file.c

#include "bootpack.h"

void file_readfat(int *fat, unsigned char *img)
{
	int i, j = 0;
	for (i = 0; i < 2880; i += 2)
	{
		fat[i] = (img[j+0] | img[j+1] << 8) & 0xfff;
		fat[i + 1] = (img[j+1] >> 4 | img[j+2] << 4) & 0xfff;
		j += 3;
	}
	return;
}

void file_loadfile(int clustno, int size, char *buf, int *fat, char *img)
{
	int i;
	for (;;)
	{
		if (size <= 512)
		{
			for (i = 0; i < size; ++i)
			{
				buf[i] = img[clustno * 512 + i];
			}
			break;
		}
		for (i = 0; i < 512; ++i)
		{
			buf[i] = img[clustno * 512 + i];
		}
		size -= 512;
		buf += 512;
		clustno = fat[clustno];
	}
	return;
}

struct FILEINFO *file_search(char *name, struct FILEINFO *finfo, int max)
{
	int x, y;
	char s[12];
	for (y = 0; y < 11; ++y)
	{
		s[y] = ' ';
	}
	y = 0;
	for (x = 0; name[x] != 0; ++x)
	{
		if (y >= 11) return 0;
		if (name[x] == '.' && y < 8)
			y = 8;
		else
		{
			s[y] = name[x];
			if ('a' <= s[y] && s[y] <= 'z')
				s[y] -= 0x20;
			++y;
		}
	}

	for (x = 0; x < max;)
	{
		if (finfo[x].name[0] == 0x00)
			break;
		if ((finfo[x].type & 0x18) == 0)
		{
			for (y = 0; y < 11; ++y)
			{
				if (finfo[x].name[y] != s[y])
					goto next_file;
			}
			return finfo+x;
		}
	next_file:
		++x;
	}
	return 0;
}