351 lines
12 KiB
C++
351 lines
12 KiB
C++
/*
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---------------------------------------------------------------------------
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Open Asset Import Library (assimp)
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---------------------------------------------------------------------------
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Copyright (c) 2006-2016, assimp team
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All rights reserved.
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Redistribution and use of this software in source and binary forms,
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with or without modification, are permitted provided that the following
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conditions are met:
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* Redistributions of source code must retain the above
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copyright notice, this list of conditions and the
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following disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the
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following disclaimer in the documentation and/or other
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materials provided with the distribution.
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* Neither the name of the assimp team, nor the names of its
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contributors may be used to endorse or promote products
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derived from this software without specific prior
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written permission of the assimp team.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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---------------------------------------------------------------------------
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*/
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/** @file Defines the StreamReader class which reads data from
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* a binary stream with a well-defined endianness.
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*/
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#ifndef AI_STREAMREADER_H_INCLUDED
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#define AI_STREAMREADER_H_INCLUDED
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#include "ByteSwapper.h"
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#include "Exceptional.h"
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#include <memory>
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#include <assimp/IOStream.hpp>
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#include <assimp/Defines.h>
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namespace Assimp {
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// --------------------------------------------------------------------------------------------
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/** Wrapper class around IOStream to allow for consistent reading of binary data in both
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* little and big endian format. Don't attempt to instance the template directly. Use
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* StreamReaderLE to read from a little-endian stream and StreamReaderBE to read from a
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* BE stream. The class expects that the endianness of any input data is known at
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* compile-time, which should usually be true (#BaseImporter::ConvertToUTF8 implements
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* runtime endianness conversions for text files).
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*
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* XXX switch from unsigned int for size types to size_t? or ptrdiff_t?*/
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// --------------------------------------------------------------------------------------------
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template <bool SwapEndianess = false, bool RuntimeSwitch = false>
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class StreamReader
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{
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public:
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// FIXME: use these data types throughout the whole library,
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// then change them to 64 bit values :-)
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typedef int diff;
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typedef unsigned int pos;
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public:
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// ---------------------------------------------------------------------
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/** Construction from a given stream with a well-defined endianness.
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*
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* The StreamReader holds a permanent strong reference to the
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* stream, which is released upon destruction.
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* @param stream Input stream. The stream is not restarted if
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* its file pointer is not at 0. Instead, the stream reader
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* reads from the current position to the end of the stream.
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* @param le If @c RuntimeSwitch is true: specifies whether the
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* stream is in little endian byte order. Otherwise the
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* endianness information is contained in the @c SwapEndianess
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* template parameter and this parameter is meaningless. */
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StreamReader(std::shared_ptr<IOStream> stream, bool le = false)
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: stream(stream)
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, le(le)
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{
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ai_assert(stream);
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InternBegin();
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}
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// ---------------------------------------------------------------------
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StreamReader(IOStream* stream, bool le = false)
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: stream(std::shared_ptr<IOStream>(stream))
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, le(le)
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{
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ai_assert(stream);
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InternBegin();
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}
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// ---------------------------------------------------------------------
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~StreamReader() {
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delete[] buffer;
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}
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public:
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// deprecated, use overloaded operator>> instead
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// ---------------------------------------------------------------------
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/** Read a float from the stream */
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float GetF4()
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{
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return Get<float>();
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}
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// ---------------------------------------------------------------------
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/** Read a double from the stream */
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double GetF8() {
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return Get<double>();
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}
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// ---------------------------------------------------------------------
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/** Read a signed 16 bit integer from the stream */
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int16_t GetI2() {
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return Get<int16_t>();
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}
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// ---------------------------------------------------------------------
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/** Read a signed 8 bit integer from the stream */
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int8_t GetI1() {
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return Get<int8_t>();
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}
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// ---------------------------------------------------------------------
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/** Read an signed 32 bit integer from the stream */
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int32_t GetI4() {
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return Get<int32_t>();
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}
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// ---------------------------------------------------------------------
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/** Read a signed 64 bit integer from the stream */
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int64_t GetI8() {
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return Get<int64_t>();
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}
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// ---------------------------------------------------------------------
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/** Read a unsigned 16 bit integer from the stream */
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uint16_t GetU2() {
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return Get<uint16_t>();
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}
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// ---------------------------------------------------------------------
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/** Read a unsigned 8 bit integer from the stream */
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uint8_t GetU1() {
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return Get<uint8_t>();
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}
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// ---------------------------------------------------------------------
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/** Read an unsigned 32 bit integer from the stream */
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uint32_t GetU4() {
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return Get<uint32_t>();
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}
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// ---------------------------------------------------------------------
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/** Read a unsigned 64 bit integer from the stream */
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uint64_t GetU8() {
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return Get<uint64_t>();
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}
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public:
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// ---------------------------------------------------------------------
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/** Get the remaining stream size (to the end of the stream) */
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unsigned int GetRemainingSize() const {
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return (unsigned int)(end - current);
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}
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// ---------------------------------------------------------------------
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/** Get the remaining stream size (to the current read limit). The
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* return value is the remaining size of the stream if no custom
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* read limit has been set. */
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unsigned int GetRemainingSizeToLimit() const {
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return (unsigned int)(limit - current);
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}
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// ---------------------------------------------------------------------
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/** Increase the file pointer (relative seeking) */
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void IncPtr(size_t plus) {
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current += plus;
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if (current > limit) {
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throw DeadlyImportError("End of file or read limit was reached");
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}
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}
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// ---------------------------------------------------------------------
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/** Get the current file pointer */
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int8_t* GetPtr() const {
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return current;
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}
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// ---------------------------------------------------------------------
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/** Set current file pointer (Get it from #GetPtr). This is if you
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* prefer to do pointer arithmetics on your own or want to copy
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* large chunks of data at once.
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* @param p The new pointer, which is validated against the size
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* limit and buffer boundaries. */
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void SetPtr(int8_t* p) {
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current = p;
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if (current > limit || current < buffer) {
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throw DeadlyImportError("End of file or read limit was reached");
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}
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}
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// ---------------------------------------------------------------------
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/** Copy n bytes to an external buffer
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* @param out Destination for copying
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* @param bytes Number of bytes to copy */
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void CopyAndAdvance(void* out, size_t bytes) {
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int8_t* ur = GetPtr();
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SetPtr(ur+bytes); // fire exception if eof
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::memcpy(out,ur,bytes);
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}
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// ---------------------------------------------------------------------
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/** Get the current offset from the beginning of the file */
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int GetCurrentPos() const {
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return (unsigned int)(current - buffer);
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}
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void SetCurrentPos(size_t pos) {
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SetPtr(buffer + pos);
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}
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// ---------------------------------------------------------------------
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/** Setup a temporary read limit
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*
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* @param limit Maximum number of bytes to be read from
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* the beginning of the file. Specifying UINT_MAX
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* resets the limit to the original end of the stream.
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* Returns the previously set limit. */
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unsigned int SetReadLimit(unsigned int _limit) {
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unsigned int prev = GetReadLimit();
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if (UINT_MAX == _limit) {
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limit = end;
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return prev;
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}
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limit = buffer + _limit;
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if (limit > end) {
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throw DeadlyImportError("StreamReader: Invalid read limit");
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}
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return prev;
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}
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// ---------------------------------------------------------------------
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/** Get the current read limit in bytes. Reading over this limit
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* accidentally raises an exception. */
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unsigned int GetReadLimit() const {
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return (unsigned int)(limit - buffer);
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}
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// ---------------------------------------------------------------------
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/** Skip to the read limit in bytes. Reading over this limit
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* accidentally raises an exception. */
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void SkipToReadLimit() {
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current = limit;
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}
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// ---------------------------------------------------------------------
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/** overload operator>> and allow chaining of >> ops. */
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template <typename T>
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StreamReader& operator >> (T& f) {
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f = Get<T>();
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return *this;
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}
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private:
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// ---------------------------------------------------------------------
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/** Generic read method. ByteSwap::Swap(T*) *must* be defined */
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template <typename T>
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T Get() {
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if ( current + sizeof(T) > limit) {
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throw DeadlyImportError("End of file or stream limit was reached");
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}
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///*#ifdef __arm__
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T f;
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::memcpy (&f, current, sizeof(T));
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//#else*/
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// T f = *((const T*)current);
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//#endif
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Intern :: Getter<SwapEndianess,T,RuntimeSwitch>() (&f,le);
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current += sizeof(T);
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return f;
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}
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// ---------------------------------------------------------------------
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void InternBegin() {
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if (!stream) {
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// in case someone wonders: StreamReader is frequently invoked with
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// no prior validation whether the input stream is valid. Since
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// no one bothers changing the error message, this message here
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// is passed down to the caller and 'unable to open file'
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// simply describes best what happened.
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throw DeadlyImportError("StreamReader: Unable to open file");
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}
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const size_t s = stream->FileSize() - stream->Tell();
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if (!s) {
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throw DeadlyImportError("StreamReader: File is empty or EOF is already reached");
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}
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current = buffer = new int8_t[s];
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const size_t read = stream->Read(current,1,s);
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// (read < s) can only happen if the stream was opened in text mode, in which case FileSize() is not reliable
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ai_assert(read <= s);
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end = limit = &buffer[read];
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}
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private:
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std::shared_ptr<IOStream> stream;
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int8_t *buffer, *current, *end, *limit;
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bool le;
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};
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// --------------------------------------------------------------------------------------------
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// `static` StreamReaders. Their byte order is fixed and they might be a little bit faster.
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#ifdef AI_BUILD_BIG_ENDIAN
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typedef StreamReader<true> StreamReaderLE;
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typedef StreamReader<false> StreamReaderBE;
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#else
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typedef StreamReader<true> StreamReaderBE;
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typedef StreamReader<false> StreamReaderLE;
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#endif
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// `dynamic` StreamReader. The byte order of the input data is specified in the
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// c'tor. This involves runtime branching and might be a little bit slower.
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typedef StreamReader<true,true> StreamReaderAny;
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} // end namespace Assimp
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#endif // !! AI_STREAMREADER_H_INCLUDED
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