/*
 * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
 * See the copyright notice in the ACK home directory, in the file "Copyright".
 */
/* $Id$ */
/* PREPROCESSOR: CONTROLLINE INTERPRETER */

#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "domacro.h"
#include "arith.h"
#include "LLlex.h"
#include "Lpars.h"
#include "idf.h"
#include "input.h"
#include "error.h"

#include "parameters.h"
#include "preprocess.h"
#include <alloc.h>
#include "class.h"
#include "macro.h"
#include "LLlex.h"
#include "bits.h"
#include "skip.h"
#include "replace.h"

extern char options[];
extern char** inctable; /* list of include directories		*/
char ifstack[IFDEPTH]; /* if-stack: the content of an entry is	*/
/* 1 if a corresponding ELSE has been	*/
/* encountered.				*/

int nestlevel = -1;
int svnestlevel[30] = { -1 };
int nestcount;
extern int do_preprocess;

/* Internal declarations */


static void do_define(void);
static void do_elif(void);
static void do_else(void);
static void push_if(void);
static void do_endif(void);
static void do_if(void);
static void do_ifdef(int);
static void do_include(void);
static void do_line(unsigned int);
static int find_name(char* , char* []);
static char* get_text(char* [], int* );
static int getparams(char* [], char []);
static int ifexpr(void);
static int macroeq(register char*, register char *);
static void skip_block(int);
static void do_error(void);

/* External dependencies to C files with no include files */
extern void If_expr(void);
extern void add_dependency(char *);


char* GetIdentifier(int skiponerr /* skip the rest of the line on error */
 )
{
	/*	Returns a pointer to the identifier that is read from the
	    input stream. When the input does not contain an
	    identifier, the rest of the line is skipped when skiponerr
	    is on, and a null-pointer is returned.
	    The substitution of macros is disabled.
	    Remember that on end-of-line EOF is returned.
	*/
	int tmp = UnknownIdIsZero;
	int tok;
	struct token tk;

	UnknownIdIsZero = ReplaceMacros = 0;
	tok = GetToken(&tk);
	ReplaceMacros = 1;
	UnknownIdIsZero = tmp;
	if (tok != IDENTIFIER)
	{
		if (skiponerr && tok != EOF)
			SkipToNewLine();
		return (char*)0;
	}
	return tk.tk_str;
}


void domacro(void)
{
	struct token tk; /* the token itself			*/
	register struct idf* id;
	int toknum;

	ReplaceMacros = 0;
	toknum = GetToken(&tk);
	ReplaceMacros = 1;
	switch (toknum)
	{ /* select control line action	*/
		case IDENTIFIER: /* is it a macro keyword?	*/
			id = findidf(tk.tk_str);
			if (!id)
			{
				error("%s: unknown control", tk.tk_str);
				SkipToNewLine();
				free(tk.tk_str);
				break;
			}
			free(tk.tk_str);
			switch (id->id_resmac)
			{
				case K_DEFINE: /* "define"	*/
					do_define();
					break;
				case K_ELIF: /* "elif"	*/
					do_elif();
					break;
				case K_ELSE: /* "else"	*/
					do_else();
					break;
				case K_ENDIF: /* "endif"	*/
					do_endif();
					break;
				case K_IF: /* "if"		*/
					do_if();
					break;
				case K_IFDEF: /* "ifdef"	*/
					do_ifdef(1);
					break;
				case K_IFNDEF: /* "ifndef"	*/
					do_ifdef(0);
					break;
				case K_INCLUDE: /* "include"	*/
					do_include();
					break;
				case K_LINE: /* "line"	*/
					/*	set LineNumber and FileName according to
					    the arguments.
					*/
					if (GetToken(&tk) != INTEGER)
					{
						error("bad #line syntax");
						SkipToNewLine();
					}
					else
						do_line((unsigned int)tk.tk_val);
					break;
				case K_ERROR: /* "error"	*/
					do_error();
					break;
				case K_PRAGMA: /* "pragma"	*/
					do_pragma();
					break;
				case K_UNDEF: /* "undef"	*/
					do_undef((char*)0);
					break;
				default:
					/* invalid word seen after the '#'	*/
					error("%s: unknown control", id->id_text);
					SkipToNewLine();
			}
			break;
		case INTEGER: /* # <integer> [<filespecifier>]?	*/
			do_line((unsigned int)tk.tk_val);
			break;
		case EOF: /* only `#' on this line: do nothing, ignore	*/
			break;
		default: /* invalid token following '#'		*/
			error("illegal # line");
			SkipToNewLine();
	}
}

static void skip_block(int to_endif)
{
	/*	skip_block() skips the input from
	    1)	a false #if, #ifdef, #ifndef or #elif until the
	        corresponding #elif (resulting in true), #else or
	        #endif is read.
	    2)	a #else corresponding to a true #if, #ifdef,
	        #ifndef or #elif until the corresponding #endif is
	        seen.
	*/
	register int ch;
	register int skiplevel = nestlevel; /* current nesting level	*/
	struct token tk;
	int toknum;
	struct idf* id;

	NoUnstack++;
	for (;;)
	{
		ch = GetChar(); /* read first character after newline	*/
		while (class(ch) == STSKIP)
			ch = GetChar();
		if (ch != '#')
		{
			if (ch == EOI)
			{
				NoUnstack--;
				return;
			}
			if (ch == '/')
			{
				ch = GetChar();
				if (ch == '*')
				{
					skipcomment();
					continue;
				}
				else if (ch == '/')
				{
					skiplinecomment();
					continue;
				}
				else
					UnGetChar();
			}
			else
				UnGetChar();
			SkipToNewLine();
			continue;
		}
		ReplaceMacros = 0;
		toknum = GetToken(&tk);
		ReplaceMacros = 1;
		if (toknum != IDENTIFIER)
		{
			if (toknum != INTEGER)
			{
				error("illegal # line");
			}
			SkipToNewLine();
			continue;
		}
		/*	an IDENTIFIER: look for #if, #ifdef and #ifndef
		    without interpreting them.
		    Interpret #else, #elif and #endif if they occur
		    on the same level.
		*/
		id = findidf(tk.tk_str);
		if (id == (struct idf*)0)
		{
			/* invalid word seen after the '#' */
			warning("%s: unknown control", tk.tk_str);
		}
		free(tk.tk_str);
		if (id == (struct idf*)0)
			continue;
		switch (id->id_resmac)
		{
			case K_DEFINE:
			case K_ERROR:
			case K_INCLUDE:
			case K_LINE:
			case K_PRAGMA:
			case K_UNDEF:
			case K_FILE:
				SkipToNewLine();
				break;
			case K_IF:
			case K_IFDEF:
			case K_IFNDEF:
				push_if();
				SkipToNewLine();
				break;
			case K_ELIF:
				if (ifstack[nestlevel])
					error("#elif after #else");
				if (!to_endif && nestlevel == skiplevel)
				{
					nestlevel--;
					push_if();
					if (ifexpr())
					{
						NoUnstack--;
						return;
					}
				}
				else
					SkipToNewLine(); /* otherwise done in ifexpr() */
				break;
			case K_ELSE:
				if (ifstack[nestlevel])
					error("#else after #else");
				++(ifstack[nestlevel]);
				if (!to_endif && nestlevel == skiplevel)
				{
					if (SkipToNewLine())
					{
						if (!options['o'])
							strict("garbage following #else");
					}
					NoUnstack--;
					return;
				}
				else
					SkipToNewLine();
				break;
			case K_ENDIF:
				assert(nestlevel > svnestlevel[nestcount]);
				if (nestlevel == skiplevel)
				{
					if (SkipToNewLine())
					{
						if (!options['o'])
							strict("garbage following #endif");
					}
					nestlevel--;
					NoUnstack--;
					return;
				}
				else
					SkipToNewLine();
				nestlevel--;
				break;
		}
	}
}

static int ifexpr(void)
{
	/*	Returns whether the restricted constant
	    expression following #if or #elif evaluates to true.  This
	    is done by calling the LLgen generated subparser for
	    constant expressions.  The result of this expression will
	    be given in the extern long variable "ifval".
	*/
	extern arith ifval;
	int errors = err_occurred;

	ifval = (arith)0;
	AccDefined = 1;
	UnknownIdIsZero = 1;
	DOT = 0; /* tricky */
	If_expr(); /* invoke constant expression parser	*/
	AccDefined = 0;
	UnknownIdIsZero = 0;
	return (errors == err_occurred) && (ifval != (arith)0);
}

static void do_include(void)
{
	/*	do_include() performs the inclusion of a file.
	*/
	char* filenm;
	char* result;
	int tok;
	struct token tk;

	AccFileSpecifier = 1;
	if (((tok = GetToken(&tk)) == FILESPECIFIER) || tok == STRING)
		filenm = tk.tk_str;
	else
	{
		error("bad include syntax");
		filenm = (char*)0;
	}
	AccFileSpecifier = 0;
	if (SkipToNewLine())
	{
		error("bad include syntax");
	}
	inctable[0] = WorkingDir;
	if (filenm)
	{
		if (!InsertFile(filenm, &inctable[tok == FILESPECIFIER], &result))
		{
			if (do_preprocess)
				error("cannot open include file \"%s\"", filenm);
			else
				warning("cannot open include file \"%s\"", filenm);
			add_dependency(filenm);
		}
		else
		{
			add_dependency(result);
			WorkingDir = getwdir(result);
			svnestlevel[++nestcount] = nestlevel;
			FileName = result;
			LineNumber = 1;
		}
	}
}

static void do_define(void)
{
	/*	do_define() interprets a #define control line.
	*/
	register char* str; /* the #defined identifier's descriptor	*/
	int nformals = -1; /* keep track of the number of formals	*/
	char* formals[NPARAMS]; /* pointers to the names of the formals	*/
	char parbuf[PARBUFSIZE]; /* names of formals	*/
	char* repl_text; /* start of the replacement text	*/
	int length; /* length of the replacement text	*/
	register int ch;

	/* read the #defined macro's name	*/
	if (!(str = GetIdentifier(1)))
	{
		error("#define: illegal macro name");
		return;
	}
	/*	there is a formal parameter list if the identifier is
	    followed immediately by a '('.
	*/
	ch = GetChar();
	if (ch == '(')
	{
		if ((nformals = getparams(formals, parbuf)) == -1)
		{
			SkipToNewLine();
			free(str);
			return; /* an error occurred	*/
		}
		ch = GetChar();
	}
	/* read the replacement text if there is any			*/
	ch = skipspaces(ch, 0); /* find first character of the text	*/
	assert(ch != EOI);
	/* UnGetChar() is not right when replacement starts with a '/' */
	ChPushBack(ch);
	repl_text = get_text((nformals > 0) ? formals : 0, &length);
	macro_def(str2idf(str, 0), repl_text, nformals, length, NOFLAG);
	LineNumber++;
}

static void push_if(void)
{
	if (nestlevel >= IFDEPTH)
		fatal("too many nested #if/#ifdef/#ifndef");
	else
		ifstack[++nestlevel] = 0;
}

static void do_elif(void)
{
	if (nestlevel <= svnestlevel[nestcount])
	{
		error("#elif without corresponding #if");
		SkipToNewLine();
	}
	else
	{ /* restart at this level as if a #if is detected.  */
		if (ifstack[nestlevel])
		{
			error("#elif after #else");
			SkipToNewLine();
		}
		nestlevel--;
		push_if();
		skip_block(1);
	}
}

static void do_else(void)
{
	if (SkipToNewLine())
	{
		if (!options['o'])
			strict("garbage following #else");
	}
	if (nestlevel <= svnestlevel[nestcount])
		error("#else without corresponding #if");
	else
	{ /* mark this level as else-d */
		if (ifstack[nestlevel])
		{
			error("#else after #else");
		}
		++(ifstack[nestlevel]);
		skip_block(1);
	}
}

static void do_endif(void)
{
	if (SkipToNewLine())
	{
		if (!options['o'])
			strict("garbage following #endif");
	}
	if (nestlevel <= svnestlevel[nestcount])
	{
		error("#endif without corresponding #if");
	}
	else
		nestlevel--;
}

static void do_if(void)
{
	push_if();
	if (!ifexpr()) /* a false #if/#elif expression */
		skip_block(0);
}

static void do_ifdef(int how)
{
	register struct idf* id;
	register char* str;

	/*	how == 1 : ifdef; how == 0 : ifndef
	*/
	push_if();
	if (!(str = GetIdentifier(1)))
	{
		error("illegal #ifdef construction");
		id = (struct idf*)0;
	}
	else
	{
		id = findidf(str);
		free(str);
	}
	if (SkipToNewLine())
	{
		if (str && !options['o'])
			strict("garbage following #%s <identifier>", how ? "ifdef" : "ifndef");
	}

	/* The next test is a shorthand for:
	    (how && !id->id_macro) || (!how && id->id_macro)
	*/
	if (how ^ (id && id->id_macro != 0))
		skip_block(0);
}

/* argstr != NULL when the undef came from a -U option */
void do_undef(char* argstr)
{
	register struct idf* id;
	register char* str = argstr;

	/* Forget a macro definition.	*/
	if (str || (str = GetIdentifier(1)))
	{
		if ((id = findidf(str)) && id->id_macro)
		{
			if (id->id_macro->mc_flag & NOUNDEF)
			{
				error("it is not allowed to #undef %s", str);
			}
			else
			{
				free(id->id_macro->mc_text);
				free_macro(id->id_macro);
				id->id_macro = (struct macro*)0;
			}
		} /* else: don't complain */
		if (!argstr)
		{
			free(str);
			if (SkipToNewLine())
			{
				if (!options['o'])
					strict("garbage following #undef");
			}
		}
	}
	else
		error("illegal #undef construction");
}

static void do_error(void)
{
	int len;
	char* get_text();
	char* bp = get_text((char**)0, &len);

	error("user error: %s", bp);
	free(bp);
	LineNumber++;
}

static int getparams(char* buf[], char parbuf[])
{
	/*	getparams() reads the formal parameter list of a macro
	    definition.
	    The number of parameters is returned.
	    As a formal parameter list is expected when calling this
	    routine, -1 is returned if an error is detected, for
	    example:
	        #define one(1), where 1 is not an identifier.
	    Note that the '(' has already been eaten.
	    The names of the formal parameters are stored into parbuf.
	*/
	register char** pbuf = &buf[0];
	register int c;
	register char* ptr = &parbuf[0];
	register char** pbuf2;

	c = GetChar();
	c = skipspaces(c, 0);
	if (c == ')')
	{ /* no parameters: #define name()	*/
		*pbuf = (char*)0;
		return 0;
	}
	for (;;)
	{ /* eat the formal parameter list	*/
		if (class(c) != STIDF && class(c) != STELL)
		{
			error("#define: bad formal parameter");
			return -1;
		}
		*pbuf = ptr; /* name of the formal	*/
		*ptr++ = c;
		if (ptr >= &parbuf[PARBUFSIZE])
			fatal("formal parameter buffer overflow");
		do
		{ /* eat the identifier name	*/
			c = GetChar();
			*ptr++ = c;
			if (ptr >= &parbuf[PARBUFSIZE])
				fatal("formal parameter buffer overflow");
		} while (in_idf(c));
		*(ptr - 1) = '\0'; /* mark end of the name		*/

		/*	Check if this formal parameter is already used.
		    Usually, macros do not have many parameters, so ...
		*/
		for (pbuf2 = pbuf - 1; pbuf2 >= &buf[0]; pbuf2--)
		{
			if (!strcmp(*pbuf2, *pbuf))
			{
				warning("formal parameter \"%s\" already used", *pbuf);
			}
		}

		pbuf++;
		c = skipspaces(c, 0);
		if (c == ')')
		{ /* end of the formal parameter list	*/
			*pbuf = (char*)0;
			return pbuf - buf;
		}
		if (c != ',')
		{
			error("#define: bad formal parameter list");
			return -1;
		}
		c = GetChar();
		c = skipspaces(c, 0);
	}
	/*NOTREACHED*/
}

void macro_def(register struct idf* id, char* text, int nformals, int length, int flags)
{
	register struct macro* newdef = id->id_macro;

	/*	macro_def() puts the contents and information of a macro
	    definition into a structure and stores it into the symbol
	    table entry belonging to the name of the macro.
	    An error is given if there was already a definition
	*/
	if (newdef)
	{ /* is there a redefinition?	*/
		if (newdef->mc_flag & NOUNDEF)
		{
			error("it is not allowed to redefine %s", id->id_text);
		}
		else if (!macroeq(newdef->mc_text, text))
			error("illegal redefine of \"%s\"", id->id_text);
		free(text);
		return;
	}
	else
	{
#ifdef DOBITS
		register char* p = id->id_text;
#define setbit(bx)                                                                                 \
	if (!*p)                                                                                       \
		goto go_on;                                                                                \
	bits[*p++] |= (bx)
		setbit(bit0);
		setbit(bit1);
		setbit(bit2);
		setbit(bit3);
		setbit(bit4);
		setbit(bit5);
		setbit(bit6);
		setbit(bit7);

	go_on:
#endif
		id->id_macro = newdef = new_macro();
	}
	newdef->mc_text = text; /* replacement text	*/
	newdef->mc_nps = nformals; /* nr of formals	*/
	newdef->mc_length = length; /* length of repl. text	*/
	newdef->mc_flag = flags; /* special flags	*/
}

static int find_name(char* nm, char *index[])
{
	/*	find_name() returns the index of "nm" in the namelist
	    "index" if it can be found there.  0 is returned if it is
	    not there.
	*/
	register char** ip = &index[0];

	while (*ip)
		if (strcmp(nm, *ip++) == 0)
			return ip - &index[0];
	/* arrived here, nm is not in the name list.	*/
	return 0;
}

#define BLANK(ch) ((ch == ' ') || (ch == '\t'))

static char* get_text(char* formals[], int* length)
{
	/*	get_text() copies the replacement text of a macro
	    definition with zero, one or more parameters, thereby
	    substituting each formal parameter by a special character
	    (non-ascii: 0200 & (order-number in the formal parameter
	    list)) in order to substitute this character later by the
	    actual parameter. The replacement text is copied into
	    itself because the copied text will contain fewer or the
	    same amount of characters. The length of the replacement
	    text is returned.

	    Implementation:
	    finite automaton : we are interested in
	    1-  white space, sequences must be mapped onto 1 single
	        blank.
	    2-  identifiers, since they might be replaced by some
	        actual parameter.
	    3-  strings and character constants, since replacing
	        variables within them is illegal, and white-space is
	        significant.
	    4-  comment, same as for 1
	    Other tokens will not be seen as such.
	*/
	register int c;
	struct repl repls;
	register struct repl* repl = &repls;
	int blank = 0;

	c = GetChar();

	repl->r_ptr = repl->r_text = Malloc((unsigned)(repl->r_size = ITEXTSIZE));
	*repl->r_ptr = '\0';
	while ((c != EOI) && (class(c) != STNL))
	{
		if (BLANK(c))
		{
			blank++;
			c = GetChar();
			continue;
		}

		if (c == '\'' || c == '"')
		{
			register int delim = c;

			if (blank)
			{
				blank = 0;
				add2repl(repl, ' ');
			}
			do
			{
				add2repl(repl, c);
				if (c == '\\')
					add2repl(repl, GetChar());
				c = GetChar();
			} while (c != delim && c != EOI && class(c) != STNL);
			if (c != delim)
			{
				strict("unclosed opening %c", delim);
				break;
			}
			add2repl(repl, c);
			c = GetChar();
		}
		else if (c == '/')
		{
			c = GetChar();
			if (c == '*')
			{
				skipcomment();
				blank++;
				c = GetChar();
				continue;
			}
			else if (c == '/')
			{
				skiplinecomment();
				blank++;
				c = GetChar();
				continue;
			}
			if (blank)
			{
				blank = 0;
				add2repl(repl, ' ');
			}
			add2repl(repl, '/');
		}
		else if (formals && (class(c) == STIDF || class(c) == STELL))
		{
			char id_buf[IDFSIZE + 1];
			register char* idp = id_buf;
			int n;

			/* read identifier: it may be a formal parameter */
			*idp++ = c;
			do
			{
				c = GetChar();
				if (idp <= &id_buf[IDFSIZE])
					*idp++ = c;
			} while (in_idf(c));
			*--idp = '\0';

			if (blank)
			{
				blank = 0;
				add2repl(repl, ' ');
			}
			/* construct the formal parameter mark or identifier */
			if ((n = find_name(id_buf, formals)))
				add2repl(repl, FORMALP | (char)n);
			else
			{
				idp = id_buf;
				while (*idp)
					add2repl(repl, *idp++);
			}
		}
		else if (class(c) == STNUM)
		{
			if (blank)
			{
				blank = 0;
				add2repl(repl, ' ');
			}
			add2repl(repl, c);
			if (c == '.')
			{
				c = GetChar();
				if (class(c) != STNUM)
				{
					continue;
				}
				add2repl(repl, c);
			}
			c = GetChar();
			while (in_idf(c) || c == '.')
			{
				add2repl(repl, c);
				if ((c = GetChar()) == 'e' || c == 'E')
				{
					add2repl(repl, c);
					c = GetChar();
					if (c == '+' || c == '-')
					{
						add2repl(repl, c);
						c = GetChar();
					}
				}
			}
		}
		else
		{
			if (blank)
			{
				blank = 0;
				add2repl(repl, ' ');
			}
			add2repl(repl, c);
			c = GetChar();
		}
	}
	*length = repl->r_ptr - repl->r_text;
	return Realloc(repl->r_text, (unsigned)(repl->r_ptr - repl->r_text + 1));
}

/*	macroeq() decides whether two macro replacement texts are
    identical. This version compares the texts, which occur
    as strings, without taking care of the leading and trailing
    blanks (spaces and tabs).
*/
static int macroeq(register char* s, register char *t)
{

	/* skip leading spaces	*/
	while (BLANK(*s))
		s++;
	while (BLANK(*t))
		t++;
	/* first non-blank encountered in both strings	*/
	/* The actual comparison loop:			*/
	while (*s && *s == *t)
		s++, t++;
	/* two cases are possible when arrived here:	*/
	if (*s == '\0')
	{ /* *s == '\0'		*/
		while (BLANK(*t))
			t++;
		return *t == '\0';
	}
	else
	{ /* *s != *t		*/
		while (BLANK(*s))
			s++;
		while (BLANK(*t))
			t++;
		return (*s == '\0') && (*t == '\0');
	}
}

static void do_line(unsigned int l)
{
	struct token tk;
	int t = GetToken(&tk);

	if (t != EOF)
		SkipToNewLine();
	LineNumber = l; /* the number of the next input line */
	if (t == STRING) /* is there a filespecifier? */
		FileName = tk.tk_str;
}
