File content as of revision 0:4617bf407fe5:

// ==================================================== Mar 04 2015, kayeks ==
// BMPFile.cpp
// ===========================================================================
// File library for Bitmap images (*.bmp, *.dib).

#include "BMPFile.h"

const char* BMPFile::StatusString[] = {
    "Success",
    "NullFileName",
    "NoSuchFile",
    "NotABitmapFile",
    "UnsupportedFormat",
    "UnsupportedDepth",
    "AllocationFailed"
};
const char* BMPFile::FormatString[] = {
    "Windows_V3",
    "Windows_V4",
    "Windows_V5",
    "OS2_V1",
    "OS2_V2",
    "Unknown"
};

BMPFile::BMPFile(const char* filename) {
    FILE*    fp;
    uint8_t  buf8[2];
    uint16_t buf16[2];
    uint32_t buf32[3];
    uint32_t offset;

    status = Success;
    format = Unknown;
    fileSize = 0;
    dataSize = 0;
    width = 0;
    height = 0;
    colorDepth = 0;
    data = NULL;
    
    // Open file
    if (!filename) {
        status = NullFilename;
        return;
    }
    fp = fopen(filename, "rb");
    if (!fp) {
        status = NoSuchFile;
        return;
    }
    
    // (0 +2) Magic number ("BM")
    fread(buf8, 1, 2, fp);
    if (buf8[0] != 'B' || buf8[1] != 'M') {
        status = NotABitmapFile;
        fclose(fp);
        return;
    }
    
    // (2 +4) File size
    // (6 +4) Reserved area
    // (10 +4) Image data offset (unconfirmed)
    fread(buf32, 4, 3, fp);
    fileSize = buf32[0];
    offset = buf32[2];
    
    // (14 +4) Header size
    fread(buf32, 4, 1, fp);
    switch (buf32[0]) {
    case 40:  // Windows V3 format
        format = Windows_V3;
        break;
    case 108:  // Windows V4 format
        format = Windows_V4;
        break;
    case 124:  // Windows V5 format
        format = Windows_V5;
        break;
    case 12:  // OS/2 V1 format
        format = OS2_V1;
        break;
    case 64:  // OS/2 V2 format
        format = OS2_V2;
        break;
    default:
        format = Unknown;
    }
    
    switch (format) {
    case Windows_V3:
        // (18 +4) Bitmap width
        // (22 +4) Bitmap height
        fread(buf32, 4, 2, fp);
        width = buf32[0];
        height = buf32[1];
        
        // (26 +2) Number of planes (unconfirmed)
        // (28 +2) Color depth
        fread(buf16, 2, 2, fp);
        colorDepth = buf16[1];
        if (colorDepth != 24) {
            status = UnsupportedDepth;
            fclose(fp);
            return;
        }
        
        // (30 +4) Compression method (unconfirmed)
        // (34 +4) Bitmap data size (unconfirmed)
        // (38 +4) Horizontal resolution (unused)
        // (42 +4) Vertical resolution (unconfirmed)
        // (46 +4) Colors (unconfirmed)
        // (50 +4) Important colors (unconfirmed)
        fread(buf32, 4, 3, fp);
        fread(buf32, 4, 3, fp);
        break;
    case Windows_V4:
    case Windows_V5:
    case OS2_V1:
    case OS2_V2:
    case Unknown:
        status = UnsupportedFormat;
        fclose(fp);
        return;
    }
    // Seek to image data offset
    fseek(fp, offset, SEEK_SET);
    
    // Calculate data length
    dataSize = ((colorDepth / 8) * width + 3) / 4 * 4 * height;
    
    // Allocate data space
    data = new uint8_t[dataSize];
    
    // Read bitmap data
    fread(data, 1, dataSize, fp);
    
    fclose(fp);
}

BMPFile::~BMPFile() {
    if (data) {
        delete[] data;
    }
}