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/*

	CPP V5 -- macro symbol table routines.

	source:  mst.c

	started: September 22, 1985

	version: May 26, 1988

	Written by Edward K. Ream.

	This software is in the public domain.

	See the read.me file for disclaimer and other information.

*/

#include "cpp.h"

/* Declare local routines. */

static int mst_hash	(unsigned char *);

/* Define the hash table used to access macro table nodes. */

#define MAC_PRIME 101

typedef struct mst_node mactab;

static struct mst_node {

	mactab * mst_next; 	/* Pointer to next bucket.	*/

	int	 mst_nargs;	/* Number of args in text.	*/

	char *	 mst_name;    	/* Pointer to name.		*/

	char *	 mst_text;    	/* Pointer to replacement text. */

};

static mactab mst_ht [MAC_PRIME];

/*

	Define the "initial undef list" for

	arguments undefined on the command line.

*/

typedef struct u_node unode;

static struct u_node {

	unode *	u_next;

	char *		u_name;

};

unode undef_list;	/* list header. */

/*

	Remove ALL instances of a symbol from the symbol table.

	This ensures that an #undef will expose any non-macro version

	of a routine.

*/

void

mst_delete (symbol)

register char * symbol;

{

	register mactab *bp1, *bp2;

	int hash;

	TRACEP("mst_delete",printf("entry: symbol=<%s>\n", symbol));

	hash = mst_hash(symbol);

	bp1 = & mst_ht [hash];

	bp2 = bp1 -> mst_next;

	while(bp2 != NULL) {

		if(str_eq(symbol, bp2 -> mst_name)) {

			TRACEP("mst_delete", printf("deletes\n"));

			bp1 -> mst_next = bp2 -> mst_next;

			m_free(bp2);

			bp2 = bp1 -> mst_next;

		}

		else {

			bp1 = bp2;

			bp2 = bp2 -> mst_next;

		}

	}

}

/*

	Place a macro in the symbol table along with the number of arguments

	to the macro and a pointer to the macro's replacement text.

	Multiple entries for a symbol can exist in which case the last entry

	defined is active.

	This code conforms to the new standard.  It rejects duplicate 

	definitions of a macro unless the new definition is exactly the

	same as the old.  

	This code also checks the "initial undef list" to see if the first

	definition of a macro should be ignored.  If the macro name is

	found on the list, it is removed from the list and no entry is made

	in the macro symbol table.

*/

void

mst_enter (symbol, txt, nargs)

register char *symbol;

register char *txt;

register int nargs;

{

	register mactab *bp, *bp2;

	int hash;

	unode *up1, *up2;

	TRACEP("mst_enter", printf("(%s, <%s>, %d)\n",

		symbol, pr_str(txt), nargs));

	/*

		Search the global "initial undef list" (created by command line

		-u arguments) to see if the initial definition of name should

		be rejected.  If the name appears on the list, remove it from

		the list and do not enter the name in the macro table.

	*/

	if (undef_list . u_next != NULL) {

		up1 = &undef_list;

		up2 = up1 -> u_next;

		while (up2 != NULL) {

			if (str_eq(symbol, up2 -> u_name)) {

				/* Remove the entry from the list. */

				up1 -> u_next = up2 -> u_next;

				return;

			}

			else {

				up1 = up2;

				up2 = up2 -> u_next;

			}

		}

	}

	/* Search down the list of mst_nodes. */

	hash = mst_hash(symbol);

	bp   = & mst_ht [hash];

	for (bp = bp -> mst_next; bp; bp = bp -> mst_next) {

		/* Reject redefinitions of a macro unless identical. */

		if (str_eq (symbol, bp -> mst_name)) {

			if (nargs == bp -> mst_nargs) {

				if (str_eq(txt, bp -> mst_text)) {

					return;

				}

			}

			err3(	"Non-identical redefinition of ", symbol,

				" ignored.");

			return;

		}

	}

	/* Dynamically allocate space for node. */

	bp2 = m_alloc(sizeof(mactab));

	/* Hang node from hash table. */

	bp = & mst_ht [hash];

	bp2 -> mst_next = bp -> mst_next;

	bp  -> mst_next = bp2;

	/* Fill in the name and text fields. */

	bp2 -> mst_name  = str_alloc(symbol);

	bp2 -> mst_text  = str_alloc(txt);

	bp2 -> mst_nargs = nargs;

}

/*

	Return the hash value for symbol.

*/

static int

mst_hash (symbol)

register unsigned char * symbol;

{

	register int hash;

	STAT("mst_hash");

	for (hash = 0; *symbol; ) {

		hash *= 3;

		hash += (int) *symbol++;

		hash %= MAC_PRIME;

	}

	return hash;

}

/*

	Initialize the macro module.

	This must be done BEFORE command line arguments are processed.

*/

void

mst_init()

{

	register int i;

	TICK("mst_init");

	/* Clear the hash table. */

	for (i = 0; i < MAC_PRIME; i++) {

		mst_ht [i] . mst_next = NULL;

		mst_ht [i] . mst_name = "<NAME>";

		mst_ht [i] . mst_text = "<TEXT>";

		mst_ht [i] . mst_nargs = 0;

	}

	/* Clear the "initial undef list." */

	undef_list . u_next = NULL;

}

/*

	Enter the predefined macros into the table.

	Do nothing if the initial definitions have been

	suppressed with -u options.

	This must be done AFTER command line options have been processed.

*/

void

mst2_init()

{

	mst_enter("__LINE__", "", -3);

	mst_enter("__FILE__", "", -3);

	mst_enter("__STDC__", "", -3);

	mst_enter("__TIME__", "", -3);

	mst_enter("__DATE__", "", -3);

}

/*

	Look up a symbol in the macro table.

	Return TRUE if found, and set text and nargs.

*/

bool

mst_lookup(symbol, text, nargs)

register char * symbol;

char ** text;

int *nargs;

{

	register mactab *bp;

	char buffer [100];

	int hash;

	TRACEP("mst_lookup", printf("(%s)\n", symbol));

	/* Calculate the hash value of the symbol. */

	hash = mst_hash(symbol);

	bp = & mst_ht [hash];

	/* Search down the list of mst_nodes. */

	for (bp = bp -> mst_next; bp; bp = bp -> mst_next) {

		if (str_eq(symbol, bp -> mst_name)) {

			/* Special case for __line__ and __file__. */

			if (bp -> mst_nargs == -3) {

				if (str_eq(bp -> mst_name, "__LINE__")) {

					/* Set current line number. */

					conv2s(t_line, buffer);

					bp -> mst_text = str_alloc(buffer);

				}

				else if (str_eq(bp -> mst_name, "__FILE__")) {

					/* Set current file name. */

					strcpy(buffer, "\"");

					strcat(buffer, t_file);

					strcat(buffer, "\"");

					bp -> mst_text = str_alloc(buffer);

				}

				else if (str_eq(bp -> mst_name, "__TIME__")) {

					/* Set current file name. */

					bp -> mst_text = systime();

				}

				else if (str_eq(bp -> mst_name, "__DATE__")) {

					bp -> mst_text = sysdate();

				}

				else if (str_eq(bp -> mst_name, "__STDC__")) {

					bp -> mst_text = "1";

				}

			}

			/* Return success. */

			*nargs = max(-1, bp -> mst_nargs);

			*text  = bp -> mst_text;

			TRACEP("mst_lookup", printf("found:\n"));

			return TRUE;

		}

	}

	TRACEP("mst_lookup", printf("not found\n"));

	/* Return failure. */

	return FALSE;

}

/*

	Add an argument to the "initial undef list."

*/

void

mst_unarg(arg)

char * arg;

{

	unode * p;

	TICK("mst_unarg");

	p = m_alloc(sizeof(unode));

	p -> u_name		= arg;

	p -> u_next		= undef_list . u_next;

	undef_list . u_next	= p;

}