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Differential D9642 Diff 31697 extern/draco/draco/src/draco/core/decoder_buffer.h

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extern/draco/draco/src/draco/core/decoder_buffer.h

  • This file was moved from extern/draco/dracoenc/src/draco/core/decoder_buffer.h.
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and // See the License for the specific language governing permissions and
// limitations under the License. // limitations under the License.
// //
#ifndef DRACO_CORE_DECODER_BUFFER_H_ #ifndef DRACO_CORE_DECODER_BUFFER_H_
#define DRACO_CORE_DECODER_BUFFER_H_ #define DRACO_CORE_DECODER_BUFFER_H_
#include <stdint.h> #include <stdint.h>
#include <cstring> #include <cstring>
#include <memory> #include <memory>
#include "draco/draco_features.h"
#include "draco/core/macros.h" #include "draco/core/macros.h"
#include "draco/draco_features.h"
namespace draco { namespace draco {
// Class is a wrapper around input data used by MeshDecoder. It provides a // Class is a wrapper around input data used by MeshDecoder. It provides a
// basic interface for decoding either typed or variable-bit sized data. // basic interface for decoding either typed or variable-bit sized data.
class DecoderBuffer { class DecoderBuffer {
public: public:
DecoderBuffer(); DecoderBuffer();
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// Ends the decoding of the bit sequence and return to the default // Ends the decoding of the bit sequence and return to the default
// byte-aligned decoding. // byte-aligned decoding.
void EndBitDecoding(); void EndBitDecoding();
// Decodes up to 32 bits into out_val. Can be called only in between // Decodes up to 32 bits into out_val. Can be called only in between
// StartBitDecoding and EndBitDecoding. Otherwise returns false. // StartBitDecoding and EndBitDecoding. Otherwise returns false.
bool DecodeLeastSignificantBits32(int nbits, uint32_t *out_value) { bool DecodeLeastSignificantBits32(int nbits, uint32_t *out_value) {
if (!bit_decoder_active()) if (!bit_decoder_active()) {
return false; return false;
}
bit_decoder_.GetBits(nbits, out_value); bit_decoder_.GetBits(nbits, out_value);
return true; return true;
} }
// Decodes an arbitrary data type. // Decodes an arbitrary data type.
// Can be used only when we are not decoding a bit-sequence. // Can be used only when we are not decoding a bit-sequence.
// Returns false on error. // Returns false on error.
template <typename T> template <typename T>
bool Decode(T *out_val) { bool Decode(T *out_val) {
if (!Peek(out_val)) if (!Peek(out_val)) {
return false; return false;
}
pos_ += sizeof(T); pos_ += sizeof(T);
return true; return true;
} }
bool Decode(void *out_data, size_t size_to_decode) { bool Decode(void *out_data, size_t size_to_decode) {
if (data_size_ < static_cast<int64_t>(pos_ + size_to_decode)) if (data_size_ < static_cast<int64_t>(pos_ + size_to_decode)) {
return false; // Buffer overflow. return false; // Buffer overflow.
}
memcpy(out_data, (data_ + pos_), size_to_decode); memcpy(out_data, (data_ + pos_), size_to_decode);
pos_ += size_to_decode; pos_ += size_to_decode;
return true; return true;
} }
// Decodes an arbitrary data, but does not advance the reading position. // Decodes an arbitrary data, but does not advance the reading position.
template <typename T> template <typename T>
bool Peek(T *out_val) { bool Peek(T *out_val) {
const size_t size_to_decode = sizeof(T); const size_t size_to_decode = sizeof(T);
if (data_size_ < static_cast<int64_t>(pos_ + size_to_decode)) if (data_size_ < static_cast<int64_t>(pos_ + size_to_decode)) {
return false; // Buffer overflow. return false; // Buffer overflow.
}
memcpy(out_val, (data_ + pos_), size_to_decode); memcpy(out_val, (data_ + pos_), size_to_decode);
return true; return true;
} }
bool Peek(void *out_data, size_t size_to_peek) { bool Peek(void *out_data, size_t size_to_peek) {
if (data_size_ < static_cast<int64_t>(pos_ + size_to_peek)) if (data_size_ < static_cast<int64_t>(pos_ + size_to_peek)) {
return false; // Buffer overflow. return false; // Buffer overflow.
}
memcpy(out_data, (data_ + pos_), size_to_peek); memcpy(out_data, (data_ + pos_), size_to_peek);
return true; return true;
} }
// Discards #bytes from the input buffer. // Discards #bytes from the input buffer.
void Advance(int64_t bytes) { pos_ += bytes; } void Advance(int64_t bytes) { pos_ += bytes; }
// Moves the parsing position to a specific offset from the beginning of the // Moves the parsing position to a specific offset from the beginning of the
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inline void ConsumeBits(int k) { bit_offset_ += k; } inline void ConsumeBits(int k) { bit_offset_ += k; }
// Returns |nbits| bits in |x|. // Returns |nbits| bits in |x|.
inline bool GetBits(int32_t nbits, uint32_t *x) { inline bool GetBits(int32_t nbits, uint32_t *x) {
DRACO_DCHECK_GE(nbits, 0); DRACO_DCHECK_GE(nbits, 0);
DRACO_DCHECK_LE(nbits, 32); DRACO_DCHECK_LE(nbits, 32);
uint32_t value = 0; uint32_t value = 0;
for (int32_t bit = 0; bit < nbits; ++bit) for (int32_t bit = 0; bit < nbits; ++bit) {
value |= GetBit() << bit; value |= GetBit() << bit;
}
*x = value; *x = value;
return true; return true;
} }
private: private:
// TODO(fgalligan): Add support for error reporting on range check. // TODO(fgalligan): Add support for error reporting on range check.
// Returns one bit from the bit buffer. // Returns one bit from the bit buffer.
inline int GetBit() { inline int GetBit() {
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