1 /*
2 * Copyright (C) 2007 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 "buffer"
18
19 #include <assert.h>
20 #include <errno.h>
21 #include <stdlib.h>
22 #include <unistd.h>
23
24 #include "buffer.h"
25 #include "loghack.h"
26
bufferCreate(size_t capacity)27 Buffer* bufferCreate(size_t capacity) {
28 Buffer* buffer = malloc(sizeof(Buffer));
29 if (buffer == NULL) {
30 return NULL;
31 }
32 buffer->capacity = capacity;
33 buffer->expected = 0;
34 buffer->data = malloc(capacity);
35 if (buffer->data == NULL) {
36 free(buffer);
37 return NULL;
38 }
39 return buffer;
40 }
41
bufferFree(Buffer * buffer)42 void bufferFree(Buffer* buffer) {
43 free(buffer->data);
44 free(buffer);
45 }
46
bufferWrap(char * data,size_t capacity,size_t size)47 Buffer* bufferWrap(char* data, size_t capacity, size_t size) {
48 Buffer* buffer = malloc(sizeof(Buffer));
49 if (buffer == NULL) {
50 return NULL;
51 }
52
53 buffer->data = data;
54 buffer->capacity = capacity;
55 buffer->size = size;
56 buffer->expected = 0;
57 return buffer;
58 }
59
bufferPrepareForRead(Buffer * buffer,size_t expected)60 int bufferPrepareForRead(Buffer* buffer, size_t expected) {
61 if (expected > buffer->capacity) {
62 // Expand buffer.
63 char* expanded = realloc(buffer->data, expected);
64 if (expanded == NULL) {
65 errno = ENOMEM;
66 return -1;
67 }
68 buffer->capacity = expected;
69 buffer->data = expanded;
70 }
71
72 buffer->size = 0;
73 buffer->expected = expected;
74 return 0;
75 }
76
bufferRead(Buffer * buffer,int fd)77 ssize_t bufferRead(Buffer* buffer, int fd) {
78 assert(buffer->size < buffer->expected);
79
80 ssize_t bytesRead = read(fd,
81 buffer->data + buffer->size,
82 buffer->expected - buffer->size);
83
84 if (bytesRead > 0) {
85 buffer->size += bytesRead;
86 return buffer->size;
87 }
88
89 return bytesRead;
90 }
91
bufferPrepareForWrite(Buffer * buffer)92 void bufferPrepareForWrite(Buffer* buffer) {
93 buffer->remaining = buffer->size;
94 }
95
bufferWrite(Buffer * buffer,int fd)96 ssize_t bufferWrite(Buffer* buffer, int fd) {
97 assert(buffer->remaining > 0);
98 assert(buffer->remaining <= buffer->size);
99
100 ssize_t bytesWritten = write(fd,
101 buffer->data + buffer->size - buffer->remaining,
102 buffer->remaining);
103
104 if (bytesWritten >= 0) {
105 buffer->remaining -= bytesWritten;
106
107 ALOGD("Buffer bytes written: %d", (int) bytesWritten);
108 ALOGD("Buffer size: %d", (int) buffer->size);
109 ALOGD("Buffer remaining: %d", (int) buffer->remaining);
110
111 return buffer->remaining;
112 }
113
114 return bytesWritten;
115 }
116
117