Add a simple license key: I take the CRC of the license info, plus

some magic numbers. This would be trivial to break, but still more
difficult than patching the binary to skip the check...

[git-p4: depot-paths = "//depot/solvespace/": change = 1853]

Makefile

@@ -39,7 +39,7 @@ SSOBJS   = $(OBJDIR)\solvespace.obj \
 RES = $(OBJDIR)\resource.res
 
 
-LIBS = user32.lib gdi32.lib comctl32.lib advapi32.lib opengl32.lib glu32.lib \
+LIBS = user32.lib gdi32.lib comctl32.lib advapi32.lib shell32.lib opengl32.lib glu32.lib \
        extlib\libpng.lib extlib\zlib.lib
 
 all: $(OBJDIR)/solvespace.exe

doc/reference.txt

@@ -1304,7 +1304,7 @@ for new users; to learn about this program, see the video tutorials.
 <h2>Licensing</h2>
 
     As downloaded, MechSketch does not include a license key. This means
-    that it cannot create files with more than seven groups. Larger files
+    that it cannot create files with more than six groups. Larger files
     may be opened, but not modified. This light version of MechSketch
     is intended for evaluation, but non-commercial / personal use is
     also permitted.

export.cpp

@@ -117,46 +117,46 @@ havepoly:
 
     // Some software, like Adobe Illustrator, insists on a header.
     fprintf(f,
-"  999\n"
+"  999\r\n"
-"file created by SolveSpace\n"
+"file created by SolveSpace\r\n"
-"  0\n"
+"  0\r\n"
-"SECTION\n"
+"SECTION\r\n"
-"  2\n"
+"  2\r\n"
-"HEADER\n"
+"HEADER\r\n"
-"  9\n"
+"  9\r\n"
-"$ACADVER\n"
+"$ACADVER\r\n"
-"  1\n"
+"  1\r\n"
-"AC1006\n"
+"AC1006\r\n"
-"  9\n"
+"  9\r\n"
-"$INSBASE\n"
+"$INSBASE\r\n"
-"  10\n"
+"  10\r\n"
-"0.0\n"
+"0.0\r\n"
-"  20\n"
+"  20\r\n"
-"0.0\n"
+"0.0\r\n"
-"  30\n"
+"  30\r\n"
-"0.0\n"
+"0.0\r\n"
-"  9\n"
+"  9\r\n"
-"$EXTMIN\n"
+"$EXTMIN\r\n"
-"  10\n"
+"  10\r\n"
-"0.0\n"
+"0.0\r\n"
-"  20\n"
+"  20\r\n"
-"0.0\n"
+"0.0\r\n"
-"  9\n"
+"  9\r\n"
-"$EXTMAX\n"
+"$EXTMAX\r\n"
-"  10\n"
+"  10\r\n"
-"10000.0\n"
+"10000.0\r\n"
-"  20\n"
+"  20\r\n"
-"10000.0\n"
+"10000.0\r\n"
-"  0\n"
+"  0\r\n"
-"ENDSEC\n");
+"ENDSEC\r\n");
 
     // Now begin the entities, which are just line segments reproduced from
     // our piecewise linear curves.
     fprintf(f,
-"  0\n"
+"  0\r\n"
-"SECTION\n"
+"SECTION\r\n"
-"  2\n"
+"  2\r\n"
-"ENTITIES\n");
+"ENTITIES\r\n");
 
     int i, j;
     for(i = 0; i < sp->l.n; i++) {
@@ -172,22 +172,22 @@ havepoly:
             double s = SS.exportScale;
 
             fprintf(f,
-"  0\n"
+"  0\r\n"
-"LINE\n"
+"LINE\r\n"
-"  8\n"     // Layer code
+"  8\r\n"     // Layer code
-"%d\n"
+"%d\r\n"
-"  10\n"    // xA
+"  10\r\n"    // xA
-"%.6f\n"
+"%.6f\r\n"
-"  20\n"    // yA
+"  20\r\n"    // yA
-"%.6f\n"
+"%.6f\r\n"
-"  30\n"    // zA
+"  30\r\n"    // zA
-"%.6f\n"
+"%.6f\r\n"
-"  11\n"    // xB
+"  11\r\n"    // xB
-"%.6f\n"
+"%.6f\r\n"
-"  21\n"    // yB
+"  21\r\n"    // yB
-"%.6f\n"
+"%.6f\r\n"
-"  31\n"    // zB
+"  31\r\n"    // zB
-"%.6f\n",
+"%.6f\r\n",
                     0,
                     e0.x/s, e0.y/s, 0.0,
                     e1.x/s, e1.y/s, 0.0);
@@ -195,10 +195,10 @@ havepoly:
     }
 
     fprintf(f,
-"  0\n"
+"  0\r\n"
-"ENDSEC\n"
+"ENDSEC\r\n"
-"  0\n"
+"  0\r\n"
-"EOF\n" );
+"EOF\r\n" );
 
     spa.Clear();
     fclose(f);

graphicswin.cpp

@@ -7,6 +7,7 @@
 #define mFile (&SolveSpace::MenuFile)
 #define mGrp  (&Group::MenuGroup)
 #define mAna  (&SolveSpace::MenuAnalyze)
+#define mHelp (&SolveSpace::MenuHelp)
 #define S 0x100
 #define C 0x200
 const GraphicsWindow::MenuEntry GraphicsWindow::menu[] = {
@@ -101,11 +102,11 @@ const GraphicsWindow::MenuEntry GraphicsWindow::menu[] = {
 { 1, "&Stop Tracing...\tCtrl+Shift+S",      MNU_STOP_TRACING,   'S'|S|C,mAna  },
 { 1, "Step &Dimension...\tCtrl+Shift+D",    MNU_STEP_DIM,       'D'|S|C,mAna  },
 
-{ 0, "&Help",                               0,                          NULL  },
+{ 0, "&Help",                               0,                  0,      NULL  },
-{ 1, "&Load License...",                    0,                          NULL  },
+{ 1, "&Load License...",                    MNU_LICENSE,        0,      mHelp },
-{ 1, NULL,                                  0,                          NULL  },
+{ 1, NULL,                                  0,                  0,      NULL  },
-{ 1, "&Website / Manual",                   0,                          NULL  },
+{ 1, "&Website / Manual",                   MNU_WEBSITE,        0,      mHelp },
-{ 1, "&About",                              0,                          NULL  },
+{ 1, "&About",                              MNU_ABOUT,          0,      mHelp },
 { -1  },
 };
 

group.cpp

@@ -17,6 +17,14 @@ void Group::AddParam(IdList<Param,hParam> *param, hParam hp, double v) {
 }
 
 void Group::MenuGroup(int id) {
+    if(!SS.license.licensed && SS.group.n >= 7) {
+        Error("The free version of this software does not support more "
+              "than six groups.\r\n\r\n"
+              "To remove this restriction, please choose Help -> "
+              "Website / Manual, and purchase a license.");
+        return;
+    }
+
     Group g;
     ZERO(&g);
     g.visible = true;

keygen.pl

@@ -0,0 +1,64 @@
+#!/usr/bin/perl
+
+$POLY = 0xedb88320;
+
+sub ProcessBit {
+    my ($bit) = @_;
+
+    my $topWasSet = ($shiftReg & (1 << 31));
+
+    $shiftReg <<= 1;
+    if($bit) {
+        $shiftReg |= 1;
+    }
+    
+    if($topWasSet) {
+        $shiftReg ^= $POLY;
+    }
+}
+
+sub ProcessByte {
+    my ($v) = @_;
+    for(0..7) {
+        ProcessBit($v & (1 << $_));
+    }
+}
+
+sub ProcessString {
+    my ($str) = @_;
+    for (split //, $str) {
+        if($_ ne "\n" and $_ ne "\r") {
+            ProcessByte(ord($_));
+        }
+    }
+}
+
+sub LicenseKey {
+    my @MAGIC = (  203, 244, 134, 225,  45, 250,  70,  65, 
+                224, 189,  35,   3, 228,  51,  77, 169, );
+    my $magic = join('', map { chr($_) } @MAGIC);
+
+    my ($line1, $line2, $users) = @_;
+
+    $shiftReg = 0;
+    ProcessString($line1);
+    ProcessString($line2);
+    ProcessString($users);
+    ProcessString($magic);
+
+    my $key = '±²³MechSketchLicense' . "\n";
+    $key .= $line1 . "\n";
+    $key .= $line2 . "\n";
+    $key .= $users . "\n";
+    $key .= sprintf("%08x\n", $shiftReg);
+
+    return $key;
+}
+
+
+$line1 = "Jonathan Westhues";
+$line2 = "";
+$users = "single-user license";
+
+print LicenseKey($line1, $line2, $users);
+

solvespace.cpp

@@ -2,7 +2,21 @@
 
 SolveSpace SS;
 
+void SolveSpace::CheckLicenseFromRegistry(void) {
+    // First, let's see if we're running licensed or free
+    CnfThawString(license.line1, sizeof(license.line1), "LicenseLine1");
+    CnfThawString(license.line2, sizeof(license.line2), "LicenseLine2");
+    CnfThawString(license.users, sizeof(license.users), "LicenseUsers");
+    license.key = CnfThawDWORD(0, "LicenseKey");
+
+    license.licensed =
+        LicenseValid(license.line1, license.line2, license.users, license.key);
+}
+
 void SolveSpace::Init(char *cmdLine) {
+    CheckLicenseFromRegistry();
+
+    // Then, load the registry settings.
     int i;
     // Default list of colors for the model material
     modelColor[0] = CnfThawDWORD(RGB(150, 150, 150), "ModelColor_0");
@@ -431,14 +445,14 @@ void SolveSpace::MenuAnalyze(int id) {
         case GraphicsWindow::MNU_STOP_TRACING: {
             char exportFile[MAX_PATH] = "";
             if(GetSaveFile(exportFile, CSV_EXT, CSV_PATTERN)) {
-                FILE *f = fopen(exportFile, "w");
+                FILE *f = fopen(exportFile, "wb");
                 if(f) {
                     int i;
                     SContour *sc = &(SS.traced.path);
                     for(i = 0; i < sc->l.n; i++) {
                         Vector p = sc->l.elem[i].p;
                         double s = SS.exportScale;
-                        fprintf(f, "%.10f, %.10f, %.10f\n",
+                        fprintf(f, "%.10f, %.10f, %.10f\r\n",
                             p.x/s, p.y/s, p.z/s);
                     }
                     fclose(f);
@@ -457,3 +471,126 @@ void SolveSpace::MenuAnalyze(int id) {
     }
 }
 
+void SolveSpace::Crc::ProcessBit(int bit) {
+    bool topWasSet = ((shiftReg & (1 << 31)) != 0);
+
+    shiftReg <<= 1;
+    if(bit) {
+        shiftReg |= 1;
+    }
+    
+    if(topWasSet) {
+        shiftReg ^= POLY;
+    }
+}
+
+void SolveSpace::Crc::ProcessByte(BYTE b) {
+    int i;
+    for(i = 0; i < 8; i++) {
+        ProcessBit(b & (1 << i));
+    }
+}
+
+void SolveSpace::Crc::ProcessString(char *s) {
+    for(; *s; s++) {
+        if(*s != '\n' && *s != '\r') {
+            ProcessByte((BYTE)*s);
+        }
+    }
+}
+
+bool SolveSpace::LicenseValid(char *line1, char *line2, char *users, DWORD key)
+{
+    BYTE magic[17] = {
+        203, 244, 134, 225,  45, 250,  70,  65, 
+        224, 189,  35,   3, 228,  51,  77, 169,
+        0
+    };
+    
+    crc.shiftReg = 0;
+    crc.ProcessString(line1);
+    crc.ProcessString(line2);
+    crc.ProcessString(users);
+    crc.ProcessString((char *)magic);
+
+    return (key == crc.shiftReg);
+}
+
+void SolveSpace::CleanEol(char *in) {
+    char *s;
+    s = strchr(in, '\r');
+    if(s) *s = '\0';
+    s = strchr(in, '\n');
+    if(s) *s = '\0';
+}
+
+void SolveSpace::LoadLicenseFile(char *filename) {
+    FILE *f = fopen(filename, "rb");
+    if(!f) {
+        Error("Couldn't open file '%s'", filename);
+        return;
+    }
+
+    char buf[100];
+    fgets(buf, sizeof(buf), f);
+    char *str = "±²³MechSketchLicense";
+    if(memcmp(buf, str, strlen(str)) != 0) {
+        fclose(f);
+        Error("This is not a license file,");
+        return;
+    }
+
+    char line1[512], line2[512], users[512];
+    fgets(line1, sizeof(line1), f);
+    CleanEol(line1);
+    fgets(line2, sizeof(line2), f);
+    CleanEol(line2);
+    fgets(users, sizeof(users), f);
+    CleanEol(users);
+
+    fgets(buf, sizeof(buf), f);
+    DWORD key = 0;
+    sscanf(buf, "%x", &key);
+
+    if(LicenseValid(line1, line2, users, key)) {
+        // Install the new key
+        CnfFreezeString(line1, "LicenseLine1");
+        CnfFreezeString(line2, "LicenseLine2");
+        CnfFreezeString(users, "LicenseUsers");
+        CnfFreezeDWORD(key, "LicenseKey");
+        Message("License key successfully installed.");
+
+        // This updates our display in the text window to show that we're
+        // licensed now.
+        CheckLicenseFromRegistry();
+        SS.later.showTW = true;
+    } else {
+        Error("License key invalid.");
+    }
+    fclose(f);
+}
+
+void SolveSpace::MenuHelp(int id) {
+    switch(id) {
+        case GraphicsWindow::MNU_WEBSITE:
+            OpenWebsite("http://www.mechsketch.com/helpmenu");
+            break;
+        
+        case GraphicsWindow::MNU_ABOUT:
+            Message("This is MechSketch version 0.1.\r\n\r\n"
+                  "For more information, see http://www.mechsketch.com/\r\n\r\n"
+                  "Built " __TIME__ " " __DATE__ ".\r\n\r\n"
+                  "Copyright 2008 Jonathan Westhues, All Rights Reserved.");
+            break;
+
+        case GraphicsWindow::MNU_LICENSE: {
+            char licenseFile[MAX_PATH] = "";
+            if(GetOpenFile(licenseFile, LICENSE_EXT, LICENSE_PATTERN)) {
+                SS.LoadLicenseFile(licenseFile);
+            }
+            break;
+        }
+                
+        default: oops();
+    }
+}

solvespace.h

@@ -64,11 +64,16 @@ int SaveFileYesNoCancel(void);
 #define DXF_EXT "dxf"
 #define CSV_PATTERN "CSV File (*.csv)\0*.csv\0All Files (*)\0*\0\0"
 #define CSV_EXT "csv"
+#define LICENSE_PATTERN \
+    "License File (*.license)\0*.license\0All Files (*)\0*\0\0"
+#define LICENSE_EXT "license"
 BOOL GetSaveFile(char *file, char *defExtension, char *selPattern);
 BOOL GetOpenFile(char *file, char *defExtension, char *selPattern);
 void GetAbsoluteFilename(char *file);
 void LoadAllFontFiles(void);
 
+void OpenWebsite(char *url);
+
 void CheckMenuById(int id, BOOL checked);
 void EnableMenuById(int id, BOOL checked);
 
@@ -92,6 +97,7 @@ void dbp(char *str, ...);
         CO((tri).a), CO((tri).b), CO((tri).c))
 
 void SetWindowTitle(char *str);
+void Message(char *str, ...);
 void Error(char *str, ...);
 void ExitNow(void);
 
@@ -376,6 +382,7 @@ public:
 
     // The platform-dependent code calls this before entering the msg loop
     void Init(char *cmdLine);
+    void CheckLicenseFromRegistry(void);
     void Exit(void);
 
     // File load/save routines, including the additional files that get
@@ -464,6 +471,29 @@ public:
         bool    generateAll;
     } later;
     void DoLater(void);
+
+    // For the licensing
+    class Crc {
+public:
+        static const DWORD POLY = 0xedb88320;
+        DWORD shiftReg;
+        
+        void ProcessBit(int bit);
+        void ProcessByte(BYTE b);
+        void ProcessString(char *s);
+    };
+    Crc crc;
+    struct {
+        bool licensed;
+        char line1[512];
+        char line2[512];
+        char users[512];
+        DWORD key;
+    } license;
+    static void MenuHelp(int id);
+    void CleanEol(char *s);
+    void LoadLicenseFile(char *filename);
+    bool LicenseValid(char *line1, char *line2, char *users, DWORD key);
 };
 
 extern SolveSpace SS;

textscreens.cpp

@@ -98,6 +98,9 @@ void TextWindow::ScreenHowGroupSolved(int link, DWORD v) {
 void TextWindow::ScreenShowConfiguration(int link, DWORD v) {
     SS.TW.GoToScreen(SCREEN_CONFIGURATION);
 }
+void TextWindow::ScreenGoToWebsite(int link, DWORD v) {
+    OpenWebsite("http://www.mechsketch.com/txtlink");
+}
 void TextWindow::ShowListOfGroups(void) {
     Printf(true, "%Ftactv  show  ok  group-name%E");
     int i;
@@ -140,6 +143,22 @@ void TextWindow::ShowListOfGroups(void) {
         &(TextWindow::ScreenShowGroupsSpecial));
     Printf(false,  "  %Fl%Ls%fconfiguration%E",
         &(TextWindow::ScreenShowConfiguration));
+
+    // Show license info
+    Printf(false, "");
+    if(SS.license.licensed) {
+        Printf(false, "%FtLicensed to:");
+        Printf(false, "%Fg  %s", SS.license.line1);
+        if(strlen(SS.license.line2)) {
+            Printf(false, "%Fg  %s", SS.license.line2);
+        }
+        Printf(false, "%Fg  %s", SS.license.users);
+    } else {
+        Printf(false, "%Fx*** THIS SOFTWARE IS NOT LICENSED ***");
+        Printf(false, "%Fx  eval / non-commercial use only");
+        Printf(false, "%Fx  buy at %Fl%f%Llhttp://www.mechsketch.com/%E",
+            &ScreenGoToWebsite);
+    }
 }
 
 

textwin.cpp

@@ -11,6 +11,7 @@ const TextWindow::Color TextWindow::fgColors[] = {
     { 'r', RGB(  0,   0,   0) },
     { 'x', RGB(255,  20,  20) },
     { 'i', RGB(  0, 255, 255) },
+    { 'g', RGB(160, 160, 160) },
     { 0, 0 },
 };
 const TextWindow::Color TextWindow::bgColors[] = {

ui.h

@@ -130,6 +130,7 @@ public:
     static void ScreenColor(int link, DWORD v);
 
     static void ScreenShowConfiguration(int link, DWORD v);
+    static void ScreenGoToWebsite(int link, DWORD v);
 
     static void ScreenStepDimSteps(int link, DWORD v);
     static void ScreenStepDimFinish(int link, DWORD v);
@@ -224,6 +225,10 @@ public:
         MNU_TRACE_PT,
         MNU_STOP_TRACING,
         MNU_STEP_DIM,
+        // Help,
+        MNU_LICENSE,
+        MNU_WEBSITE,
+        MNU_ABOUT,
     } MenuId;
     typedef void MenuHandler(int id);
     typedef struct {

win32/w32main.cpp

@@ -1,4 +1,5 @@
 #include <windows.h>
+#include <shellapi.h>
 #include <commctrl.h>
 #include <commdlg.h>
 #include <gl/gl.h> 
@@ -55,25 +56,50 @@ void dbp(char *str, ...)
     va_end(f);
 }
 
-void Error(char *str, ...)
+
+static void DoMessageBox(char *str, va_list f, BOOL error)
 {
-    va_list f;
+    char buf[1024*50];
-    char buf[1024];
-    va_start(f, str);
     vsprintf(buf, str, f);
-    va_end(f);
 
     EnableWindow(GraphicsWnd, FALSE);
     EnableWindow(TextWnd, FALSE);
 
+    int flags;
+    if(error) {
+        flags = MB_OK | MB_ICONERROR;
+    } else {
+        flags = MB_OK | MB_ICONINFORMATION;
+    }
     HWND h = GetForegroundWindow();
-    MessageBox(h, buf, "SolveSpace Error", MB_OK | MB_ICONERROR);
+    MessageBox(h, buf, "SolveSpace", flags);
 
     EnableWindow(TextWnd, TRUE);
     EnableWindow(GraphicsWnd, TRUE);
     SetForegroundWindow(GraphicsWnd);
 }
 
+void Error(char *str, ...)
+{
+    va_list f;
+    va_start(f, str);
+    DoMessageBox(str, f, TRUE);
+    va_end(f);
+}
+
+void Message(char *str, ...)
+{
+    va_list f;
+    va_start(f, str);
+    DoMessageBox(str, f, FALSE);
+    va_end(f);
+}
+
+
+void OpenWebsite(char *url) {
+    ShellExecute(GraphicsWnd, "open", url, NULL, NULL, SW_SHOWNORMAL);
+}
+
 void ExitNow(void) {
     PostQuitMessage(0);
 }