Improved XMP value toLong, toFloat and toRational using new functions parseLong, parseFloat and parseRational. (Vladimir Nadvornik)

samples/Makefile

@@ -69,6 +69,7 @@ BINSRC = addmoddel.cpp        \
          key-test.cpp         \
          largeiptc-test.cpp   \
          makernote-test.cpp   \
+         stringto-test.cpp    \
          write-test.cpp       \
          write2-test.cpp      \
          tiffparse.cpp        \

samples/stringto-test.cpp

@@ -0,0 +1,77 @@
+// ***************************************************************** -*- C++ -*-
+// stringto-test.cpp, $Rev$
+// Test conversions from string to long, float and Rational types.
+
+#include <exiv2/types.hpp>
+#include <exiv2/error.hpp>
+#include <iostream>
+#include <iomanip>
+
+const char* testcases[] = {
+    // bool
+    "True",
+    "False",
+    "t",
+    "f",
+    // long
+    "-1",
+    "0",
+    "1",
+    // float
+    "0.0",
+    "0.1",
+    "0.01",
+    "0.001",
+    "-1.49999",
+    "-1.5",
+    "1.49999",
+    "1.5",
+    // Rational
+    "0/1",
+    "1/1",
+    "1/3",
+    "-1/3",
+    "4/3",
+    "-4/3",
+    "0/0",
+    // nok
+    "text"
+};
+
+int main()
+{
+    std::cout << std::setfill(' ');
+
+    std::cout << std::setw(12) << std::left << "string";
+    std::cout << std::setw(12) << std::left << "long";
+    std::cout << std::setw(12) << std::left << "float";
+    std::cout << std::setw(12) << std::left << "Rational";
+
+    std::cout << std::endl;
+
+    for (unsigned int i = 0; i < EXV_COUNTOF(testcases); ++i) try {
+        std::string s(testcases[i]);
+        std::cout << std::setw(12) << std::left << s;
+        bool ok;
+
+        long l = Exiv2::parseLong(s, ok);
+        std::cout << std::setw(12) << std::left;
+        if (ok) std::cout << l; else std::cout << "nok";
+
+        float f = Exiv2::parseFloat(s, ok);
+        std::cout << std::setw(12) << std::left;
+        if (ok) std::cout << f; else std::cout << "nok";
+
+        Exiv2::Rational r = Exiv2::parseRational(s, ok);
+        if (ok) std::cout << r.first << "/" << r.second;
+        else std::cout << "nok";
+
+        std::cout << std::endl;
+    }
+    catch (Exiv2::AnyError& e) {
+        std::cout << "Caught Exiv2 exception '" << e << "'\n";
+        return -1;
+    }
+
+    return 0;
+}

samples/xmpsample.cpp

@@ -8,6 +8,14 @@
 #include <string>
 #include <iostream>
 #include <iomanip>
+#include <cassert>
+#include <cmath>
+
+bool isEqual(float a, float b)
+{
+    double d = std::fabs(a - b);
+    return d < 0.00001;
+}
 
 int main()
 try {
@@ -39,6 +47,59 @@ try {
     // In addition, there is a dedicated assignment operator for Exiv2::Value
     Exiv2::XmpTextValue val("Seven");
     xmpData["Xmp.dc.seven"]   = val;
+    xmpData["Xmp.dc.eight"]   = true;
+
+    // Extracting values
+    assert(xmpData["Xmp.dc.one"].toLong() == -1);
+    assert(xmpData["Xmp.dc.one"].value().ok());
+
+    const Exiv2::Value &getv1 = xmpData["Xmp.dc.one"].value();
+    assert(isEqual(getv1.toFloat(), -1)); 
+    assert(getv1.ok());
+    assert(getv1.toRational() == Exiv2::Rational(-1, 1));
+    assert(getv1.ok());
+
+    const Exiv2::Value &getv2 = xmpData["Xmp.dc.two"].value();
+    assert(isEqual(getv2.toFloat(), 3.1415)); 
+    assert(getv2.ok());
+    assert(getv2.toLong() == 3);
+    assert(getv2.ok());
+    Exiv2::Rational R = getv2.toRational();
+    assert(getv2.ok());
+    assert(isEqual(static_cast<float>(R.first) / R.second, 3.1415 ));
+
+    const Exiv2::Value &getv3 = xmpData["Xmp.dc.three"].value();
+    assert(isEqual(getv3.toFloat(), 5.0/7.0)); 
+    assert(getv3.ok());
+    assert(getv3.toLong() == 0);  // long(5.0 / 7.0) 
+    assert(getv3.ok());
+    assert(getv3.toRational() == Exiv2::Rational(5, 7));
+    assert(getv3.ok());
+    
+    const Exiv2::Value &getv6 = xmpData["Xmp.dc.six"].value();
+    assert(getv6.toLong() == 0);
+    assert(getv6.ok());
+    assert(getv6.toFloat() == 0.0);
+    assert(getv6.ok());
+    assert(getv6.toRational() == Exiv2::Rational(0, 1));
+    assert(getv6.ok());
+    
+    const Exiv2::Value &getv7 = xmpData["Xmp.dc.seven"].value();
+    getv7.toLong(); // this should fail
+    assert(!getv7.ok()); 
+
+    const Exiv2::Value &getv8 = xmpData["Xmp.dc.eight"].value();
+    assert(getv8.toLong() == 1);
+    assert(getv8.ok());
+    assert(getv8.toFloat() == 1.0);
+    assert(getv8.ok());
+    assert(getv8.toRational() == Exiv2::Rational(1, 1));
+    assert(getv8.ok());
+
+    // Deleting an XMP property
+    Exiv2::XmpData::iterator pos = xmpData.findKey(Exiv2::XmpKey("Xmp.dc.eight"));
+    if (pos == xmpData.end()) throw Exiv2::Error(1, "Key not found");
+    xmpData.erase(pos);
 
     // -------------------------------------------------------------------------
     // Exiv2 has specialized values for simple XMP properties, arrays of simple

src/crwimage.cpp

@@ -960,11 +960,7 @@ namespace Exiv2 {
         if (ifdId == canonSiIfdId) {
             // Exif.Photo.FNumber
             float f = fnumber(canonEv(aperture));
-            // Beware: primitive conversion algorithm
+            URational ur = floatToRationalCast(f);
-            uint32_t den = 1000000;
-            uint32_t nom = static_cast<uint32_t>(f * den);
-            uint32_t g = gcd(nom, den);
-            URational ur(nom/g, den/g);
             URationalValue fn;
             fn.value_.push_back(ur);
             image.exifData().add(ExifKey("Exif.Photo.FNumber"), &fn);

src/types.cpp

@@ -43,6 +43,7 @@ EXIV2_RCSID("@(#) $Id$")
 #include <cctype>
 #include <ctime>
 #include <cstdio>
+#include <cstdlib>
 #include <cassert>
 #include <cstring>
 
@@ -349,6 +350,104 @@ namespace Exiv2 {
         return str;
 #endif
     }
+
+    template<>
+    bool stringTo<bool>(const std::string& s, bool& ok)
+    {
+        std::string lcs(s); /* lowercase string */
+        for(unsigned i = 0; i < lcs.length(); i++) {
+            lcs[i] = std::tolower(s[i]);
+        }
+        /* handle the same values as xmp sdk */
+        if (lcs == "false" || lcs == "f" || lcs == "0") {
+            ok = true;
+            return false;
+        }
+        if (lcs == "true" || lcs == "t" || lcs == "1") {
+            ok = true;
+            return true;
+        }
+        ok = false;
+        return false;
+    }
+
+    long parseLong(const std::string& s, bool& ok)
+    {
+        long ret = stringTo<long>(s, ok);
+        if (ok) return ret;
+
+        float f = stringTo<float>(s, ok);
+        if (ok) return static_cast<long>(f);
+
+        Rational r = stringTo<Rational>(s, ok);
+        if (ok) {
+            if (r.second == 0) {
+                ok = false;
+                return 0;
+            }
+            return static_cast<long>(static_cast<float>(r.first) / r.second);
+        }
+
+        bool b = stringTo<bool>(s, ok);
+        if (ok) return b ? 1 : 0;
+
+        // everything failed, return from stringTo<long> is probably the best fit
+        return ret; 
+    }
+
+    float parseFloat(const std::string& s, bool& ok)
+    {
+        float ret = stringTo<float>(s, ok);
+        if (ok) return ret;
+
+        Rational r = stringTo<Rational>(s, ok);
+        if (ok) {
+            if (r.second == 0) {
+                ok = false;
+                return 0.0;
+            }
+            return static_cast<float>(r.first) / r.second;
+        }
+
+        bool b = stringTo<bool>(s, ok);
+        if (ok) return b ? 1.0 : 0.0;
+
+        // everything failed, return from stringTo<float> is probably the best fit
+        return ret;
+    }
+
+    Rational parseRational(const std::string& s, bool& ok)
+    {
+        Rational ret = stringTo<Rational>(s, ok);
+        if (ok) return ret;
+
+        long l = stringTo<long>(s, ok);
+        if (ok) return Rational(l, 1);
+
+        float f = stringTo<float>(s, ok);
+        if (ok) return floatToRationalCast(f);
+
+        bool b = stringTo<bool>(s, ok);
+        if (ok) return b ? Rational(1, 1) : Rational(0, 1);
+
+        // everything failed, return from stringTo<Rational> is probably the best fit
+        return ret;
+    }
+
+    Rational floatToRationalCast(float f)
+    {
+        // Beware: primitive conversion algorithm
+        int32_t den = 1000000;
+        if (std::labs(static_cast<long>(f)) > 2147) den = 10000;
+        if (std::labs(static_cast<long>(f)) > 214748) den = 100;
+        if (std::labs(static_cast<long>(f)) > 21474836) den = 1;
+        const float rnd = f >= 0 ? 0.5 : -0.5;
+        const int32_t nom = static_cast<int32_t>(f * den + rnd);
+        const int32_t g = gcd(nom, den);
+
+        return Rational(nom/g, den/g);
+    }
+
 }                                       // namespace Exiv2
 
 #ifdef EXV_ENABLE_NLS

src/types.hpp

@@ -321,6 +321,58 @@ namespace Exiv2 {
      */
     const char* exvGettext(const char* str);
 
+    /*!
+      @brief Return a \em long set to the value represented by \em s. 
+
+      Besides strings that represent \em long values, the function also
+      handles \em float, \em Rational and boolean
+      (see also: stringTo(const std::string& s, bool& ok)).
+
+      @param  s  String to parse
+      @param  ok Output variable indicating the success of the operation.
+      @return Returns the \em long value represented by \em s and sets \em ok
+              to \c true if the conversion was successful or \c false if not.
+    */
+    long parseLong(const std::string& s, bool& ok);
+
+    /*!
+      @brief Return a \em float set to the value represented by \em s. 
+
+      Besides strings that represent \em float values, the function also
+      handles \em long, \em Rational and boolean
+      (see also: stringTo(const std::string& s, bool& ok)).
+
+      @param  s  String to parse
+      @param  ok Output variable indicating the success of the operation.
+      @return Returns the \em float value represented by \em s and sets \em ok
+              to \c true if the conversion was successful or \c false if not.
+    */
+    float parseFloat(const std::string& s, bool& ok);
+    
+    /*!
+      @brief Return a \em Rational set to the value represented by \em s. 
+
+      Besides strings that represent \em Rational values, the function also
+      handles \em long, \em float and boolean
+      (see also: stringTo(const std::string& s, bool& ok)).
+      Uses floatToRationalCast(float f) if the string can be parsed into a
+      \em float.
+
+      @param  s  String to parse
+      @param  ok Output variable indicating the success of the operation.
+      @return Returns the \em Rational value represented by \em s and sets \em ok
+              to \c true if the conversion was successful or \c false if not.
+    */
+    Rational parseRational(const std::string& s, bool& ok);
+
+    /*!
+      @brief Very simple conversion of a \em float to a \em Rational.
+
+      Test it with the values that you expect and check the implementation
+      to see if this is really what you want!
+     */
+    Rational floatToRationalCast(float f);
+
 // *****************************************************************************
 // template and inline definitions
 
@@ -378,7 +430,7 @@ namespace Exiv2 {
     //! Template used in the COUNTOF macro to determine the size of an array
     template <typename T, int N> char (&sizer(T (&)[N]))[N];
 //! Macro to determine the size of an array
-#define EXV_COUNTOF(a) (sizeof(sizer(a)))
+#define EXV_COUNTOF(a) (sizeof(Exiv2::sizer(a)))
 
     //! Utility function to convert the argument of any type to a string
     template<typename T>
@@ -389,19 +441,42 @@ namespace Exiv2 {
         return os.str();
     }
 
-    //! Utility function to convert a string to a value of type T.
+    /*!
+      @brief Utility function to convert a string to a value of type \c T.
+
+      The string representation of the value must match that recognized by
+      the input operator for \c T for this function to succeed.
+
+      @param  s  String to convert
+      @param  ok Output variable indicating the success of the operation.
+      @return Returns the converted value and sets \em ok to \c true if the 
+              conversion was successful or \c false if not.
+     */
     template<typename T>
     T stringTo(const std::string& s, bool& ok)
     {
         std::istringstream is(s);
         T tmp;
         ok = is >> tmp ? true : false;
+        std::string rest;
+        is >> std::skipws >> rest;
+        if (!rest.empty()) ok = false;
         return tmp;
     }
 
+    /*!
+      @brief Specialization of stringTo(const std::string& s, bool& ok) for \em bool.
+
+      Handles the same string values as the XMP SDK. Converts the string to lowercase
+      and returns \c true if it is "true", "t" or "1", and \c false if it is 
+      "false", "f" or "0".
+     */
+    template<>
+    bool stringTo<bool>(const std::string& s, bool& ok);
+
     /*!
       @brief Return the greatest common denominator of n and m.
-             (implementation from Boost rational.hpp)
+             (Implementation from Boost rational.hpp)
 
       @note We use n and m as temporaries in this function, so there is no
             value in using const IntType& as we would only need to make a copy

src/value.cpp

@@ -568,17 +568,17 @@ namespace Exiv2 {
 
     long XmpTextValue::toLong(long /*n*/) const
     {
-        return stringTo<long>(value_, ok_);
+        return parseLong(value_, ok_);
     }
 
     float XmpTextValue::toFloat(long /*n*/) const
     {
-        return stringTo<float>(value_, ok_);
+        return parseFloat(value_, ok_);
     }
 
     Rational XmpTextValue::toRational(long /*n*/) const
     {
-        return stringTo<Rational>(value_, ok_);
+        return parseRational(value_, ok_);
     }
 
     XmpTextValue* XmpTextValue::clone_() const
@@ -626,17 +626,17 @@ namespace Exiv2 {
 
     long XmpArrayValue::toLong(long n) const
     {
-        return stringTo<long>(value_[n], ok_);
+        return parseLong(value_[n], ok_);
     }
 
     float XmpArrayValue::toFloat(long n) const
     {
-        return stringTo<float>(value_[n], ok_);
+        return parseFloat(value_[n], ok_);
     }
 
     Rational XmpArrayValue::toRational(long n) const
     {
-        return stringTo<Rational>(value_[n], ok_);
+        return parseRational(value_[n], ok_);
     }
 
     XmpArrayValue* XmpArrayValue::clone_() const

src/xmp.hpp

@@ -334,7 +334,7 @@ namespace Exiv2 {
 
     inline Xmpdatum& Xmpdatum::operator=(const bool& value)
     {
-        return operator=(value ? "true" : "false");
+        return operator=(value ? "True" : "False");
     }
 
     template<typename T>

test/Makefile

@@ -59,8 +59,8 @@ SHELL = /bin/sh
 # Add test drivers to this list
 TESTS = addmoddel.sh bugfixes-test.sh crw-test.sh exifdata-test.sh \
 	exiv2-test.sh ifd-test.sh imagetest.sh iotest.sh iptctest.sh \
-	makernote-test.sh modify-test.sh path-test.sh write-test.sh \
+	makernote-test.sh modify-test.sh path-test.sh stringto-test.sh \
-	write2-test.sh xmpparser-test.sh
+        write-test.sh write2-test.sh xmpparser-test.sh
 
 test:
 	@list='$(TESTS)'; for p in $$list; do \

test/data/stringto-test.out

@@ -0,0 +1,24 @@
+string      long        float       Rational    
+True        1           1           1/1
+False       0           0           0/1
+t           1           1           1/1
+f           0           0           0/1
+-1          -1          -1          -1/1
+0           0           0           0/1
+1           1           1           1/1
+0.0         0           0           0/1
+0.1         0           0.1         1/10
+0.01        0           0.01        1/100
+0.001       0           0.001       1/1000
+-1.49999    -1          -1.49999    -149999/100000
+-1.5        -1          -1.5        -3/2
+1.49999     1           1.49999     149999/100000
+1.5         1           1.5         3/2
+0/1         0           0           0/1
+1/1         1           1           1/1
+1/3         0           0.333333    1/3
+-1/3        0           -0.333333   -1/3
+4/3         1           1.33333     4/3
+-4/3        -1          -1.33333    -4/3
+0/0         nok         nok         0/0
+text        nok         nok         nok

test/data/xmpparser-test.out

@@ -287,7 +287,7 @@ Xmp.dc.two                                   XmpText     6  3.1415
 Xmp.dc.three                                 XmpText     3  5/7
 Xmp.dc.four                                  XmpText     3  255
 Xmp.dc.five                                  XmpText     3  256
-Xmp.dc.six                                   XmpText     5  false
+Xmp.dc.six                                   XmpText     5  False
 Xmp.dc.seven                                 XmpText     5  Seven
 Xmp.dc.format                                XmpText    10  image/jpeg
 Xmp.dc.creator                               XmpSeq      3  1) The first creator, 2) The second creator, 3) And another one
@@ -322,7 +322,7 @@ Xmp.xmpBJ.JobRef[2]/stJob:role               XmpText     8  Best man
    dc:three="5/7"
    dc:four="255"
    dc:five="256"
-   dc:six="false"
+   dc:six="False"
    dc:seven="Seven"
    dc:format="image/jpeg"
    ns:myProperty="myValue">

test/stringto-test.sh

@@ -0,0 +1,24 @@
+#! /bin/sh
+# Test driver for tests of stringToLong/Float/Rational
+results="./tmp/stringto-test.out"
+good="./data/stringto-test.out"
+diffargs="--strip-trailing-cr"
+tmpfile=tmp/ttt
+touch $tmpfile
+diff -q $diffargs $tmpfile $tmpfile 2>/dev/null
+if [ $? -ne 0 ] ; then
+    diffargs=""
+fi
+(
+binpath="$VALGRIND ../../samples"
+cd ./tmp
+$binpath/stringto-test
+) > $results
+
+diff -q $diffargs $results $good
+rc=$?
+if [ $rc -eq 0 ] ; then
+    echo "All testcases passed."
+else
+    diff $diffargs $results $good
+fi