view src/std.c @ 22:3fb0ec050ff3

malloc has been restructured to now work in a more logical manner malloc now allocates memory from the beginning of a block instead of the end. Additionally, memory is now 8-byte aligned instead of 16-byte aligned. malloc_init should now be called to set up all the memory information. Fixed a bug where malloc would not have iterated to find new memory locations.
author Jonathan Pevarnek <pevarnj@gmail.com>
date Wed, 16 Mar 2011 00:09:35 -0400
parents 7c2adb65ceac
children f68b59af5ea6
line wrap: on
line source

#include <std.h>

char* itoa(int n, char *a)
{
	char *ret = a;
	if(n < 0) {
		*a++ = '-';
		n *= -1;
	}
	char *b = a;
	if(!n) *b++ = '0';
	for(; n; b++) {
		*b = n%10 + '0';
		n = n/10;
	}
	*b-- = '\0';
	for(; a < b; a++, b--) { //reverse
		char temp = *b;
		*b = *a;
		*a = temp;
	}
	return ret;
}

char* ftoa(double x, char *a, unsigned int prec)
{
	char *ret = a;
	int n = (int) x; //integer part
	double d = x - (double) n; //fractional part;
	itoa(n, a);
	if(prec) { //only do the decimal part if decimal parts were asked for
		while(*a && *++a); //get to the null character from itoa
		int i; //counter variable for the for loop
		*a++ = '.'; //put the decimal in place
		for(i = 0; i < prec; i++) {
			d = d*10; //the integer part is the decimal digit
			*a++ = ((int) d) + '0'; //add the integer part of d to the string
			d -= (int) d; //chop off the integer part
		} a--; //move back to the last digit
		while(*a != '.') {
			if(*a == '0') {
				a--;
				continue;
			} else if(*a > '0' && *a <= '9') {
				a++;
				break;
			}
		}
		*a = '\0';
	}
	return ret;
}

int atoi(char *a)
{
	short neg = 0;
	int n = 0;
	if(*a == '-') {
		neg = 1;
		a++;
	} else if(*a == '+') a++;
	while(*a >= '0' && *a <= '9')
		n = n*10 + (*a++ - '0');
	if(neg) n *= -1;
	return n;
}

double atof(char *a)
{
	int n = atoi(a);
	double x = 0;
	double dec = .1;
	while(*a != '.') {
		if(!(*a >= '0' && *a <= '9')) return n;
		a++;
	} a++; //a will be immediately after the decimal point
	while(*a >= '0' && *a <= '9') { //goes through the decimal part
		x += (*a - '0')*dec;
		dec *= .1;
		a++;
	}
	return n + x;
}

void sPrint(char *a)
{
	char *b = a;
	while(*b && *++b);
	do {
		putline(a, (b - a > CON_LEN)?CON_LEN:(b - a));
		a += CON_LEN;
	} while(a < b);
}

int strcmp(const char *a, const char *b)
{
	while(1) {
		if(*a - *b) return *a - *b;
		if(*a == '\0') return 0;
		a++;
		b++;
	}
	return -1;
}

char* sGet(char *a, unsigned int n)
{
	int length = getline(a, n);
	a[(length < n)?length:n - 1] = '\0';
	return a;
}

int arrayLookup(char *text, const char array[][10], int last)
{
	int i;
	for(i = 0; i < last; i++)
		if(!strcmp(array[i], text)) return i;
	return last;
}

char* append(char *dest, char *src)
{
	char *ret = dest;
	while(*dest&& *++dest); //get to null in first string
	while((*dest++ = *src++));
	return ret;
}

static Block *allocp = NULL; //the location of the last item allocated by malloc

void malloc_init(size_t memSize)
{
	allocp = (void*)0x200000;
	allocp->next = allocp;
	allocp->size = memSize/sizeof(u64);
}

void* malloc(size_t size)
{
	unsigned int nUnits = ((size + sizeof(Block)) + sizeof(u64) - 1)/sizeof(u64);
	Block *cur, *prev, *temp;
	if(allocp == NULL) return NULL;
	prev = allocp;
	for(cur = prev->next;; prev = cur, cur = cur->next) {
		if(cur->size >= nUnits) {
			if(cur->size == nUnits) {
				prev->next = cur->next;
			} else {
				temp = cur + nUnits;
				temp->size = cur->size - nUnits;
				temp->next = cur->next;
				prev->next = temp;
				cur->size = nUnits;
			}
			allocp = prev;
			return (void*)(cur + 1);
		} else if(cur == allocp) { //We went back to the start...
			return NULL;
		}
	}
}

/*
void free(void *ptr)
{
}
*/