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#include "memory_buffer.h"
#include <c10/util/Logging.h>
namespace ffmpeg {
MemoryBuffer::MemoryBuffer(const uint8_t* buffer, size_t size)
: buffer_(buffer), len_(size) {}
int MemoryBuffer::read(uint8_t* buf, int size) {
if (pos_ < len_) {
auto available = std::min(int(len_ - pos_), size);
memcpy(buf, buffer_ + pos_, available);
pos_ += available;
return available;
}
return 0;
}
int64_t MemoryBuffer::seek(int64_t offset, int whence) {
if (whence & AVSEEK_SIZE) {
return len_;
}
// remove force flag
whence &= ~AVSEEK_FORCE;
switch (whence) {
case SEEK_SET:
if (offset >= 0 && offset <= len_) {
pos_ = offset;
}
break;
case SEEK_END:
if (len_ + offset >= 0 && len_ + offset <= len_) {
pos_ = len_ + offset;
}
break;
case SEEK_CUR:
if (pos_ + offset > 0 && pos_ + offset <= len_) {
pos_ += offset;
}
break;
default:
LOG(ERROR) << "Unknown whence flag gets provided: " << whence;
}
return pos_;
}
/* static */
DecoderInCallback MemoryBuffer::getCallback(
const uint8_t* buffer,
size_t size) {
MemoryBuffer object(buffer, size);
return
[object](uint8_t* out, int size, int whence, uint64_t timeoutMs) mutable
-> int {
if (out) { // see defs.h file
// read mode
return object.read(out, size);
}
// seek mode
if (!timeoutMs) {
// seek capability, yes - supported
return 0;
}
return object.seek(size, whence);
};
}
} // namespace ffmpeg
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