/* $Id: ncbi_util.c,v 6.81 2012/02/29 20:14:34 kazimird Exp $
 * ===========================================================================
 *
 *                            PUBLIC DOMAIN NOTICE
 *               National Center for Biotechnology Information
 *
 *  This software/database is a "United States Government Work" under the
 *  terms of the United States Copyright Act.  It was written as part of
 *  the author's official duties as a United States Government employee and
 *  thus cannot be copyrighted.  This software/database is freely available
 *  to the public for use. The National Library of Medicine and the U.S.
 *  Government have not placed any restriction on its use or reproduction.
 *
 *  Although all reasonable efforts have been taken to ensure the accuracy
 *  and reliability of the software and data, the NLM and the U.S.
 *  Government do not and cannot warrant the performance or results that
 *  may be obtained by using this software or data. The NLM and the U.S.
 *  Government disclaim all warranties, express or implied, including
 *  warranties of performance, merchantability or fitness for any particular
 *  purpose.
 *
 *  Please cite the author in any work or product based on this material.
 *
 * ===========================================================================
 *
 * Author:  Denis Vakatov, Anton Lavrentiev
 *
 * File Description:
 *   Auxiliary (optional) code mostly to support "ncbi_core.[ch]"
 *
 */

#include "ncbi_ansi_ext.h"
#include "ncbi_priv.h"
#ifndef NCBI_CXX_TOOLKIT
#  include <ncbistd.h>
#  include <ncbimisc.h>
#  include <ncbitime.h>
#else
#  include <ctype.h>
#  include <errno.h>
#  include <stdlib.h>
#  include <time.h>
#endif
#if defined(NCBI_OS_UNIX)
#  ifndef HAVE_GETPWUID
#    error "HAVE_GETPWUID is undefined on a UNIX system!"
#  endif /*!HAVE_GETPWUID*/
#  ifndef NCBI_OS_SOLARIS
#    include <limits.h>
#  endif
#  include <pwd.h>
#  include <unistd.h>
#  include <sys/stat.h>
#endif /*NCBI_OS_UNIX*/
#if defined(NCBI_OS_MSWIN)  ||  defined(NCBI_OS_CYGWIN)
#  define WIN32_LEAN_AND_MEAN
#  include <windows.h>
#endif /*NCBI_OS_MSWIN || NCBI_OS_CYGWIN*/

#define NCBI_USE_ERRCODE_X   Connect_Util

#define NCBI_USE_PRECOMPILED_CRC32_TABLES 1



/******************************************************************************
 *  MT locking
 */

extern void CORE_SetLOCK(MT_LOCK lk)
{
    MT_LOCK old_lk = g_CORE_MT_Lock;
    g_CORE_MT_Lock = lk;
    if (old_lk  &&  old_lk != lk) {
        MT_LOCK_Delete(old_lk);
    }
}


extern MT_LOCK CORE_GetLOCK(void)
{
    return g_CORE_MT_Lock;
}



/******************************************************************************
 *  ERROR HANDLING and LOGGING
 */


extern void CORE_SetLOG(LOG lg)
{
    LOG old_lg;
    CORE_LOCK_WRITE;
    old_lg = g_CORE_Log;
    g_CORE_Log = lg;
    CORE_UNLOCK;
    if (old_lg  &&  old_lg != lg) {
        LOG_Delete(old_lg);
    }
}


extern LOG CORE_GetLOG(void)
{
    return g_CORE_Log;
}


extern void CORE_SetLOGFILE_Ex
(FILE*       fp,
 ELOG_Level  cut_off,
 int/*bool*/ auto_close
 )
{
    LOG lg = LOG_Create(0, 0, 0, 0);
    LOG_ToFILE_Ex(lg, fp, cut_off, auto_close);
    CORE_SetLOG(lg);
}


extern void CORE_SetLOGFILE
(FILE*       fp,
 int/*bool*/ auto_close)
{
    CORE_SetLOGFILE_Ex(fp, eLOG_Trace, auto_close);
}


extern int/*bool*/ CORE_SetLOGFILE_NAME_Ex
(const char* filename,
 ELOG_Level  cut_off)
{
    FILE* fp = fopen(filename, "a");
    if (!fp) {
        CORE_LOGF_ERRNO_X(1, eLOG_Error, errno,
                          ("Cannot open \"%s\"", filename));
        return 0/*false*/;
    }

    CORE_SetLOGFILE_Ex(fp, cut_off, 1/*true*/);
    return 1/*true*/;
}


extern int/*bool*/ CORE_SetLOGFILE_NAME
(const char* filename
 )
{
    return CORE_SetLOGFILE_NAME_Ex(filename, eLOG_Trace);
}


static TLOG_FormatFlags s_LogFormatFlags = fLOG_Default;

extern TLOG_FormatFlags CORE_SetLOGFormatFlags(TLOG_FormatFlags flags)
{
    TLOG_FormatFlags old_flags = s_LogFormatFlags;

    s_LogFormatFlags = flags;
    return old_flags;
}


#ifdef __GNUC__
inline
#endif /*__GNUC__*/
static int/*bool*/ s_IsQuoted(unsigned char c)
{
    return (c == '\t'  ||  c == '\v'  ||  c == '\b'  ||
            c == '\r'  ||  c == '\f'  ||  c == '\a'  ||
            c == '\n'  ||  c == '\\'  ||  c == '\''  ||
            c == '"' ? 1/*true*/ : 0/*false*/);
}


extern size_t UTIL_PrintableStringSize(const char* data, size_t size)
{
    const unsigned char* c;
    size_t retval;
    if (!data)
        return 0;
    if (!size)
        size = strlen(data);
    retval = size;
    for (c = (const unsigned char*) data;  size;  size--, c++) {
        if (*c == '\n')
            retval += 3;
        else if (s_IsQuoted(*c))
            retval++;
        else if (!isprint(*c))
            retval += 3;
    }
    return retval;
}


extern char* UTIL_PrintableString(const char* data, size_t size,
                                  char* buf, int/*bool*/ full_octal)
{
    const unsigned char* s;
    unsigned char* d;

    if (!data  ||  !buf)
        return 0;
    if (!size)
        size = strlen(data);

    d = (unsigned char*) buf;
    for (s = (const unsigned char*) data;  size;  size--, s++) {
        switch (*s) {
        case '\t':
            *d++ = '\\';
            *d++ = 't';
            continue;
        case '\v':
            *d++ = '\\';
            *d++ = 'v';
            continue;
        case '\b':
            *d++ = '\\';
            *d++ = 'b';
            continue;
        case '\r':
            *d++ = '\\';
            *d++ = 'r';
            continue;
        case '\f':
            *d++ = '\\';
            *d++ = 'f';
            continue;
        case '\a':
            *d++ = '\\';
            *d++ = 'a';
            continue;
        case '\n':
            *d++ = '\\';
            *d++ = 'n';
            /*FALLTHRU*/
        case '\\':
        case '\'':
        case '"':
            *d++ = '\\';
            break;
        default:
            if (!isprint(*s)) {
                int/*bool*/ reduce;
                unsigned char v;
                if (full_octal)
                    reduce = 0/*false*/;
                else {
                    reduce = (size == 1       ||  s_IsQuoted(s[1])  ||
                              !isprint(s[1])  ||  s[1] < '0'  ||  s[1] > '7');
                }
                *d++ = '\\';
                v =  *s >> 6;
                if (v  ||  !reduce) {
                    *d++ = '0' + v;
                    reduce = 0;
                }
                v = (*s >> 3) & 7;
                if (v  ||  !reduce)
                    *d++ = '0' + v;
                v =  *s & 7;
                *d++ =     '0' + v;
                continue;
            }
            break;
        }
        *d++ = (char) *s;
    }

    return (char*) d;
}


extern const char* NcbiMessagePlusError
(int/*bool*/ *dynamic,
 const char*  message,
 int          error,
 const char*  descr)
{
    char*  buf;
    size_t mlen;
    size_t dlen;
    int/*bool*/ release = 0/*false*/;

    /* Check for an empty addition */
    if (!error  &&  (!descr  ||  !*descr)) {
        if (message)
            return message;
        *dynamic = 0/*false*/;
        return "";
    }

    /* Adjust description, if necessary and possible */
    
    if (error >=0  &&  !descr) {
#if defined(NCBI_OS_MSWIN)  &&  defined(_UNICODE)
        descr = UTIL_TcharToUtf8( _wcserror(error) );
        release = 1/*true*/;
#else
        descr = strerror(error);
#endif /*NCBI_OS_MSWIN && _UNICODE*/
    }
    if (!descr) {
        descr = "";
    }
    dlen = strlen(descr);
    while (dlen  &&  isspace((unsigned char) descr[dlen - 1]))
        dlen--;
    if (dlen > 1  &&  descr[dlen - 1] == '.')
        dlen--;

    mlen = message ? strlen(message) : 0;

    if (!(buf = (char*)(*dynamic  &&  message
                        ? realloc((void*) message, mlen + dlen + 40)
                        : malloc (                 mlen + dlen + 40)))) {
        if (*dynamic  &&  message)
            free((void*) message);
        *dynamic = 0;
        if (release)
            UTIL_ReleaseBuffer(descr);
        return "Ouch! Out of memory";
    }

    if (message) {
        if (!*dynamic)
            memcpy(buf, message, mlen);
        buf[mlen++] = ' ';
    }
    memcpy(buf + mlen, "{error=", 7);
    mlen += 7;

    if (error)
        mlen += sprintf(buf + mlen, "%d%s", error, "," + !*descr);

    memcpy((char*) memcpy(buf + mlen, descr, dlen) + dlen, "}", 2);
    if (release)
        UTIL_ReleaseBuffer(descr);

    *dynamic = 1/*true*/;
    return buf;
}


extern char* LOG_ComposeMessage
(const SLOG_Handler* call_data,
 TLOG_FormatFlags    format_flags)
{
    static const char kRawData_Begin[] =
        "\n#################### [BEGIN] Raw Data (%lu byte%s):\n";
    static const char kRawData_End[] =
        "\n#################### [END] Raw Data\n";

    char *str, *s, datetime[32];
    const char* level = 0;

    /* Calculated length of ... */
    size_t datetime_len  = 0;
    size_t level_len     = 0;
    size_t file_line_len = 0;
    size_t module_len    = 0;
    size_t message_len   = 0;
    size_t data_len      = 0;
    size_t total_len;

    /* Adjust formatting flags */
    if (call_data->level == eLOG_Trace  &&  !(format_flags & fLOG_None))
        format_flags |= fLOG_Full;
    if (format_flags == fLOG_Default) {
#if defined(NDEBUG)  &&  !defined(_DEBUG)
        format_flags = fLOG_Short;
#else
        format_flags = fLOG_Full;
#endif /*NDEBUG && !_DEBUG*/
    }

    /* Pre-calculate total message length */
    if ((format_flags & fLOG_DateTime) != 0) {
#ifdef NCBI_OS_MSWIN /*Should be compiler-dependent but C-Tkit lacks it*/
        _strdate(&datetime[datetime_len]);
        datetime_len += strlen(&datetime[datetime_len]);
        datetime[datetime_len++] = ' ';
        _strtime(&datetime[datetime_len]);
        datetime_len += strlen(&datetime[datetime_len]);
        datetime[datetime_len++] = ' ';
        datetime[datetime_len]   = '\0';
#else /*NCBI_OS_MSWIN*/
        static const char timefmt[] = "%m/%d/%y %H:%M:%S ";
        struct tm* tm;
#  ifdef NCBI_CXX_TOOLKIT
        time_t t = time(0);
#    ifdef HAVE_LOCALTIME_R
        struct tm temp;
        localtime_r(&t, &temp);
        tm = &temp;
#    else /*HAVE_LOCALTIME_R*/
        tm = localtime(&t);
#    endif/*HAVE_LOCALTIME_R*/
#  else /*NCBI_CXX_TOOLKIT*/
        struct tm temp;
        Nlm_GetDayTime(&temp);
        tm = &temp;
#  endif /*NCBI_CXX_TOOLKIT*/
        datetime_len = strftime(datetime, sizeof(datetime), timefmt, tm);
#endif /*NCBI_OS_MSWIN*/
    }
    if ((format_flags & fLOG_Level) != 0
        &&  (call_data->level != eLOG_Note
             ||  !(format_flags & fLOG_OmitNoteLevel))) {
        level = LOG_LevelStr(call_data->level);
        level_len = strlen(level) + 2;
    }
    if ((format_flags & fLOG_Module) != 0  &&
        call_data->module  &&  *call_data->module) {
        module_len = strlen(call_data->module) + 3;
    }
    if ((format_flags & fLOG_FileLine) != 0  &&
        call_data->file  &&  *call_data->file) {
        file_line_len = 12 + strlen(call_data->file) + 11;
    }
    if (call_data->message  &&  *call_data->message) {
        message_len = strlen(call_data->message);
    }

    if (call_data->raw_size) {
        data_len = (sizeof(kRawData_Begin) + 20
                    + UTIL_PrintableStringSize((const char*)
                                               call_data->raw_data,
                                               call_data->raw_size) +
                    sizeof(kRawData_End));
    }

    /* Allocate memory for the resulting message */
    total_len = (datetime_len + file_line_len + module_len
                 + level_len + message_len + data_len);
    if (!(str = (char*) malloc(total_len + 1))) {
        assert(0);
        return 0;
    }

    s = str;
    /* Compose the message */
    if (datetime_len) {
        memcpy(s, datetime, datetime_len);
        s += datetime_len;
    }
    if (file_line_len) {
        s += sprintf(s, "\"%s\", line %d: ",
                     call_data->file, (int) call_data->line);
    }
    if (module_len) {
        *s++ = '[';
        memcpy(s, call_data->module, module_len -= 3);
        s += module_len;
        *s++ = ']';
        *s++ = ' ';
    }
    if (level_len) {
        memcpy(s, level, level_len -= 2);
        s += level_len;
        *s++ = ':';
        *s++ = ' ';
    }
    if (message_len) {
        memcpy(s, call_data->message, message_len);
        s += message_len;
    }
    if (data_len) {
        s += sprintf(s, kRawData_Begin,
                     (unsigned long) call_data->raw_size,
                     &"s"[call_data->raw_size == 1]);

        s = UTIL_PrintableString((const char*)
                                 call_data->raw_data,
                                 call_data->raw_size,
                                 s, format_flags & fLOG_FullOctal);

        memcpy(s, kRawData_End, sizeof(kRawData_End));
    } else
        *s = '\0';

    assert(strlen(str) <= total_len);
    return str;
}


typedef struct {
    FILE*       fp;
    int/*bool*/ cut_off;
    int/*bool*/ auto_close;
} SLogData;


/* Callback for LOG_ToFILE[_Ex]() */
#ifdef __cplusplus
extern "C" {
#endif /*__cplusplus*/
static void s_LOG_FileHandler(void* user_data, SLOG_Handler* call_data)
{
    SLogData* data = (SLogData*) user_data;
    assert(data  &&  data->fp);
    assert(call_data);

    if (call_data->level >= data->cut_off  ||  call_data->level == eLOG_Fatal){
        char* str = LOG_ComposeMessage(call_data, s_LogFormatFlags);
        if (str) {
            fprintf(data->fp, "%s\n", str);
            fflush(data->fp);
            free(str);
        }
    }
}
#ifdef __cplusplus
}
#endif /*__cplusplus*/


/* Callback for LOG_ToFILE[_Ex]() */
#ifdef __cplusplus
extern "C" {
#endif /*__cplusplus*/
static void s_LOG_FileCleanup(void* user_data)
{
    SLogData* data = (SLogData*) user_data;

    assert(data  &&  data->fp);
    if (data->auto_close)
        fclose(data->fp);
    else
        fflush(data->fp);
    free(user_data);
}
#ifdef __cplusplus
}
#endif /*__cplusplus*/


extern void LOG_ToFILE_Ex
(LOG         lg,
 FILE*       fp,
 ELOG_Level  cut_off,
 int/*bool*/ auto_close
 )
{
    SLogData* data = (SLogData*)(fp ? malloc(sizeof(*data)) : 0);
    if (data) {
        data->fp         = fp;
        data->cut_off    = cut_off;
        data->auto_close = auto_close;
        LOG_Reset(lg, data, s_LOG_FileHandler, s_LOG_FileCleanup);
    } else {
        LOG_Reset(lg, 0/*data*/, 0/*handler*/, 0/*cleanup*/);
    }
}


extern void LOG_ToFILE
(LOG         lg,
 FILE*       fp,
 int/*bool*/ auto_close
 )
{
    LOG_ToFILE_Ex(lg, fp, eLOG_Trace, auto_close);
}



/******************************************************************************
 *  REGISTRY
 */

extern void CORE_SetREG(REG rg)
{
    REG old_rg;
    CORE_LOCK_WRITE;
    old_rg = g_CORE_Registry;
    g_CORE_Registry = rg;
    CORE_UNLOCK;
    if (old_rg  &&  old_rg != rg) {
        REG_Delete(old_rg);
    }
}


extern REG CORE_GetREG(void)
{
    return g_CORE_Registry;
}



/******************************************************************************
 *  CORE_GetNcbiSid
 */

extern const char* CORE_GetNcbiSid(void)
{
    return g_CORE_GetSid ? g_CORE_GetSid() : getenv("HTTP_NCBI_SID");
}



/******************************************************************************
 *  CORE_GetAppName
 */

extern const char* CORE_GetAppName(void)
{
    const char* an;
    return !g_CORE_GetAppName  ||  !(an = g_CORE_GetAppName()) ? "" : an;
}



/******************************************************************************
 *  CORE_GetPlatform
 */

extern const char* CORE_GetPlatform(void)
{
#ifndef NCBI_CXX_TOOLKIT
    return Nlm_PlatformName();
#else
    return HOST;
#endif /*NCBI_CXX_TOOLKIT*/
}



/****************************************************************************
 * CORE_GetUsername
 */

static char* x_Savestr(const char* str, char* buf, size_t bufsize)
{
    assert(str);
    if (buf) {
        size_t len = strlen(str);
        if (len++ < bufsize)
            return (char*) memcpy(buf, str, len);
        errno = ERANGE;
    } else
        errno = EINVAL;
    return 0;
}

extern const char* CORE_GetUsername(char* buf, size_t bufsize)
{
#if defined(NCBI_OS_UNIX)
    struct passwd* pwd;
    struct stat    st;
    uid_t          uid;
#  ifndef NCBI_OS_SOLARIS
#    define NCBI_GETUSERNAME_MAXBUFSIZE 1024
#    ifdef HAVE_GETLOGIN_R
#      ifndef LOGIN_NAME_MAX
#        ifdef _POSIX_LOGIN_NAME_MAX
#          define LOGIN_NAME_MAX _POSIX_LOGIN_NAME_MAX
#        else
#          define LOGIN_NAME_MAX 256
#        endif /*_POSIX_LOGIN_NAME_MAX*/
#      endif /*!LOGIN_NAME_MAX*/
#      define     NCBI_GETUSERNAME_BUFSIZE   LOGIN_NAME_MAX
#    endif /*HAVE_GETLOGIN_R*/
#    ifdef NCBI_HAVE_GETPWUID_R
#      ifndef NCBI_GETUSERNAME_BUFSIZE
#        define   NCBI_GETUSERNAME_BUFSIZE   NCBI_GETUSERNAME_MAXBUFSIZE
#      else
#        if       NCBI_GETUSERNAME_BUFSIZE < NCBI_GETUSERNAME_MAXBUFSIZE
#          undef  NCBI_GETUSERNAME_BUFSIZE
#          define NCBI_GETUSERNAME_BUFSIZE   NCBI_GETUSERNAME_MAXBUFSIZE
#        endif /* NCBI_GETUSERNAME_BUFSIZE < NCBI_GETUSERNAME_MAXBUFSIZE */
#      endif /*NCBI_GETUSERNAME_BUFSIZE*/
#    endif /*NCBI_HAVE_GETPWUID_R*/
#    ifdef       NCBI_GETUSERNAME_BUFSIZE
    char temp   [NCBI_GETUSERNAME_BUFSIZE + sizeof(*pwd)];
#    endif /*    NCBI_GETUSERNAME_BUFSIZE    */
#  endif /*!NCBI_OS_SOLARIS*/
#elif defined(NCBI_OS_MSWIN)
    TCHAR temp  [256 + 1];
    DWORD size = sizeof(temp)/sizeof(temp[0]) - 1;
#endif /*NCBI_OS*/
    const char* login;

    assert(buf  &&  bufsize);

#ifndef NCBI_OS_UNIX

#  ifdef NCBI_OS_MSWIN
    if (GetUserName(temp, &size)) {
        assert(size < sizeof(temp)/sizeof(temp[0]));
        temp[size] = (TCHAR) 0;
        login = UTIL_TcharToUtf8(temp);
        buf = x_Savestr(login, buf, bufsize);
        UTIL_ReleaseBuffer(login);
        return buf;
    }
    if ((login = getenv("USERNAME")) != 0)
        return x_Savestr(login, buf, bufsize);
#  endif /*NCBI_OS_MSWIN*/

#else

    /* NOTE:  getlogin() is not a very reliable call at least on Linux
     * especially if programs mess up with "utmp":  since getlogin() first
     * calls ttyname() to get the line name for FD 0, then searches "utmp"
     * for the record of this line and returns the user name, any discrepancy
     * can cause a false (stale) name to be returned.  So we use getlogin()
     * here only as a fallback.
     */
    if (!isatty(STDIN_FILENO)  ||  fstat(STDIN_FILENO, &st) < 0) {
#  if defined(NCBI_OS_SOLARIS)  ||  !defined(HAVE_GETLOGIN_R)
        /* NB:  getlogin() is MT-safe on Solaris, yet getlogin_r() comes in two
         * flavors that differ only in return type, so to make things simpler,
         * use plain getlogin() here */
#    ifndef NCBI_OS_SOLARIS
        CORE_LOCK_WRITE;
#    endif /*!NCBI_OS_SOLARIS*/
        if ((login = getlogin()) != 0)
            buf = x_Savestr(login, buf, bufsize);
#    ifndef NCBI_OS_SOLARIS
        CORE_UNLOCK;
#    endif /*!NCBI_OS_SOLARIS*/
        if (login)
            return buf;
#  else
        if (getlogin_r(temp, sizeof(temp) - 1) == 0) {
            temp[sizeof(temp) - 1] = '\0';
            return x_Savestr(temp, buf, bufsize);
        }
#  endif /*NCBI_OS_SOLARIS || !HAVE_GETLOGIN_R*/
        uid = getuid();
    } else
        uid = st.st_uid;

#  if defined(NCBI_OS_SOLARIS)  ||  !defined(NCBI_HAVE_GETPWUID_R)
    /* NB:  getpwuid() is MT-safe on Solaris, so use it here, if available */
#  ifndef NCBI_OS_SOLARIS
    CORE_LOCK_WRITE;
#  endif /*!NCBI_OS_SOLARIS*/
    if ((pwd = getpwuid(uid)) != 0) {
        if (pwd->pw_name)
            buf = x_Savestr(pwd->pw_name, buf, bufsize);
        else
            pwd = 0;
    }
#  ifndef NCBI_OS_SOLARIS
    CORE_UNLOCK;
#  endif /*!NCBI_OS_SOLARIS*/
    if (pwd)
        return buf;
#  elif defined(NCBI_HAVE_GETPWUID_R)
#    if   NCBI_HAVE_GETPWUID_R == 4
    /* obsolete but still existent */
    pwd = getpwuid_r(uid, (struct passwd*) temp, temp + sizeof(*pwd),
                     sizeof(temp) - sizeof(*pwd));
#    elif NCBI_HAVE_GETPWUID_R == 5
    /* POSIX-conforming */
    if (getpwuid_r(uid, (struct passwd*) temp, temp + sizeof(*pwd),
                   sizeof(temp) - sizeof(*pwd), &pwd) != 0) {
        pwd = 0;
    }
#    else
#      error "Unknown value of NCBI_HAVE_GETPWUID_R: 4 or 5 expected."
#    endif /*NCBI_HAVE_GETPWUID_R*/
    if (pwd  &&  pwd->pw_name)
        return x_Savestr(pwd->pw_name, buf, bufsize);
#  endif /*NCBI_HAVE_GETPWUID_R*/

#endif /*!NCBI_OS_UNIX*/

    /* last resort */
    if (!(login = getenv("USER"))  &&  !(login = getenv("LOGNAME")))
        login = "";
    return x_Savestr(login, buf, bufsize);
}



/****************************************************************************
 * CORE_GetVMPageSize:  Get page size granularity
 * See also at corelib's ncbi_system.cpp::GetVirtualMemoryPageSize().
 */

size_t CORE_GetVMPageSize(void)
{
    static size_t ps = 0;

    if (!ps) {
#if defined(NCBI_OS_MSWIN)  ||  defined(NCBI_OS_CYGWIN)
        SYSTEM_INFO si;
        GetSystemInfo(&si);
        ps = (size_t) si.dwPageSize;
#elif defined(NCBI_OS_UNIX) 
#  if   defined(_SC_PAGESIZE)
#    define NCBI_SC_PAGESIZE _SC_PAGESIZE
#  elif defined(_SC_PAGE_SIZE)
#    define NCBI_SC_PAGESIZE _SC_PAGE_SIZE
#  elif defined(NCBI_SC_PAGESIZE)
#    undef  NCBI_SC_PAGESIZE
#  endif
#  ifndef   NCBI_SC_PAGESIZE
        long x = 0;
#  else
        long x = sysconf(NCBI_SC_PAGESIZE);
#    undef  NCBI_SC_PAGESIZE
#  endif
        if (x <= 0) {
#  ifdef HAVE_GETPAGESIZE
            if ((x = getpagesize()) <= 0)
                return 0;
#  else
            return 0;
#  endif
        }
        ps = (size_t) x;
#endif /*OS_TYPE*/
    }
    return ps;
}



/****************************************************************************
 * CRC32
 */

/* Standard Ethernet/ZIP polynomial */
#define CRC32_POLY 0x04C11DB7UL


#ifdef NCBI_USE_PRECOMPILED_CRC32_TABLES

static const unsigned int s_CRC32Table[256] = {
    0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9,
    0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
    0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61,
    0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
    0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9,
    0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
    0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011,
    0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
    0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
    0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
    0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81,
    0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
    0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49,
    0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
    0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1,
    0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
    0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae,
    0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
    0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
    0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
    0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
    0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
    0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066,
    0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
    0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e,
    0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
    0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6,
    0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
    0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
    0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
    0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686,
    0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
    0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637,
    0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
    0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f,
    0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
    0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47,
    0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
    0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
    0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
    0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7,
    0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
    0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f,
    0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
    0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7,
    0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
    0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f,
    0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
    0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
    0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
    0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
    0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
    0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30,
    0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
    0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088,
    0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
    0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0,
    0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
    0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
    0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
    0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0,
    0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
    0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668,
    0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
};

#else

static unsigned int s_CRC32Table[256];

static void s_CRC32_Init(void)
{
    size_t i;

    if (s_CRC32Table[255])
        return;

    for (i = 0;  i < 256;  i++) {
        unsigned int byteCRC = (unsigned int) i << 24;
        int j;
        for (j = 0;  j < 8;  j++) {
            if (byteCRC & 0x80000000UL) {
                byteCRC <<= 1;
                byteCRC  ^= CRC32_POLY;
            } else
                byteCRC <<= 1;
        }
        s_CRC32Table[i] = byteCRC;
    }
}

#endif /*NCBI_USE_PRECOMPILED_CRC32_TABLES*/


extern unsigned int UTIL_CRC32_Update(unsigned int checksum,
                                      const void *ptr, size_t len)
{
    const unsigned char* data = (const unsigned char*) ptr;
    size_t i;

#ifndef NCBI_USE_PRECOMPILED_CRC32_TABLES
    s_CRC32_Init();
#endif /*NCBI_USE_PRECOMPILED_CRC32_TABLES*/

    for (i = 0;  i < len;  i++) {
        size_t k = ((checksum >> 24) ^ *data++) & 0xFF;
        checksum <<= 8;
        checksum  ^= s_CRC32Table[k];
    }

    return checksum;
}


#define MOD_ADLER          65521
#define MAXLEN_ADLER       5548  /* max len to run without overflows */
#define ADJUST_ADLER(a)    a = (a & 0xFFFF) + (a >> 16) * (0x10000 - MOD_ADLER)
#define FINALIZE_ADLER(a)  if (a >= MOD_ADLER) a -= MOD_ADLER

unsigned int UTIL_Adler32_Update(unsigned int checksum,
                                 const void* ptr, size_t len)
{
    const unsigned char* data = (const unsigned char*) ptr;
    unsigned int a = checksum & 0xFFFF, b = checksum >> 16;

    while (len) {
        size_t i;
        if (len >= MAXLEN_ADLER) {
            len -= MAXLEN_ADLER;
            for (i = 0;  i < MAXLEN_ADLER/4;  ++i) {
                b += a += data[0];
                b += a += data[1];
                b += a += data[2];
                b += a += data[3];
                data += 4;
            }
        } else {
            for (i = len >> 2;  i;  --i) {
                b += a += data[0];
                b += a += data[1];
                b += a += data[2];
                b += a += data[3];
                data += 4;
            }
            for (len &= 3;  len;  --len) {
                b += a += *data++;
            }
        }
        ADJUST_ADLER(a);
        ADJUST_ADLER(b);
    }
    /* It can be shown that a <= 0x1013A here, so a single subtract will do. */
    FINALIZE_ADLER(a);
    /* It can be shown that b can reach 0xFFEF1 here. */
    ADJUST_ADLER(b);
    FINALIZE_ADLER(b);
    return (b << 16) | a;
}

#undef MOD_ADLER
#undef MAXLEN_ADLER
#undef ADJUST_ADLER
#undef FINALIZE_ADLER



/******************************************************************************
 *  MISCELLANEOUS
 */

extern int/*bool*/ UTIL_MatchesMaskEx(const char* name, const char* mask,
                                      int/*bool*/ ignore_case)
{
    for (;;) {
        char c = *mask++;
        char d;
        if (!c) {
            break;
        } else if (c == '?') {
            if (!*name++)
                return 0/*false*/;
        } else if (c == '*') {
            c = *mask;
            while (c == '*')
                c = *++mask;
            if (!c)
                return 1/*true*/;
            while (*name) {
                if (UTIL_MatchesMaskEx(name, mask, ignore_case))
                    return 1/*true*/;
                name++;
            }
            return 0/*false*/;
        } else {
            d = *name++;
            if (ignore_case) {
                c = tolower((unsigned char) c);
                d = tolower((unsigned char) d);
            }
            if (c != d)
                return 0/*false*/;
        }
    }
    return !*name;
}


extern int/*bool*/ UTIL_MatchesMask(const char* name, const char* mask)
{
    return UTIL_MatchesMaskEx(name, mask, 1/*ignore case*/);
}


extern char* UTIL_NcbiLocalHostName(char* hostname)
{
    static const struct {
        const char*  text;
        const size_t len;
    } kEndings[] = {
        {".ncbi.nlm.nih.gov", 17},
        {".ncbi.nih.gov",     13}
    };
    size_t len = hostname ? strlen(hostname) : 0;

    if (len) {
        size_t i;
        for (i = 0;  i < sizeof(kEndings) / sizeof(kEndings[0]);  i++) {
            assert(strlen(kEndings[i].text) == kEndings[i].len);
            if (len > kEndings[i].len) {
                size_t prefix = len - kEndings[i].len;
                if (strcasecmp(hostname + prefix, kEndings[i].text) == 0) {
                    hostname[prefix] = '\0';
                    return hostname;
                }
            }
        }
    }
    return 0;
}


#ifdef NCBI_OS_MSWIN


#  ifdef _UNICODE

extern const char* UTIL_TcharToUtf8OnHeap(const TCHAR* buffer)
{
    const char* p = UTIL_TcharToUtf8(buffer);
    UTIL_ReleaseBufferOnHeap(buffer);
    return p;
}


/*
 * UTIL_TcharToUtf8() is defined in ncbi_strerror.c
 */


extern const TCHAR* UTIL_Utf8ToTchar(const char* buffer)
{
    TCHAR* p = NULL;
    if (buffer) {
        int n = MultiByteToWideChar(CP_UTF8, 0, buffer, -1, NULL, 0);
        if (n >= 0) {
            p = (wchar_t*) LocalAlloc(LMEM_FIXED, (n + 1) * sizeof(wchar_t));
            if (p) {
                MultiByteToWideChar(CP_UTF8, 0, buffer, -1, p,    n);
                p[n] = 0;
            }
        }
    }
    return p;
}

#  endif /*_UNICODE*/


/*
 * UTIL_ReleaseBufferOnHeap() is defined in ncbi_strerror.c
 */


#endif /*NCBI_OS_MSWIN*/