#include <qpdf/Pl_SHA2.hh>

#include <qpdf/QPDFCryptoProvider.hh>

#include <qpdf/QUtil.hh>

#include <stdexcept>

Pl_SHA2::Pl_SHA2(int bits, Pipeline* next) :

    Pipeline("sha2", next),

    in_progress(false)

{

    if (bits) {

        resetBits(bits);

    }

}

void

Pl_SHA2::write(unsigned char const* buf, size_t len)

{

    if (!this->in_progress) {

        this->in_progress = true;

    }

    // Write in chunks in case len is too big to fit in an int. Assume int is at least 32 bits.

    static size_t const max_bytes = 1 << 30;

    size_t bytes_left = len;

    unsigned char const* data = buf;

    while (bytes_left > 0) {

        size_t bytes = (bytes_left >= max_bytes ? max_bytes : bytes_left);

        this->crypto->SHA2_update(data, bytes);

        bytes_left -= bytes;

        data += bytes;

    }

    if (this->getNext(true)) {

        this->getNext()->write(buf, len);

    }

}

void

Pl_SHA2::finish()

{

    if (this->getNext(true)) {

        this->getNext()->finish();

    }

    this->crypto->SHA2_finalize();

    this->in_progress = false;

}

void

Pl_SHA2::resetBits(int bits)

{

    if (this->in_progress) {

        throw std::logic_error("bit reset requested for in-progress SHA2 Pipeline");

    }

    this->crypto = QPDFCryptoProvider::getImpl();

    this->crypto->SHA2_init(bits);

}

std::string

Pl_SHA2::getRawDigest()

{

    if (this->in_progress) {

        throw std::logic_error("digest requested for in-progress SHA2 Pipeline");

    }

    return this->crypto->SHA2_digest();

}

std::string

Pl_SHA2::getHexDigest()

{

    if (this->in_progress) {

        throw std::logic_error("digest requested for in-progress SHA2 Pipeline");

    }

    return QUtil::hex_encode(getRawDigest());

}