#include <qpdf/Pl_RC4.hh>

#include <qpdf/QUtil.hh>

Pl_RC4::Pl_RC4(
    char const* identifier,
    Pipeline* next,
    unsigned char const* key_data,
    int key_len,
    size_t out_bufsize) :
    Pipeline(identifier, next),
    out_bufsize(out_bufsize),
    rc4(key_data, key_len)
{
    if (!next) {
        throw std::logic_error("Attempt to create Pl_RC4 with nullptr as next");
    }
    this->outbuf = QUtil::make_shared_array<unsigned char>(out_bufsize);
}

void
Pl_RC4::write(unsigned char const* data, size_t len)
{
    if (this->outbuf == nullptr) {
        throw std::logic_error(this->identifier + ": Pl_RC4: write() called after finish() called");
    }

    size_t bytes_left = len;
    unsigned char const* p = data;

    while (bytes_left > 0) {
        size_t bytes = (bytes_left < this->out_bufsize ? bytes_left : out_bufsize);
        bytes_left -= bytes;
        // lgtm[cpp/weak-cryptographic-algorithm]
        rc4.process(p, bytes, outbuf.get());
        p += bytes;
        next()->write(outbuf.get(), bytes);
    }
}

void
Pl_RC4::finish()
{
    outbuf = nullptr;
    next()->finish();
}