Espresso/drivers/fs/sfs.c

#include <drivers/ide.h>
#include <stdio.h>
#include <stdlib.h>

#include <fs/sfs.h>


#define SFS_BEGINNING_LBA 8

#pragma pack(push, 1)
typedef struct sfs_file_header {
  uint16_t magic; /* 0xBEEF */
  /*
    32 chars for the filename itself,
    4 chars for the file's extension,
    and 1 char for the null zero.
  */
  char filename[37];
  
  uint64_t data_beginning; /* Actually a 48 bit LBA mind you */
  uint32_t num_sectors; /* Number of sectors after data_beginning that are this file's data */
  
  uint8_t padding[13]; /* Padding to 64 bytes total */
} sfs_file_header_t;
#pragma pack(pop)

static sfs_file_header_t* base;




int32_t sfs_init(bool format)
{
  uint8_t buffer[512] = { 0 };

  int32_t kl = read_sector(SFS_BEGINNING_LBA, buffer);
  
  if (kl != 0)
  {
    return -1;
  }
  
  volatile sfs_file_header_t null_file;
  memcpy(&null_file, buffer, sizeof(sfs_file_header_t));
  
  if ((&null_file)->magic != 0xBEEF)
  {
    if (!format)
    {
      return -2;
    }
    
    //sfs_format();
    return -2;
  }
  
  memcpy(base, &null_file, sizeof(sfs_file_header_t));
  
  return 0;
}

bool sfs_get_formatted_name(const char* raw_name, char output[37])
{
  size_t len = strlen(raw_name);

  if (len > 36 || strchr(raw_name, '/') || strchr(raw_name, '*') || strchr(raw_name, '\\')) {
    return false;
  }

  memset(output, ' ', 36);
  output[36] = '\0';

  memcpy(output, raw_name, len);

  return true;
}


/* 
  Note: if a negative value is passed for num, then read the whole file
*/
int32_t sfs_read_file(char* _name, void* buffer, uint32_t num)
{
  char name[37] = { '\0' };
  
  if (sfs_get_formatted_name(_name, name))
  {
    return -128;
  }
  
  printf("%s", name);
  
  return 0;
}