/*	$OpenBSD: cplus-dem.c,v 1.2 1998/02/15 18:49:13 niklas Exp $	*/

/* Demangler for GNU C++ 
   Copyright (C) 1989, 1992 Free Software Foundation, Inc.
   written by James Clark (jjc@jclark.uucp)
   
   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, 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., 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* This is for g++ 1.36.1 (November 6 version). It will probably
   require changes for any other version. */

/* This file exports one function
   
   char *cplus_demangle (const char *name)
   
   If `name' is a mangled function name produced by g++, then
   a pointer to a malloced string giving a C++ representation
   of the name will be returned; otherwise NULL will be returned.
   It is the caller's responsibility to free the string which
   is returned.
   
   For example,
   
   cplus_demangle ("_foo__1Ai")
   
   returns
   
   "A::foo(int)"
   
   This file imports xmalloc and xrealloc, which are like malloc and
   realloc except that they generate a fatal error if there is no
   available memory. */

/* #define nounderscore 1 /* define this is names don't start with _ */
    
#include <stdio.h>
#include <string.h>
#include <ctype.h>
    
#if !defined(sequent) && !defined(NeXT)
#include <memory.h>
#else
#define memcpy(s1, s2, n) strncpy(s1, s2, n) 
#define memcmp(s1, s2, n) strncmp(s1, s2, n)
#define strchr(s, c) index(s, c) 
#endif

#if __STDC__ != 1
#define const
#endif

#if __STDC__ == 1
extern char *cplus_demangle (const char *type);
#else
extern char *cplus_demangle ();
#endif

#if __STDC__ == 1
extern char *xmalloc (int);
extern char *xrealloc (char *, int);
#else
extern char *xmalloc ();
extern char *xrealloc ();
#endif

static char **typevec = 0;
static int ntypes = 0;
static int typevec_size = 0;

static struct {
	const char *in;
	const char *out;
} optable[] = {
	"new", " new",
	"delete", " delete",
	"ne", "!=",
	"eq", "==",
	"ge", ">=",
	"gt", ">",
	"le", "<=",
	"lt", "<",
	"plus", "+",
	"minus", "-",
	"mult", "*",
	"negate", "-",
	"trunc_mod", "%",
	"trunc_div", "/",
	"truth_andif", "&&",
	"truth_orif", "||",
	"postincrement", "++",
	"postdecrement", "--",
	"bit_ior", "|",
	"bit_xor", "^",
	"bit_and", "&",
	"bit_not", "~",
	"call", "()",
	"cond", "?:",
	"alshift", "<<",
	"arshift", ">>",
	"component", "->",
	"nop", "",			/* for operator= */
};

/* Beware: these aren't '\0' terminated. */

typedef struct {
	char *b;			/* pointer to start of string */
	char *p;			/* pointer after last character */
	char *e;			/* pointer after end of allocated space */
} string;

#if __STDC__ == 1
static void string_need (string *s, int n);
static void string_delete (string *s);
static void string_init (string *s);
static void string_clear (string *s);
static int string_empty (string *s);
static void string_append (string *p, const char *s);
static void string_appends (string *p, string *s);
static void string_appendn (string *p, const char *s, int n);
static void string_prepend (string *p, const char *s);
#if 0
static void string_prepends (string *p, string *s);
#endif
static void string_prependn (string *p, const char *s, int n);
static int get_count (const char **type, int *count);
static int do_args (const char **type, string *decl);
static int do_type (const char **type, string *result);
static int do_arg (const char **type, string *result);
static int do_args (const char **type, string *decl);
static void munge_function_name (string *name);
#else
static void string_need ();
static void string_delete ();
static void string_init ();
static void string_clear ();
static int string_empty ();
static void string_append ();
static void string_appends ();
static void string_appendn ();
static void string_prepend ();
static void string_prepends ();
static void string_prependn ();
static int get_count ();
static int do_args ();
static int do_type ();
static int do_arg ();
static int do_args ();
static void munge_function_name ();
#endif

char *
    cplus_demangle (type)
const char *type;
{
	string decl;
	int n;
	int success = 0;
	int constructor = 0;
	int const_flag = 0;
	int i;
	const char *p;
	
	if (type == NULL || *type == '\0')
	    return NULL;
#ifndef nounderscore
	if (*type++ != '_')
	    return NULL;
#endif
	p = type;
	while (*p != '\0' && !(*p == '_' && p[1] == '_'))
	    p++;
	if (*p == '\0')
	    {
		    /* destructor */
		    if (type[0] == '_' && type[1] == '$' && type[2] == '_')
			{
				int n = (strlen (type) - 3)*2 + 3 + 2 + 1;
				char *tem = (char *) xmalloc (n);
				strcpy (tem, type + 3);
				strcat (tem, "::~");
				strcat (tem, type + 3);
				strcat (tem, "()");
				return tem;
			}
		    /* static data member */
		    if (*type != '_' && (p = strchr (type, '$')) != '\0')
			{
				int n = strlen (type) + 2;
				char *tem = (char *) xmalloc (n);
				memcpy (tem, type, p - type);
				strcpy (tem + (p - type), "::");
				strcpy (tem + (p - type) + 2, p + 1);
				return tem;
			}
		    return NULL;
	    }
	
	string_init (&decl);
	
	if (p == type)
	    {
		    if (!isdigit (p[2]))
			{
				string_delete (&decl);
				return NULL;
			}
		    constructor = 1;
	    }
	else
	    {
		    string_appendn (&decl, type, p - type);
		    munge_function_name (&decl);
	    }
	p += 2;
	
	switch (*p)
	    {
	    case 'C':
		    /* a const member function */
		    if (!isdigit (p[1]))
			{
				string_delete (&decl);
				return NULL;
			}
		    p += 1;
		    const_flag = 1;
		    /* fall through */
	    case '0':
	    case '1':
	    case '2':
	    case '3':
	    case '4':
	    case '5':
	    case '6':
	    case '7':
	    case '8':
	    case '9':
		    n = 0;
		    do
			{
				n *= 10;
				n += *p - '0';
				p += 1;
			}
		    while (isdigit (*p));
		    if (strlen (p) < n)
			{
				string_delete (&decl);
				return NULL;
			}
		    if (constructor)
			{
				string_appendn (&decl, p, n);
				string_append (&decl, "::");
				string_appendn (&decl, p, n);
			}
		    else
			{
				string_prepend (&decl, "::");
				string_prependn (&decl, p, n);
			}
		    p += n;
		    success = do_args (&p, &decl);
		    if (const_flag)
			string_append (&decl, " const");
		    break;
	    case 'F':
		    p += 1;
		    success = do_args (&p, &decl);
		    break;
	    }
	
	for (i = 0; i < ntypes; i++)
	    if (typevec[i] != NULL)
		free (typevec[i]);
	ntypes = 0;
	if (typevec != NULL)
	    {
		    free ((char *)typevec);
		    typevec = NULL;
		    typevec_size = 0;
	    }
	
	if (success)
	    {
		    string_appendn (&decl, "", 1);
		    return decl.b;
	    }
	else
	    {
		    string_delete (&decl);
		    return NULL;
	    }
}

static int
    get_count (type, count)
const char **type;
int *count;
{
	if (!isdigit (**type))
	    return 0;
	*count = **type - '0';
	*type += 1;
	/* see flush_repeats in cplus-method.c */
	if (isdigit (**type))
	    {
		    const char *p = *type;
		    int n = *count;
		    do 
			{
				n *= 10;
				n += *p - '0';
				p += 1;
			} 
		    while (isdigit (*p));
		    if (*p == '_')
			{
				*type = p + 1;
				*count = n;
			}
	    }
	return 1;
}

/* result will be initialised here; it will be freed on failure */

static int
    do_type (type, result)
const char **type;
string *result;
{
	int n;
	int done;
	int non_empty;
	int success;
	string decl;
	const char *remembered_type;
	
	string_init (&decl);
	string_init (result);
	
	done = 0;
	success = 1;
	while (success && !done)
	    {
		    int member;
		    switch (**type)
			{
			case 'P':
				*type += 1;
				string_prepend (&decl, "*");
				break;
				
			case 'R':
				*type += 1;
				string_prepend (&decl, "&");
				break;
				
			case 'T':
				*type += 1;
				if (!get_count (type, &n) || n >= ntypes)
				    success = 0;
				else
				    {
					    remembered_type = typevec[n];
					    type = &remembered_type;
				    }
				break;
				
			case 'F':
				*type += 1;
				if (!string_empty (&decl) && decl.b[0] == '*')
				    {
					    string_prepend (&decl, "(");
					    string_append (&decl, ")");
				    }
				if (!do_args (type, &decl) || **type != '_')
				    success = 0;
				else
				    *type += 1;
				break;
				
			case 'M':
			case 'O':
				{
					int constp = 0;
					int volatilep = 0;
					
					member = **type == 'M';
					*type += 1;
					if (!isdigit (**type))
					    {
						    success = 0;
						    break;
					    }
					n = 0;
					do
					    {
						    n *= 10;
						    n += **type - '0';
						    *type += 1;
					    } 
					while (isdigit (**type));
					if (strlen (*type) < n)
					    {
						    success = 0;
						    break;
					    }
					string_append (&decl, ")");
					string_prepend (&decl, "::");
					string_prependn (&decl, *type, n);
					string_prepend (&decl, "(");
					*type += n;
					if (member)
					    {
						    if (**type == 'C')
							{
								*type += 1;
								constp = 1;
							}
						    if (**type == 'V')
							{
								*type += 1;
								volatilep = 1;
							}
						    if (*(*type)++ != 'F')
							{
								success = 0;
								break;
							}
					    }
					if ((member && !do_args (type, &decl)) || **type != '_')
					    {
						    success = 0;
						    break;
					    }
					*type += 1;
					if (constp)
					    {
						    if (non_empty)
							string_append (&decl, " ");
						    else
							non_empty = 1;
						    string_append (&decl, "const");
					    }
					if (volatilep)
					    {
						    if (non_empty)
							string_append (&decl, " ");
						    else
							non_empty = 1;
						    string_append (&decl, "volatilep");
					    }
					break;
				}
				
			case 'C':
				if ((*type)[1] == 'P')
				    {
					    *type += 1;
					    if (!string_empty (&decl))
						string_prepend (&decl, " ");
					    string_prepend (&decl, "const");
					    break;
				    }
				
				/* fall through */
			default:
				done = 1;
				break;
			}
	    }
	
	done = 0;
	non_empty = 0;
	while (success && !done)
	    {
		    switch (**type)
			{
			case 'C':
				*type += 1;
				if (non_empty)
				    string_append (result, " ");
				else
				    non_empty = 1;
				string_append (result, "const");
				break;
			case 'U':
				*type += 1;
				if (non_empty)
				    string_append (result, " ");
				else
				    non_empty = 1;
				string_append (result, "unsigned");
				break;
			case 'V':
				*type += 1;
				if (non_empty)
				    string_append (result, " ");
				else
				    non_empty = 1;
				string_append (result, "volatile");
				break;
			default:
				done = 1;
				break;
			}
	    }
	
	if (success)
	    switch (**type)
		{
		case '\0':
		case '_':
			break;
		case 'v':
			*type += 1;
			if (non_empty)
			    string_append (result, " ");
			string_append (result, "void");
			break;
		case 'l':
			*type += 1;
			if (non_empty)
			    string_append (result, " ");
			string_append (result, "long");
			break;
		case 'i':
			*type += 1;
			if (non_empty)
			    string_append (result, " ");
			string_append (result, "int");
			break;
		case 's':
			*type += 1;
			if (non_empty)
			    string_append (result, " ");
			string_append (result, "short");
			break;
		case 'c':
			*type += 1;
			if (non_empty)
			    string_append (result, " ");
			string_append (result, "char");
			break;
		case 'r':
			*type += 1;
			if (non_empty)
			    string_append (result, " ");
			string_append (result, "long double");
			break;
		case 'd':
			*type += 1;
			if (non_empty)
			    string_append (result, " ");
			string_append (result, "double");
			break;
		case 'f':
			*type += 1;
			if (non_empty)
			    string_append (result, " ");
			string_append (result, "float");
			break;
		case 'G':
			*type += 1;
			if (!isdigit (**type))
			    {
				    success = 0;
				    break;
			    }
			/* fall through */
		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
		case '8':
		case '9':
			n = 0;
			do
			    {
				    n *= 10;
				    n += **type - '0';
				    *type += 1;
			    }
			while (isdigit (**type));
			if (strlen (*type) < n)
			    {
				    success = 0;
				    break;
			    }
			if (non_empty)
			    string_append (result, " ");
			string_appendn (result, *type, n);
			*type += n;
			break;
		default:
			success = 0;
			break;
		}
	
	if (success)
	    {
		    if (!string_empty (&decl))
			{
				string_append (result, " ");
				string_appends (result, &decl);
			}
		    string_delete (&decl);
		    return 1;
	    }
	else
	    {
		    string_delete (&decl);
		    string_delete (result);
		    return 0;
	    }
}

/* `result' will be initialised in do_type; it will be freed on failure */

static int
    do_arg (type, result)
const char **type;
string *result;
{
	char *tem;
	int len;
	const char *start;
	const char *end;
	
	start = *type;
	if (!do_type (type, result))
	    return 0;
	end = *type;
	if (ntypes >= typevec_size)
	    {
		    if (typevec_size == 0)
			{
				typevec_size = 3;
				typevec = (char **) xmalloc (sizeof (char*)*typevec_size);
			}
		    else
			{
				typevec_size *= 2;
				typevec = (char **) xrealloc ((char *)typevec, sizeof (char*)*typevec_size);
			}
	    }
	len = end - start;
	tem = (char *) xmalloc (len + 1);
	memcpy (tem, start, len);
	tem[len] = '\0';
	typevec[ntypes++] = tem;
	return 1;
}

/* `decl' must be already initialised, usually non-empty;
   it won't be freed on failure */

static int
    do_args (type, decl)
const char **type;
string *decl;
{
	string arg;
	int need_comma = 0;
	
	string_append (decl, "(");
	
	while (**type != '_' && **type != '\0' && **type != 'e' && **type != 'v')
	    {
		    if (**type == 'N')
			{
				int r;
				int t;
				*type += 1;
				if (!get_count (type, &r) || !get_count (type, &t) || t >= ntypes)
				    return 0;
				while (--r >= 0)
				    {
					    const char *tem = typevec[t];
					    if (need_comma)
						string_append (decl, ", ");
					    if (!do_arg (&tem, &arg))
						return 0;
					    string_appends (decl, &arg);
					    string_delete (&arg);
					    need_comma = 1;
				    }
			}
		    else
			{
				if (need_comma)
				    string_append (decl, ", ");
				if (!do_arg (type, &arg))
				    return 0;
				string_appends (decl, &arg);
				string_delete (&arg);
				need_comma = 1;
			}
	    }
	
	if (**type == 'v')
	    *type += 1;
	else if (**type == 'e')
	    {
		    *type += 1;
		    if (need_comma)
			string_append (decl, ",");
		    string_append (decl, "...");
	    }
	
	string_append (decl, ")");
	return 1;
}

static void
    munge_function_name (name)
string *name;
{
	if (!string_empty (name) && name->p - name->b >= 3 
	    && name->b[0] == 'o' && name->b[1] == 'p' && name->b[2] == '$')
	    {
		    int i;
		    /* see if it's an assignment expression */
		    if (name->p - name->b >= 10 /* op$assign_ */
			&& memcmp (name->b + 3, "assign_", 7) == 0)
			{
				for (i = 0; i < sizeof (optable)/sizeof (optable[0]); i++)
				    {
					    int len = name->p - name->b - 10;
					    if (strlen (optable[i].in) == len
						&& memcmp (optable[i].in, name->b + 10, len) == 0)
						{
							string_clear (name);
							string_append (name, "operator");
							string_append (name, optable[i].out);
							string_append (name, "=");
							return;
						}
				    }
			}
		    else
			{
				for (i = 0; i < sizeof (optable)/sizeof (optable[0]); i++)
				    {
					    int len = name->p - name->b - 3;
					    if (strlen (optable[i].in) == len 
						&& memcmp (optable[i].in, name->b + 3, len) == 0)
						{
							string_clear (name);
							string_append (name, "operator");
							string_append (name, optable[i].out);
							return;
						}
				    }
			}
		    return;
	    }
	else if (!string_empty (name) && name->p - name->b >= 5
		 && memcmp (name->b, "type$", 5) == 0)
	    {
		    /* type conversion operator */
		    string type;
		    const char *tem = name->b + 5;
		    if (do_type (&tem, &type))
			{
				string_clear (name);
				string_append (name, "operator ");
				string_appends (name, &type);
				string_delete (&type);
				return;
			}
	    }
}

/* a mini string-handling package */

static void
    string_need (s, n)
string *s;
int n;
{
	if (s->b == NULL)
	    {
		    if (n < 32)
			n = 32;
		    s->p = s->b = (char *) xmalloc (n);
		    s->e = s->b + n;
	    }
	else if (s->e - s->p < n)
	    {
		    int tem = s->p - s->b;
		    n += tem;
		    n *= 2;
		    s->b = (char *) xrealloc (s->b, n);
		    s->p = s->b + tem;
		    s->e = s->b + n;
	    }
}

static void
    string_delete (s)
string *s;
{
	if (s->b != NULL)
	    {
		    free (s->b);
		    s->b = s->e = s->p = NULL;
	    }
}

static void
    string_init (s)
string *s;
{
	s->b = s->p = s->e = NULL;
}

static void 
    string_clear (s)
string *s;
{
	s->p = s->b;
}

static int
    string_empty (s)
string *s;
{
	return s->b == s->p;
}

static void
    string_append (p, s)
string *p;
const char *s;
{
	int n;
	if (s == NULL || *s == '\0')
	    return;
	n = strlen (s);
	string_need (p, n);
	memcpy (p->p, s, n);
	p->p += n;
}

static void
    string_appends (p, s)
string *p, *s;
{
	int n;
	if (s->b == s->p)
	    return;
	n = s->p - s->b;
	string_need (p, n);
	memcpy (p->p, s->b, n);
	p->p += n;
}

static void
    string_appendn (p, s, n)
string *p;
const char *s;
int n;
{
	if (n == 0)
	    return;
	string_need (p, n);
	memcpy (p->p, s, n);
	p->p += n;
}

static void
    string_prepend (p, s)
string *p;
const char *s;
{
	if (s == NULL || *s == '\0')
	    return;
	string_prependn (p, s, strlen (s));
}

#if 0
static void
    string_prepends (p, s)
string *p, *s;
{
	if (s->b == s->p)
	    return;
	string_prependn (p, s->b, s->p - s->b);
}
#endif

static void
    string_prependn (p, s, n)
string *p;
const char *s;
int n;
{
	char *q;
	
	if (n == 0)
	    return;
	string_need (p, n);
	for (q = p->p - 1; q >= p->b; q--)
	    q[n] = q[0];
	memcpy (p->b, s, n);
	p->p += n;
}

/* end of cplus-dem.c */