#ifndef	QCC_H
#define	QCC_H
#include "qtools.h"

/*
 * ============================================================================
 * 
 * TODO:
 * 
 * "stopped at 10 errors"
 * 
 * other pointer types for models and clients?
 * 
 * compact string heap?
 * 
 * allways initialize all variables to something safe
 * 
 * the def->type->type arrangement is really silly.
 * 
 * return type checking
 * 
 * parm count type checking
 * 
 * immediate overflow checking
 * 
 * pass the first two parms in call->b and call->c
 * 
 * ============================================================================
 */

/*
 * ============================================================================
 * 
 * comments
 * --------
 * // comments discard text until the end of line
 * / *  * / comments discard all enclosed text (spaced out on this line because this documentation is in a regular C comment block, and typing them in normally causes a parse error)
 * 
 * code structure
 * --------------
 * A definition is:
 * <type> <name> [ = <immediate>] {, <name> [ = <immediate>] };
 * 
 * 
 * types
 * -----
 * simple types: void, float, vector, string, or entity
 * float                width, height;
 * string               name;
 * entity               self, other;
 * 
 * vector types:
 * vector               org;    // also creates org_x, org_y, and org_z float defs
 * 
 * 
 * A function type is specified as:     simpletype ( type name {,type name} )
 * The names are ignored except when the function is initialized.       
 * void()               think;
 * entity()     FindTarget;
 * void(vector destination, float speed, void() callback)       SUB_CalcMove;
 * void(...)    dprint;         // variable argument builtin
 * 
 * A field type is specified as:  .type
 * .vector              origin;
 * .string              netname;
 * .void()              think, touch, use;
 * 
 * 
 * names
 * -----
 * Names are a maximum of 64 characters, must begin with A-Z,a-z, or _, and can continue with those characters or 0-9.
 * 
 * There are two levels of scoping: global, and function.  The parameter list of a function and any vars declared inside a function with the "local" statement are only visible within that function, 
 * 
 * 
 * immediates
 * ----------
 * Float immediates must begin with 0-9 or minus sign.  .5 is illegal.
 * 
 * A parsing ambiguity is present with negative constants. "a-5" will be parsed as "a", then "-5", causing an error.  Seperate the - from the digits with a space "a - 5" to get the proper behavior.
 * 12
 * 1.6
 * 0.5
 * -100
 * 
 * Vector immediates are three float immediates enclosed in single quotes.
 * '0 0 0'
 * '20.5 -10 0.00001'
 * 
 * String immediates are characters enclosed in double quotes.  The string cannot contain explicit newlines, but the escape character \n can embed one.  The \" escape can be used to include a quote in the string.
 * "maps/jrwiz1.bsp"
 * "sound/nin/pain.wav"
 * "ouch!\n"
 * 
 * Code immediates are statements enclosed in {} braces.
 * statement:
 * { <multiple statements> }
 * <expression>;
 * local <type> <name> [ = <immediate>] {, <name> [ = <immediate>] };
 * return <expression>;
 * if ( <expression> ) <statement> [ else <statement> ];
 * while ( <expression> ) <statement>;
 * do <statement> while ( <expression> );
 * <function name> ( <function parms> );
 * 
 * expression:
 * combiations of names and these operators with standard C precedence:
 * "&&", "||", "<=", ">=","==", "!=", "!", "*", "/", "-", "+", "=", ".", "<", ">", "&", "|"
 * Parenthesis can be used to alter order of operation.
 * The & and | operations perform integral bit ops on floats
 * 
 * A built in function immediate is a number sign followed by an integer.
 * #1
 * #12
 * 
 * 
 * compilation
 * -----------
 * Source files are processed sequentially without dumping any state, so if a defs file is the first one processed, the definitions will be available to all other files.
 * 
 * The language is strongly typed and there are no casts.
 * 
 * Anything that is initialized is assumed to be constant, and will have immediates folded into it.  If you change the value, your program will malfunction.  All uninitialized globals will be saved to savegame files.
 * 
 * Functions cannot have more than eight parameters.
 * 
 * Error recovery during compilation is minimal.  It will skip to the next global definition, so you will never see more than one error at a time in a given function.  All compilation aborts after ten error messages.
 * 
 * Names can be defined multiple times until they are defined with an initialization, allowing functions to be prototyped before their definition.
 * 
 * void()       MyFunction;                     // the prototype
 * 
 * void()       MyFunction =            // the initialization
 * {
 * dprint ("we're here\n");
 * };
 * 
 * 
 * entities and fields
 * -------------------
 * 
 * 
 * execution
 * ---------
 * Code execution is initiated by C code in quake from two main places:  the timed think routines for periodic control, and the touch function when two objects impact each other.
 * 
 * There are three global variables that are set before beginning code execution:
 * entity       world;          // the server's world object, which holds all global
 * // state for the server, like the deathmatch flags
 * // and the body ques.
 * entity       self;           // the entity the function is executing for
 * entity       other;          // the other object in an impact, not used for thinks
 * float        time;           // the current game time.  Note that because the
 * // entities in the world are simulated sequentially,
 * // time is NOT strictly increasing.  An impact late
 * // in one entity's time slice may set time higher
 * // than the think function of the next entity. 
 * // The difference is limited to 0.1 seconds.
 * Execution is also caused by a few uncommon events, like the addition of a new client to an existing server.
 * 
 * There is a runnaway counter that stops a program if 100000 statements are executed, assuming it is in an infinite loop.
 * 
 * It is acceptable to change the system set global variables.  This is usually done to pose as another entity by changing self and calling a function.
 * 
 * The interpretation is fairly efficient, but it is still over an order of magnitude slower than compiled C code.  All time consuming operations should be made into built in functions.
 * 
 * A profile counter is kept for each function, and incremented for each interpreted instruction inside that function.  The "profile" console command in Quake will dump out the top 10 functions, then clear all the counters.  The "profile all" command will dump sorted stats for every function that has been executed.
 * 
 * 
 * afunc ( 4, bfunc(1,2,3));
 * will fail because there is a shared parameter marshaling area, which will cause the 1 from bfunc to overwrite the 4 allready placed in parm0.  When a function is called, it copies the parms from the globals into it's privately scoped variables, so there is no collision when calling another function.
 * 
 * total = factorial(3) + factorial(4);
 * Will fail because the return value from functions is held in a single global area.  If this really gets on your nerves, tell me and I can work around it at a slight performance and space penalty by allocating a new register for the function call and copying it out.
 * 
 * 
 * built in functions
 * ------------------
 * void(string text)    dprint;
 * Prints the string to the server console.
 * 
 * void(entity client, string text)     cprint;
 * Prints a message to a specific client.
 * 
 * void(string text)    bprint;
 * Broadcast prints a message to all clients on the current server.
 * 
 * entity()     spawn;
 * Returns a totally empty entity.  You can manually set everything up, or just set the origin and call one of the existing entity setup functions.
 * 
 * entity(entity start, .string field, string match) find;
 * Searches the server entity list beginning at start, looking for an entity that has entity.field = match.  To start at the beginning of the list, pass world.  World is returned when the end of the list is reached.
 * 
 * <FIXME: define all the other functions...>
 * 
 * 
 * gotchas
 * -------
 * 
 * The && and || operators DO NOT EARLY OUT like C!
 * 
 * Don't confuse single quoted vectors with double quoted strings
 * 
 * The function declaration syntax takes a little getting used to.
 * 
 * Don't forget the ; after the trailing brace of a function initialization.
 * 
 * Don't forget the "local" before defining local variables.
 * 
 * There are no ++ / -- operators, or operate/assign operators.
 * 
 * ============================================================================
 */

#define	MAX_ERRORS		10
#define	MAX_NAME		64					       // chars long
#define	MAX_REGS		16384

#define	MAX_FRAMES		256

#define	MAX_STRINGS		500000
#define	MAX_GLOBALS		16384
#define	MAX_FIELDS		1024
#define	MAX_STATEMENTS		65536
#define	MAX_FUNCTIONS		8192

#define	MAX_SOUNDS		1024
#define	MAX_MODELS		1024
#define	MAX_FILES		1024
#define	MAX_DATA_PATH		64

#define	MAX_PARMS	8


#define	TOP_PRIORITY	6
#define	NOT_PRIORITY	4

//============================================================================

typedef int func_t;
typedef int string_t;

typedef enum {
  ev_void, ev_string, ev_float, ev_vector, ev_entity, ev_field, ev_function, ev_pointer
} etype_t;

#define	OFS_NULL		0
#define	OFS_RETURN		1
#define	OFS_PARM0		4					       // leave 3 ofs for each parm to hold vectors
#define	OFS_PARM1		7
#define	OFS_PARM2		10
#define	OFS_PARM3		13
#define	OFS_PARM4		16
#define	OFS_PARM5		19
#define	OFS_PARM6		22
#define	OFS_PARM7		25
#define	RESERVED_OFS		28

enum {
  OP_DONE,
  OP_MUL_F,
  OP_MUL_V,
  OP_MUL_FV,
  OP_MUL_VF,
  OP_DIV_F,
  OP_ADD_F,
  OP_ADD_V,
  OP_SUB_F,
  OP_SUB_V,

  OP_EQ_F,
  OP_EQ_V,
  OP_EQ_S,
  OP_EQ_E,
  OP_EQ_FNC,

  OP_NE_F,
  OP_NE_V,
  OP_NE_S,
  OP_NE_E,
  OP_NE_FNC,

  OP_LE,
  OP_GE,
  OP_LT,
  OP_GT,

  OP_LOAD_F,
  OP_LOAD_V,
  OP_LOAD_S,
  OP_LOAD_ENT,
  OP_LOAD_FLD,
  OP_LOAD_FNC,

  OP_ADDRESS,

  OP_STORE_F,
  OP_STORE_V,
  OP_STORE_S,
  OP_STORE_ENT,
  OP_STORE_FLD,
  OP_STORE_FNC,

  OP_STOREP_F,
  OP_STOREP_V,
  OP_STOREP_S,
  OP_STOREP_ENT,
  OP_STOREP_FLD,
  OP_STOREP_FNC,

  OP_RETURN,
  OP_NOT_F,
  OP_NOT_V,
  OP_NOT_S,
  OP_NOT_ENT,
  OP_NOT_FNC,
  OP_IF,
  OP_IFNOT,
  OP_CALL0,
  OP_CALL1,
  OP_CALL2,
  OP_CALL3,
  OP_CALL4,
  OP_CALL5,
  OP_CALL6,
  OP_CALL7,
  OP_CALL8,
  OP_STATE,
  OP_GOTO,
  OP_AND,
  OP_OR,

  OP_BITAND,
  OP_BITOR
};

typedef struct statement_s {
  unsigned short int op;
  short int a, b, c;
} dstatement_t;

typedef struct {
  unsigned short int type;							       // if DEF_SAVEGLOBGAL bit is set
  // the variable needs to be saved in savegames

  unsigned short int ofs;
  int s_name;
} ddef_t;

#define	DEF_SAVEGLOBGAL	(1<<15)

typedef struct {
  int first_statement;							       // negative numbers are builtins

  int parm_start;
  int locals;								       // total ints of parms + locals

  int profile;								       // runtime

  int s_name;
  int s_file;								       // source file defined in

  int numparms;
  unsigned char parm_size[MAX_PARMS];
} dfunction_t;

#define	PROG_VERSION	6
typedef struct {
  int version;
  int crc;								       // check of header file

  int ofs_statements;
  int numstatements;							       // statement 0 is an error

  int ofs_globaldefs;
  int numglobaldefs;

  int ofs_fielddefs;
  int numfielddefs;

  int ofs_functions;
  int numfunctions;							       // function 0 is an empty

  int ofs_strings;
  int numstrings;							       // first string is a null string

  int ofs_globals;
  int numglobals;

  int entityfields;
} dprograms_t;

//=============================================================================

// offsets are allways multiplied by 4 before using
typedef int gofs_t;							       // offset in global data block

typedef struct function_s function_t;

typedef struct type_s {
  etype_t type;
  struct def_s *def;							       // a def that points to this type

  struct type_s *next;
// function types are more complex
  struct type_s *aux_type;						       // return type or field type

  int num_parms;							       // -1 = variable args

  struct type_s *parm_types[MAX_PARMS];					       // only [num_parms] allocated

} type_t;

typedef struct def_s {
  type_t *type;
  char *name;
  struct def_s *next;

  struct def_s *search_next;						       // for finding faster

  gofs_t ofs;
  struct def_s *scope;							       // function the var was defined in, or NULL

  int initialized;							       // 1 when a declaration included "= immediate"

} def_t;

//=============================================================================

typedef union eval_s {
  string_t string;
  float _float;
  float vector[3];
  func_t function;
  int _int;
  union eval_s *ptr;
} eval_t;

struct function_s {
  int builtin;								       // if non 0, call an internal function

  int code;								       // first statement

  char *file;								       // source file with definition

  int file_line;
  struct def_s *def;
  int parm_ofs[MAX_PARMS];						       // allways contiguous, right?

};

//
// output generated by prog parsing
//
typedef struct {
  char *memory;
  int max_memory;
  int current_memory;
  type_t *types;

  def_t def_head;							       // unused head of linked list

  def_t *def_tail;							       // add new defs after this and move it

  def_t *search;							       // search chain through defs

  int size_fields;
} pr_info_t;

typedef struct {
  char *name;
  char *opname;
  float priority;
  bool right_associative;
  def_t *type_a, *type_b, *type_c;
} opcode_t;

//============================================================================

typedef enum {
  tt_eof,								       // end of file reached
   tt_name,								       // an alphanumeric name token
   tt_punct,								       // code punctuation
   tt_immediate,							       // string, float, vector
} token_type_t;

#define	G_FLOAT(o) (pr_globals[o])
#define	G_INT(o) (*(int *)&pr_globals[o])
#define	G_VECTOR(o) (&pr_globals[o])
#define	G_STRING(o) (strings + *(string_t *)&pr_globals[o])
#define	G_FUNCTION(o) (*(func_t *)&pr_globals[o])

//=============================================================================
#endif