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Light ROM 1
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LIGHT-ROM 1 (Amiga Library Services)(1994).iso
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d935.lha
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AmiCDROM
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rock.c
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C/C++ Source or Header
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1993-12-20
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5KB
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178 lines
/* rock.c:
*
* Support for the Rock Ridge filing system.
*
* ----------------------------------------------------------------------
* This code is (C) Copyright 1993 by Frank Munkert.
* All rights reserved.
* This software may be freely distributed and redistributed for
* non-commercial purposes, provided this notice is included.
* ----------------------------------------------------------------------
* History:
*
* 16-Oct-93 fmu Adapted to new VOLUME structure.
*/
#include <stdlib.h>
#include <string.h>
#include <exec/memory.h>
#include <clib/exec_protos.h>
#ifdef AZTEC_C
#include <pragmas/exec_lib.h>
#endif
#ifdef LATTICE
#include <pragmas/exec_pragmas.h>
#endif
#if defined(_DCC) && defined(REGISTERED)
#include <pragmas/exec_pragmas.h>
extern struct Library *SysBase;
#endif
#include "rock.h"
#define VOL(vol,tag) (((t_iso_vol_info *)(vol->vol_info))->tag)
#define OBJ(obj,tag) (((t_iso_obj_info *)(obj->obj_info))->tag)
/* Check whether the given volume uses the Rock Ridge Interchange Protocol.
* The protocol is identified by the sequence
* 'S' 'P' 7 1 0xbe 0xef
* in the system use field of the (00) directory in the root directory of
* the volume.
*
* Returns 1 iff the RR protocol is used; 0 otherwise.
* If the RR protocol is used, *p_skip will be set to the skip length
* specified in the SP system use field.
*/
t_bool Uses_Rock_Ridge_Protocol (VOLUME *p_volume, int *p_skip)
{
unsigned long loc = VOL(p_volume,pvd).root.extent_loc_m;
directory_record *dir;
int system_use_pos;
unsigned char *sys;
if (!(dir = Get_Directory_Record (p_volume, loc, 0)))
return 0;
system_use_pos = 33 + dir->file_id_length;
if (system_use_pos & 1)
system_use_pos++;
if (system_use_pos >= dir->length)
return 0;
sys = (unsigned char *) dir + system_use_pos;
if (sys[0] == 'S' && sys[1] == 'P' && sys[2] == 7 &&
sys[3] == 1 && sys[4] == 0xbe && sys[5] == 0xef) {
*p_skip = sys[6];
return 1;
} else
return 0;
}
/* Searches for the system use field with name p_name in the directory record
* p_dir and fills the buffer p_buf (with length p_buf_len) with the information
* contained in the system use field.
*
* p_index is the ordinal number of the system use field (if more than one
* system use field with the same name is recorded.) 0=first occurrence,
* 1=second occurrence, and so on.
*
* 1 is returned if the system use field has been found; otherwise 0
* is returned.
*/
int Get_System_Use_Field (VOLUME *p_volume, directory_record *p_dir,
char *p_name, char *p_buf, int p_buf_len,
int p_index)
{
int system_use_pos;
int slen, len;
unsigned long length = p_dir->length;
unsigned char *buf = (unsigned char *) p_dir;
system_use_pos = 33 + p_dir->file_id_length;
if (system_use_pos & 1)
system_use_pos++;
system_use_pos += VOL(p_volume,skip);
/* the system use field must be at least 4 bytes long */
while (system_use_pos + 3 < length) {
slen = buf[system_use_pos+2];
if (buf[system_use_pos] == p_name[0] &&
buf[system_use_pos+1] == p_name[1]) {
if (p_index)
p_index--;
else {
len = (slen < p_buf_len) ? slen : p_buf_len;
memcpy (p_buf, buf + system_use_pos, len);
return 1;
}
}
/* look for continuation area: */
if (buf[system_use_pos] == 'C' &&
buf[system_use_pos+1] == 'E') {
unsigned long newloc, offset;
memcpy (&newloc, buf + system_use_pos + 8, 4);
memcpy (&offset, buf + system_use_pos + 16, 4);
memcpy (&length, buf + system_use_pos + 24, 4);
if (!Read_Sector (p_volume->cd, newloc))
return 0;
buf = p_volume->cd->buffer;
system_use_pos = offset;
continue;
}
/* look for system use field terminator: */
if (buf[system_use_pos] == 'S' &&
buf[system_use_pos+1] == 'T')
return 0;
system_use_pos += slen;
}
return 0;
}
/* Determines the Rock Ridge file name of the CDROM object p_obj.
* The file name will be stored in the buffer p_buf (with length p_buf_len).
* The file name will NOT be null-terminated. The number of characters in
* the file name is returned. If there is no Rock Ridge file name for
* p_obj, then -1 is returned.
*/
int Get_RR_File_Name (VOLUME *p_volume, directory_record *p_dir,
char *p_buf, int p_buf_len)
{
__unaligned struct nm_system_use_field {
char id[2];
unsigned char length;
unsigned char version;
unsigned char flags;
char name[210];
} nm;
int len, slen;
int index = 0;
int total = 0;
for (;;) {
if (!Get_System_Use_Field (p_volume, p_dir, "NM",
(char *) &nm, sizeof (nm), index))
return -1;
slen = nm.length-5;
len = (p_buf_len < slen) ? p_buf_len : slen;
if (len)
memcpy (p_buf, nm.name, len);
total += len;
if (!(nm.flags & 1))
return total;
p_buf += len;
p_buf_len -= len;
index++;
}
}