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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "Utils.h"
     18 #include "SkUtils.h"
     19 #include "SkData.h"
     20 
     21 using namespace android;
     22 
     23 AssetStreamAdaptor::AssetStreamAdaptor(Asset* asset)
     24     : fAsset(asset)
     25 {
     26 }
     27 
     28 bool AssetStreamAdaptor::rewind() {
     29     off64_t pos = fAsset->seek(0, SEEK_SET);
     30     if (pos == (off64_t)-1) {
     31         SkDebugf("----- fAsset->seek(rewind) failed\n");
     32         return false;
     33     }
     34     return true;
     35 }
     36 
     37 size_t AssetStreamAdaptor::getLength() const {
     38     return fAsset->getLength();
     39 }
     40 
     41 bool AssetStreamAdaptor::isAtEnd() const {
     42     return fAsset->getRemainingLength() == 0;
     43 }
     44 
     45 SkStreamRewindable* AssetStreamAdaptor::duplicate() const {
     46     // Cannot create a duplicate, since each AssetStreamAdaptor
     47     // would be modifying the Asset.
     48     //return new AssetStreamAdaptor(fAsset);
     49     return NULL;
     50 }
     51 
     52 size_t AssetStreamAdaptor::read(void* buffer, size_t size) {
     53     ssize_t amount;
     54 
     55     if (NULL == buffer) {
     56         if (0 == size) {
     57             return 0;
     58         }
     59         // asset->seek returns new total offset
     60         // we want to return amount that was skipped
     61 
     62         off64_t oldOffset = fAsset->seek(0, SEEK_CUR);
     63         if (-1 == oldOffset) {
     64             SkDebugf("---- fAsset->seek(oldOffset) failed\n");
     65             return 0;
     66         }
     67         off64_t newOffset = fAsset->seek(size, SEEK_CUR);
     68         if (-1 == newOffset) {
     69             SkDebugf("---- fAsset->seek(%d) failed\n", size);
     70             return 0;
     71         }
     72         amount = newOffset - oldOffset;
     73     } else {
     74         amount = fAsset->read(buffer, size);
     75         if (amount <= 0) {
     76             SkDebugf("---- fAsset->read(%d) returned %d\n", size, amount);
     77         }
     78     }
     79 
     80     if (amount < 0) {
     81         amount = 0;
     82     }
     83     return amount;
     84 }
     85 
     86 SkMemoryStream* android::CopyAssetToStream(Asset* asset) {
     87     if (NULL == asset) {
     88         return NULL;
     89     }
     90 
     91     const off64_t seekReturnVal = asset->seek(0, SEEK_SET);
     92     if ((off64_t)-1 == seekReturnVal) {
     93         SkDebugf("---- copyAsset: asset rewind failed\n");
     94         return NULL;
     95     }
     96 
     97     const off64_t size = asset->getLength();
     98     if (size <= 0) {
     99         SkDebugf("---- copyAsset: asset->getLength() returned %d\n", size);
    100         return NULL;
    101     }
    102 
    103     SkAutoTUnref<SkData> data(SkData::NewUninitialized(size));
    104     const off64_t len = asset->read(data->writable_data(), size);
    105     if (len != size) {
    106         SkDebugf("---- copyAsset: asset->read(%d) returned %d\n", size, len);
    107         return NULL;
    108     }
    109 
    110     return new SkMemoryStream(data);
    111 }
    112 
    113 jobject android::nullObjectReturn(const char msg[]) {
    114     if (msg) {
    115         SkDebugf("--- %s\n", msg);
    116     }
    117     return NULL;
    118 }
    119 
    120 bool android::isSeekable(int descriptor) {
    121     return ::lseek64(descriptor, 0, SEEK_CUR) != -1;
    122 }
    123