#ifndef __STUB_H__
#define __STUB_H__

#ifdef _WIN32
//windows
#include <windows.h>
#include <processthreadsapi.h>
#else
//linux
#include <unistd.h>
#include <bits/stdint-uintn.h>
#include <sys/mman.h>
#endif
//c
#include <cstddef>
#include <cstring>
//c++
#include <map>


#define ADDR(CLASS_NAME,MEMBER_NAME) (&CLASS_NAME::MEMBER_NAME)

/**********************************************************
                  replace function
**********************************************************/
#ifdef _WIN32
#define CACHEFLUSH(addr, size) FlushInstructionCache(GetCurrentProcess(), addr, size)
#else
#define CACHEFLUSH(addr, size) __builtin___clear_cache(addr, addr + size)
#endif

#if defined(__aarch64__) || defined(_M_ARM64)
    #define CODESIZE 16U
    #define CODESIZE_MIN 16U
    #define CODESIZE_MAX CODESIZE
    // ldr x9, +8
    // br x9
    // addr
    #define REPLACE_FAR(t, fn, fn_stub)\
        ((uint32_t*)fn)[0] = 0x58000040 | 9;\
        ((uint32_t*)fn)[1] = 0xd61f0120 | (9 << 5);\
        *(long long *)(fn + 8) = (long long )fn_stub;\
        CACHEFLUSH((char *)fn, CODESIZE);
    #define REPLACE_NEAR(t, fn, fn_stub) REPLACE_FAR(t, fn, fn_stub)
#elif defined(__arm__) || defined(_M_ARM)
    #define CODESIZE 8U
    #define CODESIZE_MIN 8U
    #define CODESIZE_MAX CODESIZE
    // ldr pc, [pc, #-4]
    #define REPLACE_FAR(t, fn, fn_stub)\
        ((uint32_t*)fn)[0] = 0xe51ff004;\
        ((uint32_t*)fn)[1] = (uint32_t)fn_stub;\
        CACHEFLUSH((char *)fn, CODESIZE);
    #define REPLACE_NEAR(t, fn, fn_stub) REPLACE_FAR(t, fn, fn_stub)
#elif defined(__mips64)
    #define CACHEFLUSH(addr, size) __builtin___clear_cache(addr, addr + size)
    #define CODESIZE 80U
    #define CODESIZE_MIN 80U
    #define CODESIZE_MAX CODESIZE
    //mips没有PC指针，所以需要手动入栈出栈
    //120000ce0:  67bdffe0    daddiu  sp, sp, -32  //入栈
    //120000ce4:  ffbf0018    sd  ra, 24(sp)
    //120000ce8:  ffbe0010    sd  s8, 16(sp)
    //120000cec:  ffbc0008    sd  gp, 8(sp)
    //120000cf0:  03a0f025    move    s8, sp

    //120000d2c:  03c0e825    move    sp, s8  //出栈
    //120000d30:  dfbf0018    ld  ra, 24(sp)
    //120000d34:  dfbe0010    ld  s8, 16(sp)
    //120000d38:  dfbc0008    ld  gp, 8(sp)
    //120000d3c:  67bd0020    daddiu  sp, sp, 32
    //120000d40:  03e00008    jr  ra

    #define REPLACE_FAR(t, fn, fn_stub)\
        ((uint32_t *)fn)[0] = 0x67bdffe0;\
        ((uint32_t *)fn)[1] = 0xffbf0018;\
        ((uint32_t *)fn)[2] = 0xffbe0010;\
        ((uint32_t *)fn)[3] = 0xffbc0008;\
        ((uint32_t *)fn)[4] = 0x03a0f025;\
        *(uint16_t *)(fn + 20) = (long long)fn_stub >> 32;\
        *(fn + 22) = 0x19;\
        *(fn + 23) = 0x24;\
        ((uint32_t *)fn)[6] = 0x0019cc38;\
        *(uint16_t *)(fn + 28) = (long long)fn_stub >> 16;\
        *(fn + 30) = 0x39;\
        *(fn + 31) = 0x37;\
        ((uint32_t *)fn)[8] = 0x0019cc38;\
        *(uint16_t *)(fn + 36) = (long long)fn_stub;\
        *(fn + 38) = 0x39;\
        *(fn + 39) = 0x37;\
        ((uint32_t *)fn)[10] = 0x0320f809;\
        ((uint32_t *)fn)[11] = 0x00000000;\
        ((uint32_t *)fn)[12] = 0x00000000;\
        ((uint32_t *)fn)[13] = 0x03c0e825;\
        ((uint32_t *)fn)[14] = 0xdfbf0018;\
        ((uint32_t *)fn)[15] = 0xdfbe0010;\
        ((uint32_t *)fn)[16] = 0xdfbc0008;\
        ((uint32_t *)fn)[17] = 0x67bd0020;\
        ((uint32_t *)fn)[18] = 0x03e00008;\
        ((uint32_t *)fn)[19] = 0x00000000;\
        CACHEFLUSH((char *)fn, CODESIZE);
    #define REPLACE_NEAR(t, fn, fn_stub) REPLACE_FAR(t, fn, fn_stub)
#elif defined(__thumb__) || defined(_M_THUMB)
    #error "Thumb is not supported"
#else //__i386__ _x86_64__
    #define CODESIZE 13U
    #define CODESIZE_MIN 5U
    #define CODESIZE_MAX CODESIZE
    //13 byte(jmp m16:64)
    //movabs $0x102030405060708,%r11
    //jmpq   *%r11
    static void REPLACE_FAR(void *t, char *fn, char *fn_stub)
    {
        *fn = 0x49;
        *(fn + 1) = 0xbb;
        *(long long *)(fn + 2) = (long long)fn_stub;
        *(fn + 10) = 0x41;
        *(fn + 11) = 0xff;
        *(fn + 12) = 0xe3;
        CACHEFLUSH((char *)fn, CODESIZE);
    }
    //5 byte(jmp rel32)
    #define REPLACE_NEAR(t, fn, fn_stub)\
        *fn = 0xE9;\
        *(int *)(fn + 1) = (int)(fn_stub - fn - CODESIZE_MIN);\
        CACHEFLUSH((char *)fn, CODESIZE);
#endif

struct func_stub
{
    char *fn;
    unsigned char code_buf[CODESIZE];
    bool far_jmp;
};

class Stub
{
public:
    Stub()
    {
#ifdef _WIN32
        SYSTEM_INFO sys_info;
        GetSystemInfo(&sys_info);
        m_pagesize = sys_info.dwPageSize;
#else
        m_pagesize = sysconf(_SC_PAGE_SIZE);
#endif

        if (m_pagesize < 0)
        {
            m_pagesize = 4096;
        }
    }
    ~Stub()
    {
        clear();
    }

    virtual void clear()
    {
        std::map<char*,func_stub*>::iterator iter;
        struct func_stub *pstub;
        for(iter=m_result.begin(); iter != m_result.end(); iter++)
        {
            pstub = iter->second;
#ifdef _WIN32
            DWORD lpflOldProtect;
            if(0 != VirtualProtect(pageof(pstub->fn), m_pagesize * 2, PAGE_EXECUTE_READWRITE, &lpflOldProtect))
#else
            if (0 == mprotect(pageof(pstub->fn), m_pagesize * 2, PROT_READ | PROT_WRITE | PROT_EXEC))
#endif
            {

                if(pstub->far_jmp)
                {
                    std::memcpy(pstub->fn, pstub->code_buf, CODESIZE_MAX);
                }
                else
                {
                    std::memcpy(pstub->fn, pstub->code_buf, CODESIZE_MIN);
                }

#ifdef _WIN32
                VirtualProtect(pageof(pstub->fn), m_pagesize * 2, PAGE_EXECUTE_READ, &lpflOldProtect);
#else
                CACHEFLUSH(pstub->fn,CODESIZE);
                mprotect(pageof(pstub->fn), m_pagesize * 2, PROT_READ | PROT_EXEC);
#endif
            }

            iter->second  = NULL;
            delete pstub;
        }

        m_result.clear();
        return;
    }
    template<typename T,typename S>
    bool set(T addr, S addr_stub)
    {
        char * fn;
        char * fn_stub;
        fn = addrof(addr);
        fn_stub = addrof(addr_stub);
        struct func_stub *pstub;
        std::map<char*,func_stub*>::iterator iter = m_result.find(fn);

        if (iter == m_result.end())
        {
            pstub = new func_stub;
            //start
            pstub->fn = fn;

            if(distanceof(fn, fn_stub))
            {
                pstub->far_jmp = true;
                std::memcpy(pstub->code_buf, fn, CODESIZE_MAX);
            }
            else
            {
                pstub->far_jmp = false;
                std::memcpy(pstub->code_buf, fn, CODESIZE_MIN);
            }
        }
        else {
            pstub = iter->second;
            pstub->far_jmp = distanceof(fn, fn_stub);
        }



#ifdef _WIN32
        DWORD lpflOldProtect;
        if(0 == VirtualProtect(pageof(pstub->fn), m_pagesize * 2, PAGE_EXECUTE_READWRITE, &lpflOldProtect))
#else
        if (-1 == mprotect(pageof(pstub->fn), static_cast<size_t>(m_pagesize * 2), PROT_READ | PROT_WRITE | PROT_EXEC))
#endif
        {
            //throw("stub set memory protect to w+r+x faild");
            return  false;
        }

        if(pstub->far_jmp)
        {
            REPLACE_FAR(this, fn, fn_stub);
        }
        else
        {
            REPLACE_NEAR(this, fn, fn_stub);
        }


#ifdef _WIN32
        if(0 == VirtualProtect(pageof(pstub->fn), m_pagesize * 2, PAGE_EXECUTE_READ, &lpflOldProtect))
#else
        if (-1 == mprotect(pageof(pstub->fn), m_pagesize * 2, PROT_READ | PROT_EXEC))
#endif
        {
            //throw("stub set memory protect to r+x failed");
            return false;
        }
        m_result.insert(std::pair<char*,func_stub*>(fn,pstub));
        return true;
    }

    template<typename T>
    bool reset(T addr)
    {
        char * fn;
        fn = addrof(addr);

        std::map<char*,func_stub*>::iterator iter = m_result.find(fn);

        if (iter == m_result.end())
        {
            return true;
        }
        struct func_stub *pstub;
        pstub = iter->second;

#ifdef _WIN32
        DWORD lpflOldProtect;
        if(0 == VirtualProtect(pageof(pstub->fn), m_pagesize * 2, PAGE_EXECUTE_READWRITE, &lpflOldProtect))
#else
        if (-1 == mprotect(pageof(pstub->fn), m_pagesize * 2, PROT_READ | PROT_WRITE | PROT_EXEC))
#endif
        {
            //throw("stub reset memory protect to w+r+x faild");
            return false;
        }

        if(pstub->far_jmp)
        {
            std::memcpy(pstub->fn, pstub->code_buf, CODESIZE_MAX);
        }
        else
        {
            std::memcpy(pstub->fn, pstub->code_buf, CODESIZE_MIN);
        }

#ifdef _WIN32
        if(0 == VirtualProtect(pageof(pstub->fn), m_pagesize * 2, PAGE_EXECUTE_READ, &lpflOldProtect))
#else
        CACHEFLUSH(pstub->fn,CODESIZE);
        if (-1 == mprotect(pageof(pstub->fn), m_pagesize * 2, PROT_READ | PROT_EXEC))
#endif
        {
            //throw("stub reset memory protect to r+x failed");
            return false;
        }

        m_result.erase(iter);
        delete pstub;

        return true;
    }
protected:
    char *pageof(char* addr)
    {
#ifdef _WIN32
        return (char *)((unsigned long long)addr & ~(m_pagesize - 1));
#else
        return (char *)((unsigned long)addr & ~(m_pagesize - 1));
#endif
    }

    template<typename T>
    char* addrof(T addr)
    {
        union
        {
          T _s;
          char* _d;
        }ut;
        ut._s = addr;
        return ut._d;
    }

    bool distanceof(char* addr, char* addr_stub)
    {
        std::ptrdiff_t diff = addr_stub >= addr ? addr_stub - addr : addr - addr_stub;
        if((sizeof(addr) > 4) && (((diff >> 31) - 1) > 0))
        {
            return true;
        }
        return false;
    }

protected:
#ifdef _WIN32
    //LLP64
    long long m_pagesize;
#else
    //LP64
    long m_pagesize;
#endif
    std::map<char*, func_stub*> m_result;
};

#endif
