diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/androidfw/AttributeFinder.h | 201 | ||||
| -rw-r--r-- | include/androidfw/ResourceTypes.h | 26 |
2 files changed, 224 insertions, 3 deletions
diff --git a/include/androidfw/AttributeFinder.h b/include/androidfw/AttributeFinder.h new file mode 100644 index 0000000..a0ffeb3 --- /dev/null +++ b/include/androidfw/AttributeFinder.h @@ -0,0 +1,201 @@ +/* + * Copyright (C) 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 H_ATTRIBUTE_FINDER +#define H_ATTRIBUTE_FINDER + +#include <stdint.h> +#include <utils/KeyedVector.h> + +namespace android { + +static inline uint32_t getPackage(uint32_t attr) { + return attr >> 24; +} + +/** + * A helper class to search linearly for the requested + * attribute, maintaining it's position and optimizing for + * the case that subsequent searches will involve an attribute with + * a higher attribute ID. + * + * In the case that a subsequent attribute has a different package ID, + * its resource ID may not be larger than the preceding search, so + * back tracking is supported for this case. This + * back tracking requirement is mainly for shared library + * resources, whose package IDs get assigned at runtime + * and thus attributes from a shared library may + * be out of order. + * + * We make two assumptions about the order of attributes: + * 1) The input has the same sorting rules applied to it as + * the attribute data contained by this class. + * 2) Attributes are grouped by package ID. + * 3) Among attributes with the same package ID, the attributes are + * sorted by increasing resource ID. + * + * Ex: 02010000, 02010001, 010100f4, 010100f5, 0x7f010001, 07f010003 + * + * The total order of attributes (including package ID) can not be linear + * as shared libraries get assigned dynamic package IDs at runtime, which + * may break the sort order established at build time. + */ +template <typename Derived, typename Iterator> +class BackTrackingAttributeFinder { +public: + BackTrackingAttributeFinder(const Iterator& begin, const Iterator& end); + + Iterator find(uint32_t attr); + +private: + void jumpToClosestAttribute(uint32_t packageId); + void markCurrentPackageId(uint32_t packageId); + + Iterator mBegin; + Iterator mEnd; + Iterator mCurrent; + Iterator mLargest; + uint32_t mLastPackageId; + uint32_t mCurrentAttr; + + // Package Offsets (best-case, fast look-up). + Iterator mFrameworkStart; + Iterator mAppStart; + + // Worst case, we have shared-library resources. + KeyedVector<uint32_t, Iterator> mPackageOffsets; +}; + +template <typename Derived, typename Iterator> inline +BackTrackingAttributeFinder<Derived, Iterator>::BackTrackingAttributeFinder(const Iterator& begin, const Iterator& end) + : mBegin(begin) + , mEnd(end) + , mCurrent(begin) + , mLargest(begin) + , mLastPackageId(0) + , mCurrentAttr(0) + , mFrameworkStart(end) + , mAppStart(end) { +} + +template <typename Derived, typename Iterator> +void BackTrackingAttributeFinder<Derived, Iterator>::jumpToClosestAttribute(const uint32_t packageId) { + switch (packageId) { + case 0x01: + mCurrent = mFrameworkStart; + break; + case 0x7f: + mCurrent = mAppStart; + break; + default: { + ssize_t idx = mPackageOffsets.indexOfKey(packageId); + if (idx >= 0) { + // We have seen this package ID before, so jump to the first + // attribute with this package ID. + mCurrent = mPackageOffsets[idx]; + } else { + mCurrent = mEnd; + } + break; + } + } + + // We have never seen this package ID yet, so jump to the + // latest/largest index we have processed so far. + if (mCurrent == mEnd) { + mCurrent = mLargest; + } + + if (mCurrent != mEnd) { + mCurrentAttr = static_cast<const Derived*>(this)->getAttribute(mCurrent); + } +} + +template <typename Derived, typename Iterator> +void BackTrackingAttributeFinder<Derived, Iterator>::markCurrentPackageId(const uint32_t packageId) { + switch (packageId) { + case 0x01: + mFrameworkStart = mCurrent; + break; + case 0x7f: + mAppStart = mCurrent; + break; + default: + mPackageOffsets.add(packageId, mCurrent); + break; + } +} + +template <typename Derived, typename Iterator> +Iterator BackTrackingAttributeFinder<Derived, Iterator>::find(uint32_t attr) { + if (!(mBegin < mEnd)) { + return mEnd; + } + + if (mCurrentAttr == 0) { + // One-time initialization. + mCurrentAttr = static_cast<const Derived*>(this)->getAttribute(mBegin); + mLastPackageId = getPackage(mCurrentAttr); + markCurrentPackageId(mLastPackageId); + } + + // Looking for the needle (attribute we're looking for) + // in the haystack (the attributes we're searching through) + const uint32_t needlePackageId = getPackage(attr); + if (mLastPackageId != needlePackageId) { + jumpToClosestAttribute(needlePackageId); + mLastPackageId = needlePackageId; + } + + // Walk through the xml attributes looking for the requested attribute. + while (mCurrent != mEnd) { + const uint32_t haystackPackageId = getPackage(mCurrentAttr); + if (needlePackageId == haystackPackageId && attr < mCurrentAttr) { + // The attribute we are looking was not found. + break; + } + const uint32_t prevAttr = mCurrentAttr; + + // Move to the next attribute in the XML. + ++mCurrent; + if (mCurrent != mEnd) { + mCurrentAttr = static_cast<const Derived*>(this)->getAttribute(mCurrent); + const uint32_t newHaystackPackageId = getPackage(mCurrentAttr); + if (haystackPackageId != newHaystackPackageId) { + // We've moved to the next group of attributes + // with a new package ID, so we should record + // the offset of this new package ID. + markCurrentPackageId(newHaystackPackageId); + } + } + + if (mCurrent > mLargest) { + // We've moved past the latest attribute we've + // seen. + mLargest = mCurrent; + } + + if (attr == prevAttr) { + // We found the attribute we were looking for. + return mCurrent - 1; + } + } + return mEnd; +} + +} // namespace android + +#endif // H_ATTRIBUTE_FINDER diff --git a/include/androidfw/ResourceTypes.h b/include/androidfw/ResourceTypes.h index a44975b..ba72cd5 100644 --- a/include/androidfw/ResourceTypes.h +++ b/include/androidfw/ResourceTypes.h @@ -36,6 +36,17 @@ namespace android { +/** + * In C++11, char16_t is defined as *at least* 16 bits. We do a lot of + * casting on raw data and expect char16_t to be exactly 16 bits. + */ +#if __cplusplus >= 201103L +struct __assertChar16Size { + static_assert(sizeof(char16_t) == sizeof(uint16_t), "char16_t is not 16 bits"); + static_assert(alignof(char16_t) == alignof(uint16_t), "char16_t is not 16-bit aligned"); +}; +#endif + /** ******************************************************************** * PNG Extensions * @@ -253,7 +264,8 @@ struct Res_value // Type of the data value. enum { - // Contains no data. + // The 'data' is either 0 or 1, specifying this resource is either + // undefined or empty, respectively. TYPE_NULL = 0x00, // The 'data' holds a ResTable_ref, a reference to another resource // table entry. @@ -351,6 +363,14 @@ struct Res_value COMPLEX_MANTISSA_MASK = 0xffffff }; + // Possible data values for TYPE_NULL. + enum { + // The value is not defined. + DATA_NULL_UNDEFINED = 0, + // The value is explicitly defined as empty. + DATA_NULL_EMPTY = 1 + }; + // The data for this item, as interpreted according to dataType. uint32_t data; @@ -836,7 +856,7 @@ struct ResTable_package uint32_t id; // Actual name of this package, \0-terminated. - char16_t name[128]; + uint16_t name[128]; // Offset to a ResStringPool_header defining the resource // type symbol table. If zero, this package is inheriting from @@ -1441,7 +1461,7 @@ struct ResTable_lib_entry uint32_t packageId; // The package name of the shared library. \0 terminated. - char16_t packageName[128]; + uint16_t packageName[128]; }; /** |