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/*

    		 Crown Copyright (c) 1997

    This TenDRA(r) Computer Program is subject to Copyright

    owned by the United Kingdom Secretary of State for Defence

    acting through the Defence Evaluation and Research Agency

    (DERA).  It is made available to Recipients with a

    royalty-free licence for its use, reproduction, transfer

    to other parties and amendment for any purpose not excluding

    product development provided that any such use et cetera

    shall be deemed to be acceptance of the following conditions:-

        (1) Its Recipients shall ensure that this Notice is

        reproduced upon any copies or amended versions of it;

        (2) Any amended version of it shall be clearly marked to

        show both the nature of and the organisation responsible

        for the relevant amendment or amendments;

        (3) Its onward transfer from a recipient to another

        party shall be deemed to be that party's acceptance of

        these conditions;

        (4) DERA gives no warranty or assurance as to its

        quality or suitability for any purpose and DERA accepts

        no liability whatsoever in relation to any use to which

        it may be put.

*/

#include "config.h"

#include <limits.h>

#include "c_types.h"

#include "error.h"

#include "char.h"

#include "ustring.h"

#include "xalloc.h"

/*

    CONTROLLED VERSION OF MALLOC

    All the program's memory allocation is through the routines defined in

    this file.  This routine allocates sz bytes of memory.

*/

gen_ptr xmalloc

    PROTO_N ( ( sz ) )

    PROTO_T ( gen_size sz )

{

    gen_ptr p ;

    if ( sz == 0 ) sz = 1 ;

    p = malloc ( ( size_t ) sz ) ;

    if ( p == NULL ) {

	max_errors = ULONG_MAX ;

	error ( ERROR_INTERNAL, "Memory allocation error" ) ;

	term_error ( 1 ) ;

    }

    return ( p ) ;

}

/*

    CONTROLLED VERSION OF REALLOC

    This routine reallocates the block of memory p to contain sz bytes.

    p can be the result of a previous memory allocation routine, or NULL.

*/

gen_ptr xrealloc

    PROTO_N ( ( p, sz ) )

    PROTO_T ( gen_ptr p X gen_size sz )

{

    gen_ptr q ;

    if ( sz == 0 ) sz = 1 ;

    if ( p ) {

	q = realloc ( p, ( size_t ) sz ) ;

    } else {

	q = malloc ( ( size_t ) sz ) ;

    }

    if ( q == NULL ) {

	max_errors = ULONG_MAX ;

	error ( ERROR_INTERNAL, "Memory allocation error" ) ;

	term_error ( 1 ) ;

    }

    return ( q ) ;

}

/*

    CONTROLLED VERSION OF FREE

    This routine frees the block of memory p.  p can be the result of a

    previous memory allocation routine, or NULL.

*/

void xfree

    PROTO_N ( ( p ) )

    PROTO_T ( gen_ptr p )

{

    if ( p ) free ( p ) ;

    return ;

}

/*

    STRING ALLOCATION BUFFER

    This buffer is used in the allocation of small strings.

*/

static gen_size chars_left = 0 ;

static string chars_free = NULL ;

/*

    ALLOCATE SPACE FOR A STRING

    This routine allocates space for n characters.  The memory allocation

    is buffered except for very long strings.

*/

string xustr

    PROTO_N ( ( n ) )

    PROTO_T ( gen_size n )

{

    string r ;

    if ( n < 1000 ) {

	/* Small strings */

	if ( n >= chars_left ) {

	    chars_left = 5000 ;

	    chars_free = xmalloc_nof ( character, chars_left ) ;

	}

	r = chars_free ;

	chars_free += n ;

	chars_left -= n ;

    } else {

	/* Large strings */

	r = xmalloc_nof ( character, n ) ;

    }

    return ( r ) ;

}

/*

    FREE SPACE ALLOCATED FOR A STRING

    This routine frees the space allocated by a previous call to xustr.

    For small strings the memory is only freed for the last call to xustr.

*/

void xufree

    PROTO_N ( ( s, n ) )

    PROTO_T ( string s X gen_size n )

{

    if ( s ) {

	if ( n < 1000 ) {

	    /* Small strings */

	    if ( s + n == chars_free ) {

		chars_free = s ;

		chars_left += n ;

	    }

	} else {

	    /* Large strings */

	    xfree_nof ( s ) ;

	}

    }

    return ;

}

/*

    COPY A STRING OF A GIVEN LENGTH

    This routine allocates space for a persistent copy of the string s

    of length n.  There is only one copy of each small string, otherwise

    xustr is used to allocate the space.

*/

string xustrncpy

    PROTO_N ( ( s, n ) )

    PROTO_T ( string s X gen_size n )

{

    string r ;

    if ( n < 2 ) {

	/* Small strings */

	static character buff [ NO_CHAR ] [2] ;

	int c = ( int ) s [0] ;

	if ( c < NO_CHAR ) {

	    r = buff [c] ;

	    r [0] = ( character ) c ;

	    r [1] = 0 ;

	    return ( r ) ;

	}

    }

    /* Large strings */

    r = xustr ( n + 1 ) ;

    ustrcpy_v ( r, s ) ;

    return ( r ) ;

}

/*

    COPY A STRING

    This routine allocates space for a persistent copy of the string s.

*/

string xustrcpy

    PROTO_N ( ( s ) )

    PROTO_T ( string s )

{

    gen_size n ;

    if ( s == NULL ) return ( NULL ) ;

    n = ( gen_size ) ustrlen ( s ) ;

    return ( xustrncpy ( s, n ) ) ;

}

/*

    CONCATENATE TWO STRINGS

    This routine allocates space for a persistent copy of the string s

    followed by the string t.  The memory is allocated using xustr.

*/

string xustrcat

    PROTO_N ( ( s, t ) )

    PROTO_T ( string s X string t )

{

    string r ;

    gen_size n, m ;

    if ( s == NULL ) return ( xustrcpy ( t ) ) ;

    if ( t == NULL ) return ( xustrcpy ( s ) ) ;

    n = ( gen_size ) ustrlen ( s ) ;

    m = n + ( gen_size ) ustrlen ( t ) + 1 ;

    r = xustr ( m ) ;

    ustrcpy_v ( r, s ) ;

    ustrcpy_v ( r + n, t ) ;

    return ( r ) ;

}

/*

    COPY A NUMBER OF CHARACTERS

    This routine copies n characters from t to s.

*/

void xumemcpy

    PROTO_N ( ( s, t, n ) )

    PROTO_T ( string s X string t X gen_size n )

{

    if ( n ) memcpy_v ( ( gen_ptr ) s, ( gen_ptr ) t, ( size_t ) n ) ;

    return ;

}

/*

    COMPARE TWO SEQUENCES OF CHARACTERS

    This routine compares the n characters given by s and t.

*/

int xumemcmp

    PROTO_N ( ( s, t, n ) )

    PROTO_T ( string s X string t X gen_size n )

{

    if ( s == t || n == 0 ) return ( 0 ) ;

    return ( memcmp ( ( gen_ptr ) s, ( gen_ptr ) t, ( size_t ) n ) ) ;

}