/*++

Copyright (c) 2013 Minoca Corp.

    This file is licensed under the terms of the GNU General Public License
    version 3. Alternative licensing terms are available. Contact
    info@minocacorp.com for details. See the LICENSE file at the root of this
    project for complete licensing information.

Module Name:

    wscan.c

Abstract:

    This module implements wide string scanning functions.

Author:

    Evan Green 27-Aug-2013

Environment:

    User Mode C Library

--*/

//
// ------------------------------------------------------------------- Includes
//

#include "libcp.h"
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>

//
// ---------------------------------------------------------------- Definitions
//

//
// ------------------------------------------------------ Data Type Definitions
//

//
// ----------------------------------------------- Internal Function Prototypes
//

BOOL
ClpStreamScannerGetInputWide (
    PSCAN_INPUT Input,
    PWCHAR Character
    );

//
// -------------------------------------------------------------------- Globals
//

//
// ------------------------------------------------------------------ Functions
//

LIBC_API
int
swscanf (
    const wchar_t *Input,
    const wchar_t *Format,
    ...
    )

/*++

Routine Description:

    This routine scans in a wide string and converts it to a number of arguments
    based on a format string.

Arguments:

    Input - Supplies a pointer to the wide input string to scan.

    Format - Supplies the format wide string that specifies how to convert the
        input to the arguments.

    ... - Supplies the remaining pointer arguments where the scanned data will
        be returned.

Return Value:

    Returns the number of successfully matched items on success. If the input
    ends before the first matching failure or conversion, EOF is returned. If
    a read error occurs, EOF shall be returned and errno shall be set to
    indicate the error.

--*/

{

    va_list ArgumentList;
    ULONG FormatLength;
    ULONG InputLength;
    ULONG ItemsScanned;
    int ReturnValue;
    KSTATUS Status;

    va_start(ArgumentList, Format);
    InputLength = MAX_ULONG;
    FormatLength = MAX_ULONG;
    Status = RtlStringScanVaListWide((PWSTR)Input,
                                     InputLength,
                                     (PWSTR)Format,
                                     FormatLength,
                                     CharacterEncodingDefault,
                                     &ItemsScanned,
                                     ArgumentList);

    if (!KSUCCESS(Status)) {
        ReturnValue = EOF;
        errno = ClConvertKstatusToErrorNumber(Status);
        if (Status != STATUS_END_OF_FILE) {
            if (ItemsScanned != 0) {
                ReturnValue = ItemsScanned;
            }
        }

    } else {
        ReturnValue = ItemsScanned;
    }

    va_end(ArgumentList);
    return ReturnValue;
}

LIBC_API
int
vswscanf (
    const wchar_t *String,
    const wchar_t *Format,
    va_list ArgumentList
    )

/*++

Routine Description:

    This routine scans in a wide string and converts it to a number of arguments
    based on a format string.

Arguments:

    String - Supplies a pointer to the wide input string to scan.

    Format - Supplies the wide format string that specifies how to convert the
        input to the arguments.

    ArgumentList - Supplies the remaining arguments, which are all pointers to
        various types to be scanned.

Return Value:

    Returns the number of successfully matched items on success. If the input
    ends before the first matching failure or conversion, EOF is returned. If
    a read error occurs, EOF shall be returned and errno shall be set to
    indicate the error.

--*/

{

    ULONG FormatLength;
    ULONG InputLength;
    ULONG ItemsScanned;
    int ReturnValue;
    KSTATUS Status;

    InputLength = MAX_ULONG;
    FormatLength = MAX_ULONG;
    Status = RtlStringScanVaListWide((PWSTR)String,
                                     InputLength,
                                     (PWSTR)Format,
                                     FormatLength,
                                     CharacterEncodingDefault,
                                     &ItemsScanned,
                                     ArgumentList);

    if (!KSUCCESS(Status)) {
        ReturnValue = EOF;
        errno = ClConvertKstatusToErrorNumber(Status);
        if (Status != STATUS_END_OF_FILE) {
            if (ItemsScanned != 0) {
                ReturnValue = ItemsScanned;
            }
        }

    } else {
        ReturnValue = ItemsScanned;
    }

    return ReturnValue;
}

LIBC_API
int
fwscanf (
    FILE *Stream,
    const wchar_t *Format,
    ...
    )

/*++

Routine Description:

    This routine scans in a string from a stream and converts it to a number
    of arguments based on a wide format string.

Arguments:

    Stream - Supplies a pointer to the input stream.

    Format - Supplies the wide format string that specifies how to convert the
        input to the arguments.

    ... - Supplies the remaining arguments, which are all pointers to
        various types to be scanned.

Return Value:

    Returns the number of successfully matched items on success. If the input
    ends before the first matching failure or conversion, EOF is returned. If
    a read error occurs, EOF shall be returned and errno shall be set to
    indicate the error.

--*/

{

    va_list ArgumentList;
    int Result;

    va_start(ArgumentList, Format);
    Result = vfwscanf(Stream, Format, ArgumentList);
    va_end(ArgumentList);
    return Result;
}

LIBC_API
int
vfwscanf (
    FILE *Stream,
    const wchar_t *Format,
    va_list ArgumentList
    )

/*++

Routine Description:

    This routine scans in a string from a stream and converts it to a number
    of arguments based on a format string.

Arguments:

    Stream - Supplies a pointer to the input stream.

    Format - Supplies the wide format string that specifies how to convert the
        input to the arguments.

    ArgumentList - Supplies the remaining arguments, which are all pointers to
        various types to be scanned.

Return Value:

    Returns the number of successfully matched items on success. If the input
    ends before the first matching failure or conversion, EOF is returned. If
    a read error occurs, EOF shall be returned and errno shall be set to
    indicate the error.

--*/

{

    int Result;

    ClpLockStream(Stream);
    Result = vfwscanf_unlocked(Stream, Format, ArgumentList);
    ClpUnlockStream(Stream);
    return Result;
}

LIBC_API
int
vfwscanf_unlocked (
    FILE *Stream,
    const wchar_t *Format,
    va_list ArgumentList
    )

/*++

Routine Description:

    This routine scans in a string from a stream and converts it to a number
    of arguments based on a format string. This routine does not acquire the
    stream's lock.

Arguments:

    Stream - Supplies a pointer to the input stream.

    Format - Supplies the side format string that specifies how to convert the
        input to the arguments.

    ArgumentList - Supplies the remaining arguments, which are all pointers to
        various types to be scanned.

Return Value:

    Returns the number of successfully matched items on success. If the input
    ends before the first matching failure or conversion, EOF is returned. If
    a read error occurs, EOF shall be returned and errno shall be set to
    indicate the error.

--*/

{

    SCAN_INPUT Input;
    ULONG ItemsScanned;
    int ReturnValue;
    KSTATUS Status;

    RtlZeroMemory(&Input, sizeof(SCAN_INPUT));
    Input.DataU.Context = Stream;
    Input.ReadU.GetInputWide = ClpStreamScannerGetInputWide;
    Status = RtlScanWide(&Input,
                         (PWSTR)Format,
                         MAX_ULONG,
                         &ItemsScanned,
                         ArgumentList);

    if (!KSUCCESS(Status)) {
        ReturnValue = EOF;
        errno = ClConvertKstatusToErrorNumber(Status);
        if (Status != STATUS_END_OF_FILE) {
            if (ItemsScanned != 0) {
                ReturnValue = ItemsScanned;
            }
        }

    } else {
        ReturnValue = ItemsScanned;
    }

    return ReturnValue;
}

LIBC_API
int
wscanf (
    const wchar_t *Format,
    ...
    )

/*++

Routine Description:

    This routine scans in a string from standard in and converts it to a number
    of arguments based on a format string.

Arguments:

    Format - Supplies the wide format string that specifies how to convert the
        input to the arguments.

    ... - Supplies the remaining arguments, which are all pointers to
        various types to be scanned.

Return Value:

    Returns the number of successfully matched items on success. If the input
    ends before the first matching failure or conversion, EOF is returned. If
    a read error occurs, EOF shall be returned and errno shall be set to
    indicate the error.

--*/

{

    va_list ArgumentList;
    int Result;

    va_start(ArgumentList, Format);
    Result = vwscanf(Format, ArgumentList);
    va_end(ArgumentList);
    return Result;
}

LIBC_API
int
vwscanf (
    const wchar_t *Format,
    va_list ArgumentList
    )

/*++

Routine Description:

    This routine scans in a string from standard in and converts it to a number
    of arguments based on a format string.

Arguments:

    Format - Supplies the wide format string that specifies how to convert the
        input to the arguments.

    ArgumentList - Supplies the remaining arguments, which are all pointers to
        various types to be scanned.

Return Value:

    Returns the number of successfully matched items on success. If the input
    ends before the first matching failure or conversion, EOF is returned. If
    a read error occurs, EOF shall be returned and errno shall be set to
    indicate the error.

--*/

{

    int Result;

    Result = vfwscanf(stdin, Format, ArgumentList);
    return Result;
}

LIBC_API
float
wcstof (
    const wchar_t *String,
    wchar_t **StringAfterScan
    )

/*++

Routine Description:

    This routine converts the initial portion of the given wide string into a
    float. This routine will scan past any whitespace at the beginning of
    the string.

Arguments:

    String - Supplies a pointer to the null terminated wide string to convert
        to afloat.

    StringAfterScan - Supplies a pointer where a pointer will be returned
        representing the remaining portion of the string after the float was
        scanned. If the entire string is made up of whitespace or invalid
        characters, then this will point to the beginning of the given string
        (the scanner will not be advanced).

Return Value:

    Returns the float representation of the string. If the value could not be
    converted, 0 is returned, and errno will be set to either EINVAL if the
    number could not be converted or ERANGE if the number is outside of the
    return type's expressible range.

--*/

{

    double Double;

    Double = wcstod(String, StringAfterScan);
    return (float)Double;
}

LIBC_API
double
wcstod (
    const wchar_t *String,
    wchar_t **StringAfterScan
    )

/*++

Routine Description:

    This routine converts the initial portion of the given wide string into a
    double. This routine will scan past any whitespace at the beginning of
    the string.

Arguments:

    String - Supplies a pointer to the null terminated wide string to convert
        to a double.

    StringAfterScan - Supplies a pointer where a pointer will be returned
        representing the remaining portion of the wide string after the double
        was scanned. If the entire string is made up of whitespace or invalid
        characters, then this will point to the beginning of the given string
        (the scanner will not be advanced).

Return Value:

    Returns the double representation of the wide string. If the value could
    not be converted, 0 is returned, and errno will be set to either EINVAL if
    the number could not be converted or ERANGE if the number is outside of the
    return type's expressible range.

--*/

{

    double Double;
    PCWSTR RemainingString;
    KSTATUS Status;
    ULONG StringLength;

    StringLength = MAX_ULONG;
    RemainingString = (PWSTR)String;
    Status = RtlStringScanDoubleWide(&RemainingString, &StringLength, &Double);
    if (StringAfterScan != NULL) {
        *StringAfterScan = (PWSTR)RemainingString;
    }

    if (!KSUCCESS(Status)) {
        errno = ClConvertKstatusToErrorNumber(Status);
        return 0;
    }

    return Double;
}

LIBC_API
long double
wcstold (
    const wchar_t *String,
    wchar_t **StringAfterScan
    )

/*++

Routine Description:

    This routine converts the initial portion of the given wide string into a
    long double. This routine will scan past any whitespace at the beginning of
    the string.

Arguments:

    String - Supplies a pointer to the null terminated wide string to convert
        to a long double.

    StringAfterScan - Supplies a pointer where a pointer will be returned
        representing the remaining portion of the string after the long double
        was scanned. If the entire string is made up of whitespace or invalid
        characters, then this will point to the beginning of the given string
        (the scanner will not be advanced).

Return Value:

    Returns the long double representation of the string. If the value could not
    be converted, 0 is returned, and errno will be set to either EINVAL if the
    number could not be converted or ERANGE if the number is outside of the
    return type's expressible range.

--*/

{

    double Double;

    Double = wcstod(String, StringAfterScan);
    return (long double)Double;
}

LIBC_API
long
wcstol (
    const wchar_t *String,
    wchar_t **StringAfterScan,
    int Base
    )

/*++

Routine Description:

    This routine converts the initial portion of the given wide string into an
    integer. This routine will scan past any whitespace at the beginning of
    the string. The string may have an optional plus or minus in front of the
    number to indicate sign.

Arguments:

    String - Supplies a pointer to the null terminated wide string to convert
        to an integer.

    StringAfterScan - Supplies a pointer where a pointer will be returned
        representing the remaining portion of the wide string after the integer
        was scanned. If the entire string is made up of whitespace or invalid
        characters, then this will point to the beginning of the given string
        (the scanner will not be advanced).

    Base - Supplies the base system to interpret the number as. If zero is
        supplied, the base will be figured out based on the contents of the
        string. If the string begins with 0, it's treated as an octal (base 8)
        number. If the string begins with 1-9, it's treated as a decimal
        (base 10) number. And if the string begins with 0x or 0X, it's treated
        as a hexadecimal (base 16) number. Other base values must be specified
        explicitly here.

Return Value:

    Returns the integer representation of the string. If the value could not be
    converted, 0 is returned, and errno will be set to either EINVAL if the
    number could not be converted or ERANGE if the number is outside of the
    return type's expressible range.

--*/

{

    LONGLONG Integer;
    PCWSTR RemainingString;
    KSTATUS Status;
    ULONG StringLength;

    StringLength = MAX_ULONG;
    RemainingString = (PWSTR)String;
    Status = RtlStringScanIntegerWide(&RemainingString,
                                      &StringLength,
                                      Base,
                                      TRUE,
                                      &Integer);

    if (StringAfterScan != NULL) {
        *StringAfterScan = (PWSTR)RemainingString;
    }

    if (!KSUCCESS(Status)) {
        errno = ClConvertKstatusToErrorNumber(Status);

        //
        // On integer overflow, set errno to ERANGE, but still return the
        // value, which will be a very extreme value.
        //

        if (Status == STATUS_INTEGER_OVERFLOW) {
            if (Integer == LLONG_MAX) {
                return LONG_MAX;
            }

            return LONG_MIN;

        } else {
            return 0;
        }
    }

    if (Integer > LONG_MAX) {
        errno = ERANGE;
        return LONG_MAX;

    } else if (Integer < LONG_MIN) {
        errno = ERANGE;
        return LONG_MIN;
    }

    return (LONG)Integer;
}

LIBC_API
long long
wcstoll (
    const wchar_t *String,
    wchar_t **StringAfterScan,
    int Base
    )

/*++

Routine Description:

    This routine converts the initial portion of the given wide string into an
    integer. This routine will scan past any whitespace at the beginning of
    the string. The string may have an optional plus or minus in front of the
    number to indicate sign.

Arguments:

    String - Supplies a pointer to the null terminated wide string to convert
        to an integer.

    StringAfterScan - Supplies a pointer where a pointer will be returned
        representing the remaining portion of the wide string after the integer
        was scanned. If the entire string is made up of whitespace or invalid
        characters, then this will point to the beginning of the given string
        (the scanner will not be advanced).

    Base - Supplies the base system to interpret the number as. If zero is
        supplied, the base will be figured out based on the contents of the
        string. If the string begins with 0, it's treated as an octal (base 8)
        number. If the string begins with 1-9, it's treated as a decimal
        (base 10) number. And if the string begins with 0x or 0X, it's treated
        as a hexadecimal (base 16) number. Other base values must be specified
        explicitly here.

Return Value:

    Returns the integer representation of the string. If the value could not be
    converted, 0 is returned, and errno will be set to EINVAL to indicate the
    number could not be converted.

--*/

{

    LONGLONG Integer;
    PCWSTR RemainingString;
    KSTATUS Status;
    ULONG StringLength;

    StringLength = MAX_ULONG;
    RemainingString = (PWSTR)String;
    Status = RtlStringScanIntegerWide(&RemainingString,
                                      &StringLength,
                                      Base,
                                      TRUE,
                                      &Integer);

    if (StringAfterScan != NULL) {
        *StringAfterScan = (PWSTR)RemainingString;
    }

    if (!KSUCCESS(Status)) {
        if (Status != STATUS_INTEGER_OVERFLOW) {
            Integer = 0;
        }

        errno = ClConvertKstatusToErrorNumber(Status);
    }

    return Integer;
}

LIBC_API
long
wcstoul (
    const wchar_t *String,
    wchar_t **StringAfterScan,
    int Base
    )

/*++

Routine Description:

    This routine converts the initial portion of the given wide string into an
    integer. This routine will scan past any whitespace at the beginning of
    the string. The string may have an optional plus or minus in front of the
    number to indicate sign.

Arguments:

    String - Supplies a pointer to the null terminated wide string to convert
        to an integer.

    StringAfterScan - Supplies a pointer where a pointer will be returned
        representing the remaining portion of the wide string after the integer
        was scanned. If the entire string is made up of whitespace or invalid
        characters, then this will point to the beginning of the given string
        (the scanner will not be advanced).

    Base - Supplies the base system to interpret the number as. If zero is
        supplied, the base will be figured out based on the contents of the
        string. If the string begins with 0, it's treated as an octal (base 8)
        number. If the string begins with 1-9, it's treated as a decimal
        (base 10) number. And if the string begins with 0x or 0X, it's treated
        as a hexadecimal (base 16) number. Other base values must be specified
        explicitly here.

Return Value:

    Returns the integer representation of the string. If the value could not be
    converted, 0 is returned, and errno will be set to either EINVAL if the
    number could not be converted or ERANGE if the number is outside of the
    return type's expressible range.

--*/

{

    LONGLONG Integer;
    PCWSTR RemainingString;
    KSTATUS Status;
    ULONG StringLength;

    StringLength = MAX_ULONG;
    RemainingString = (PWSTR)String;
    Status = RtlStringScanIntegerWide(&RemainingString,
                                      &StringLength,
                                      Base,
                                      FALSE,
                                      &Integer);

    if (StringAfterScan != NULL) {
        *StringAfterScan = (PWSTR)RemainingString;
    }

    if (!KSUCCESS(Status)) {
        errno = ClConvertKstatusToErrorNumber(Status);
        if (Status == STATUS_INTEGER_OVERFLOW) {
            return ULONG_MAX;

        } else {
            return 0;
        }
    }

    if ((ULONGLONG)Integer > ULONG_MAX) {
        errno = ERANGE;
        return ULONG_MAX;
    }

    return (ULONG)(ULONGLONG)Integer;
}

LIBC_API
long long
wcstoull (
    const wchar_t *String,
    wchar_t **StringAfterScan,
    int Base
    )

/*++

Routine Description:

    This routine converts the initial portion of the given wide string into an
    integer. This routine will scan past any whitespace at the beginning of
    the string. The string may have an optional plus or minus in front of the
    number to indicate sign.

Arguments:

    String - Supplies a pointer to the null terminated wide string to convert
        to an integer.

    StringAfterScan - Supplies a pointer where a pointer will be returned
        representing the remaining portion of the wide string after the integer
        was scanned. If the entire string is made up of whitespace or invalid
        characters, then this will point to the beginning of the given string
        (the scanner will not be advanced).

    Base - Supplies the base system to interpret the number as. If zero is
        supplied, the base will be figured out based on the contents of the
        string. If the string begins with 0, it's treated as an octal (base 8)
        number. If the string begins with 1-9, it's treated as a decimal
        (base 10) number. And if the string begins with 0x or 0X, it's treated
        as a hexadecimal (base 16) number. Other base values must be specified
        explicitly here.

Return Value:

    Returns the integer representation of the string. If the value could not be
    converted, 0 is returned, and errno will be set to EINVAL to indicate the
    number could not be converted.

--*/

{

    LONGLONG Integer;
    PCWSTR RemainingString;
    KSTATUS Status;
    ULONG StringLength;

    StringLength = MAX_ULONG;
    RemainingString = (PWSTR)String;
    Status = RtlStringScanIntegerWide(&RemainingString,
                                      &StringLength,
                                      Base,
                                      FALSE,
                                      &Integer);

    if (StringAfterScan != NULL) {
        *StringAfterScan = (PWSTR)RemainingString;
    }

    if (!KSUCCESS(Status)) {
        if (Status != STATUS_INTEGER_OVERFLOW) {
            Integer = 0;
        }

        errno = ClConvertKstatusToErrorNumber(Status);
    }

    return (ULONGLONG)Integer;
}

//
// --------------------------------------------------------- Internal Functions
//

BOOL
ClpStreamScannerGetInputWide (
    PSCAN_INPUT Input,
    PWCHAR Character
    )

/*++

Routine Description:

    This routine retrieves another byte of input from the input scanner for a
    stream based scanner.

Arguments:

    Input - Supplies a pointer to the input scanner structure.

    Character - Supplies a pointer where the character will be returned on
        success.

Return Value:

    TRUE if a character was read.

    FALSE if the end of the file or string was encountered.

--*/

{

    wint_t NewCharacter;

    NewCharacter = fgetwc_unlocked(Input->DataU.Context);
    if (NewCharacter == WEOF) {
        return FALSE;
    }

    *Character = (WCHAR)NewCharacter;
    Input->CharactersRead += 1;
    return TRUE;
}