#pragma once
#include <iostream>
#include <utility>
#include <algorithm>
#include <string>
#include <cmath>
#include <memory>
class BufferedReader {
public:
explicit BufferedReader(PackageStream *stream) : stream(stream),
buffer(new char[stream->PackageLen()]) {
}
int32_t Read(char *output_buffer, int32_t buffer_len) {
int32_t buffer_size = static_cast<int>(strlen(buffer.get()));
int32_t real_size = std::min<int32_t>(buffer_size, buffer_len);
memcpy(output_buffer, buffer.get(), real_size);
memcpy(buffer.get(), buffer.get() + real_size,
buffer_size - real_size);
AddZero(buffer.get(), buffer_size - real_size);
unique_ptr<char[]> tmp_buf(new char[stream->PackageLen()]);
for (int32_t last_result = INT32_MAX;
real_size < buffer_len && last_result != 0;) {
last_result = stream->ReadPackage(tmp_buf.get());
int32_t add_size;
if (real_size + last_result > buffer_len) {
add_size = buffer_len - real_size;
memcpy(output_buffer + real_size, tmp_buf.get(), add_size);
memcpy(buffer.get(), tmp_buf.get() + add_size,
real_size + last_result - buffer_len);
AddZero(buffer.get(), real_size + last_result - buffer_len);
} else {
add_size = last_result;
memcpy(output_buffer + real_size, tmp_buf.get(), add_size);
}
real_size += add_size;
}
return real_size;
}
private:
void AddZero(char* c, int32_t index) {
c[index] = 0;
}
PackageStream *stream;
unique_ptr<char[]> buffer;
};