inputstream_wrapper.cpp revision a8221bbdb8ece9b02dbf7b72565f9fbc5b314f7c 
1/*
2 * Copyright (C) 2013 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 "inputstream_wrapper.h"
18#include "error_codes.h"
19
20jmethodID InputStreamWrapper::sReadID = NULL;
21jmethodID InputStreamWrapper::sSkipID = NULL;
22
23int32_t InputStreamWrapper::read(int32_t length, int32_t offset) {
24    if (offset < 0 || length < 0 || (offset + length) > getBufferSize()) {
25        return J_ERROR_BAD_ARGS;
26    }
27    int32_t bytesRead = 0;
28    mEnv->ReleaseByteArrayElements(mByteArray, mBytes, JNI_COMMIT);
29    mBytes = NULL;
30    if (mEnv->ExceptionCheck()) {
31        return J_EXCEPTION;
32    }
33    bytesRead = static_cast<int32_t>(mEnv->CallIntMethod(mStream, sReadID,
34            mByteArray, offset, length));
35    if (mEnv->ExceptionCheck()) {
36        return J_EXCEPTION;
37    }
38    mBytes = mEnv->GetByteArrayElements(mByteArray, NULL);
39    if (mBytes == NULL || mEnv->ExceptionCheck()) {
40        return J_EXCEPTION;
41    }
42    if (bytesRead == END_OF_STREAM) {
43        return J_DONE;
44    }
45    return bytesRead;
46}
47
48int64_t InputStreamWrapper::skip(int64_t count) {
49    int64_t bytesSkipped = 0;
50    bytesSkipped = static_cast<int64_t>(mEnv->CallLongMethod(mStream, sSkipID,
51            static_cast<jlong>(count)));
52    if (mEnv->ExceptionCheck() || bytesSkipped < 0) {
53        return J_EXCEPTION;
54    }
55    return bytesSkipped;
56}
57
58// Acts like a read call that returns the End Of Image marker for a JPEG file.
59int32_t InputStreamWrapper::forceReadEOI() {
60    mBytes[0] = (jbyte) 0xFF;
61    mBytes[1] = (jbyte) 0xD9;
62    return 2;
63}
64
65void InputStreamWrapper::setReadSkipMethodIDs(jmethodID readID,
66        jmethodID skipID) {
67    sReadID = readID;
68    sSkipID = skipID;
69}
70