65 lines
2.2 KiB
C++
65 lines
2.2 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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* Functions for interpreting LEB128 (little endian base 128) values
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*/
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#include "Leb128.h"
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/*
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* Reads an unsigned LEB128 value, updating the given pointer to point
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* just past the end of the read value and also indicating whether the
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* value was syntactically valid. The only syntactically *invalid*
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* values are ones that are five bytes long where the final byte has
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* any but the low-order four bits set. Additionally, if the limit is
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* passed as non-NULL and bytes would need to be read past the limit,
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* then the read is considered invalid.
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*/
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int readAndVerifyUnsignedLeb128(const u1** pStream, const u1* limit,
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bool* okay) {
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const u1* ptr = *pStream;
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int result = readUnsignedLeb128(pStream);
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if (((limit != NULL) && (*pStream > limit))
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|| (((*pStream - ptr) == 5) && (ptr[4] > 0x0f))) {
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*okay = false;
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}
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return result;
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}
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/*
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* Reads a signed LEB128 value, updating the given pointer to point
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* just past the end of the read value and also indicating whether the
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* value was syntactically valid. The only syntactically *invalid*
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* values are ones that are five bytes long where the final byte has
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* any but the low-order four bits set. Additionally, if the limit is
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* passed as non-NULL and bytes would need to be read past the limit,
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* then the read is considered invalid.
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*/
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int readAndVerifySignedLeb128(const u1** pStream, const u1* limit,
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bool* okay) {
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const u1* ptr = *pStream;
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int result = readSignedLeb128(pStream);
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if (((limit != NULL) && (*pStream > limit))
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|| (((*pStream - ptr) == 5) && (ptr[4] > 0x0f))) {
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*okay = false;
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}
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return result;
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}
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