1/*
2 * Copyright (C) 2012 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_NDEBUG 0
18#define LOG_TAG "SkipCutBuffer"
19#include <utils/Log.h>
20
21#include <media/stagefright/foundation/ADebug.h>
22#include <media/stagefright/MediaBuffer.h>
23#include <media/stagefright/SkipCutBuffer.h>
24
25namespace android {
26
27SkipCutBuffer::SkipCutBuffer(int32_t skip, int32_t cut) {
28    mFrontPadding = mSkip = skip;
29    mBackPadding = cut;
30    mWriteHead = 0;
31    mReadHead = 0;
32    mCapacity = cut + 4096;
33    mCutBuffer = new char[mCapacity];
34    ALOGV("skipcutbuffer %d %d %d", skip, cut, mCapacity);
35}
36
37SkipCutBuffer::~SkipCutBuffer() {
38    delete[] mCutBuffer;
39}
40
41void SkipCutBuffer::submit(MediaBuffer *buffer) {
42    int32_t offset = buffer->range_offset();
43    int32_t buflen = buffer->range_length();
44
45    // drop the initial data from the buffer if needed
46    if (mFrontPadding > 0) {
47        // still data left to drop
48        int32_t to_drop = (buflen < mFrontPadding) ? buflen : mFrontPadding;
49        offset += to_drop;
50        buflen -= to_drop;
51        buffer->set_range(offset, buflen);
52        mFrontPadding -= to_drop;
53    }
54
55
56    // append data to cutbuffer
57    char *src = ((char*) buffer->data()) + offset;
58    write(src, buflen);
59
60
61    // the mediabuffer is now empty. Fill it from cutbuffer, always leaving
62    // at least mBackPadding bytes in the cutbuffer
63    char *dst = (char*) buffer->data();
64    size_t copied = read(dst, buffer->size());
65    buffer->set_range(0, copied);
66}
67
68void SkipCutBuffer::submit(const sp<ABuffer>& buffer) {
69    int32_t offset = buffer->offset();
70    int32_t buflen = buffer->size();
71
72    // drop the initial data from the buffer if needed
73    if (mFrontPadding > 0) {
74        // still data left to drop
75        int32_t to_drop = (buflen < mFrontPadding) ? buflen : mFrontPadding;
76        offset += to_drop;
77        buflen -= to_drop;
78        buffer->setRange(offset, buflen);
79        mFrontPadding -= to_drop;
80    }
81
82
83    // append data to cutbuffer
84    char *src = (char*) buffer->data();
85    write(src, buflen);
86
87
88    // the mediabuffer is now empty. Fill it from cutbuffer, always leaving
89    // at least mBackPadding bytes in the cutbuffer
90    char *dst = (char*) buffer->base();
91    size_t copied = read(dst, buffer->capacity());
92    buffer->setRange(0, copied);
93}
94
95void SkipCutBuffer::clear() {
96    mWriteHead = mReadHead = 0;
97    mFrontPadding = mSkip;
98}
99
100void SkipCutBuffer::write(const char *src, size_t num) {
101    int32_t sizeused = (mWriteHead - mReadHead);
102    if (sizeused < 0) sizeused += mCapacity;
103
104    // Everything must fit. Make sure the buffer is a little larger than needed,
105    // so there is no ambiguity as to whether mWriteHead == mReadHead means buffer
106    // full or empty
107    size_t available = mCapacity - sizeused - 32;
108    if (available < num) {
109        int32_t newcapacity = mCapacity + (num - available);
110        char * newbuffer = new char[newcapacity];
111        memcpy(newbuffer, mCutBuffer, mCapacity);
112        delete [] mCutBuffer;
113        mCapacity = newcapacity;
114        mCutBuffer = newbuffer;
115        ALOGV("reallocated buffer at size %d", newcapacity);
116    }
117
118    size_t copyfirst = (mCapacity - mWriteHead);
119    if (copyfirst > num) copyfirst = num;
120    if (copyfirst) {
121        memcpy(mCutBuffer + mWriteHead, src, copyfirst);
122        num -= copyfirst;
123        src += copyfirst;
124        mWriteHead += copyfirst;
125        CHECK_LE(mWriteHead, mCapacity);
126        if (mWriteHead == mCapacity) mWriteHead = 0;
127        if (num) {
128            memcpy(mCutBuffer, src, num);
129            mWriteHead += num;
130        }
131    }
132}
133
134size_t SkipCutBuffer::read(char *dst, size_t num) {
135    int32_t available = (mWriteHead - mReadHead);
136    if (available < 0) available += mCapacity;
137
138    available -= mBackPadding;
139    if (available <=0) {
140        return 0;
141    }
142    if (available < int32_t(num)) {
143        num = available;
144    }
145
146    size_t copyfirst = (mCapacity - mReadHead);
147    if (copyfirst > num) copyfirst = num;
148    if (copyfirst) {
149        memcpy(dst, mCutBuffer + mReadHead, copyfirst);
150        num -= copyfirst;
151        dst += copyfirst;
152        mReadHead += copyfirst;
153        CHECK_LE(mReadHead, mCapacity);
154        if (mReadHead == mCapacity) mReadHead = 0;
155        if (num) {
156            memcpy(dst, mCutBuffer, num);
157            mReadHead += num;
158        }
159    }
160    return available;
161}
162
163size_t SkipCutBuffer::size() {
164    int32_t available = (mWriteHead - mReadHead);
165    if (available < 0) available += mCapacity;
166    return available;
167}
168
169}  // namespace android
170