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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _MESSAGE_BUF_H_
#define _MESSAGE_BUF_H_
#include <endian.h>
#include <cstring>
namespace android {
namespace nanohub {
/*
* Marshaling helper;
* deals with alignment and endianness.
* Assumption is:
* read*() parse buffer from device in LE format;
* return host endianness, aligned data
* write*() primitives take host endinnness, aligned data,
* generate buffer to be passed to device in LE format
*
* Primitives do minimal error checking, only to ensure buffer read/write
* safety. Caller is responsible for making sure correct amount of data
* has been processed.
*/
class MessageBuf {
char *data;
size_t size;
size_t pos;
bool readOnly;
public:
MessageBuf(char *buf, size_t bufSize) {
size = bufSize;
pos = 0;
data = buf;
readOnly = false;
}
MessageBuf(const char *buf, size_t bufSize) {
size = bufSize;
pos = 0;
data = const_cast<char *>(buf);
readOnly = true;
}
void reset() { pos = 0; }
const char *getData() const { return data; }
size_t getSize() const { return size; }
size_t getPos() const { return pos; }
size_t getRoom() const { return size - pos; }
uint8_t readU8() {
if (pos == size) {
return 0;
}
return data[pos++];
}
void writeU8(uint8_t val) {
if (pos == size || readOnly)
return;
data[pos++] = val;
}
uint16_t readU16() {
if (pos > (size - sizeof(uint16_t))) {
return 0;
}
uint16_t val;
memcpy(&val, &data[pos], sizeof(val));
pos += sizeof(val);
return le16toh(val);
}
void writeU16(uint16_t val) {
if (pos > (size - sizeof(uint16_t)) || readOnly) {
return;
}
uint16_t tmp = htole16(val);
memcpy(&data[pos], &tmp, sizeof(tmp));
pos += sizeof(tmp);
}
uint32_t readU32() {
if (pos > (size - sizeof(uint32_t))) {
return 0;
}
uint32_t val;
memcpy(&val, &data[pos], sizeof(val));
pos += sizeof(val);
return le32toh(val);
}
void writeU32(uint32_t val) {
if (pos > (size - sizeof(uint32_t)) || readOnly) {
return;
}
uint32_t tmp = htole32(val);
memcpy(&data[pos], &tmp, sizeof(tmp));
pos += sizeof(tmp);
}
uint64_t readU64() {
if (pos > (size - sizeof(uint64_t))) {
return 0;
}
uint64_t val;
memcpy(&val, &data[pos], sizeof(val));
pos += sizeof(val);
return le32toh(val);
}
void writeU64(uint64_t val) {
if (pos > (size - sizeof(uint64_t)) || readOnly) {
return;
}
uint64_t tmp = htole64(val);
memcpy(&data[pos], &tmp, sizeof(tmp));
pos += sizeof(tmp);
}
const void *readRaw(size_t bufSize) {
if (pos > (size - bufSize)) {
return nullptr;
}
const void *buf = &data[pos];
pos += bufSize;
return buf;
}
void writeRaw(const void *buf, size_t bufSize) {
if (pos > (size - bufSize) || readOnly) {
return;
}
memcpy(&data[pos], buf, bufSize);
pos += bufSize;
}
};
}; // namespace nanohub
}; // namespace android
#endif