PortableGraymapReader.cpp

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#include "Utilities/PortableGraymapReader.h"
 
#include <cstdint>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <sstream>
 
PortableGraymapReader::PortableGraymapReader(const std::string& input) {
    std::ifstream in(input);
    readHeader(in);
    pixels_m.resize(width_m * height_m);
 
    if (type_m == ASCII) {
        readImageAscii(in);
    } else {
        readImageBinary(in);
    }
}
 
std::string PortableGraymapReader::getNextPart(std::istream& in) {
    do {
        char c = in.get();
        if (c == '#') {
            do {
                c = in.get();
            } while (c != '\n');
        } else if (!(c == ' ' || c == '\t' || c == '\n' || c == '\r')) {
            in.putback(c);
            break;
        }
    } while (true);
 
    std::string nextPart;
    in >> nextPart;
 
    return nextPart;
}
 
void PortableGraymapReader::readHeader(std::istream& in) {
    std::string magicValue = getNextPart(in);
 
    if (magicValue == "P2") {
        type_m = ASCII;
    } else if (magicValue == "P5") {
        type_m = BINARY;
    } else {
        throw OpalException(
                "PortableGraymapReader::readHeader", "Unknown magic value: '" + magicValue + "'");
    }
 
    {
        std::string tmp = getNextPart(in);
        std::istringstream conv;
        conv.str(tmp);
        conv >> width_m;
    }
 
    {
        std::string tmp = getNextPart(in);
        std::istringstream conv;
        conv.str(tmp);
        conv >> height_m;
    }
 
    {
        std::string tmp = getNextPart(in);
        std::istringstream conv;
        conv.str(tmp);
        conv >> depth_m;
    }
 
    char tmp;
    in.read(&tmp, 1);
}
 
void PortableGraymapReader::readImageAscii(std::istream& in) {
    unsigned int size = height_m * width_m;
    unsigned int i    = 0;
    while (i < size) {
        unsigned int c;
        in >> c;
 
        pixels_m[i] = c;
        ++i;
    }
}
 
void PortableGraymapReader::readImageBinary(std::istream& in) {
    unsigned int numPixels = 0;
    char c[]               = {0, 0};
    unsigned char uc;
    for (unsigned int row = 0; row < height_m; ++row) {
        for (unsigned int col = 0; col < width_m; ++col) {
            if (depth_m > 255) {
                in.read(&c[1], 1);
                in.read(&c[0], 1);
                const uint16_t* val = reinterpret_cast<const uint16_t*>(&c[0]);
                pixels_m[numPixels] = val[0];
            } else {
                in.read(&c[0], 1);
                uc                  = c[0];
                pixels_m[numPixels] = uc;
            }
            ++numPixels;
        }
    }
}
 
void PortableGraymapReader::print(std::ostream& /*out*/) const {
    const unsigned int printWidth = 5;
    for (unsigned int i = 0; i < height_m; ++i) {
        for (unsigned int j = 0; j < width_m; ++j) {
            unsigned int idx = getIdx(i, j);
            std::cout << "  " << std::setw(printWidth) << pixels_m[idx];
        }
        std::cout << std::endl;
    }
}