nes-proj/platform/c64/lib/pfs-dir.c
Oliver Schmidt d864e73579 Added directory functions to the Commodore Platform File System.
They reduce the Telnet server's run size by 1231 bytes.
2016-10-15 18:36:54 +02:00

172 lines
5.1 KiB
C

/*
* Copyright (c) 2016, Greg King
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions, and the following
* disclaimer, in the documentation and/or other materials provided
* with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS"; AND, ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* This file is a part of the Contiki operating system.
*/
/*
** Open a directory listing, so that it can be read by pfs_readdir().
**
** Read one file-name from a directory listing that was opened by pfs_opendir().
**
** 2012-05-30, Ullrich von Bassewitz
** 2016-04-22, Greg King
*/
#include "cfs.h"
typedef struct {
int fd; /* File descriptor for a directory */
} DIR;
/*---------------------------------------------------------------------------*/
/*
** Read characters from the directory into the supplied buffer.
** Return true if the read was successful, and false otherwise.
*/
extern unsigned char __fastcall__ _pfs_dirread(struct cfs_dir *dir, void *buf,
unsigned char count);
/*
** Read one byte from the directory into the supplied buffer.
** Return true if the read was successful, and false otherwise.
*/
extern unsigned char __fastcall__ _pfs_dirread1(struct cfs_dir *dir, void *buf);
/*---------------------------------------------------------------------------*/
int __fastcall__
pfs_opendir(struct cfs_dir *dirp, register const char *name)
{
static int fd;
static char buf[2 + 1] = "$";
/* Set up the actual file name that is sent to the DOS.
** We accept "0:", "1:", "/", and "." as directory names.
*/
if(name == NULL || name[0] == '\0' || (name[0] == '.' || name[0] == '/') && name[1] == '\0') {
buf[1] = '\0';
} else if((name[0] == '0' || name[0] == '1') && name[1] == ':' && name[2] == '\0') {
buf[1] = name[0];
buf[2] = '\0';
} else {
return -1;
}
/* Open the directory on a disk, for reading. */
fd = pfs_open(buf, CFS_READ);
if(fd >= 0) {
((DIR *)dirp)->fd = fd;
/* Skip the load address. */
if(_pfs_dirread(dirp, buf + 1, 2)) {
return 0;
} else {
pfs_close(fd);
}
}
return -1;
}
/*---------------------------------------------------------------------------*/
int __fastcall__
pfs_readdir(struct cfs_dir *dirp, register struct cfs_dirent *dirent)
{
register unsigned char *b;
register unsigned char i;
register unsigned char count;
unsigned char buffer[0x40];
static unsigned char s;
static unsigned char j;
/* Skip the BASIC line-link. */
if(!_pfs_dirread(dirp, buffer, 2)) {
return -1;
}
/* Read the number of blocks. It's a two-byte number; but, the size is
** a four-byte number. Zero the size; then, put the block number in
** the first two bytes. It works because the 6502 CPU's numbers are
** little-endian.
*/
dirent->size = 0;
if(!_pfs_dirread(dirp, &dirent->size, 2)) {
return -1;
}
/* Read the next file entry into a buffer. */
for(count = 0, b = buffer; count < sizeof(buffer); ++b) {
if(!_pfs_dirread1(dirp, b)) {
return -1;
}
++count;
if(*b == '\0') {
break;
}
}
/* The end of the directory was reached if the buffer contains "blocks free."
** It is sufficient here to check for the leading 'b'. The buffer will have
** at least one byte if we come here.
*/
if(buffer[0] == 'b') {
return -1;
}
/* Parse the buffer for the file-name. */
b = buffer;
j = 0;
s = 0;
i = 0;
while(i < count) {
switch(s) {
case 0:
/* Search for the start of the file-name. */
if(*b == '"') {
s = 1;
}
break;
case 1:
/* Within the file-name. */
if(*b == '"') {
/* The end of the file-name was found. */
dirent->name[j] = '\0';
return 0;
} else if(j < sizeof(dirent->name) - 1) {
dirent->name[j] = *b;
++j;
}
break;
}
++b;
++i;
}
/* The file-name is too long for the buffer. Return what could be read. */
dirent->name[j] = '\0';
return 0;
}