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#define LOG_TAG "Stream"
18
19#include "Stream.h"
20
21#include <string.h>
22
23#include "JNIHelpers.h"
24#include "utils/log.h"
25#include "utils/math.h"
26
27static struct {
28    jmethodID read;
29    jmethodID reset;
30} gInputStreamClassInfo;
31
32Stream::Stream()
33    : mPeekBuffer(0)
34    , mPeekSize(0)
35    , mPeekOffset(0) {
36}
37
38Stream::~Stream() {
39    delete mPeekBuffer;
40}
41
42size_t Stream::peek(void* buffer, size_t size) {
43    size_t peek_remaining = mPeekSize - mPeekOffset;
44    if (size > peek_remaining) {
45        char* old_peek = mPeekBuffer;
46        mPeekBuffer = new char[size];
47        if (old_peek) {
48            memcpy(mPeekBuffer, old_peek + mPeekOffset, peek_remaining);
49            delete old_peek;
50        }
51        size_t read = doRead(mPeekBuffer + mPeekOffset, size - peek_remaining);
52        mPeekOffset = 0;
53        mPeekSize = peek_remaining + read;
54    }
55    size = min(size, mPeekSize - mPeekOffset);
56    memcpy(buffer, mPeekBuffer + mPeekOffset, size);
57    return size;
58}
59
60size_t Stream::read(void* buffer, size_t size) {
61    size_t bytes_read = 0;
62    size_t peek_remaining = mPeekSize - mPeekOffset;
63    if (peek_remaining) {
64        bytes_read = min(size, peek_remaining);
65        memcpy(buffer, mPeekBuffer + mPeekOffset, bytes_read);
66        mPeekOffset += bytes_read;
67        if (mPeekOffset == mPeekSize) {
68            delete mPeekBuffer;
69            mPeekBuffer = 0;
70            mPeekOffset = 0;
71            mPeekSize = 0;
72        }
73        size -= bytes_read;
74        buffer = ((char*) buffer) + bytes_read;
75    }
76    if (size) {
77        bytes_read += doRead(buffer, size);
78    }
79    return bytes_read;
80}
81
82size_t MemoryStream::doRead(void* buffer, size_t size) {
83    size = min(size, mRemaining);
84    memcpy(buffer, mBuffer, size);
85    mBuffer += size;
86    mRemaining -= size;
87    return size;
88}
89
90size_t FileStream::doRead(void* buffer, size_t size) {
91    return fread(buffer, 1, size, mFd);
92}
93
94size_t JavaInputStream::doRead(void* dstBuffer, size_t size) {
95    size_t totalBytesRead = 0;
96
97    do {
98        size_t requested = min(size, mByteArrayLength);
99
100        jint bytesRead = mEnv->CallIntMethod(mInputStream,
101                gInputStreamClassInfo.read, mByteArray, 0, requested);
102        if (mEnv->ExceptionCheck() || bytesRead < 0) {
103            return 0;
104        }
105
106        mEnv->GetByteArrayRegion(mByteArray, 0, bytesRead, (jbyte*)dstBuffer);
107        dstBuffer = (char*)dstBuffer + bytesRead;
108        totalBytesRead += bytesRead;
109        size -= bytesRead;
110    } while (size > 0);
111
112    return totalBytesRead;
113}
114
115jint JavaStream_OnLoad(JNIEnv* env) {
116    // Skip the verbose logging on error for these, as they won't be subject
117    // to obfuscators or similar and are thus unlikely to ever fail
118    jclass inputStreamClazz = env->FindClass("java/io/InputStream");
119    if (!inputStreamClazz) {
120        return -1;
121    }
122    gInputStreamClassInfo.read = env->GetMethodID(inputStreamClazz, "read", "([BII)I");
123    gInputStreamClassInfo.reset = env->GetMethodID(inputStreamClazz, "reset", "()V");
124    if (!gInputStreamClassInfo.read || !gInputStreamClassInfo.reset) {
125        return -1;
126    }
127    return 0;
128}
129