把二进制文件按字节读到vector中

 1    std::vector<unsigned char> readFromFile1(const char* filePath) {
 2        FILE* file = fopen(filePath, "rb");
 3        std::vector<unsigned char> result;
 4        if (file == nullptr) {
 5            return result;
 6        }
 7
 8        // 获取文件大小，尽量一次读完
 9        size_t fileSize = getFileSize(file);
10        if (fileSize != 0) {
11            result.resize(fileSize);
12            size_t n = fread(&result[0], 1, fileSize, file);
13            assert(n <= fileSize);
14            if (n != fileSize) {
15                result.resize(n);
16            }
17        }
18
19        // 在读取过程当中，有可能文件大小有变化，再尝试读取
20        const size_t read_len = 1024;
21        char buf[read_len];
22        for (;;) {
23            size_t n = fread(buf, 1, read_len, file);
24            result.insert(result.end(), buf, buf + n);
25            if (n < read_len) {
26                break;
27            }
28        }
29        fclose(file);
30        return result;
31    }

1
2    std::vector<unsigned char> readFromFile2(const char* filePath) {
3        std::ifstream inputFile(filePath, std::ios::binary);
4        std::vector<unsigned char> fileData((std::istreambuf_iterator<char>(inputFile)),
5                                            std::istreambuf_iterator<char>());
6        return fileData;
7    }