StreamReader.h

/* -*- mode: c++; indent-tabs-mode: nil -*- */
/*
  StreamReader.h

  Qore Programming Language

  Copyright (C) 2016 - 2017 Qore Technologies, s.r.o.

  Permission is hereby granted, free of charge, to any person obtaining a
  copy of this software and associated documentation files (the "Software"),
  to deal in the Software without restriction, including without limitation
  the rights to use, copy, modify, merge, publish, distribute, sublicense,
  and/or sell copies of the Software, and to permit persons to whom the
  Software is furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  DEALINGS IN THE SOFTWARE.

  Note that the Qore library is released under a choice of three open-source
  licenses: MIT (as above), LGPL 2+, or GPL 2+; see README-LICENSE for more
  information.
*/

#ifndef _QORE_STREAMREADER_H
#define _QORE_STREAMREADER_H

#include <cstdint>

#include "qore/qore_bitopts.h"
#include "qore/InputStream.h"
#include "qore/intern/StringReaderHelper.h"

DLLLOCAL extern qore_classid_t CID_STREAMREADER;
DLLLOCAL extern QoreClass* QC_STREAMREADER;

class StreamReader : public AbstractPrivateData {
public:
    DLLLOCAL StreamReader(ExceptionSink* xsink, InputStream* is, const QoreEncoding* encoding = QCS_DEFAULT) :
        in(is, xsink),
        enc(encoding) {
    }

    virtual DLLLOCAL ~StreamReader() {
    }

    DLLLOCAL const QoreEncoding* getEncoding() const {
        return enc;
    }

    DLLLOCAL const InputStream* getInputStream() const {
        return *in;
    }

    DLLLOCAL void setEncoding(const QoreEncoding* n_enc) {
        enc = n_enc;
    }


    DLLLOCAL BinaryNode* readBinary(int64 limit, ExceptionSink* xsink) {
        if (limit == 0)
            return 0;
        SimpleRefHolder<BinaryNode> b(new BinaryNode());
        char buffer[STREAMREADER_BUFFER_SIZE];
        if (limit == -1) {
            while (true) {
                int rc = readData(xsink, buffer, STREAMREADER_BUFFER_SIZE, false);
                if (*xsink)
                    return 0;
                if (rc == 0)
                    break;
                b->append(buffer, rc);
            }
        }
        else {
            while (limit > 0) {
                int rc = readData(xsink, buffer, QORE_MIN(limit, STREAMREADER_BUFFER_SIZE), false);
                if (*xsink)
                    return 0;
                if (rc == 0)
                    break;
                b->append(buffer, rc);
                limit -= rc;
            }
        }

        return b->empty() ? 0 : b.release();
    }


    DLLLOCAL QoreStringNode* readString(int64 size, ExceptionSink* xsink) {
        return q_read_string(xsink, size, enc, std::bind(&StreamReader::readData, this, _3, _1, _2, false));
    }


    DLLLOCAL QoreStringNode* readLine(const QoreStringNode* eol, bool trim, ExceptionSink* xsink) {
        if (!eol && !enc->isAsciiCompat()) {
            QoreString nl("\n");
            return readLineEol(&nl, trim, xsink);
        }

        return eol ? readLineEol(eol, trim, xsink) : readLine(trim, xsink);
    }

    DLLLOCAL QoreStringNode* readLineEol(const QoreString* eol, bool trim, ExceptionSink* xsink) {
        TempEncodingHelper eolstr(eol, enc, xsink);
        if (*xsink)
            return 0;
        eolstr.removeBom();

        SimpleRefHolder<QoreStringNode> str(new QoreStringNode(enc));

        qore_size_t eolpos = 0;

        while (true) {
            char c;
            int64 rc = readData(xsink, &c, 1, false);
            //printd(5, "StreamReader::readLineEol() eolpos: %d/%d rc: %d c: %d str: '%s' (%s)\n", eolpos, eolstr->size(), rc, c, str->c_str(), enc->getCode());
            if (*xsink)
                return 0;
            if (!rc)
                return str->empty() ? 0 : q_remove_bom_utf16(str.release(), enc);

            // add the char to the string
            str->concat(c);

            if ((**eolstr)[eolpos] == c) {
                ++eolpos;
                if (eolpos == eolstr->size()) {
                    if (trim)
                        str->terminate(str->size() - eolpos);
                    return q_remove_bom_utf16(str.release(), enc);
                }
            }
            else if (eolpos) {
                // check all positions to see if the string matches
                bool found = false;
                for (size_t i = eolpos; i; --i) {
                    // we have to use memcmp here because we could be dealing with character
                    // encodings that include nulls in the string (ex: UTF-16*)
                    if (!memcmp(eolstr->c_str(), str->c_str() + str->size() - i, i)) {
                        found = true;
                        if (eolpos != i)
                            eolpos = i;
                        break;
                    }
                }
                if (!found)
                eolpos = 0;
            }
        }
    }

    DLLLOCAL QoreStringNode* readLine(bool trim, ExceptionSink* xsink) {
        SimpleRefHolder<QoreStringNode> str(new QoreStringNode(enc));

        while (true) {
            char c;
            int64 rc = readData(xsink, &c, 1, false);
            if (*xsink)
                return 0;
            if (!rc) { // End of stream.
                return str->empty() ? 0 : str.release();
            }

            if (c == '\n') {
                if (!trim)
                str->concat(c);
                return str.release();
            }
            else if (c == '\r') {
                if (!trim)
                    str->concat(c);
                int64 p = peek(xsink);
                if (*xsink)
                    return 0;
                if (p == '\n') {
                    readData(xsink, &c, 1);
                if (!trim)
                    str->concat((char)p);
                }
                return str.release();
            }
            str->concat(c);
        }
    }

    DLLLOCAL int64 readi1(ExceptionSink* xsink) {
        char i = 0;
        if (readData(xsink, &i, 1) < 0)
            return 0;
        return i;
    }

    DLLLOCAL int64 readi2(ExceptionSink* xsink) {
        short i = 0;
        if (readData(xsink, &i, 2) < 0)
            return 0;
        i = ntohs(i);
        return i;
    }

    DLLLOCAL int64 readi4(ExceptionSink* xsink) {
        int32_t i = 0;
        if (readData(xsink, &i, 4) < 0)
            return 0;
        i = ntohl(i);
        return i;
    }

    DLLLOCAL int64 readi8(ExceptionSink* xsink) {
        int64 i = 0;
        if (readData(xsink, &i, 8) < 0)
            return 0;
        i = i8MSB(i);
        return i;
    }

    DLLLOCAL int64 readi2LSB(ExceptionSink* xsink) {
        short i = 0;
        if (readData(xsink, &i, 2) < 0)
            return 0;
        i = i2LSB(i);
        return i;
    }

    DLLLOCAL int64 readi4LSB(ExceptionSink* xsink) {
        int32_t i = 0;
        if (readData(xsink, &i, 4) < 0)
            return 0;
        i = i4LSB(i);
        return i;
    }

    DLLLOCAL int64 readi8LSB(ExceptionSink* xsink) {
        int64 i = 0;
        if (readData(xsink, &i, 8) < 0)
            return 0;
        i = i8LSB(i);
        return i;
    }

    DLLLOCAL int64 readu1(ExceptionSink* xsink) {
        unsigned char i = 0;
        if (readData(xsink, &i, 1) < 0)
            return 0;
        return i;
    }

    DLLLOCAL int64 readu2(ExceptionSink* xsink) {
        unsigned short i = 0;
        if (readData(xsink, &i, 2) < 0)
            return 0;
        i = ntohs(i);
        return i;
    }

    DLLLOCAL int64 readu4(ExceptionSink* xsink) {
        uint32_t i = 0;
        if (readData(xsink, &i, 4) < 0)
            return 0;
        i = ntohl(i);
        return i;
    }

    DLLLOCAL int64 readu2LSB(ExceptionSink* xsink) {
        unsigned short i = 0;
        if (readData(xsink, &i, 2) < 0)
            return 0;
        i = i2LSB(i);
        return i;
    }

    DLLLOCAL int64 readu4LSB(ExceptionSink* xsink) {
        uint32_t i = 0;
        if (readData(xsink, &i, 4) < 0)
            return 0;
        i = i4LSB(i);
        return i;
    }

    int64 peekCheck(ExceptionSink* xsink) {
        int64 rc = peek(xsink);
        if (rc < 0) {
            if (!*xsink) {
                if (rc == -1) {
                    xsink->raiseException("END-OF-STREAM-ERROR", "there is not enough data available in the stream; 1 byte was requested, and 0 were read");
                }
                else {
                    assert(*xsink);
                }
            }
            return -1;
        }
        return rc;
    }


    DLLLOCAL virtual qore_offset_t read(ExceptionSink* xsink, void* dest, qore_size_t limit, bool require_all = true) {
        return readData(xsink, dest, limit, require_all);
    }

    DLLLOCAL virtual const char* getName() const { return "StreamReader"; }

protected:
    // default buffer size (note that I/O is generally unbuffered in this class)
    static const int STREAMREADER_BUFFER_SIZE = 4096;

    ReferenceHolder<InputStream> in;

    const QoreEncoding* enc;

private:

    DLLLOCAL virtual qore_offset_t readData(ExceptionSink* xsink, void* dest, qore_size_t limit, bool require_all = true) {
        assert(dest);
        assert(limit > 0);
        char* destPtr = static_cast<char*>(dest);
        qore_size_t read = 0;
        while (true) {
            int64 rc = in->read(destPtr + read, limit - read, xsink);
            if (*xsink)
                return -1;
            //printd(5, "StreamReader::readData() dest: %p limit: " QLLD " read: " QLLD " rc: " QLLD " char: %d\n", dest, limit, read, rc, destPtr[0]);
            if (!rc) {
                if (require_all) {
                    xsink->raiseException("END-OF-STREAM-ERROR", "there is not enough data available in the stream; " QSD " bytes were requested, and " QSD " were read", limit, read);
                    return -1;
                }
                break;
            }
            read += rc;
            if (read == limit)
                break;
        }
        return read;
    }

    virtual int64 peek(ExceptionSink* xsink) {
        return in->peek(xsink);
    }
};

#endif // _QORE_STREAMREADER_H