/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $URL$
 * $Id$
 *
 */


#ifndef _SCI_SEG_MANAGER_H
#define _SCI_SEG_MANAGER_H

#include "sci/engine/int_hashmap.h"
#include "sci/include/sys_strings.h"
#include "sci/include/vm.h"

namespace Sci {

#define DEFAULT_SCRIPTS 32
#define DEFAULT_OBJECTS 8	    // default # of objects per script
#define DEFAULT_OBJECTS_INCREMENT 4 // Number of additional objects to instantiate if we're running out of them

// SCRIPT_ID must be 0
typedef enum {
	SCRIPT_ID,
	SEG_ID
} id_flag;

//void dbg_print( const char* msg, void *i );	// for debug only

// verify the the given condition is true, output the message if condition is false, and exit
// Parameters:
//   cond - condition to be verified
//   msg  - the message to be printed if condition fails
// return:
//   none, terminate the program if fails
#define VERIFY( cond, msg ) if (!(cond)) {\
		sciprintf("%s, line, %d, %s\n", __FILE__, __LINE__, msg); \
		BREAKPOINT(); \
	}

#define MEM_OBJ_INVALID		0
#define MEM_OBJ_SCRIPT		1
#define MEM_OBJ_CLONES		2
#define MEM_OBJ_LOCALS		3
#define MEM_OBJ_STACK		4
#define MEM_OBJ_SYS_STRINGS	5
#define MEM_OBJ_LISTS		6
#define MEM_OBJ_NODES		7
#define MEM_OBJ_HUNK		8
#define MEM_OBJ_DYNMEM		9
#define MEM_OBJ_RESERVED	10
#define MEM_OBJ_MAX		MEM_OBJ_RESERVED // For sanity checking

typedef int mem_obj_enum;

#define GET_SEGMENT(mgr, index, rtype) ((index) > 0 && (mgr).heap_size > index) ?		\
		(((mgr).heap[index] && (mgr).heap[index]->type == rtype)? (mgr).heap[index]	: NULL) : NULL

#define GET_SEGMENT_ANY(mgr, index) ((index) > 0 && (mgr).heap_size > index) ?			\
		(((mgr).heap[index])? (mgr).heap[index]	: NULL) : NULL

#define GET_OBJECT_SEGMENT(mgr, index) ((index) > 0 && (mgr).heap_size > index) ?		\
		(((mgr).heap[index]	&& ((mgr).heap[index]->type == MEM_OBJ_SCRIPT || (mgr).heap[index]->type == MEM_OBJ_CLONES))? (mgr).heap[index]	\
		: NULL): NULL

struct SegManager {
	int_hash_map_t *id_seg_map; // id - script id; seg - index of heap
	mem_obj_t **heap;
	int heap_size;		// size of the heap
	int reserved_id;
	int exports_wide;
	int sci1_1;

	int gc_mark_bits;
	// For standard Mark&Sweep:
	// 1 or 0, depending on what unreachable/freshly allocated
	// memory is tagged as
	size_t mem_allocated; // Total amount of memory allocated

	seg_id_t clones_seg_id; // ID of the (a) clones segment
	seg_id_t lists_seg_id; // ID of the (a) list segment
	seg_id_t nodes_seg_id; // ID of the (a) node segment
	seg_id_t hunks_seg_id; // ID of the (a) hunk segment
};

// Toplevel functionality

void sm_init(SegManager *self, int sci1_1);
// Initialize the segment manager

void sm_destroy(SegManager *self);
// Deallocate all memory associated with the segment manager

void sm_gc(SegManager *self, EngineState *s);
// Perform garbage collection
// Parameters: (state_t *) s: The state to operate on
// Effects   : Unreachable objects in 's' are deallocated

// 1. Scripts

void sm_free_script(mem_obj_t* mem);

mem_obj_t *sm_allocate_script(SegManager* self, EngineState *s, int script_nr, int* seg_id);
// Allocate a script into the segment manager
// Parameters: (int) script_nr: number of the script to load
//	       (state_t *) s: The state containing resource manager handlers to load the
//			      script data
// Returns   : (int) 0 on failure, 1 on success
//	       (int) *seg_id: The segment ID of the newly allocated segment, on success

// The script must then be initialised; see section (1b.), below.

int sm_deallocate_script(SegManager* self, int script_nr);
// Forcefully deallocate a previously allocated script
// Parameters: (int) script_nr: number of the script to deallocate
// Returns   : (int) 1 on success, 0 on failure

int sm_script_is_loaded(SegManager* self, int id, id_flag flag);
// Determines whether a script has been loaded yet
// Parameters: (int) id: number of the script or ID of the script segment to check for
//             (id_flag) flag: Whether to address the script by script number (SCRIPT_ID) or
//				by its segment (SEG_ID). SEG_ID is faster than SCRIPT_ID,
//				but less convenient.

uint16 sm_validate_export_func(SegManager* self, int pubfunct, int seg);
// Validate whether the specified public function is exported by the script in the specified segment
// Parameters:	(int) pubfunct: Index of the function to validate
//		(int) seg: Segment ID of the script the check is to be performed for
// Returns   :  (uint16) 0 if the public function is invalid, its offset into the script's segment
//			  otherwise

int sm_seg_get(SegManager* self, int script_nr);
// Get the segment ID associated with a script number
// Parameters: (int) script_nr: Number of the script to look up
// Returns   : (int) The associated segment ID, or -1 if no matching segment exists
// This function is "pure" (i.e, it doesn't modify anything).



// script lock operations

void sm_increment_lockers(SegManager *self, int id, id_flag flag);
// Increments the number of lockers of the script in question by one
// Parameters: (int) id: ID of the script or script segment to modify
//             (id_flag) flag: Whether to address the script by script number (SCRIPT_ID) or
//				by its segment (SEG_ID). SEG_ID is faster than SCRIPT_ID,
//				but less convenient.


void sm_decrement_lockers(SegManager *self, int id, id_flag flag);
// Decrements the number of lockers of the script in question by one
// Parameters: (int) id: ID of the script or script segment to modify
//             (id_flag) flag: Whether to address the script by script number (SCRIPT_ID) or
//				by its segment (SEG_ID). SEG_ID is faster than SCRIPT_ID,
//				but less convenient.

int sm_get_lockers(SegManager *self, int id, id_flag flag);
// Retrieves the number of locks held on this script
// Parameters: (int) id: ID of the script or script segment to read from
//             (id_flag) flag: Whether to address the script by script number (SCRIPT_ID) or
//				by its segment (SEG_ID). SEG_ID is faster than SCRIPT_ID,
//				but less convenient.
// Returns   : (int) The number of locks held on the previously identified script


void sm_set_lockers(SegManager *self, int lockers, int id, id_flag flag);
// Sets the number of locks held on the specified script
// Parameters: (int) id: ID of the script or script segment to modify
//             (id_flag) flag: Whether to address the script by script number (SCRIPT_ID) or
//				by its segment (SEG_ID). SEG_ID is faster than SCRIPT_ID,
//				but less convenient.


byte *sm_get_synonyms(SegManager *self, int id, id_flag flag);
// Retrieves a pointer to the synonyms associated with the specified script
// Parameters: (int) id: ID of the script or script segment to read from
//             (id_flag) flag: Whether to address the script by script number (SCRIPT_ID) or
//				by its segment (SEG_ID). SEG_ID is faster than SCRIPT_ID,
//				but less convenient.
// Returns   : (byte *) Pointer to the synonyms, in non-parsed format.
// A dynamic failure is issued if the specified ID does not reference a proper script.


int sm_get_synonyms_nr(SegManager *self, int id, id_flag flag);
// Retrieves the number of synonyms associated with the specified script
// Parameters: (int) id: ID of the script or script segment to read from
//             (id_flag) flag: Whether to address the script by script number (SCRIPT_ID) or
//				by its segment (SEG_ID). SEG_ID is faster than SCRIPT_ID,
//				but less convenient.
// Returns   : (int) The number of synonyms associated with the specified script
// A dynamic failure is issued if the specified ID does not reference a proper script.



// 1b. Script Initialisation					

// The set of functions below are intended 
// to be used during script instantiation, 
// i.e. loading and linking.		   

void sm_script_initialise_locals_zero(SegManager *self, seg_id_t seg, int nr);
// Initializes a script's local variable block
// Parameters: (seg_id_t) seg: Segment containing the script to initialize
//             (int) nr: Number of local variables to allocate
// All variables are initialized to zero.


void sm_script_initialise_locals(SegManager *self, reg_t location);
// Initializes a script's local variable block according to a prototype
// Parameters: (reg_t) location: Location to initialize from


object_t *sm_script_obj_init(SegManager *self, EngineState *s, reg_t obj_pos);
// Initializes an object within the segment manager
// Parameters: (reg_t) obj_pos: Location (segment, offset) of the object
// Returns   : (object_t *) A newly created object_t describing the object
// obj_pos must point to the beginning of the script/class block (as opposed
// to what the VM considers to be the object location)
// The corresponding object_t is stored within the relevant script.


void sm_script_add_code_block(SegManager *self, reg_t location);
// Informs the segment manager that a code block must be relocated
// Parameters: (reg_t) location: Start of block to relocate


void sm_set_export_width(SegManager *self, int flag);
// Tells the segment manager whether exports are wide (32-bit) or not.
// Parameters: (int) flag: 1 if exports are wide, 0 otherwise 

void sm_script_relocate(SegManager *self, reg_t block);
// Processes a relocation block witin a script
// Parameters: (reg_t) obj_pos: Location (segment, offset) of the block
// Returns   : (object_t *) Location of the relocation block
// This function is idempotent, but it must only be called after all
// objects have been instantiated, or a run-time error will occur.


void sm_script_free_unused_objects(SegManager *self, seg_id_t segid);
// Deallocates all unused but allocated entries for objects
// Parameters: (seg_id_t) segid: segment of the script to prune in this way
// These entries are created during script instantiation; deallocating them
// frees up some additional memory.


void sm_set_export_table_offset(SegManager *self, int offset, int id, id_flag flag);
// Sets the script-relative offset of the exports table
// Parameters: (int) offset: The script-relative exports table offset
//	       (int) id: ID of the script or script segment to write to
//             (id_flag) flag: Whether to address the script by script number (SCRIPT_ID) or
//				by its segment (SEG_ID). SEG_ID is faster than SCRIPT_ID,
//				but less convenient.
// A dynamic failure is issued if the specified ID does not reference a proper script.


void sm_set_synonyms_offset(SegManager *self, int offset, int id, id_flag flag);
// Sets the script-relative offset of the synonyms associated with the specified script
// Parameters: (int) offset: The script-relative offset of the synonyms block
//	       (int) id: ID of the script or script segment to write to
//             (id_flag) flag: Whether to address the script by script number (SCRIPT_ID) or
//				by its segment (SEG_ID). SEG_ID is faster than SCRIPT_ID,
//				but less convenient.
// A dynamic failure is issued if the specified ID does not reference a proper script.


void sm_set_synonyms_nr(SegManager *self, int nr, int id, id_flag flag);
// Sets the number of synonyms associated with the specified script
// Parameters: (int) nr: The number of synonyms, as to be stored within the script
//	       (int) id: ID of the script or script segment to write to
//             (id_flag) flag: Whether to address the script by script number (SCRIPT_ID) or
//				by its segment (SEG_ID). SEG_ID is faster than SCRIPT_ID,
//				but less convenient.
// A dynamic failure is issued if the specified ID does not reference a proper script.


void sm_mark_script_deleted(SegManager *self, int script_nr);
// Marks the script identified by its script number as deleted
// Parameters: (int) script_nr: Script number to mark as deleted
// This will not actually delete the script.  If references remain present on the
// heap or the stack, the script will stay in memory in a quasi-deleted state until
// either unreachable (resulting in its eventual deletion) or reloaded (resulting
// in its data being updated).


void sm_unmark_script_deleted(SegManager *self, int script_nr);
// Marks the script identified by its script number as not deleted
// Parameters: (int) script_nr: Script number to mark as not deleted


int sm_script_is_marked_as_deleted(SegManager *self, seg_id_t seg);
// Determines whether the script referenced by the indicated segment is marked as being deleted.
// Parameters: (seg_id_t) Segment ID of the script to investigate
// Returns   : (int) 1 iff seg points to a script and the segment is deleted, 0 otherwise
// Will return 0 when applied to an invalid or non-script seg.


// 2. Clones							

clone_t *sm_alloc_clone(SegManager *self, reg_t *addr);
// Allocate a fresh clone
// Returns : (clone_t*): Reference to the memory allocated for the clone
//           (reg_t) *addr: The offset of the freshly allocated clone


void sm_free_clone(SegManager *self, reg_t addr);
// Deallocates a clone
// Parameters: (reg_t) addr: Offset of the clone scheduled for termination


// Objects (static, from Scripts, and dynmic, from Clones)	

// Not all of these functions are fully operational for clones ATM 

int16 sm_get_heap(SegManager* self, reg_t reg);
// Retrieves a 16 bit value from within a script's heap representation
// Parameters: (reg_t) reg: The address to read from
// Returns   : (int16) The value read from the specified location


void sm_put_heap(SegManager *self, reg_t reg, int16 value);
// Writes a 16 bit value into a script's heap representation
// Parameters: (reg_t) reg: The address to write to
//	       (int16) value: The value to write


void sm_mcpy_in_out(SegManager* self, int dst, const void *src, size_t n, int id, int flag);
// Copies a byte string into a script's heap representation
// Parameters: (int) dst: The script-relative offset of the destination area
//	       (const void *) src: Pointer to the data source location
//	       (size_t) n: Number of bytes to copy
//	       (int) id: ID of the script or script segment to write to
//             (id_flag) flag: Whether to address the script by script number (SCRIPT_ID) or
//				by its segment (SEG_ID). SEG_ID is faster than SCRIPT_ID,
//				but less convenient.
// A dynamic failure is issued if the specified ID does not reference a proper script.


// 4. Stack							

dstack_t *sm_allocate_stack(SegManager *self, int size, seg_id_t *segid);
// Allocates a data stack
// Parameters: (int) size: Number of stack entries to reserve
// Returns   : (dstack_t *): The physical stack
//             (seg_id_t) segid: Segment ID of the stack


// 5. System Strings						

sys_strings_t *sm_allocate_sys_strings(SegManager *self, seg_id_t *segid);
// Allocates a system string table
// Returns   : (dstack_t *): The physical stack
//             (seg_id_t) segid: Segment ID of the stack
// See also sys_string_acquire();


// 6, 7. Lists and Nodes					

list_t *sm_alloc_list(SegManager *self, reg_t *addr);
// Allocate a fresh list
// Returns : (listY_t*): Reference to the memory allocated for the list
//           (reg_t) *addr: The offset of the freshly allocated list


void sm_free_list(SegManager *self, reg_t addr);
// Deallocates a list
// Parameters: (reg_t) addr: Offset of the list scheduled for termination


node_t *sm_alloc_node(SegManager *self, reg_t *addr);
// Allocate a fresh node
// Returns : (node_t*): Reference to the memory allocated for the node
//           (reg_t) *addr: The offset of the freshly allocated node

void sm_free_node(SegManager *self, reg_t addr);
// Deallocates a list node
// Parameters: (reg_t) addr: Offset of the node scheduled for termination


// 8. Hunk Memory						

hunk_t *sm_alloc_hunk_entry(SegManager *self, const char *hunk_type, int size, reg_t *addr);
// Allocate a fresh chunk of the hunk
// Parameters: (int) size: Number of bytes to allocate for the hunk entry
//             (const char *) hunk_type: A descriptive string for the hunk entry,
//				for debugging purposes
// Returns   : (hunk_t*): Reference to the memory allocated for the hunk piece
//             (reg_t) *addr: The offset of the freshly allocated hunk entry


void sm_free_hunk_entry(SegManager *self, reg_t addr);
// Deallocates a hunk eentry
// Parameters: (reg_t) addr: Offset of the hunk entry to delete


// 9. Dynamic Memory						

unsigned char *sm_alloc_dynmem(SegManager *self, int size, const char *description, reg_t *addr);
// Allocate some dynamic memory
// Parameters: (int) size: Number of bytes to allocate
//             (const char_ *) description: A descriptive string,
//				for debugging purposes
// Returns   : (unsigned char*): Raw pointer into the allocated dynamic memory
//             (reg_t) *addr: The offset of the freshly allocated X

int sm_free_dynmem(SegManager *self, reg_t addr);
// Deallocates a piece of dynamic memory
// Parameters: (reg_t) addr: Offset of the dynmem chunk to free


const char *sm_get_description(SegManager *self, reg_t addr);
// Gets the description of a dynmem segment
// Parameters: (reg_t) addr: Segment to describe
// Returns   : (const char *): Pointer to the descriptive string set in
// sm_alloc_dynmem


// 10. Reserved segments					

seg_id_t sm_allocate_reserved_segment(SegManager *self, char *name);
// Reserves a special-purpose segment
// Parameters: (char *) name: A string name identifying the segment (the string is cloned and retained)
// Returns   : A fresh segment ID for the segment in question
// Reserved segments are never used by the segment manager.  They can be used to tag special-purpose addresses.
// Segment 0 is implicitly reserved for numbers.


// Generic Operations on Segments and Addresses			

byte *sm_dereference(SegManager *self, reg_t reg, int *size);
// Dereferences a raw memory pointer
// Parameters: (reg_t) reg: The reference to dereference
// Returns   : (byte *) The data block referenced
//             (int) size: (optionally) the theoretical maximum size of it

// 11. Segment interface, primarily for GC			

typedef struct _seg_interface {
	SegManager *segmgr;
	mem_obj_t *mobj;
	seg_id_t seg_id;
	mem_obj_enum type_id;	// Segment type 
	const char *type;	// String description of the segment type 

	reg_t (*find_canonic_address)(struct _seg_interface *self, reg_t sub_addr);
	// Finds the canonic address associated with sub_reg
	// Parameters: (reg_t) sub_addr: The base address whose canonic address is to be found
	// For each valid address a, there exists a canonic address c(a) such that c(a) = c(c(a)).
	// This address "governs" a in the sense that deallocating c(a) will deallocate a.
	
	void (*free_at_address)(struct _seg_interface *self, reg_t sub_addr);
	// Deallocates all memory associated with the specified address
	// Parameters: (reg_t) sub_addr: The address (within the given segment) to deallocate
	
	void (*list_all_deallocatable)(struct _seg_interface *self, void *param, void (*note)(void *param, reg_t addr));
	// Iterates over and reports all addresses within the current segment
	// Parameters: note : (voidptr * addr) -> (): Invoked for each address on which free_at_address()
	//                                makes sense
	//             (void *) param: Parameter passed to 'note'
	
	void (*list_all_outgoing_references)(struct _seg_interface *self, EngineState *s, reg_t object, void *param, void (*note)(void *param, reg_t addr));
	// Iterates over all references reachable from the specified object
	// Parameters: (reg_t) object: The object (within the current segment) to analyse
	//             (void *) param: Parameter passed to 'note'
	//             note : (voidptr * addr) -> (): Invoked for each outgoing reference within the object
	// Note: This function may also choose to report numbers (segment 0) as adresses
	
	void (*deallocate_self)(struct _seg_interface *self);
	// Deallocates the segment interface
} seg_interface_t;

seg_interface_t *get_seg_interface(SegManager *self, seg_id_t segid);
// Retrieves the segment interface to the specified segment
// Parameters: (seg_id_t) segid: ID of the segment to look up
// Returns   : (seg_interface_t *): An interface to the specified segment ID, or NULL on error
// The returned interface 'si' must be freed after use by calling 'si->dealloc_self(si)';

} // End of namespace Sci

#endif