/*

	compat: Some compatibility functions (basic memory & string stuff in separate file)

	The mpg123 code is determined to keep it's legacy. A legacy of old, old UNIX.

	So anything possibly somewhat advanced should be considered to be put here, with proper #ifdef;-)

	copyright 2007-2016 by the mpg123 project - free software under the terms of the LGPL 2.1

	see COPYING and AUTHORS files in distribution or http://mpg123.org

	initially written by Thomas Orgis, Windows Unicode stuff by JonY.

*/

#include "config.h"

/* This source file does need _POSIX_SOURCE to get some sigaction. */

#define _POSIX_SOURCE

#include "compat.h"

#ifdef _MSC_VER

#include <io.h>

#if(defined(WINAPI_FAMILY) && (WINAPI_FAMILY==WINAPI_FAMILY_APP))

#define WINDOWS_UWP

#endif

#endif

#ifdef HAVE_SYS_STAT_H

#  include <sys/stat.h>

#endif

#ifdef HAVE_DIRENT_H

#  include <dirent.h>

#endif

/* Win32 is only supported with unicode now. These headers also cover

   module stuff. The WANT_WIN32_UNICODE macro is synonymous with

   "want windows-specific API, and only the unicode variants of which". */

#ifdef WANT_WIN32_UNICODE

#include <wchar.h>

#include <windows.h>

#include <winnls.h>

#include <shlwapi.h>

#endif

#ifdef USE_MODULES

#  ifdef HAVE_DLFCN_H

#    include <dlfcn.h>

#  endif

#endif

#include "debug.h"

#ifndef WINDOWS_UWP

char *compat_getenv(const char* name)

{

	char *ret = NULL;

#ifdef WANT_WIN32_UNICODE

	wchar_t *env;

	wchar_t *wname = NULL;

	if(win32_utf8_wide(name, &wname, NULL) > 0)

	{

		env = _wgetenv(wname);

		free(wname);

		if(env)

			win32_wide_utf8(env, &ret, NULL);

	}

#else

	ret = getenv(name);

	if(ret)

		ret = compat_strdup(ret);

#endif

	return ret;

}

#ifdef WANT_WIN32_UNICODE

/* Convert unix UTF-8 (or ASCII) paths to Windows wide character paths. */

static wchar_t* u2wpath(const char *upath)

{

	wchar_t* wpath, *p;

	if(!upath || win32_utf8_wide(upath, &wpath, NULL) < 1)

		return NULL;

	for(p=wpath; *p; ++p)

		if(*p == L'/')

			*p = L'\\';

	return wpath;

}

/* Convert Windows wide character paths to unix UTF-8. */

static char* w2upath(const wchar_t *wpath)

{

	char* upath, *p;

	if(!wpath || win32_wide_utf8(wpath, &upath, NULL) < 1)

		return NULL;

	for(p=upath; *p; ++p)

		if(*p == '\\')

			*p = '/';

	return upath;

}

/* An absolute path that is too long and not already marked with

   \\?\ can be marked as a long one and still work. */

static int wpath_need_elongation(wchar_t *wpath)

{

	if( wpath && !PathIsRelativeW(wpath)

	&&	wcslen(wpath) > MAX_PATH-1

	&&	wcsncmp(L"\\\\?\\", wpath, 4) )

		return 1;

	else

		return 0;

}

/* Take any wide windows path and turn it into a path that is allowed

   to be longer than MAX_PATH, if it is not already. */

static wchar_t* wlongpath(wchar_t *wpath)

{

	size_t len, plen;

	const wchar_t *prefix = L"";

	wchar_t *wlpath = NULL;

	if(!wpath)

		return NULL;

	/* Absolute paths that do not start with \\?\ get that prepended

	   to allow them being long. */

	if(!PathIsRelativeW(wpath) && wcsncmp(L"\\\\?\\", wpath, 4))

	{

		if(wcslen(wpath) >= 2 && PathIsUNCW(wpath))

		{

			/* \\server\path -> \\?\UNC\server\path */

			prefix = L"\\\\?\\UNC";

			++wpath; /* Skip the first \. */

		}

		else /* c:\some/path -> \\?\c:\some\path */

			prefix = L"\\\\?\\";

	}

	plen = wcslen(prefix);

	len = plen + wcslen(wpath);

	wlpath = malloc(len+1*sizeof(wchar_t));

	if(wlpath)

	{

		/* Brute force memory copying, swprintf is too dandy. */

		memcpy(wlpath, prefix, sizeof(wchar_t)*plen);

		memcpy(wlpath+plen, wpath, sizeof(wchar_t)*(len-plen));

		wlpath[len] = 0;

	}

	return wlpath;

}

/* Convert unix path to wide windows path, optionally marking

   it as long path if necessary. */

static wchar_t* u2wlongpath(const char *upath)

{

	wchar_t *wpath  = NULL;

	wchar_t *wlpath = NULL;

	wpath = u2wpath(upath);

	if(wpath_need_elongation(wpath))

	{

		wlpath = wlongpath(wpath);

		free(wpath);

		wpath = wlpath;

	}

	return wpath;

}

#endif

#else

static wchar_t* u2wlongpath(const char *upath)

{

	wchar_t* wpath, *p;

	if (!upath || win32_utf8_wide(upath, &wpath, NULL) < 1)

		return NULL;

	for (p = wpath; *p; ++p)

		if (*p == L'/')

			*p = L'\\';

	return wpath;

}

#endif

/* Always add a default permission mask in case of flags|O_CREAT. */

int compat_open(const char *filename, int flags)

{

	int ret;

#if defined (WANT_WIN32_UNICODE)

	wchar_t *frag = NULL;

	frag = u2wlongpath(filename);

	/* Fallback to plain open when ucs-2 conversion fails */

	if(!frag)

		goto open_fallback;

	/*Try _wopen */

	ret = _wopen(frag, flags|_O_BINARY, _S_IREAD | _S_IWRITE);

	if(ret != -1 )

		goto open_ok; /* msdn says -1 means failure */

open_fallback:

#endif

#if (defined(WIN32) && !defined (__CYGWIN__))

	/* MSDN says POSIX function is deprecated beginning in Visual C++ 2005 */

	/* Try plain old _open(), if it fails, do nothing */

	ret = _open(filename, flags|_O_BINARY, _S_IREAD | _S_IWRITE);

#else

	ret = open(filename, flags, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);

#endif

#if defined (WANT_WIN32_UNICODE)

open_ok:

	free(frag);

#endif

	return ret;

}

/* Moved over from wav.c, logic with fallbacks added from the

   example of compat_open(). */

FILE* compat_fopen(const char *filename, const char *mode)

{

	FILE* stream = NULL;

#ifdef WANT_WIN32_UNICODE

	int cnt = 0;

	wchar_t *wname = NULL;

	wchar_t *wmode = NULL;

	wname = u2wlongpath(filename);

	if(!wname)

		goto fopen_fallback;

	cnt = win32_utf8_wide(mode, &wmode, NULL);

	if( (wmode == NULL) || (cnt == 0))

		goto fopen_fallback;

	stream = _wfopen(wname, wmode);

	if(stream) goto fopen_ok;

fopen_fallback:

#endif

	stream = fopen(filename, mode);

#ifdef WANT_WIN32_UNICODE

fopen_ok:

	free(wmode);

	free(wname);

#endif

	return stream;

}

FILE* compat_fdopen(int fd, const char *mode)

{

	return fdopen(fd, mode);

}

int compat_close(int infd)

{

#if (defined(WIN32) && !defined (__CYGWIN__)) /* MSDN says POSIX function is deprecated beginning in Visual C++ 2005 */

	return _close(infd);

#else

	return close(infd);

#endif

}

int compat_fclose(FILE *stream)

{

	return fclose(stream);

}

/* Windows Unicode stuff */

#ifdef WANT_WIN32_UNICODE

int win32_wide_utf8(const wchar_t * const wptr, char **mbptr, size_t * buflen)

{

  size_t len;

  char *buf;

  int ret = 0;

  len = WideCharToMultiByte(CP_UTF8, 0, wptr, -1, NULL, 0, NULL, NULL); /* Get utf-8 string length */

  buf = calloc(len + 1, sizeof (char)); /* Can we assume sizeof char always = 1? */

  if(!buf) len = 0;

  else {

    if (len != 0) ret = WideCharToMultiByte(CP_UTF8, 0, wptr, -1, buf, len, NULL, NULL); /*Do actual conversion*/

    buf[len] = '0'; /* Must terminate */

  }

  *mbptr = buf; /* Set string pointer to allocated buffer */

  if(buflen != NULL) *buflen = (len) * sizeof (char); /* Give length of allocated memory if needed. */

  return ret;

}

int win32_utf8_wide(const char *const mbptr, wchar_t **wptr, size_t *buflen)

{

  size_t len;

  wchar_t *buf;

  int ret = 0;

  len = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, mbptr, -1, NULL, 0); /* Get converted size */

  buf = calloc(len + 1, sizeof (wchar_t)); /* Allocate memory accordingly */

  if(!buf) len = 0;

  else {

    if (len != 0) ret = MultiByteToWideChar (CP_UTF8, MB_ERR_INVALID_CHARS, mbptr, -1, buf, len); /* Do conversion */

    buf[len] = L'0'; /* Must terminate */

  }

  *wptr = buf; /* Set string pointer to allocated buffer */

  if (buflen != NULL) *buflen = len * sizeof (wchar_t); /* Give length of allocated memory if needed. */

  return ret; /* Number of characters written */

}

#endif

#ifndef WINDOWS_UWP

/*

	The Windows file and path stuff is an extract of jon_y's win32 loader

	prototype from the loader_rework branch. It's been divided in to

	reusable functons by ThOr in the hope to work out some generic-looking

	loader code for both POSIX and Windows. The routines might be

	helpful for consistent path work in other parts of mpg123, too.

	This all is about getting some working code on a wide range of

	systems while staying somewhat sane. If it does ridiculously inefficient

	things with extraneous copies and grabbing of functions that made

	it late to some official APIs, that's still fine with us.

*/

char* compat_catpath(const char *prefix, const char* path)

{

	char *ret = NULL;

#ifdef WANT_WIN32_UNICODE

	wchar_t *wprefix = NULL; /* Wide windows versions of */

	wchar_t *wpath   = NULL; /* input arguments. */

	wchar_t *locwret = NULL; /* Tmp return value from LocalAlloc */

	/*

		This variation of combinepath can work with long and UNC paths, but

		is not officially exposed in any DLLs, It also allocates all its buffers

		internally via LocalAlloc, avoiding buffer overflow problems.

		ThOr: I presume this hack is for supporting pre-8 Windows, as

		from Windows 8 on, this is documented in the API.

	*/

	HRESULT (__stdcall *mypac)( const wchar_t *in, const wchar_t* more

	,	unsigned long flags, wchar_t **out ) = NULL;

	HMODULE pathcch = NULL;

	if(!prefix && !path)

		goto catpath_end;

	wprefix = u2wpath(prefix);

	wpath   = u2wpath(path);

	if((prefix && !wprefix) || (path && !wpath))

		goto catpath_end;

	/* Again: I presume this whole fun is to get at PathAllocCombine

	   even when pathcch.h is not available (like in MinGW32). */

	if( (pathcch = GetModuleHandleA("kernelbase")) )

		mypac = (void *)GetProcAddress(pathcch, "PathAllocCombine");

	if(mypac) /* PATHCCH_ALLOW_LONG_PATH = 1 per API docs */

	{

		debug("Actually calling PathAllocCombine!");

		mypac(wprefix, wpath, 1, &locwret);

	}

	else

	{

		/* Playing safe, if we'd care much about performance, this would be on

		   the stack. */

		locwret = LocalAlloc(LPTR, sizeof(wchar_t)*MAX_PATH);

		if(locwret)

			PathCombineW(locwret, wprefix, wpath);

	}

	ret = w2upath(locwret);

catpath_end:

	LocalFree(locwret);

	free(wprefix);

	free(wpath);

#else

	size_t len, prelen, patlen;

	if(path && path[0] == '/')

		prefix = NULL; /* Absolute path stays as it is. */

	prelen = prefix ? strlen(prefix) : 0;

	patlen = path   ? strlen(path)   : 0;

	/* Concatenate the two, put a / in between if both present. */

	len = ((prefix && path) ? 1 : 0) + prelen + patlen;

	ret = malloc(len+1);

	if(ret)

	{

		size_t off=0;

		memcpy(ret, prefix, prelen);

		if(prefix && path)

			ret[prelen+(off++)] = '/';

		memcpy(ret+prelen+off, path, patlen);

		ret[len] = 0;

	}

#endif

	return ret;

}

int compat_isdir(const char *path)

{

	int ret = 0;

#ifdef WANT_WIN32_UNICODE

	wchar_t *wpath;

	wpath = u2wlongpath(path);

	if(wpath)

	{

		DWORD attr = GetFileAttributesW(wpath);

		if(attr != INVALID_FILE_ATTRIBUTES && attr & FILE_ATTRIBUTE_DIRECTORY)

			ret=1;

		free(wpath);

	}

#else

	struct stat sb;

	if(path && !stat(path, &sb))

	{

		if(S_ISDIR(sb.st_mode))

			ret=1;

	}

#endif

	return ret;

}

struct compat_dir

{

	char *path;

#ifdef WANT_WIN32_UNICODE

	int gotone; /* Got a result stored from FindFirstFileW. */

	WIN32_FIND_DATAW d;

	HANDLE ffn;

#else

	DIR* dir;

#endif

};

struct compat_dir* compat_diropen(char *path)

{

	struct compat_dir *cd;

	if(!path)

		return NULL;

	cd = malloc(sizeof(*cd));

	if(!cd)

		return NULL;

#ifdef WANT_WIN32_UNICODE

	cd->gotone = 0;

	{

		char *pattern;

		wchar_t *wpattern;

		pattern = compat_catpath(path, "*");

		wpattern = u2wlongpath(pattern);

		if(wpattern)

		{

			cd->ffn = FindFirstFileW(wpattern, &(cd->d));

			if(cd->ffn == INVALID_HANDLE_VALUE)

			{

				/* FindClose() only needed after successful first find, right? */

				free(cd);

				cd = NULL;

			}

			else

				cd->gotone = 1;

		}

		free(wpattern);

		free(pattern);

	}

#else

	cd->dir = opendir(path);

	if(!cd->dir)

	{

		free(cd);

		cd = NULL;

	}

#endif

	if(cd)

	{

		cd->path = compat_strdup(path);

		if(!cd->path)

		{

			compat_dirclose(cd);

			cd = NULL;

		}

	}

	return cd;

}

void compat_dirclose(struct compat_dir *cd)

{

	if(cd)

	{

		free(cd->path);

#ifdef WANT_WIN32_UNICODE

		FindClose(cd->ffn);

#else

		closedir(cd->dir);

#endif

		free(cd);

	}

}

char* compat_nextfile(struct compat_dir *cd)

{

	if(!cd)

		return NULL;

#ifdef WANT_WIN32_UNICODE

	while(cd->gotone || FindNextFileW(cd->ffn, &(cd->d)))

	{

		cd->gotone = 0;

		if(!(cd->d.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))

		{

			char *ret;

			win32_wide_utf8(cd->d.cFileName, &ret, NULL);

			return ret;

		}

	}

#else

	{

		struct dirent *dp;

		while((dp = readdir(cd->dir)))

		{

			struct stat fst;

			char *fullpath = compat_catpath(cd->path, dp->d_name);

			if(fullpath && !stat(fullpath, &fst) && S_ISREG(fst.st_mode))

			{

				free(fullpath);

				return compat_strdup(dp->d_name);

			}

			free(fullpath);

		}

	}

#endif

	return NULL;

}

char* compat_nextdir(struct compat_dir *cd)

{

	if(!cd)

		return NULL;

#ifdef WANT_WIN32_UNICODE

	while(cd->gotone || FindNextFileW(cd->ffn, &(cd->d)))

	{

		cd->gotone = 0;

		if(cd->d.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)

		{

			char *ret;

			win32_wide_utf8(cd->d.cFileName, &ret, NULL);

			return ret;

		}

	}

#else

	{

		struct dirent *dp;

		while((dp = readdir(cd->dir)))

		{

			struct stat fst;

			char *fullpath = compat_catpath(cd->path, dp->d_name);

			if(fullpath && !stat(fullpath, &fst) && S_ISDIR(fst.st_mode))

			{

				free(fullpath);

				return compat_strdup(dp->d_name);

			}

			free(fullpath);

		}

	}

#endif

	return NULL;

}

#endif

#ifdef USE_MODULES

/*

	This is what I expected the platform-specific dance for dynamic module

	support to be. Little did I know about the peculiarities of (long)

	paths and directory/file search on Windows.

*/

void *compat_dlopen(const char *path)

{

	void *handle = NULL;

#ifdef WANT_WIN32_UNICODE

	wchar_t *wpath;

	wpath = u2wlongpath(path);

	if(wpath)

		handle = LoadLibraryW(wpath);

	free(wpath);

#else

	handle = dlopen(path, RTLD_NOW);

#endif

	return handle;

}

void *compat_dlsym(void *handle, const char *name)

{

	void *sym = NULL;

	if(!handle)

		return NULL;

#ifdef WANT_WIN32_UNICODE

	sym = GetProcAddress(handle, name);

#else

	sym = dlsym(handle, name);

#endif

	return sym;

}

void compat_dlclose(void *handle)

{

	if(!handle)

		return;

#ifdef WANT_WIN32_UNICODE

	FreeLibrary(handle);

#else

	dlclose(handle);

#endif

}

#endif /* USE_MODULES */

/* This shall survive signals and any return value less than given byte count

   is an error */

size_t unintr_write(int fd, void const *buffer, size_t bytes)

{

	size_t written = 0;

	while(bytes)

	{

		ssize_t part = write(fd, (char*)buffer+written, bytes);

		if(part < 0 && errno != EINTR)

			break;

		bytes   -= part;

		written += part;

	}

	return written;

}

/* Same for reading the data. */

size_t unintr_read(int fd, void *buffer, size_t bytes)

{

	size_t got = 0;

	while(bytes)

	{

		ssize_t part = read(fd, (char*)buffer+got, bytes);

		if(part < 0 && errno != EINTR)

			break;

		bytes -= part;

		got   += part;

	}

	return got;

}

#ifndef NO_CATCHSIGNAL

#if (!defined(WIN32) || defined (__CYGWIN__)) && defined(HAVE_SIGNAL_H)

void (*catchsignal(int signum, void(*handler)()))()

{

	struct sigaction new_sa;

	struct sigaction old_sa;

#ifdef DONT_CATCH_SIGNALS

	fprintf (stderr, "Not catching any signals.\n");

	return ((void (*)()) -1);

#endif

	new_sa.sa_handler = handler;

	sigemptyset(&new_sa.sa_mask);

	new_sa.sa_flags = 0;

	if(sigaction(signum, &new_sa, &old_sa) == -1)

		return ((void (*)()) -1);

	return (old_sa.sa_handler);

}

#endif

#endif