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4394 ripley 1 
/*
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 * GraphApp - Cross-Platform Graphics Programming Library.
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 *
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 * File: array.c -- memory allocation functions.
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 * Platform: Neutral  Version: 2.35  Date: 1998/03/04
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 *
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 * Version: 2.30  Changes: Original version by Lachlan Patrick.
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 * Version: 2.35  Changes: Join and append improved by Jim McDonald.
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 */
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/* Copyright (C) 1993-1998 Lachlan Patrick
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   This file is part of GraphApp, a cross-platform C graphics library.
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   GraphApp is free software; you can redistribute it and/or modify it
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   under the terms of the GNU Library General Public License.
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   GraphApp is distributed in the hope that it will be useful, but
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   WITHOUT ANY WARRANTY.
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   See the file COPYLIB.TXT for details.
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*/
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#include <stdlib.h>
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#include "internal.h"
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#ifndef array
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#define create(type)  ( (type*) memalloc(sizeof(type)) )
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#define array(n,type) ( (type*) memalloc(n*sizeof(type)) )
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#define len(a)        ( memlength((char*)(a))/sizeof((a)[0]) )
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#define element(a,i)  ( (((i)<len(a)) && ((i)>=0)) ? (a)[i] : 0 )
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#define append(a,e)   ( *(char**)&(a)=memexpand((char*)(a),sizeof((a)[0])), \
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				(a)[len(a)-1]=(e) )
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#define shrink(a,ns)  ( *(char**)&(a)=memrealloc((char*)(a),(ns)) )
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#define join(a,b)     ( *(char**)&(a)=memjoin((char*)(a),(char*)(b)) )
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#define discard(a)    ( memfree((char*)(a)), (a)=0 )
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char *	memalloc(long size);
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char *	memrealloc(char *a, long new_size);
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void	memfree(char *a);
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long	memlength(char *a);
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char *	memexpand(char *a, long extra);
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char *	memjoin(char *a, char *b);
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#endif /* array defintions */
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#define TRACEAR(a)
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char * memalloc(long size)
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{
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	long *block;
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	char *a;
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	long i, datasize;
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        TRACEAR("alloc");
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	datasize = (((size + 4) >> 2) << 2);
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	#ifdef COMPILER
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	  #if (COMPILER <= 16)
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		if ((sizeof(long)+datasize) >= (1<<16))
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			return NULL;
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	  #endif
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	#endif
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	block = (long *) malloc(sizeof(long) + datasize);
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	if (block == NULL)
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		return NULL;
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	block[0] = size;
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	a = (char *) & block[1];
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	for (i=0; i<datasize; i++)
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		a[i] = '\0';
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	return a;
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}
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char * memrealloc(char *a, long new_size)
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{
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	long *block;
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	long i, size, oldsize, newsize;
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        TRACEAR("realloc");
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	if (new_size <= 0) {
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		memfree(a);
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		return NULL;
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	}
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	if (a == NULL) {
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		block = NULL;
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		size = 0;
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	}
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	else {
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		block = ((long*)a) - 1;
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		size = block[0];
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	}
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	oldsize = size ? (((size + 4) >> 2) << 2) : 0;
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	newsize = (((new_size + 4) >> 2) << 2);
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	if ( newsize != oldsize ) {
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		#ifdef COMPILER
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		  #if (COMPILER <= 16)
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			if ((sizeof(long)+newsize) >= (1<<16))
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				return NULL;
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		  #endif
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		#endif
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		block = (long *) realloc(block, sizeof(long) + newsize);
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		if (block == NULL)
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			return NULL;
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		a = (char *) & block[1];
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		for (i=oldsize; i<newsize; i++)
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			a[i] = '\0';
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	}
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	block[0] = new_size;
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	return a;
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}
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long memlength(char *a)
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{
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	return (a) ? ((long*)(a)-1)[0] : 0;
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}
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void memfree(char *a)
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{
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	if (a) free((long*)(a)-1);
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}
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char * memexpand(char *a, long extra)
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{
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	long *block;
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	long i, size, oldsize, newsize;
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        TRACEAR("exp");
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	if (extra == 0)
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		return a;
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	if (a == NULL) {
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		block = NULL;
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		size = 0;
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	}
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	else {
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		block = ((long*)a) - 1;
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		size = block[0];
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	}
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	oldsize = size ? (((size + 4) >> 2) << 2) : 0;
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	newsize = (((size + extra + 4) >> 2) << 2);
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	if ( newsize != oldsize ) {
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		#ifdef COMPILER
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		  #if (COMPILER <= 16)
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			if ((sizeof(long)+newsize) >= (1<<16))
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				return NULL;
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		  #endif
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		#endif
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		block = (long *) realloc(block, sizeof(long) + newsize);
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		if (block == NULL)
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			return NULL;
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		a = (char *) & block[1];
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		for (i=oldsize; i<newsize; i++)
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			a[i] = '\0';
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	}
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	block[0] = size + extra;
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	return a;
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}
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char * memjoin(char *a, char *b)
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{
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	long i, size, extra;
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	size = memlength(a);
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	extra = memlength(b);
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	a = memexpand(a, extra);
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	if (a) {
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		for (i=0; i<extra; i++)
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			a[i+size] = b[i];
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	}
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	return a;
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}
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