#include "common.h"
#include "ZReader.h"
#include "ZScanner.h"
#include <fcntl.h>
#include <unistd.h>

ZReader::ZReader(const char* fn) : file(-1), pBuffer(0), nMax(0), nSize(0), sFilename(fn), iLastError(0) {
    allocateBuffer(1 * 1024 * 1024);
}

ZReader::ZReader() : file(0), pBuffer(0), nMax(0), nSize(0), sFilename("STDIN"), iLastError(0) {
    allocateBuffer(1 * 1024 * 1024);
}

ZReader::~ZReader() {
    if (0 < file) {
        closeFile();
    }
}

void ZReader::allocateBuffer(int cb) {
    pBuffer = new char[cb+1];
    nMax = cb;
    nSize = 0;
}

bool ZReader::openFile() {
    file = open(sFilename,0);
    if (file < 0) {
        iLastError = errno;
        perror(sFilename);
        return false;
    }
    return true;
}

bool ZReader::scanFile(ZScanner& scanner) {
    ZString sLine;
    for (;;) {
        int nWanted = nMax - nSize;
        nWanted &= ~(0xFFFF);     // read in 64KB quanta 
        int nRead = read(file,pBuffer + nSize,nWanted);
        if (nRead <= 0) {
            break;
        }
        nSize += nRead;
        pBuffer[nSize] = 0;
        char* pBase = pBuffer;
        char* pEOB = pBuffer + nSize;
        for (;;) {
            char* pEOL = strchr(pBase,'\n');
            if (!pEOL) {
                int n = nSize - (int)(pBase - pBuffer);
                memmove(pBuffer,pBase,n);
                nSize = n;
                break;
            }
            int n = (int)(pEOL - pBase) + 1;
            sLine.strcpy(pBase,n);
            scanner.onLine(sLine);
            pBase += n;
            if (pEOB <= pBase) {
                nSize = 0;
                break;
            }
        }
    }
    if (0 < nSize) {
        sLine.strcpy(pBuffer,nSize);
        scanner.onLine(sLine);
    }
    scanner.onEOF();
    return true;
}

void ZReader::closeFile() {
    if (0 < file) {
        close(file);
        file = -1;
    }
}

void ZReader::scanFiles(ZScanner& scanner, int iBase, int ac, char** av) {
    for (int i=iBase; i<ac; ++i) {
        const char* sFilename = av[i];
        ZReader reader(sFilename);
        scanner.onFile(sFilename);
        if (!reader.openFile()) {
            scanner.onError(sFilename,reader.iLastError);
            return;
        }
        bool bOK = reader.scanFile(scanner);
        if (!bOK) {
            fprintf(stderr,"FAIL  '%s'\n",sFilename);
        }
        reader.closeFile();
    }
}