From 1d856b2761ced15984360e60ad3b372b67d6e5cd Mon Sep 17 00:00:00 2001 From: Milo Yip Date: Thu, 11 Feb 2016 16:08:17 +0800 Subject: [PATCH] Add Writer::SetMaxDecimalPlaces() --- include/rapidjson/internal/dtoa.h | 36 ++++++++++-- include/rapidjson/writer.h | 40 ++++++++++++-- test/unittest/CMakeLists.txt | 1 + test/unittest/dtoatest.cpp | 91 +++++++++++++++++++++++++++++++ 4 files changed, 159 insertions(+), 9 deletions(-) create mode 100644 test/unittest/dtoatest.cpp diff --git a/include/rapidjson/internal/dtoa.h b/include/rapidjson/internal/dtoa.h index d04ae21..940d61a 100644 --- a/include/rapidjson/internal/dtoa.h +++ b/include/rapidjson/internal/dtoa.h @@ -145,7 +145,7 @@ inline char* WriteExponent(int K, char* buffer) { return buffer; } -inline char* Prettify(char* buffer, int length, int k) { +inline char* Prettify(char* buffer, int length, int k, int maxDecimalPlaces) { const int kk = length + k; // 10^(kk-1) <= v < 10^kk if (length <= kk && kk <= 21) { @@ -160,7 +160,16 @@ inline char* Prettify(char* buffer, int length, int k) { // 1234e-2 -> 12.34 std::memmove(&buffer[kk + 1], &buffer[kk], static_cast(length - kk)); buffer[kk] = '.'; - return &buffer[length + 1]; + if (length > kk + maxDecimalPlaces) { + // When maxDecimalPlaces = 2, 1.2345 -> 1.23, 1.102 -> 1.1 + // Remove extra trailing zeros (at least one) after truncation. + for (int i = kk + maxDecimalPlaces; i > kk + 1; i--) + if (buffer[i] != '0') + return &buffer[i + 1]; + return &buffer[kk + 2]; // Reserve one zero + } + else + return &buffer[length + 1]; } else if (-6 < kk && kk <= 0) { // 1234e-6 -> 0.001234 @@ -170,7 +179,23 @@ inline char* Prettify(char* buffer, int length, int k) { buffer[1] = '.'; for (int i = 2; i < offset; i++) buffer[i] = '0'; - return &buffer[length + offset]; + if (length + offset > maxDecimalPlaces) { + // When maxDecimalPlaces = 2, 0.123 -> 0.12, 0.102 -> 0.1 + // Remove extra trailing zeros (at least one) after truncation. + for (int i = maxDecimalPlaces + 1; i > 2; i--) + if (buffer[i] != '0') + return &buffer[i + 1]; + return &buffer[3]; // Reserve one zero + } + else + return &buffer[length + offset]; + } + else if (kk < -maxDecimalPlaces) { + // Truncate to zero + buffer[0] = '0'; + buffer[1] = '.'; + buffer[2] = '0'; + return &buffer[3]; } else if (length == 1) { // 1e30 @@ -186,7 +211,8 @@ inline char* Prettify(char* buffer, int length, int k) { } } -inline char* dtoa(double value, char* buffer) { +inline char* dtoa(double value, char* buffer, int maxDecimalPlaces = 324) { + RAPIDJSON_ASSERT(maxDecimalPlaces >= 1); Double d(value); if (d.IsZero()) { if (d.Sign()) @@ -203,7 +229,7 @@ inline char* dtoa(double value, char* buffer) { } int length, K; Grisu2(value, buffer, &length, &K); - return Prettify(buffer, length, K); + return Prettify(buffer, length, K, maxDecimalPlaces); } } diff --git a/include/rapidjson/writer.h b/include/rapidjson/writer.h index 4f42b9e..fbf6715 100644 --- a/include/rapidjson/writer.h +++ b/include/rapidjson/writer.h @@ -56,6 +56,8 @@ class Writer { public: typedef typename SourceEncoding::Ch Ch; + static const int kDefaultMaxDecimalPlaces = 324; + //! Constructor /*! \param os Output stream. \param stackAllocator User supplied allocator. If it is null, it will create a private one. @@ -63,11 +65,11 @@ public: */ explicit Writer(OutputStream& os, StackAllocator* stackAllocator = 0, size_t levelDepth = kDefaultLevelDepth) : - os_(&os), level_stack_(stackAllocator, levelDepth * sizeof(Level)), hasRoot_(false) {} + os_(&os), level_stack_(stackAllocator, levelDepth * sizeof(Level)), maxDecimalPlaces_(kDefaultMaxDecimalPlaces), hasRoot_(false) {} explicit Writer(StackAllocator* allocator = 0, size_t levelDepth = kDefaultLevelDepth) : - os_(0), level_stack_(allocator, levelDepth * sizeof(Level)), hasRoot_(false) {} + os_(0), level_stack_(allocator, levelDepth * sizeof(Level)), maxDecimalPlaces_(kDefaultMaxDecimalPlaces), hasRoot_(false) {} //! Reset the writer with a new stream. /*! @@ -101,6 +103,35 @@ public: return hasRoot_ && level_stack_.Empty(); } + int GetMaxDecimalPlaces() const { + return maxDecimalPlaces_; + } + + //! Sets the maximum number of decimal places for double output. + /*! + This setting truncates the output with specified number of decimal places. + + For example, + + \code + writer.SetMaxDecimalPlaces(3); + writer.StartArray(); + writer.Double(0.12345); // "0.123" + writer.Double(0.0001); // "0.0" + writer.Double(1.234567890123456e30); // "1.234567890123456e30" (do not truncate significand for positive exponent) + writer.Double(1.23e-4); // "0.0" (do truncate significand for negative exponent) + writer.EndArray(); + \endcode + + The default setting does not truncate any decimal places. You can restore to this setting by calling + \code + writer.SetMaxDecimalPlaces(Writer::kDefaultMaxDecimalPlaces); + \endcode + */ + void SetMaxDecimalPlaces(int maxDecimalPlaces) { + maxDecimalPlaces_ = maxDecimalPlaces; + } + /*!@name Implementation of Handler \see Handler */ @@ -246,7 +277,7 @@ protected: return false; char buffer[25]; - char* end = internal::dtoa(d, buffer); + char* end = internal::dtoa(d, buffer, maxDecimalPlaces_); PutReserve(*os_, static_cast(end - buffer)); for (char* p = buffer; p != end; ++p) PutUnsafe(*os_, static_cast(*p)); @@ -353,6 +384,7 @@ protected: OutputStream* os_; internal::Stack level_stack_; + int maxDecimalPlaces_; bool hasRoot_; private: @@ -401,7 +433,7 @@ inline bool Writer::WriteDouble(double d) { return false; char *buffer = os_->Push(25); - char* end = internal::dtoa(d, buffer); + char* end = internal::dtoa(d, buffer, maxDecimalPlaces_); os_->Pop(static_cast(25 - (end - buffer))); return true; } diff --git a/test/unittest/CMakeLists.txt b/test/unittest/CMakeLists.txt index 9c13816..0ae1662 100644 --- a/test/unittest/CMakeLists.txt +++ b/test/unittest/CMakeLists.txt @@ -2,6 +2,7 @@ set(UNITTEST_SOURCES allocatorstest.cpp bigintegertest.cpp documenttest.cpp + dtoatest.cpp encodedstreamtest.cpp encodingstest.cpp fwdtest.cpp diff --git a/test/unittest/dtoatest.cpp b/test/unittest/dtoatest.cpp new file mode 100644 index 0000000..da02095 --- /dev/null +++ b/test/unittest/dtoatest.cpp @@ -0,0 +1,91 @@ +// Tencent is pleased to support the open source community by making RapidJSON available. +// +// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved. +// +// Licensed under the MIT License (the "License"); you may not use this file except +// in compliance with the License. You may obtain a copy of the License at +// +// http://opensource.org/licenses/MIT +// +// Unless required by applicable law or agreed to in writing, software distributed +// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR +// CONDITIONS OF ANY KIND, either express or implied. See the License for the +// specific language governing permissions and limitations under the License. + +#include "unittest.h" +#include "rapidjson/internal/dtoa.h" + +#ifdef __GNUC__ +RAPIDJSON_DIAG_PUSH +RAPIDJSON_DIAG_OFF(type-limits) +#endif + +using namespace rapidjson::internal; + +TEST(dtoa, normal) { + char buffer[30]; + +#define TEST_DTOA(d, a)\ + *dtoa(d, buffer) = '\0';\ + EXPECT_STREQ(a, buffer) + + TEST_DTOA(0.0, "0.0"); + TEST_DTOA(-0.0, "-0.0"); + TEST_DTOA(1.0, "1.0"); + TEST_DTOA(-1.0, "-1.0"); + TEST_DTOA(1.2345, "1.2345"); + TEST_DTOA(1.2345678, "1.2345678"); + TEST_DTOA(0.123456789012, "0.123456789012"); + TEST_DTOA(1234567.8, "1234567.8"); + TEST_DTOA(0.000001, "0.000001"); + TEST_DTOA(0.0000001, "1e-7"); + TEST_DTOA(1e30, "1e30"); + TEST_DTOA(1.234567890123456e30, "1.234567890123456e30"); + TEST_DTOA(5e-324, "5e-324"); // Min subnormal positive double + TEST_DTOA(2.225073858507201e-308, "2.225073858507201e-308"); // Max subnormal positive double + TEST_DTOA(2.2250738585072014e-308, "2.2250738585072014e-308"); // Min normal positive double + TEST_DTOA(1.7976931348623157e308, "1.7976931348623157e308"); // Max double + +#undef TEST_DTOA +} + +TEST(dtoa, maxDecimalPlaces) { + char buffer[30]; + +#define TEST_DTOA(m, d, a)\ + *dtoa(d, buffer, m) = '\0';\ + EXPECT_STREQ(a, buffer) + + TEST_DTOA(3, 0.0, "0.0"); + TEST_DTOA(1, 0.0, "0.0"); + TEST_DTOA(3, -0.0, "-0.0"); + TEST_DTOA(3, 1.0, "1.0"); + TEST_DTOA(3, -1.0, "-1.0"); + TEST_DTOA(3, 1.2345, "1.234"); + TEST_DTOA(2, 1.2345, "1.23"); + TEST_DTOA(1, 1.2345, "1.2"); + TEST_DTOA(3, 1.2345678, "1.234"); + TEST_DTOA(3, 1.0001, "1.0"); + TEST_DTOA(2, 1.0001, "1.0"); + TEST_DTOA(1, 1.0001, "1.0"); + TEST_DTOA(3, 0.123456789012, "0.123"); + TEST_DTOA(2, 0.123456789012, "0.12"); + TEST_DTOA(1, 0.123456789012, "0.1"); + TEST_DTOA(4, 0.0001, "0.0001"); + TEST_DTOA(3, 0.0001, "0.0"); + TEST_DTOA(2, 0.0001, "0.0"); + TEST_DTOA(1, 0.0001, "0.0"); + TEST_DTOA(3, 1234567.8, "1234567.8"); + TEST_DTOA(3, 1e30, "1e30"); + TEST_DTOA(3, 5e-324, "0.0"); // Min subnormal positive double + TEST_DTOA(3, 2.225073858507201e-308, "0.0"); // Max subnormal positive double + TEST_DTOA(3, 2.2250738585072014e-308, "0.0"); // Min normal positive double + TEST_DTOA(3, 1.7976931348623157e308, "1.7976931348623157e308"); // Max double + +#undef TEST_DTOA +} + + +#ifdef __GNUC__ +RAPIDJSON_DIAG_POP +#endif