/* Copyright (C) 1989, 1992, 1993, 1994 Aladdin Enterprises.  All rights reserved.
  
  This file is part of GNU Ghostscript.
  
  GNU Ghostscript is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY.  No author or distributor accepts responsibility to
  anyone for the consequences of using it or for whether it serves any
  particular purpose or works at all, unless he says so in writing.  Refer
  to the GNU Ghostscript General Public License for full details.
  
*/

/* iutil.c */
/* Utilities for Ghostscript interpreter */
#include "memory_.h"
#include "string_.h"
#include "ghost.h"
#include "errors.h"
#include "idict.h"
#include "imemory.h"
#include "iname.h"
#include "ipacked.h"			/* for array_get */
#include "iutil.h"			/* for checking prototypes */
#include "ivmspace.h"
#include "oper.h"
#include "store.h"
#include "gsmatrix.h"
#include "gsutil.h"

/* ------ Object utilities ------ */

/* Copy refs from one place to another. */
int
refcpy_to_old(ref *aref, uint index, register const ref *from,
  register uint size, client_name_t cname)
{	register ref *to = aref->value.refs + index;
	int code = refs_check_space(from, size, r_space(aref));
	if ( code < 0 )
		return code;
	/* We have to worry about aliasing.... */
	if ( to <= from || from + size <= to )
		while ( size-- )
			ref_assign_old(aref, to, from, cname), to++, from++;
	else
		for ( from += size, to += size; size--; )
			from--, to--, ref_assign_old(aref, to, from, cname);
	return 0;
}
void
refcpy_to_new(register ref *to, register const ref *from, register uint size)
{	while ( size-- )
		ref_assign_new(to, from), to++, from++;
}

/* Fill a new object with nulls. */
void
refset_null(register ref *to, register uint size)
{	while ( size-- ) make_null_new(to), to++;
}

/* Compare two objects for equality.  Return 1 if equal, 0 if not. */
int
obj_eq(register const ref *pref1, register const ref *pref2)
{	ref nref;
	if ( r_type(pref1) != r_type(pref2) )
	   {	/* Only a few cases need be considered here: */
		/* integer/real (and vice versa), name/string */
		/* (and vice versa), and extended operators. */
		switch ( r_type(pref1) )
		   {
		case t_integer:
			return (r_has_type(pref2, t_real) &&
				pref2->value.realval == pref1->value.intval);
		case t_real:
			return (r_has_type(pref2, t_integer) &&
				pref2->value.intval == pref1->value.realval);
		case t_name:
			if ( !r_has_type(pref2, t_string) )
				return 0;
			name_string_ref(pref1, &nref);
			pref1 = &nref;
			break;
		case t_save:
			return (r_has_type(pref2, t_save) &&
				pref2->value.saveid == pref1->value.saveid);
		case t_string:
			if ( !r_has_type(pref2, t_name) )
				return 0;
			name_string_ref(pref2, &nref);
			pref2 = &nref;
			break;
		default:
			if ( r_btype(pref1) != r_btype(pref2) )
				return 0;
		   }
	   }
	/* Now do a type-dependent comparison. */
	/* This would be very simple if we always filled in */
	/* all 8 bytes of a ref, but we currently don't. */
	switch ( r_btype(pref1) )
	   {
	case t_array:
		return (pref1->value.refs == pref2->value.refs &&
			r_size(pref1) == r_size(pref2));
	case t_mixedarray:
	case t_shortarray:
		return (pref1->value.packed == pref2->value.packed &&
			r_size(pref1) == r_size(pref2));
	case t_boolean:
		return (pref1->value.boolval == pref2->value.boolval);
	case t_dictionary:
		return (pref1->value.pdict == pref2->value.pdict);
	case t_file:
		return (pref1->value.pfile == pref2->value.pfile &&
			r_size(pref1) == r_size(pref2));
	case t_integer:
		return (pref1->value.intval == pref2->value.intval);
	case t_mark:
	case t_null:
		return 1;
	case t_name:
		return (pref1->value.pname == pref2->value.pname);
	case t_oparray:
	case t_operator:
		return (op_index(pref1) == op_index(pref2));
	case t_real:
		return (pref1->value.realval == pref2->value.realval);
	case t_string:
		return (!bytes_compare(pref1->value.bytes, r_size(pref1),
				       pref2->value.bytes, r_size(pref2)));
	case t_device:
		return (pref1->value.pdevice == pref2->value.pdevice);
	case t_fontID:
	case t_struct:
	case t_astruct:
		return (pref1->value.pstruct == pref2->value.pstruct);
	   }
	return 0;			/* shouldn't happen! */
}

/* Create a printable representation of an object, a la cvs. */
/* Return 0 if OK, <0 if the destination wasn't large enough or */
/* the object's contents weren't readable. */
/* If the object was a string or name, store a pointer to its characters */
/* even if it was too large. */
int
obj_cvs(const ref *op, byte *str, uint len, uint *prlen, byte **pchars)
{	char buf[30];			/* big enough for any float */
	byte *pstr = (byte *)buf;
	uint plen;
	ref nref;
	switch ( r_btype(op) )
	   {
	case t_boolean:
		pstr = (byte *)(op->value.boolval ? "true" : "false");
		break;
	case t_integer:
		sprintf(buf, "%ld", op->value.intval);
		break;
	case t_name:
		name_string_ref(op, &nref);	/* name string */
cvname:		pstr = nref.value.bytes;
		plen = r_size(&nref);
		if ( pchars != 0 )
			*pchars = pstr;
		goto nl;
	case t_oparray:
		{ uint index = op_index(op);
		  const op_array_table *opt = op_index_op_array_table(index);
		  name_index_ref(opt->nx_table[index - opt->base_index], &nref);
		}
		name_string_ref(&nref, &nref);
		goto cvname;
	case t_operator:
	   {	/* Recover the name from the initialization table. */
		uint index = op_index(op);
		/* Check the validity of the index.  (An out-of-bounds */
		/* index is only possible when examining an invalid */
		/* object using the debugger.) */
		if ( index > 0 && index < op_def_count )
		   {	pstr = (byte *)(op_def_table[index]->oname + 1);
			break;
		   }
	   }
		/* Internal operator, no name. */
		sprintf(buf, "operator_0x%lx", (ulong)op->value.opproc);
		break;
	case t_real:
		sprintf(buf, "%g", op->value.realval);
		/* Make sure the output has a decimal point. */
		/* This is needed for compatibility with */
		/* Adobe (and other) interpreters. */
		/* Old Borland compilers require &buf[0], not just buf. */
		if ( strchr(&buf[0], '.') != NULL ) break;
		{	char *ept = strchr(&buf[0], 'e');
			if ( ept == NULL )
				strcat(buf, ".0");
			else
			{	/* Insert the .0 before the exponent. */
				/* What a nuisance! */
				char buf1[30];
				strcpy(&buf1[0], ept);
				strcpy(ept, ".0");
				strcat(&buf[0], &buf1[0]);
			}
		}
		break;
	case t_string:
		check_read(*op);
		pstr = op->value.bytes;
		plen = r_size(op);
		if ( pchars != 0 )
			*pchars = pstr;
		goto nl;
	default:
		pstr = (byte *)"--nostringval--";
	   }
	plen = strlen((char *)pstr);
nl:	*prlen = plen;
	if ( plen > len )
		return_error(e_rangecheck);
	memcpy(str, pstr, plen);
	return 0;
}

/* Find the index of an operator that doesn't have one stored in it. */
ushort
op_find_index(const ref *pref /* t_operator */)
{	op_proc_p proc = real_opproc(pref);
	register const op_def_ptr *opp = op_def_table;
	register const op_def_ptr *opend = opp + op_def_count;
	for ( ; ++opp < opend; )
	{	if ( (*opp)->proc == proc )
			return opp - op_def_table;
	}
	/* Lookup failed!  This isn't possible.... */
	return 0;
}

/*
 * Convert an operator index to an operator or oparray ref.
 * This is only used for debugging and for 'get' from packed arrays,
 * so it doesn't have to be very fast.
 */
void
op_index_ref(uint index, ref *pref)
{	const op_array_table *opt;
	if ( op_index_is_operator(index) )
	  {	make_oper(pref, index, op_index_proc(index));
		return;
	  }
	opt = op_index_op_array_table(index);
	make_tasv(pref, t_oparray, opt->attrs, index,
                  const_refs, (opt->table.value.const_refs
                               + index - opt->base_index));
}

/* Get an element from an array of some kind. */
/* This is also used to index into Encoding vectors, */
/* the error name vector, etc. */
int
array_get(const ref *aref, long index_long, ref *pref)
{	if ( (ulong)index_long >= r_size(aref) )
		return_error(e_rangecheck);
	switch ( r_type(aref) )
	   {
	case t_array:
	   {	const ref *pvalue =
		   aref->value.refs + (uint)index_long;
		ref_assign(pref, pvalue);
	   }	return 0;
	case t_mixedarray:
	   {	const ref_packed *packed = aref->value.packed;
		uint index = (uint)index_long;
		for ( ; index--; ) packed = packed_next(packed);
		packed_get(packed, pref);
	   }	return 0;
	case t_shortarray:
	   {	const ref_packed *packed =
		   aref->value.packed + (uint)index_long;
		packed_get(packed, pref);
	   }	return 0;
	default:
		return_error(e_typecheck);
	   }
}

/* Get an element from a packed array. */
/* (This works for ordinary arrays too.) */
/* Source and destination are allowed to overlap if the source is packed, */
/* or if they are identical. */
void
packed_get(const ref_packed *packed, ref *pref)
{	const ref_packed elt = *packed;
	uint value = elt & packed_value_mask;
	switch ( elt >> r_packed_type_shift )
	{
	default:			/* (shouldn't happen) */
		make_null(pref);
		break;
	case pt_executable_operator:
		op_index_ref(value, pref);
		break;
	case pt_integer:
		make_int(pref, (int)value + packed_min_intval);
		break;
	case pt_literal_name:
		name_index_ref(value, pref);
		break;
	case pt_executable_name:
		name_index_ref(value, pref);
		r_set_attrs(pref, a_executable);
		break;
	case pt_full_ref:
	case pt_full_ref+1:
		ref_assign(pref, (const ref *)packed);
	}
}

/* Check to make sure an interval contains no object references */
/* to a space younger than a given one. */
/* Return 0 or e_invalidaccess. */
int
refs_check_space(register const ref *bot, register uint size, uint space)
{	for ( ; size--; bot++ )
	  store_check_space(space, bot);
	return 0;
}

/* ------ String utilities ------ */

/* Convert a C string to a Ghostscript string */
int
string_to_ref(const char *cstr, ref *pref, gs_ref_memory_t *mem,
  client_name_t cname)
{	uint size = strlen(cstr);
	int code = gs_alloc_string_ref(mem, pref, a_all, size, cname);
	if ( code < 0 )
	  return code;
	memcpy(pref->value.bytes, cstr, size);
	return 0;
}

/* Convert a Ghostscript string to a C string. */
/* Return 0 iff the buffer can't be allocated. */
char *
ref_to_string(const ref *pref, gs_memory_t *mem, client_name_t cname)
{	uint size = r_size(pref);
	char *str = (char *)gs_alloc_string(mem, size + 1, cname);
	if ( str == 0 )
		return 0;
	memcpy(str, (const char *)pref->value.bytes, size);
	str[size] = 0;
	return str;
}

/* ------ Operand utilities ------ */

/* Get N numeric operands from the stack or an array. */
/* Return a bit-mask indicating which ones are integers, */
/* or a (negative) error indication. */
/* The 1-bit in the bit-mask refers to the first operand. */
/* Store float versions of the operands at pval. */
/* The stack underflow check (check for t__invalid) is harmless */
/* if the operands come from somewhere other than the stack. */
int
num_params(const ref *op, int count, float *pval)
{	int mask = 0;
	pval += count;
	while ( --count >= 0 )
	   {	mask <<= 1;
		switch ( r_type(op) )
		   {
		case t_real:
			*--pval = op->value.realval;
			break;
		case t_integer:
			*--pval = op->value.intval;
			mask++;
			break;
		case t__invalid:
			return_error(e_stackunderflow);
		default:
			return_error(e_typecheck);
		   }
		op--;
	   }
	/* If count is very large, mask might overflow. */
	/* In this case we clearly don't care about the value of mask. */
	return (mask < 0 ? 0 : mask);
}

/* Get a single real parameter. */
/* The only possible error is e_typecheck. */
/* If an error is returned, the return value is not updated. */
int
real_param(const ref *op, float *pparam)
{	switch ( r_type(op) )
	   {
	case t_integer:
		*pparam = op->value.intval;
		break;
	case t_real:
		*pparam = op->value.realval;
		break;
	default:
		return_error(e_typecheck);
	   }
	return 0;
}

/* Make real values on the operand stack. */
void
make_reals(ref *op, const float *pval, int count)
{	for ( ; count--; op++, pval++ )
		make_real(op, *pval);
}

/* Compute the error code when check_proc fails. */
/* Note that the client, not this procedure, uses return_error. */
/* The stack underflow check is harmless in the off-stack case. */
int
check_proc_failed(const ref *pref)
{	return (r_is_array(pref) ? e_invalidaccess :
		r_has_type(pref, t__invalid) ? e_stackunderflow :
		e_typecheck);
}

/* Compute the error code when a type check on the stack fails. */
/* Note that the client, not this procedure, uses return_error. */
int
check_type_failed(const ref *op)
{	return (r_has_type(op, t__invalid) ? e_stackunderflow : e_typecheck);
}

/* ------ Matrix utilities ------ */

/* Read a matrix operand. */
/* Return 0 if OK, error code if not. */
int
read_matrix(const ref *op, gs_matrix *pmat)
{	int code;
	check_read_type(*op, t_array);
	if ( r_size(op) != 6 )
		return_error(e_rangecheck);
	code = num_params(op->value.refs + 5, 6, (float *)pmat);
	return (code < 0 ? code : 0);
}

/* Write a matrix operand. */
/* Return 0 if OK, error code if not. */
int
write_matrix(register ref *op, const gs_matrix *pmat)
{	ref *aptr;
	const float *pel;
	int i;
	check_write_type(*op, t_array);
	if ( r_size(op) != 6 )
		return_error(e_rangecheck);
	aptr = op->value.refs;
	pel = (float *)pmat;
	for ( i = 5; i >= 0; i--, aptr++, pel++ )
	{	ref_save(op, aptr, "write_matrix");
		make_real_new(aptr, *pel);
	}
	return 0;
}