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#include "SeekTable.h"
#include "read.h"
#include "global_elements.h"
#include "vint.h"
#include <stdio.h>
#include <assert.h>
#ifdef WA_VALIDATE
extern uint32_t num_seekhead_elements_found;
extern uint32_t num_seek_elements_found;
#endif
bool nsmkv::SeekTable::GetEntry(uint64_t id, uint64_t *position)
{
return EnumEntry(0, id, position);
}
bool nsmkv::SeekTable::EnumEntry(size_t i, uint64_t id, uint64_t *position)
{
SeekMap::iterator found = seekMap.find(id);
if (found != seekMap.end())
{
SeekEntries *entries = found->second;
if (entries && entries->size() > i)
{
*position = entries->at(i).position;
return true;
}
}
return false;
}
bool nsmkv::SeekTable::EnumEntry(size_t i, uint64_t id, SeekEntry **seek_entry)
{
SeekMap::iterator found = seekMap.find(id);
if (found != seekMap.end())
{
SeekEntries *entries = found->second;
if (entries && entries->size() > i)
{
*seek_entry = &entries->at(i);
return true;
}
}
return false;
}
void nsmkv::SeekTable::AddEntry(nsmkv::SeekEntry &entry, int flags)
{
// check for duplicates
size_t i=0;
SeekEntry *seek_entry;
while (EnumEntry(i++, entry.id, &seek_entry))
{
if (flags & ADDENTRY_SINGLE)
{
if (flags & ADDENTRY_FOUND)
seek_entry->position = entry.position;
return;
}
if (entry.position == seek_entry->position)
{
return;
}
}
SeekEntries *&entries = seekMap[entry.id];
if (!entries)
{
entries = new SeekEntries;
}
entries->push_back(entry);
#ifdef WA_VALIDATE
num_seek_elements_found++;
#endif
}
void nsmkv::SeekTable::Dump()
{
SeekMap::iterator itr;
for (itr=seekMap.begin();itr!=seekMap.end();itr++)
{
SeekEntries *entries = itr->second;
if (entries)
{
SeekEntries::iterator seekItr;
for (seekItr=entries->begin();seekItr!=entries->end();seekItr++)
{
SeekEntry &entry = *seekItr;
printf("Seek Entry -> id=%I64x, position=%I64u\n", entry.id, entry.position);
}
}
}
}
// returns bytes read. 0 means EOF
static uint64_t ReadSeek(nsmkv::MKVReader *reader, uint64_t size, nsmkv::SeekTable &seekTable)
{
uint64_t total_bytes_read=0;
nsmkv::SeekEntry entry;
enum
{
ID_FIELD_PARSED = 0x1,
POSITION_FIELD_PARSED = 0x2,
};
int fields_parsed=0;
while (size)
{
ebml_node node;
uint64_t bytes_read = read_ebml_node(reader, &node);
if (bytes_read == 0)
return 0;
// benski> checking bytes_read and node.size separately prevents possible integer overflow attack
if (bytes_read > size)
return 0;
total_bytes_read+=bytes_read;
size-=bytes_read;
if (node.size > size)
return 0;
total_bytes_read+=node.size;
size-=node.size;
switch(node.id)
{
case mkv_metaseek_seekid:
{
uint8_t binary[9] = {0};
if (!node.size || node.size > 9)
{
#ifdef WA_VALIDATE
printf(" SeekID size invalid, size=%d\n",node.size);
#endif
assert(node.size<9);
return 0;
}
size_t bytes_read;
reader->Read(binary, (size_t)node.size, &bytes_read);
if (bytes_read != (size_t)node.size)
return 0;
#ifdef WA_VALIDATE
printf(" SeekID: %I64x\n", vint_read_ptr_len(node.size-1, binary));
#endif
entry.id = vint_read_ptr_len((uint8_t)node.size-1, binary);
fields_parsed |= ID_FIELD_PARSED;
}
break;
case mkv_metaseek_seekposition:
{
uint64_t val;
if (read_unsigned(reader, node.size, &val) == 0)
return 0;
#ifdef WA_VALIDATE
printf(" SeekPosition: %I64u\n", val);
#endif
entry.position = val;
fields_parsed |= POSITION_FIELD_PARSED;
}
break;
default:
nsmkv::ReadGlobal(reader, node.id, node.size);
}
}
if (fields_parsed == 0x3)
{
//entry.state = nsmkv::NOT_READ;
seekTable.AddEntry(entry);
}
#ifdef WA_VALIDATE
else if (fields_parsed == 0x2)
{
printf(" Seek only contains SeekPosition\n");
} else if (fields_parsed == 0x01)
{
printf(" Seek element only contains SeekID\n");
}
#endif
return total_bytes_read;
}
// returns bytes read. 0 means EOF
uint64_t nsmkv::ReadSeekHead(nsmkv::MKVReader *reader, uint64_t size, nsmkv::SeekTable &seekTable)
{
uint64_t total_bytes_read=0;
#ifdef WA_VALIDATE
num_seekhead_elements_found++;
#endif
while (size)
{
ebml_node node;
uint64_t bytes_read = read_ebml_node(reader, &node);
if (bytes_read == 0)
return 0;
// benski> checking bytes_read and node.size separately prevents possible integer overflow attack
if (bytes_read > size)
return 0;
total_bytes_read+=bytes_read;
size-=bytes_read;
if (node.size > size)
return 0;
total_bytes_read+=node.size;
size-=node.size;
switch(node.id)
{
case mkv_metaseek_seek:
{
#ifdef WA_VALIDATE
printf(" Seek\n");
#endif
ReadSeek(reader, node.size, seekTable);
}
break;
default:
ReadGlobal(reader, node.id, node.size);
}
}
return total_bytes_read;
}
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