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 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 42 void bufferFree(Buffer* buffer) { 43 free(buffer->data); 44 free(buffer); 45 } 46 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 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 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 92 void bufferPrepareForWrite(Buffer* buffer) { 93 buffer->remaining = buffer->size; 94 } 95 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
