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/*
* HT Editor
* relfile.cc
*
* Copyright (C) 1999-2002 Stefan Weyergraf
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <string.h>
#include "htdebug.h"
#include "relfile.h"
#include "tools.h"
#define MAX_RELOC_ITEM_LEN 8
/*
* ht_reloc_file
*/
ht_reloc_file::ht_reloc_file(File *s, bool os)
: FileLayer(s, os)
{
relocs = new AVLTree(true);
enabled = true;
}
ht_reloc_file::~ht_reloc_file()
{
delete relocs;
}
void ht_reloc_file::finalize()
{
// relocs->set_compare_keys(compare_keys_uint);
}
int ht_reloc_file::vcntl(uint cmd, va_list vargs)
{
switch (cmd) {
case FCNTL_GET_RELOC: {
bool *e = va_arg(vargs, bool*);
*e = enabled;
return 0;
}
case FCNTL_SET_RELOC: {
enabled = (bool)(va_arg(vargs, int));
return 0;
}
}
return FileLayer::vcntl(cmd, vargs);
}
void ht_reloc_file::insert_reloc(FileOfs o, Object *reloc)
{
relocs->insert(new KeyValue(new UInt64(o), reloc));
}
uint ht_reloc_file::read(void *buf, uint size)
{
FileOfs o = tell();
/* read fine data. */
uint ret = FileLayer::read(buf, size);
uint c = ret;
if (enabled) {
ObjHandle oh;
if ((MAX_RELOC_ITEM_LEN+1) <= o) {
KeyValue kv(new UInt64(o - (MAX_RELOC_ITEM_LEN+1)), NULL);
oh = relocs->findG(&kv);
} else {
oh = relocs->findFirst();
}
/* enum through 'relocs' - the tree that contains all our
* dear relocations - starting some bytes before the current
* (stream) offset to get all the relocation items that may
* intersect with our fine read data. */
while (oh != invObjHandle) {
KeyValue *kv = (KeyValue *)relocs->get(oh);
UInt64 *k = (UInt64 *)kv->mKey;
/* buffer to apply relocation to */
byte b[MAX_RELOC_ITEM_LEN];
/* stop if the item is "behind" the area this function
* should work on. */
if (k->value >= o+c) break;
/* if relocation item intersects with the beginning of
* this read, copy buf to b+s */
uint s = (k->value < o) ? o - k->value : 0;
/* if relocation item intersects with the end of
* this read, copy buf+e to b */
uint e = (k->value > o) ? k->value - o : 0;
/* complicated calculation to get the size of the
* intended intersection (=: mm) of the read and b. */
uint l = (k->value + sizeof b > o+c) ?
k->value + sizeof b - o - c : 0;
uint mm = MIN(sizeof b - l, sizeof b - s);
/* probably cleaner to clear it all before we start
* because if the read is smaller then the reloc item
* we'd have some undefined bytes in b. */
memset(b, 0, sizeof b);
/* never memmove beyond Bounds of b. (maybe you didn't call finalize()?) */
assert(mm+s <= sizeof b);
/* move read data to b as good as we can. */
memmove(b+s, ((byte*)buf)+e, mm);
/* apply complete relocation item. */
reloc_apply(kv->mValue, b);
/* overwrite read with relocated/read data as good as we can. */
memcpy(((byte*)buf)+e, b+s, mm);
oh = relocs->findG(kv);
}
}
return ret;
}
uint ht_reloc_file::write(const void *buf, uint size)
{
/* documentation: see read(). */
FileOfs o;
if (enabled) {
o = tell();
uint c = size;
ObjHandle oh;
if ((MAX_RELOC_ITEM_LEN+1) <= o) {
KeyValue kv(new UInt64(o - (MAX_RELOC_ITEM_LEN+1)), NULL);
oh = relocs->findG(&kv);
} else {
oh = relocs->findFirst();
}
while (oh != invObjHandle) {
KeyValue *kv = (KeyValue *)relocs->get(oh);
UInt64 *k = (UInt64 *)kv->mKey;
byte b[MAX_RELOC_ITEM_LEN];
if (k->value >= o+c) break;
uint s = (k->value < o) ? o - k->value : 0;
uint e = (k->value > o) ? k->value - o : 0;
uint l = (k->value+sizeof b > o+c) ?
k->value + sizeof b - o - c : 0;
memset(b, 0, sizeof b);
uint mm = MIN(sizeof b - l, sizeof b - s);
assert(mm+s <= sizeof b);
memmove(b+s, ((byte*)buf)+e, mm);
// FIXME: return here ???
if (!reloc_unapply(kv->mValue, b)) /*return 0*/;
// FIXME: violation of function declaration "const void *buf"
memcpy(((byte*)buf)+e, b+s, mm);
oh = relocs->findG(kv);
}
}
return FileLayer::write(buf, size);
}
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