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// Copyright (c) 2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/data_pack.h"
#include "base/file_util.h"
#include "base/logging.h"
#include "base/string_piece.h"
// For details of the file layout, see
// http://dev.chromium.org/developers/design-documents/linuxresourcesandlocalizedstrings
namespace {
static const uint32_t kFileFormatVersion = 1;
// Length of file header: version and entry count.
static const size_t kHeaderLength = 2 * sizeof(uint32_t);
struct DataPackEntry {
uint32_t resource_id;
uint32_t file_offset;
uint32_t length;
static int CompareById(const void* void_key, const void* void_entry) {
uint32_t key = *reinterpret_cast<const uint32_t*>(void_key);
const DataPackEntry* entry =
reinterpret_cast<const DataPackEntry*>(void_entry);
if (key < entry->resource_id) {
return -1;
} else if (key > entry->resource_id) {
return 1;
} else {
return 0;
}
}
} __attribute((packed));
} // anonymous namespace
namespace base {
// In .cc for MemoryMappedFile dtor.
DataPack::DataPack() : resource_count_(0) {
}
DataPack::~DataPack() {
}
bool DataPack::Load(const FilePath& path) {
mmap_.reset(new file_util::MemoryMappedFile);
if (!mmap_->Initialize(path)) {
mmap_.reset();
return false;
}
// Parse the header of the file.
// First uint32_t: version; second: resource count.
const uint32* ptr = reinterpret_cast<const uint32_t*>(mmap_->data());
uint32 version = ptr[0];
if (version != kFileFormatVersion) {
LOG(ERROR) << "Bad data pack version: got " << version << ", expected "
<< kFileFormatVersion;
mmap_.reset();
return false;
}
resource_count_ = ptr[1];
// Sanity check the file.
// 1) Check we have enough entries.
if (kHeaderLength + resource_count_ * sizeof(DataPackEntry) >
mmap_->length()) {
LOG(ERROR) << "Data pack file corruption: too short for number of "
"entries specified.";
mmap_.reset();
return false;
}
// 2) Verify the entries are within the appropriate bounds.
for (size_t i = 0; i < resource_count_; ++i) {
const DataPackEntry* entry = reinterpret_cast<const DataPackEntry*>(
mmap_->data() + kHeaderLength + (i * sizeof(DataPackEntry)));
if (entry->file_offset + entry->length > mmap_->length()) {
LOG(ERROR) << "Entry #" << i << " in data pack points off end of file. "
<< "Was the file corrupted?";
mmap_.reset();
return false;
}
}
return true;
}
bool DataPack::Get(uint32_t resource_id, StringPiece* data) {
// It won't be hard to make this endian-agnostic, but it's not worth
// bothering to do right now.
#if defined(__BYTE_ORDER)
// Linux check
COMPILE_ASSERT(__BYTE_ORDER == __LITTLE_ENDIAN,
datapack_assumes_little_endian);
#elif defined(__BIG_ENDIAN__)
// Mac check
#error DataPack assumes little endian
#endif
DataPackEntry* target = reinterpret_cast<DataPackEntry*>(
bsearch(&resource_id, mmap_->data() + kHeaderLength, resource_count_,
sizeof(DataPackEntry), DataPackEntry::CompareById));
if (!target) {
LOG(ERROR) << "No resource found with id: " << resource_id;
return false;
}
data->set(mmap_->data() + target->file_offset, target->length);
return true;
}
} // namespace base
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