/* vim: set ts=4 sw=4 tw=99 et:

 *

 * Copyright (C) 2012 David Anderson

 *

 * This file is part of SourcePawn.

 *

 * SourcePawn is free software: you can redistribute it and/or modify it under

 * the terms of the GNU General Public License as published by the Free

 * Software Foundation, either version 3 of the License, or (at your option)

 * any later version.

 * 

 * SourcePawn is distributed in the hope that it will be useful, but WITHOUT ANY

 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License along with

 * SourcePawn. If not, see http://www.gnu.org/licenses/.

 */

#define WIN32_LEAN_AND_MEAN

#include <Windows.h>

#include <direct.h>

#include <sys/stat.h>

#include "Platform.h"

using namespace ke;

static inline DWORD

ToProtBits(OS::Protection prot)

{

    switch (prot) {

      case OS::Prot_ReadWrite:

        return PAGE_READWRITE;

      case OS::Prot_ReadWriteExecute:

        return PAGE_EXECUTE_READWRITE;

      default:

        assert(prot == OS::Prot_ReadExecute);

        return PAGE_EXECUTE_READ;

    }

}

Address

OS::MapMemory(size_t amount, MapMode mode, Protection prot_)

{

    DWORD prot = ToProtBits(prot_);

    DWORD type = MEM_RESERVE;

    if (mode == Map_Commit)

        type |= MEM_COMMIT;

    return (Address)VirtualAlloc(NULL, amount, type, prot);

}

bool

OS::CommitMemory(Address address, size_t amount, Protection prot_)

{

    DWORD prot = ToProtBits(prot_);

    return !!VirtualAlloc(address, amount, MEM_COMMIT, prot);

}

void

OS::UnmapMemory(Address address, size_t size)

{

    VirtualFree(address, 0, MEM_RELEASE);

}

static Address

MapMemoryAt(Address address, size_t amount, OS::MapMode mode, OS::Protection prot_)

{

    DWORD bits = ToProtBits(prot_);

    DWORD flags = MEM_RESERVE;

    if (mode == OS::Map_Commit)

        flags |= MEM_COMMIT;

    return (Address)VirtualAlloc((LPVOID)address, amount, flags, bits);

}

OS::AlignableMapping

OS::MapAlignedMemory(size_t amount, size_t alignment, MapMode mode)

{

    Address addr = MapMemory(amount, mode, OS::Prot_ReadWrite);

    if (!addr)

        return AlignableMapping(NULL, alignment, 0);

    if (!IsAligned(addr, alignment)) {

        UnmapMemory(addr, amount);

        // Try to grab the next available aligned address.

        addr = AlignedBase(addr, alignment);

        addr = MapMemoryAt(addr + alignment, amount, mode, OS::Prot_ReadWrite);

        while (!addr) {

            // Try to over-allocate to get the right region. This can race

            // with other threads; we expect this to be rare. If this turns

            // out to be a problem, the API is set up such that we can just

            // return two pointers: the base, and the aligned address into

            // the over-allocated region.

            addr = MapMemory(amount + alignment, mode, OS::Prot_ReadWrite);

            if (!addr)

                return AlignableMapping(NULL, alignment, 0);

            UnmapMemory(addr, amount + alignment);

            addr = AlignedBase(addr, alignment);

            addr = MapMemoryAt(addr + alignment, amount, mode, OS::Prot_ReadWrite);

        }

    }

    return AlignableMapping(addr, alignment, amount);

}

void

OS::UnmapAlignedMemory(Address address, size_t size)

{

    OS::UnmapMemory(address, size);

}

bool

OS::GetAbsolutePath(const char *path, AutoFree<char> &chars)

{

    char try1[MAX_PATH];

    DWORD result = GetFullPathName(path, sizeof(try1), try1, NULL);

    if (result <= 0)

        return false;

    // +1 because if result < MAX_PATH, it doesn't include the null terminator.

    chars = (char *)calloc(result + 1, sizeof(char));

    if (!*chars)

        return false;

    if (result <= MAX_PATH) {

        strcpy(*chars, try1);

        return true;

    }

    // We should get the same output on the next try.

    return GetFullPathName(path, result, *chars, NULL) == result - 1;

}

bool

OS::SplitPath(const char *path, AutoFree<char> &base, AutoFree<char> &name)

{

    size_t len = strlen(path);

    // Skip trailing slashes.

    while (len > 1 && (path[len - 1] == '/' || path[len - 1] == '\\'))

        len--;

    for (size_t i = len - 1; i < len; i--) {

        if (path[i] == '\\' || path[i] == '/') {

            name = (char *)calloc(len - i, sizeof(char));

            if (!*name)

                return false;

            strcpy(*name, &path[i + 1]);

            base = (char *)calloc(i + 1, sizeof(char));

            if (!*base)

                return false;

            memcpy(*base, path, i);

            (*base)[i] = '\0';

            return true;

        }

    }

    // The path should have been absolute, which contains at least one separator.

    return false;

}

const char *

OS::PathSeparator()

{

    return "\\";

}

OS::PathType

OS::InspectPath(const char *path)

{

    struct _stat s;

    int result = _stat(path, &s);

    if (result != 0)

        return OS::Path_Invalid;

    if (s.st_mode & _S_IFDIR)

        return OS::Path_Folder;

    if (s.st_mode & _S_IFREG)

        return OS::Path_File;

    return OS::Path_Invalid;

}