Replaced the complex implementation of valueToString(double).
The previous one was confusing and prone to buffer overflows, and didn't
work correctly with 16-decimal-digit numbers. The new one simply uses
snprintf with a standard format string.
The major change is that we don't always print a decimal point now.
Fortunately, JSON doesn't distinguish between integers and reals.
diff --git a/src/lib_json/json_writer.cpp b/src/lib_json/json_writer.cpp
index 68c73e7..dfbaa52 100644
--- a/src/lib_json/json_writer.cpp
+++ b/src/lib_json/json_writer.cpp
@@ -73,40 +73,19 @@
std::string valueToString( double value )
{
+ // Allocate a buffer that is more than large enough to store the 16 digits of
+ // precision requested below.
char buffer[32];
+
+ // Print into the buffer. We need not request the alternative representation
+ // that always has a decimal point because JSON doesn't distingish the
+ // concepts of reals and integers.
#if defined(_MSC_VER) && defined(__STDC_SECURE_LIB__) // Use secure version with visual studio 2005 to avoid warning.
- sprintf_s(buffer, sizeof(buffer), "%#.16g", value);
-#else
- snprintf(buffer, sizeof(buffer), "%#.16g", value);
+ sprintf_s(buffer, sizeof(buffer), "%.16g", value);
+#else
+ snprintf(buffer, sizeof(buffer), "%.16g", value);
#endif
- char* ch = buffer + strlen(buffer) - 1;
- if (*ch != '0') return buffer; // nothing to truncate, so save time
- while(ch > buffer && *ch == '0'){
- --ch;
- }
- char* last_nonzero = ch;
- while(ch >= buffer){
- switch(*ch){
- case '0':
- case '1':
- case '2':
- case '3':
- case '4':
- case '5':
- case '6':
- case '7':
- case '8':
- case '9':
- --ch;
- continue;
- case '.':
- // Truncate zeroes to save bytes in output, but keep one.
- *(last_nonzero+2) = '\0';
- return buffer;
- default:
- return buffer;
- }
- }
+
return buffer;
}
diff --git a/src/test_lib_json/main.cpp b/src/test_lib_json/main.cpp
index b2d5d19..1d89721 100644
--- a/src/test_lib_json/main.cpp
+++ b/src/test_lib_json/main.cpp
@@ -462,7 +462,7 @@
JSONTEST_ASSERT_EQUAL(0.0, val.asDouble());
JSONTEST_ASSERT_EQUAL(0.0, val.asFloat());
JSONTEST_ASSERT_EQUAL(false, val.asBool());
- JSONTEST_ASSERT_STRING_EQUAL("0.0", val.asString());
+ JSONTEST_ASSERT_STRING_EQUAL("0", val.asString());
// Zero (signed constructor arg)
val = Json::Value(0);
@@ -546,7 +546,7 @@
JSONTEST_ASSERT_EQUAL(0.0, val.asDouble());
JSONTEST_ASSERT_EQUAL(0.0, val.asFloat());
JSONTEST_ASSERT_EQUAL(false, val.asBool());
- JSONTEST_ASSERT_STRING_EQUAL("0.0", val.asString());
+ JSONTEST_ASSERT_STRING_EQUAL("0", val.asString());
// 2^20 (signed constructor arg)
val = Json::Value(1 << 20);
@@ -629,7 +629,7 @@
JSONTEST_ASSERT_EQUAL((1 << 20), val.asDouble());
JSONTEST_ASSERT_EQUAL((1 << 20), val.asFloat());
JSONTEST_ASSERT_EQUAL(true, val.asBool());
- JSONTEST_ASSERT_STRING_EQUAL("1048576.0", normalizeFloatingPointStr(val.asString()));
+ JSONTEST_ASSERT_STRING_EQUAL("1048576", normalizeFloatingPointStr(val.asString()));
// -2^20
val = Json::Value(-(1 << 20));
@@ -869,7 +869,7 @@
JSONTEST_ASSERT_EQUAL((Json::Int64(1) << 40), val.asDouble());
JSONTEST_ASSERT_EQUAL((Json::Int64(1) << 40), val.asFloat());
JSONTEST_ASSERT_EQUAL(true, val.asBool());
- JSONTEST_ASSERT_STRING_EQUAL("1099511627776.0", normalizeFloatingPointStr(val.asString()));
+ JSONTEST_ASSERT_STRING_EQUAL("1099511627776", normalizeFloatingPointStr(val.asString()));
// -2^40
val = Json::Value(-(Json::Int64(1) << 40));
@@ -1035,7 +1035,7 @@
JSONTEST_ASSERT_EQUAL(1e19, val.asDouble());
JSONTEST_ASSERT_EQUAL(1e19, val.asFloat());
JSONTEST_ASSERT_EQUAL(true, val.asBool());
- JSONTEST_ASSERT_STRING_EQUAL("1.000000000000000e+19", normalizeFloatingPointStr(val.asString()));
+ JSONTEST_ASSERT_STRING_EQUAL("1e+19", normalizeFloatingPointStr(val.asString()));
// uint64 max
val = Json::Value(Json::UInt64(kuint64max));
@@ -1114,7 +1114,7 @@
JSONTEST_ASSERT_EQUAL(1, val.asUInt());
JSONTEST_ASSERT_EQUAL(1, val.asLargestUInt());
JSONTEST_ASSERT_EQUAL(true, val.asBool());
- JSONTEST_ASSERT_EQUAL("1.50", val.asString());
+ JSONTEST_ASSERT_EQUAL("1.5", val.asString());
// Small negative number
val = Json::Value(-1.5);
@@ -1140,7 +1140,7 @@
JSONTEST_ASSERT_EQUAL(-1, val.asInt());
JSONTEST_ASSERT_EQUAL(-1, val.asLargestInt());
JSONTEST_ASSERT_EQUAL(true, val.asBool());
- JSONTEST_ASSERT_EQUAL("-1.50", val.asString());
+ JSONTEST_ASSERT_EQUAL("-1.5", val.asString());
// A bit over int32 max
val = Json::Value(kint32max + 0.5);
@@ -1169,7 +1169,7 @@
JSONTEST_ASSERT_EQUAL(2147483647U, val.asLargestUInt());
#endif
JSONTEST_ASSERT_EQUAL(true, val.asBool());
- JSONTEST_ASSERT_EQUAL("2147483647.50", normalizeFloatingPointStr(val.asString()));
+ JSONTEST_ASSERT_EQUAL("2147483647.5", normalizeFloatingPointStr(val.asString()));
// A bit under int32 min
val = Json::Value(kint32min - 0.5);
@@ -1196,7 +1196,7 @@
JSONTEST_ASSERT_EQUAL(-Json::Int64(1)<< 31, val.asLargestInt());
#endif
JSONTEST_ASSERT_EQUAL(true, val.asBool());
- JSONTEST_ASSERT_EQUAL("-2147483648.50", normalizeFloatingPointStr(val.asString()));
+ JSONTEST_ASSERT_EQUAL("-2147483648.5", normalizeFloatingPointStr(val.asString()));
// A bit over uint32 max
val = Json::Value(kuint32max + 0.5);
@@ -1224,15 +1224,15 @@
JSONTEST_ASSERT_EQUAL((Json::UInt64(1) << 32)-Json::UInt64(1), val.asLargestUInt());
#endif
JSONTEST_ASSERT_EQUAL(true, val.asBool());
- JSONTEST_ASSERT_EQUAL("4294967295.50", normalizeFloatingPointStr(val.asString()));
+ JSONTEST_ASSERT_EQUAL("4294967295.5", normalizeFloatingPointStr(val.asString()));
val = Json::Value(1.2345678901234);
- JSONTEST_ASSERT_STRING_EQUAL( "1.23456789012340", normalizeFloatingPointStr(val.asString()));
+ JSONTEST_ASSERT_STRING_EQUAL( "1.2345678901234", normalizeFloatingPointStr(val.asString()));
// A 16-digit floating point number.
val = Json::Value(2199023255552000.0f);
JSONTEST_ASSERT_EQUAL(float(2199023255552000), val.asFloat());
- JSONTEST_ASSERT_STRING_EQUAL("2199023255552000.", normalizeFloatingPointStr(val.asString()));
+ JSONTEST_ASSERT_STRING_EQUAL("2199023255552000", normalizeFloatingPointStr(val.asString()));
// A very large floating point number.
val = Json::Value(3.402823466385289e38);
@@ -1242,7 +1242,7 @@
// An even larger floating point number.
val = Json::Value(1.2345678e300);
JSONTEST_ASSERT_EQUAL(double(1.2345678e300), val.asDouble());
- JSONTEST_ASSERT_STRING_EQUAL("1.234567800000000e+300", normalizeFloatingPointStr(val.asString()));
+ JSONTEST_ASSERT_STRING_EQUAL("1.2345678e+300", normalizeFloatingPointStr(val.asString()));
}