112 lines
3.1 KiB
C++
112 lines
3.1 KiB
C++
#include "Lacing.h"
|
|
#include "Cluster.h"
|
|
#include "vint.h"
|
|
|
|
|
|
|
|
bool nsmkv::Lacing::GetState(uint8_t flags, const uint8_t *data, size_t data_len, nsmkv::LacingState *state)
|
|
{
|
|
// TODO: error check by making sure data_len doesn't go below 0
|
|
switch(flags & BlockBinary::LACE_MASK)
|
|
{
|
|
case BlockBinary::NO_LACING:
|
|
state->laces = 1;
|
|
state->positions[0] = 0;
|
|
state->sizes[0] = data_len;
|
|
#ifdef WA_VALIDATE
|
|
printf(" Lacing = NO_LACING\n");
|
|
#endif
|
|
return true;
|
|
case BlockBinary::EBML_LACING:
|
|
{
|
|
uint16_t number_of_frames = state->laces = *data++ + 1;
|
|
uint64_t delta = vint_get_number_bytes(data[0]);
|
|
state->sizes[0] = vint_read_ptr_len((uint8_t)delta, data);
|
|
delta++;
|
|
state->positions[0] = 1;
|
|
state->positions[1] = 1+state->sizes[0];
|
|
for (uint16_t i=1;i<number_of_frames-1;i++)
|
|
{
|
|
uint8_t this_len = vint_get_number_bytes(data[delta]);
|
|
state->sizes[i] = vsint_read_ptr_len(this_len, data+delta);
|
|
state->sizes[i] += state->sizes[i-1];
|
|
state->positions[i+1] = state->positions[i] + state->sizes[i];
|
|
delta+=this_len + 1;
|
|
}
|
|
state->sizes[number_of_frames-1] = data_len - state->positions[number_of_frames-1] - delta;
|
|
|
|
for (uint16_t i=0;i<number_of_frames;i++)
|
|
{
|
|
state->positions[i] += delta;
|
|
}
|
|
#ifdef WA_VALIDATE
|
|
printf(" Lacing = EBML_LACING\n");
|
|
#endif
|
|
}
|
|
return true;
|
|
case BlockBinary::XIPH_LACING:
|
|
{
|
|
const uint8_t *orig_data = data;
|
|
uint16_t number_of_frames=state->laces = *data++ + 1;
|
|
for (uint16_t i=0;i!=number_of_frames-1;i++)
|
|
{
|
|
size_t frame_len = 0;
|
|
do
|
|
{
|
|
frame_len += *data;
|
|
} while (data && *data++ == 255);
|
|
state->sizes[i] = frame_len;
|
|
}
|
|
uint64_t delta = data - orig_data;
|
|
uint64_t last_position = delta;
|
|
uint64_t last_size = 0;
|
|
for (uint16_t i=0;i!=number_of_frames;i++)
|
|
{
|
|
state->positions[i] = last_position + last_size;
|
|
last_position = state->positions[i];
|
|
last_size = state->sizes[i];
|
|
}
|
|
state->sizes[number_of_frames-1] = data_len - state->positions[number_of_frames-1];
|
|
#ifdef WA_VALIDATE
|
|
printf(" Lacing = XIPH LACING\n");
|
|
#endif
|
|
}
|
|
return true;
|
|
case BlockBinary::FIXED_LACING:
|
|
{
|
|
uint16_t number_of_frames=state->laces=data[0]+1;
|
|
uint32_t size_per_frame = (uint32_t)(data_len-1) / number_of_frames;
|
|
for (uint16_t i=0;i<number_of_frames;i++)
|
|
{
|
|
state->positions[i] = (uint64_t)(1 + size_per_frame*i);
|
|
state->sizes[i] = size_per_frame;
|
|
}
|
|
#ifdef WA_VALIDATE
|
|
printf(" Lacing = FIXED LACING\n");
|
|
#endif
|
|
}
|
|
return true;
|
|
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
bool nsmkv::Lacing::GetFrame(uint16_t frame_number, const uint8_t *data, size_t data_len, const uint8_t **frame, size_t *frame_len, const LacingState *state)
|
|
{
|
|
if (frame_number >= state->laces)
|
|
return false;
|
|
|
|
const uint8_t *lace = data + state->positions[frame_number];
|
|
size_t lace_len = (size_t)state->sizes[frame_number];
|
|
if (lace < data // if the lace starts before our data
|
|
|| (state->positions[frame_number] + lace_len) > data_len) // or extends out past our data
|
|
{
|
|
return false;
|
|
}
|
|
|
|
*frame = lace;
|
|
*frame_len = lace_len;
|
|
return true;
|
|
}
|