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