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Diffstat (limited to 'media/img_utils/include/img_utils/EndianUtils.h')
| -rw-r--r-- | media/img_utils/include/img_utils/EndianUtils.h | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/media/img_utils/include/img_utils/EndianUtils.h b/media/img_utils/include/img_utils/EndianUtils.h new file mode 100644 index 0000000..e99be1a --- /dev/null +++ b/media/img_utils/include/img_utils/EndianUtils.h @@ -0,0 +1,250 @@ +/* + * Copyright 2014 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef IMG_UTILS_ENDIAN_UTILS +#define IMG_UTILS_ENDIAN_UTILS + +#include <img_utils/Output.h> + +#include <cutils/compiler.h> +#include <utils/Errors.h> +#include <stdint.h> +#include <endian.h> +#include <assert.h> + +namespace android { +namespace img_utils { + +/** + * Endianness types supported. + */ +enum ANDROID_API Endianness { + UNDEFINED_ENDIAN, // Default endianness will be used. + BIG, + LITTLE +}; + +/** + * Convert from the native device endianness to big endian. + */ +template<typename T> +T convertToBigEndian(T in); + +/** + * Convert from the native device endianness to little endian. + */ +template<typename T> +T convertToLittleEndian(T in); + +/** + * A utility class for writing to an Output with the given endianness. + */ +class ANDROID_API EndianOutput : public Output { + public: + /** + * Wrap the given Output. Calling write methods will result in + * writes to this output. + */ + EndianOutput(Output* out, Endianness end=LITTLE); + + virtual ~EndianOutput(); + + /** + * Call open on the wrapped output. + */ + virtual status_t open(); + + /** + * Call close on the wrapped output. + */ + virtual status_t close(); + + /** + * Set the endianness to use when writing. + */ + virtual void setEndianness(Endianness end); + + /** + * Get the currently configured endianness. + */ + virtual Endianness getEndianness() const; + + /** + * Get the current number of bytes written by this EndianOutput. + */ + virtual uint32_t getCurrentOffset() const; + + + // TODO: switch write methods to uint32_t instead of size_t, + // the max size of a TIFF files is bounded + + /** + * The following methods will write elements from given input buffer to the output. + * Count elements in the buffer will be written with the endianness set for this + * EndianOutput. If the given offset is greater than zero, that many elements will + * be skipped in the buffer before writing. + * + * Returns OK on success, or a negative error code. + */ + virtual status_t write(const uint8_t* buf, size_t offset, size_t count); + + virtual status_t write(const int8_t* buf, size_t offset, size_t count); + + virtual status_t write(const uint16_t* buf, size_t offset, size_t count); + + virtual status_t write(const int16_t* buf, size_t offset, size_t count); + + virtual status_t write(const uint32_t* buf, size_t offset, size_t count); + + virtual status_t write(const int32_t* buf, size_t offset, size_t count); + + virtual status_t write(const uint64_t* buf, size_t offset, size_t count); + + virtual status_t write(const int64_t* buf, size_t offset, size_t count); + + virtual status_t write(const float* buf, size_t offset, size_t count); + + virtual status_t write(const double* buf, size_t offset, size_t count); + + protected: + template<typename T> + inline status_t writeHelper(const T* buf, size_t offset, size_t count); + + uint32_t mOffset; + Output* mOutput; + Endianness mEndian; +}; + +template<typename T> +inline status_t EndianOutput::writeHelper(const T* buf, size_t offset, size_t count) { + assert(offset <= count); + status_t res = OK; + size_t size = sizeof(T); + switch(mEndian) { + case BIG: { + for (size_t i = offset; i < count; ++i) { + T tmp = convertToBigEndian<T>(buf[offset + i]); + if ((res = mOutput->write(reinterpret_cast<uint8_t*>(&tmp), 0, size)) + != OK) { + return res; + } + mOffset += size; + } + break; + } + case LITTLE: { + for (size_t i = offset; i < count; ++i) { + T tmp = convertToLittleEndian<T>(buf[offset + i]); + if ((res = mOutput->write(reinterpret_cast<uint8_t*>(&tmp), 0, size)) + != OK) { + return res; + } + mOffset += size; + } + break; + } + default: { + return BAD_VALUE; + } + } + return res; +} + +template<> +inline uint8_t convertToBigEndian(uint8_t in) { + return in; +} + +template<> +inline int8_t convertToBigEndian(int8_t in) { + return in; +} + +template<> +inline uint16_t convertToBigEndian(uint16_t in) { + return htobe16(in); +} + +template<> +inline int16_t convertToBigEndian(int16_t in) { + return htobe16(in); +} + +template<> +inline uint32_t convertToBigEndian(uint32_t in) { + return htobe32(in); +} + +template<> +inline int32_t convertToBigEndian(int32_t in) { + return htobe32(in); +} + +template<> +inline uint64_t convertToBigEndian(uint64_t in) { + return htobe64(in); +} + +template<> +inline int64_t convertToBigEndian(int64_t in) { + return htobe64(in); +} + +template<> +inline uint8_t convertToLittleEndian(uint8_t in) { + return in; +} + +template<> +inline int8_t convertToLittleEndian(int8_t in) { + return in; +} + +template<> +inline uint16_t convertToLittleEndian(uint16_t in) { + return htole16(in); +} + +template<> +inline int16_t convertToLittleEndian(int16_t in) { + return htole16(in); +} + +template<> +inline uint32_t convertToLittleEndian(uint32_t in) { + return htole32(in); +} + +template<> +inline int32_t convertToLittleEndian(int32_t in) { + return htole32(in); +} + +template<> +inline uint64_t convertToLittleEndian(uint64_t in) { + return htole64(in); +} + +template<> +inline int64_t convertToLittleEndian(int64_t in) { + return htole64(in); +} + +} /*namespace img_utils*/ +} /*namespace android*/ + +#endif /*IMG_UTILS_ENDIAN_UTILS*/ + |