Ui.h revision 4fd606d1f5abe38e1f42c38de1d2e895166bd0f4
/** @file
Private structure, MACRO and function definitions for User Interface related functionalities.
Copyright (c) 2004 - 2012, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#ifndef _UI_H_
#define _UI_H_
//
// Globals
//
#define REGULAR_NUMERIC 0
#define TIME_NUMERIC 1
#define DATE_NUMERIC 2
#define SUBTITLE_INDENT 2
//
// It take 23 characters including the NULL to print a 64 bits number with "[" and "]".
// pow(2, 64) = [18446744073709551616]
//
#define MAX_NUMERIC_INPUT_WIDTH 23
typedef enum {
UiNoOperation,
UiSelect,
UiUp,
UiDown,
UiLeft,
UiRight,
UiReset,
UiPrevious,
UiPageUp,
UiPageDown,
UiHotKey,
UiMaxOperation
} UI_SCREEN_OPERATION;
typedef enum {
CfInitialization,
CfCheckSelection,
CfRepaint,
CfRefreshHighLight,
CfUpdateHelpString,
CfPrepareToReadKey,
CfReadKey,
CfScreenOperation,
CfUiSelect,
CfUiReset,
CfUiLeft,
CfUiRight,
CfUiUp,
CfUiPageUp,
CfUiPageDown,
CfUiDown,
CfUiDefault,
CfUiNoOperation,
CfExit,
CfUiHotKey,
CfMaxControlFlag
} UI_CONTROL_FLAG;
#define UI_ACTION_NONE 0
#define UI_ACTION_REFRESH_FORM 1
#define UI_ACTION_REFRESH_FORMSET 2
#define UI_ACTION_EXIT 3
typedef struct _UI_MENU_LIST UI_MENU_LIST;
typedef struct {
EFI_HII_HANDLE Handle;
//
// Target formset/form/Question information
//
EFI_GUID FormSetGuid;
UINT16 FormId;
UINT16 QuestionId;
UINTN Sequence; // used for time/date only.
UINTN TopRow;
UINTN BottomRow;
UINTN PromptCol;
UINTN OptionCol;
UINTN CurrentRow;
//
// Ation for Browser to taken:
// UI_ACTION_NONE - navigation inside a form
// UI_ACTION_REFRESH_FORM - re-evaluate expressions and repaint form
// UI_ACTION_REFRESH_FORMSET - re-parse formset IFR binary
//
UINTN Action;
//
// Current selected fomset/form/Question
//
FORM_BROWSER_FORMSET *FormSet;
FORM_BROWSER_FORM *Form;
FORM_BROWSER_STATEMENT *Statement;
//
// Whether the Form is editable
//
BOOLEAN FormEditable;
UI_MENU_LIST *CurrentMenu;
} UI_MENU_SELECTION;
#define UI_MENU_OPTION_SIGNATURE SIGNATURE_32 ('u', 'i', 'm', 'm')
#define UI_MENU_LIST_SIGNATURE SIGNATURE_32 ('u', 'i', 'm', 'l')
typedef struct {
UINTN Signature;
LIST_ENTRY Link;
EFI_HII_HANDLE Handle;
FORM_BROWSER_STATEMENT *ThisTag;
UINT16 EntryNumber;
UINTN Row;
UINTN Col;
UINTN OptCol;
CHAR16 *Description;
UINTN Skip; // Number of lines
//
// Display item sequence for date/time
// Date: Month/Day/Year
// Sequence: 0 1 2
//
// Time: Hour : Minute : Second
// Sequence: 0 1 2
//
//
UINTN Sequence;
BOOLEAN GrayOut;
BOOLEAN ReadOnly;
//
// Whether user could change value of this item
//
BOOLEAN IsQuestion;
} UI_MENU_OPTION;
#define MENU_OPTION_FROM_LINK(a) CR (a, UI_MENU_OPTION, Link, UI_MENU_OPTION_SIGNATURE)
struct _UI_MENU_LIST {
UINTN Signature;
LIST_ENTRY Link;
EFI_HII_HANDLE HiiHandle;
EFI_GUID FormSetGuid;
UINT16 FormId;
UINT16 QuestionId;
UINTN Sequence; // used for time/date only.
UI_MENU_LIST *Parent;
LIST_ENTRY ChildListHead;
};
#define UI_MENU_LIST_FROM_LINK(a) CR (a, UI_MENU_LIST, Link, UI_MENU_LIST_SIGNATURE)
typedef struct _MENU_REFRESH_ENTRY MENU_REFRESH_ENTRY;
struct _MENU_REFRESH_ENTRY {
MENU_REFRESH_ENTRY *Next;
UI_MENU_OPTION *MenuOption; // Describes the entry needing an update
UI_MENU_SELECTION *Selection;
UINTN CurrentColumn;
UINTN CurrentRow;
UINTN CurrentAttribute;
EFI_EVENT Event;
};
typedef struct {
UINT16 ScanCode;
UI_SCREEN_OPERATION ScreenOperation;
} SCAN_CODE_TO_SCREEN_OPERATION;
typedef struct {
UI_SCREEN_OPERATION ScreenOperation;
UI_CONTROL_FLAG ControlFlag;
} SCREEN_OPERATION_T0_CONTROL_FLAG;
extern LIST_ENTRY gMenuOption;
extern MENU_REFRESH_ENTRY *gMenuRefreshHead;
extern UI_MENU_SELECTION *gCurrentSelection;
extern BOOLEAN mHiiPackageListUpdated;
//
// Global Functions
//
/**
Initialize Menu option list.
**/
VOID
UiInitMenu (
VOID
);
/**
Initialize Menu option list.
**/
VOID
UiInitMenuList (
VOID
);
/**
Free Menu option linked list.
**/
VOID
UiFreeMenu (
VOID
);
/**
Create a menu with specified formset GUID and form ID, and add it as a child
of the given parent menu.
@param Parent The parent of menu to be added.
@param HiiHandle Hii handle related to this formset.
@param FormSetGuid The Formset Guid of menu to be added.
@param FormId The Form ID of menu to be added.
@return A pointer to the newly added menu or NULL if memory is insufficient.
**/
UI_MENU_LIST *
UiAddMenuList (
IN OUT UI_MENU_LIST *Parent,
IN EFI_HII_HANDLE HiiHandle,
IN EFI_GUID *FormSetGuid,
IN UINT16 FormId
);
/**
Search Menu with given FormId in the parent menu and all its child menus.
@param Parent The parent of menu to search.
@param FormSetGuid The Formset GUID of the menu to search.
@param FormId The Form ID of menu to search.
@return A pointer to menu found or NULL if not found.
**/
UI_MENU_LIST *
UiFindChildMenuList (
IN UI_MENU_LIST *Parent,
IN EFI_GUID *FormSetGuid,
IN UINT16 FormId
);
/**
Search Menu with given FormSetGuid and FormId in all cached menu list.
@param FormSetGuid The Formset GUID of the menu to search.
@param FormId The Form ID of menu to search.
@return A pointer to menu found or NULL if not found.
**/
UI_MENU_LIST *
UiFindMenuList (
IN EFI_GUID *FormSetGuid,
IN UINT16 FormId
);
/**
Free Menu option linked list.
**/
VOID
UiFreeRefreshList (
VOID
);
/**
Add one menu option by specified description and context.
@param String String description for this option.
@param Handle Hii handle for the package list.
@param Form The form this statement belong to.
@param Statement Statement of this Menu Option.
@param NumberOfLines Display lines for this Menu Option.
@param MenuItemCount The index for this Option in the Menu.
@retval Pointer Pointer to the added Menu Option.
**/
UI_MENU_OPTION *
UiAddMenuOption (
IN CHAR16 *String,
IN EFI_HII_HANDLE Handle,
IN FORM_BROWSER_FORM *Form,
IN FORM_BROWSER_STATEMENT *Statement,
IN UINT16 NumberOfLines,
IN UINT16 MenuItemCount
);
/**
Display menu and wait for user to select one menu option, then return it.
If AutoBoot is enabled, then if user doesn't select any option,
after period of time, it will automatically return the first menu option.
@param Selection Menu selection.
@return Return the pointer of the menu which selected,
@return otherwise return NULL.
**/
EFI_STATUS
UiDisplayMenu (
IN OUT UI_MENU_SELECTION *Selection
);
/**
Free up the resource allocated for all strings required
by Setup Browser.
**/
VOID
FreeBrowserStrings (
VOID
);
/**
Process the goto op code, update the info in the selection structure.
@param Statement The statement belong to goto op code.
@param Selection The selection info.
@param Repaint Whether need to repaint the menu.
@param NewLine Whether need to create new line.
@retval EFI_SUCCESS The menu process successfully.
@return Other value if the process failed.
**/
EFI_STATUS
ProcessGotoOpCode (
IN OUT FORM_BROWSER_STATEMENT *Statement,
IN OUT UI_MENU_SELECTION *Selection,
OUT BOOLEAN *Repaint,
OUT BOOLEAN *NewLine
);
/**
The worker function that send the displays to the screen. On output,
the selection made by user is returned.
@param Selection On input, Selection tell setup browser the information
about the Selection, form and formset to be displayed.
On output, Selection return the screen item that is selected
by user.
@retval EFI_SUCCESS The page is displayed successfully.
@return Other value if the page failed to be diplayed.
**/
EFI_STATUS
SetupBrowser (
IN OUT UI_MENU_SELECTION *Selection
);
/**
Set Buffer to Value for Size bytes.
@param Buffer Memory to set.
@param Size Number of bytes to set
@param Value Value of the set operation.
**/
VOID
SetUnicodeMem (
IN VOID *Buffer,
IN UINTN Size,
IN CHAR16 Value
);
/**
Wait for a given event to fire, or for an optional timeout to expire.
@param Event The event to wait for
@param Timeout An optional timeout value in 100 ns units.
@param RefreshInterval Menu refresh interval (in seconds).
@retval EFI_SUCCESS Event fired before Timeout expired.
@retval EFI_TIME_OUT Timout expired before Event fired.
**/
EFI_STATUS
UiWaitForSingleEvent (
IN EFI_EVENT Event,
IN UINT64 Timeout, OPTIONAL
IN UINT8 RefreshInterval OPTIONAL
);
/**
Draw a pop up windows based on the dimension, number of lines and
strings specified.
@param ScreenWidth The width of the pop-up.
@param NumberOfLines The number of lines.
@param ... A series of text strings that displayed in the pop-up.
**/
VOID
EFIAPI
CreateMultiStringPopUp (
IN UINTN ScreenWidth,
IN UINTN NumberOfLines,
...
);
/**
Get string or password input from user.
@param MenuOption Pointer to the current input menu.
@param Prompt The prompt string shown on popup window.
@param StringPtr Old user input and destination for use input string.
@retval EFI_SUCCESS If string input is read successfully
@retval EFI_DEVICE_ERROR If operation fails
**/
EFI_STATUS
ReadString (
IN UI_MENU_OPTION *MenuOption,
IN CHAR16 *Prompt,
IN OUT CHAR16 *StringPtr
);
/**
Get selection for OneOf and OrderedList (Left/Right will be ignored).
@param Selection Pointer to current selection.
@param MenuOption Pointer to the current input menu.
@retval EFI_SUCCESS If Option input is processed successfully
@retval EFI_DEVICE_ERROR If operation fails
**/
EFI_STATUS
GetSelectionInputPopUp (
IN UI_MENU_SELECTION *Selection,
IN UI_MENU_OPTION *MenuOption
);
/**
This routine reads a numeric value from the user input.
@param Selection Pointer to current selection.
@param MenuOption Pointer to the current input menu.
@retval EFI_SUCCESS If numerical input is read successfully
@retval EFI_DEVICE_ERROR If operation fails
**/
EFI_STATUS
GetNumericInput (
IN UI_MENU_SELECTION *Selection,
IN UI_MENU_OPTION *MenuOption
);
/**
Update status bar on the bottom of menu.
@param Selection Current selection info.
@param MessageType The type of message to be shown.
@param Flags The flags in Question header.
@param State Set or clear.
**/
VOID
UpdateStatusBar (
IN UI_MENU_SELECTION *Selection,
IN UINTN MessageType,
IN UINT8 Flags,
IN BOOLEAN State
);
/**
Process Question Config.
@param Selection The UI menu selection.
@param Question The Question to be peocessed.
@retval EFI_SUCCESS Question Config process success.
@retval Other Question Config process fail.
**/
EFI_STATUS
ProcessQuestionConfig (
IN UI_MENU_SELECTION *Selection,
IN FORM_BROWSER_STATEMENT *Question
);
/**
Print Question Value according to it's storage width and display attributes.
@param Question The Question to be printed.
@param FormattedNumber Buffer for output string.
@param BufferSize The FormattedNumber buffer size in bytes.
@retval EFI_SUCCESS Print success.
@retval EFI_BUFFER_TOO_SMALL Buffer size is not enough for formatted number.
**/
EFI_STATUS
PrintFormattedNumber (
IN FORM_BROWSER_STATEMENT *Question,
IN OUT CHAR16 *FormattedNumber,
IN UINTN BufferSize
);
/**
Search an Option of a Question by its value.
@param Question The Question
@param OptionValue Value for Option to be searched.
@retval Pointer Pointer to the found Option.
@retval NULL Option not found.
**/
QUESTION_OPTION *
ValueToOption (
IN FORM_BROWSER_STATEMENT *Question,
IN EFI_HII_VALUE *OptionValue
);
/**
Return data element in an Array by its Index.
@param Array The data array.
@param Type Type of the data in this array.
@param Index Zero based index for data in this array.
@retval Value The data to be returned
**/
UINT64
GetArrayData (
IN VOID *Array,
IN UINT8 Type,
IN UINTN Index
);
/**
Set value of a data element in an Array by its Index.
@param Array The data array.
@param Type Type of the data in this array.
@param Index Zero based index for data in this array.
@param Value The value to be set.
**/
VOID
SetArrayData (
IN VOID *Array,
IN UINT8 Type,
IN UINTN Index,
IN UINT64 Value
);
/**
Process a Question's Option (whether selected or un-selected).
@param Selection Pointer to UI_MENU_SELECTION.
@param MenuOption The MenuOption for this Question.
@param Selected TRUE: if Question is selected.
@param OptionString Pointer of the Option String to be displayed.
@retval EFI_SUCCESS Question Option process success.
@retval Other Question Option process fail.
**/
EFI_STATUS
ProcessOptions (
IN UI_MENU_SELECTION *Selection,
IN UI_MENU_OPTION *MenuOption,
IN BOOLEAN Selected,
OUT CHAR16 **OptionString
);
/**
Process the help string: Split StringPtr to several lines of strings stored in
FormattedString and the glyph width of each line cannot exceed gHelpBlockWidth.
@param StringPtr The entire help string.
@param FormattedString The oupput formatted string.
@param RowCount TRUE: if Question is selected.
**/
UINTN
ProcessHelpString (
IN CHAR16 *StringPtr,
OUT CHAR16 **FormattedString,
IN UINTN RowCount
);
/**
Update key's help imformation.
@param Selection Tell setup browser the information about the Selection
@param MenuOption The Menu option
@param Selected Whether or not a tag be selected
**/
VOID
UpdateKeyHelp (
IN UI_MENU_SELECTION *Selection,
IN UI_MENU_OPTION *MenuOption,
IN BOOLEAN Selected
);
/**
Clear retangle with specified text attribute.
@param LeftColumn Left column of retangle.
@param RightColumn Right column of retangle.
@param TopRow Start row of retangle.
@param BottomRow End row of retangle.
@param TextAttribute The character foreground and background.
**/
VOID
ClearLines (
IN UINTN LeftColumn,
IN UINTN RightColumn,
IN UINTN TopRow,
IN UINTN BottomRow,
IN UINTN TextAttribute
);
/**
Count the storage space of a Unicode string.
This function handles the Unicode string with NARROW_CHAR
and WIDE_CHAR control characters. NARROW_HCAR and WIDE_CHAR
does not count in the resultant output. If a WIDE_CHAR is
hit, then 2 Unicode character will consume an output storage
space with size of CHAR16 till a NARROW_CHAR is hit.
If String is NULL, then ASSERT ().
@param String The input string to be counted.
@return Storage space for the input string.
**/
UINTN
GetStringWidth (
IN CHAR16 *String
);
/**
Will copy LineWidth amount of a string in the OutputString buffer and return the
number of CHAR16 characters that were copied into the OutputString buffer.
@param InputString String description for this option.
@param LineWidth Width of the desired string to extract in CHAR16
characters
@param Index Where in InputString to start the copy process
@param OutputString Buffer to copy the string into
@return Returns the number of CHAR16 characters that were copied into the OutputString buffer.
**/
UINT16
GetLineByWidth (
IN CHAR16 *InputString,
IN UINT16 LineWidth,
IN OUT UINTN *Index,
OUT CHAR16 **OutputString
);
/**
Get the supported width for a particular op-code
@param Statement The FORM_BROWSER_STATEMENT structure passed in.
@param Handle The handle in the HII database being used
@return Returns the number of CHAR16 characters that is support.
**/
UINT16
GetWidth (
IN FORM_BROWSER_STATEMENT *Statement,
IN EFI_HII_HANDLE Handle
);
/**
Concatenate a narrow string to another string.
@param Destination The destination string.
@param Source The source string. The string to be concatenated.
to the end of Destination.
**/
VOID
NewStrCat (
IN OUT CHAR16 *Destination,
IN CHAR16 *Source
);
/**
Wait for a key to be pressed by user.
@param Key The key which is pressed by user.
@retval EFI_SUCCESS The function always completed successfully.
**/
EFI_STATUS
WaitForKeyStroke (
OUT EFI_INPUT_KEY *Key
);
/**
Reset stack pointer to begin of the stack.
**/
VOID
ResetScopeStack (
VOID
);
/**
Push the expression options onto the Stack.
@param Pointer Pointer to the current expression.
@param Level Which type this expression belong to. Form,
statement or option?
@retval EFI_SUCCESS The value was pushed onto the stack.
@retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the stack.
**/
EFI_STATUS
PushConditionalExpression (
IN FORM_EXPRESSION *Pointer,
IN EXPRESS_LEVEL Level
);
/**
Pop the expression options from the Stack
@param Level Which type this expression belong to. Form,
statement or option?
@retval EFI_SUCCESS The value was pushed onto the stack.
@retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the stack.
**/
EFI_STATUS
PopConditionalExpression (
IN EXPRESS_LEVEL Level
);
/**
Get the expression Buffer pointer.
@param Level Which type this expression belong to. Form,
statement or option?
@retval The start pointer of the expression buffer or NULL.
**/
FORM_EXPRESSION **
GetConditionalExpressionList (
IN EXPRESS_LEVEL Level
);
/**
Get the expression list count.
@param Level Which type this expression belong to. Form,
statement or option?
@retval >=0 The expression count
@retval -1 Input parameter error.
**/
INTN
GetConditionalExpressionCount (
IN EXPRESS_LEVEL Level
);
/**
Push an Operand onto the Stack
@param Operand Operand to push.
@retval EFI_SUCCESS The value was pushed onto the stack.
@retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the
stack.
**/
EFI_STATUS
PushScope (
IN UINT8 Operand
);
/**
Pop an Operand from the Stack
@param Operand Operand to pop.
@retval EFI_SUCCESS The value was pushed onto the stack.
@retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the
stack.
**/
EFI_STATUS
PopScope (
OUT UINT8 *Operand
);
/**
Reset stack pointer to begin of the stack.
**/
VOID
ResetCurrentExpressionStack (
VOID
);
/**
Push current expression onto the Stack
@param Pointer Pointer to current expression.
@retval EFI_SUCCESS The value was pushed onto the stack.
@retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the stack.
**/
EFI_STATUS
PushCurrentExpression (
IN VOID *Pointer
);
/**
Pop current expression from the Stack
@param Pointer Pointer to current expression to be pop.
@retval EFI_SUCCESS The value was pushed onto the stack.
@retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the stack.
**/
EFI_STATUS
PopCurrentExpression (
OUT VOID **Pointer
);
/**
Reset stack pointer to begin of the stack.
**/
VOID
ResetMapExpressionListStack (
VOID
);
/**
Push the list of map expression onto the Stack
@param Pointer Pointer to the list of map expression to be pushed.
@retval EFI_SUCCESS The value was pushed onto the stack.
@retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the stack.
**/
EFI_STATUS
PushMapExpressionList (
IN VOID *Pointer
);
/**
Pop the list of map expression from the Stack
@param Pointer Pointer to the list of map expression to be pop.
@retval EFI_SUCCESS The value was pushed onto the stack.
@retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the stack.
**/
EFI_STATUS
PopMapExpressionList (
OUT VOID **Pointer
);
/**
Get Form given its FormId.
@param FormSet The formset which contains this form.
@param FormId Id of this form.
@retval Pointer The form.
@retval NULL Specified Form is not found in the formset.
**/
FORM_BROWSER_FORM *
IdToForm (
IN FORM_BROWSER_FORMSET *FormSet,
IN UINT16 FormId
);
/**
Search a Question in Formset scope using its QuestionId.
@param FormSet The formset which contains this form.
@param Form The form which contains this Question.
@param QuestionId Id of this Question.
@retval Pointer The Question.
@retval NULL Specified Question not found in the form.
**/
FORM_BROWSER_STATEMENT *
IdToQuestion (
IN FORM_BROWSER_FORMSET *FormSet,
IN FORM_BROWSER_FORM *Form,
IN UINT16 QuestionId
);
/**
Zero extend integer/boolean/date/time to UINT64 for comparing.
@param Value HII Value to be converted.
**/
VOID
ExtendValueToU64 (
IN EFI_HII_VALUE *Value
);
/**
Compare two Hii value.
@param Value1 Expression value to compare on left-hand.
@param Value2 Expression value to compare on right-hand.
@param Result Return value after compare.
retval 0 Two operators equal.
return Positive value if Value1 is greater than Value2.
retval Negative value if Value1 is less than Value2.
@param HiiHandle Only required for string compare.
@retval other Could not perform compare on two values.
@retval EFI_SUCCESS Compare the value success.
**/
EFI_STATUS
CompareHiiValue (
IN EFI_HII_VALUE *Value1,
IN EFI_HII_VALUE *Value2,
OUT INTN *Result,
IN EFI_HII_HANDLE HiiHandle OPTIONAL
);
/**
Evaluate the result of a HII expression
If Expression is NULL, then ASSERT.
@param FormSet FormSet associated with this expression.
@param Form Form associated with this expression.
@param Expression Expression to be evaluated.
@retval EFI_SUCCESS The expression evaluated successfuly
@retval EFI_NOT_FOUND The Question which referenced by a QuestionId
could not be found.
@retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the
stack.
@retval EFI_ACCESS_DENIED The pop operation underflowed the stack
@retval EFI_INVALID_PARAMETER Syntax error with the Expression
**/
EFI_STATUS
EvaluateExpression (
IN FORM_BROWSER_FORMSET *FormSet,
IN FORM_BROWSER_FORM *Form,
IN OUT FORM_EXPRESSION *Expression
);
/**
Return the result of the expression list. Check the expression list and
return the highest priority express result.
Priority: DisableIf > SuppressIf > GrayOutIf > FALSE
@param ExpList The input expression list.
@param Evaluate Whether need to evaluate the expression first.
@param FormSet FormSet associated with this expression. Only
needed when Evaluate is TRUE
@param Form Form associated with this expression. Only
needed when Evaluate is TRUE
@retval EXPRESS_RESULT Return the higher priority express result.
DisableIf > SuppressIf > GrayOutIf > FALSE
**/
EXPRESS_RESULT
EvaluateExpressionList (
IN FORM_EXPRESSION_LIST *ExpList,
IN BOOLEAN Evaluate,
IN FORM_BROWSER_FORMSET *FormSet, OPTIONAL
IN FORM_BROWSER_FORM *Form OPTIONAL
);
#endif // _UI_H