// 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/itoa.h"

#ifdef __GNUC__
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(type-limits)
#endif

using namespace rapidjson::internal;

template <typename T>
struct Traits {
};

template <>
struct Traits<uint32_t> {
    enum { kBufferSize = 11 };
    enum { kMaxDigit = 10 };
    static uint32_t Negate(uint32_t x) { return x; }
};

template <>
struct Traits<int32_t> {
    enum { kBufferSize = 12 };
    enum { kMaxDigit = 10 };
    static int32_t Negate(int32_t x) { return -x; }
};

template <>
struct Traits<uint64_t> {
    enum { kBufferSize = 21 };
    enum { kMaxDigit = 20 };
    static uint64_t Negate(uint64_t x) { return x; }
};

template <>
struct Traits<int64_t> {
    enum { kBufferSize = 22 };
    enum { kMaxDigit = 20 };
    static int64_t Negate(int64_t x) { return -x; }
};

template <typename T>
static void VerifyValue(T value, void(*f)(T, char*), char* (*g)(T, char*)) {
    char buffer1[Traits<T>::kBufferSize];
    char buffer2[Traits<T>::kBufferSize];

    f(value, buffer1);
    *g(value, buffer2) = '\0';
    

    EXPECT_STREQ(buffer1, buffer2);
}

template <typename T>
static void Verify(void(*f)(T, char*), char* (*g)(T, char*)) {
    // Boundary cases
    VerifyValue<T>(0, f, g);
    VerifyValue<T>((std::numeric_limits<T>::min)(), f, g);
    VerifyValue<T>((std::numeric_limits<T>::max)(), f, g);

    // 2^n - 1, 2^n, 10^n - 1, 10^n until overflow
    for (int power = 2; power <= 10; power += 8) {
        T i = 1, last;
        do {
            VerifyValue<T>(i - 1, f, g);
            VerifyValue<T>(i, f, g);
            if (std::numeric_limits<T>::min() < 0) {
                VerifyValue<T>(Traits<T>::Negate(i), f, g);
                VerifyValue<T>(Traits<T>::Negate(i + 1), f, g);
            }
            last = i;
            if (i > static_cast<T>(std::numeric_limits<T>::max() / static_cast<T>(power)))
                break;
            i *= static_cast<T>(power);
        } while (last < i);
    }
}

static void u32toa_naive(uint32_t value, char* buffer) {
    char temp[10];
    char *p = temp;
    do {
        *p++ = static_cast<char>(char(value % 10) + '0');
        value /= 10;
    } while (value > 0);

    do {
        *buffer++ = *--p;
    } while (p != temp);

    *buffer = '\0';
}

static void i32toa_naive(int32_t value, char* buffer) {
    uint32_t u = static_cast<uint32_t>(value);
    if (value < 0) {
        *buffer++ = '-';
        u = ~u + 1;
    }
    u32toa_naive(u, buffer);
}

static void u64toa_naive(uint64_t value, char* buffer) {
    char temp[20];
    char *p = temp;
    do {
        *p++ = static_cast<char>(char(value % 10) + '0');
        value /= 10;
    } while (value > 0);

    do {
        *buffer++ = *--p;
    } while (p != temp);

    *buffer = '\0';
}

static void i64toa_naive(int64_t value, char* buffer) {
    uint64_t u = static_cast<uint64_t>(value);
    if (value < 0) {
        *buffer++ = '-';
        u = ~u + 1;
    }
    u64toa_naive(u, buffer);
}

TEST(itoa, u32toa) {
    Verify(u32toa_naive, u32toa);
}

TEST(itoa, i32toa) {
    Verify(i32toa_naive, i32toa);
}

TEST(itoa, u64toa) {
    Verify(u64toa_naive, u64toa);
}

TEST(itoa, i64toa) {
    Verify(i64toa_naive, i64toa);
}

#ifdef __GNUC__
RAPIDJSON_DIAG_POP
#endif