * position 'v'. All other variables can be considered redundant.  The array
 * returned is valid until the next call to this function and will be
 * deallocated on reset.
 *
 * TODO: this is just a stub and actually not really implemented yet.
 */
const unsigned char * aiger_coi (aiger *);		/* [1..maxvar] */

/*------------------------------------------------------------------------*/
/* Read an AIG from a FILE, a string, or through a generic interface.  These
 * functions return a non zero error message if an error occurred and
 * otherwise 0.  The paramater 'aiger_get' has the same return values as
 * 'getc', e.g. it returns 'EOF' when done.  After an error occurred the
 * library becomes invalid.  Only 'aiger_reset' or 'aiger_error' can be
 * used.  The latter returns the previously returned error message.
 */
const char *aiger_read_from_file (aiger *, FILE *);
const char *aiger_read_from_string (aiger *, const char *str);
const char *aiger_read_generic (aiger *, void *state, aiger_get);

/*------------------------------------------------------------------------*/
/* Returns a previously generated error message if the library is in an
 * invalid state.  After this function returns a non zero error message,
 * only 'aiger_reset' can be called (beside 'aiger_error').  The library can
 * reach an invalid through a failed read attempt, or if 'aiger_check'
 * failed.
 */
const char *aiger_error (aiger *);

/*------------------------------------------------------------------------*/
/* Same semantics as with 'aiger_open_and_write_to_file' for reading.
 */
const char *aiger_open_and_read_from_file (aiger *, const char *);

/*------------------------------------------------------------------------*/
/* Write symbol table or the comments to a file.  Result is zero on failure.
 */
int aiger_write_symbols_to_file (aiger *, FILE * file);
int aiger_write_comments_to_file (aiger *, FILE * file);

/*------------------------------------------------------------------------*/
/* Remove symbols and comments.  The result is the number of symbols
 * and comments removed.
 */
unsigned aiger_strip_symbols_and_comments (aiger *);

/*------------------------------------------------------------------------*/
/* If 'lit' is an input or a latch with a name, the symbolic name is
 * returned.   Note, that literals can be used for multiple outputs.
 * Therefore there is no way to associate a name with a literal itself.
 * Names for outputs are stored in the 'outputs' symbols and can only be
 * accesed through a linear traversal of the output symbols.
 */
const char *aiger_get_symbol (aiger *, unsigned lit);

/*------------------------------------------------------------------------*/
/* Return tag of the literal:
 *
 * 0 = constant
 * 1 = input
 * 2 = latch
 * 3 = and
 */

int aiger_lit2tag (aiger *, unsigned lit);

/*------------------------------------------------------------------------*/
/* Check whether the given unsigned, e.g. even, literal was defined as
 * 'input', 'latch' or 'and'.  The command returns a zero pointer if the
 * literal was not defined as 'input', 'latch', or 'and' respectively.
 * Otherwise a pointer to the corresponding input or latch symbol is returned.
 * In the case of an 'and' the AND node is returned.  The returned symbol
 * if non zero is in the respective array of 'inputs', 'latches' and 'ands'.
 * It thus also allows to extract the position of an input or latch literal.
 * For outputs this is not possible, since the same literal may be used for
 * several outputs.
 */
aiger_symbol *aiger_is_input (aiger *, unsigned lit);
aiger_symbol *aiger_is_latch (aiger *, unsigned lit);
aiger_and *aiger_is_and (aiger *, unsigned lit);

#ifdef __cplusplus
}
#endif

#endif