public/fpdf_dataavail.h

// Copyright 2014 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com

#ifndef PUBLIC_FPDF_DATAAVAIL_H_
#define PUBLIC_FPDF_DATAAVAIL_H_

#include <stddef.h>  // For size_t.

#include "fpdfview.h"

/** The result of the process which check linearized PDF. */
#define FSDK_IS_LINEARIZED          1
#define FSDK_NOT_LINEARIZED         0
#define FSDK_UNKNOW_LINEARIZED      -1


#ifdef __cplusplus
extern "C" {
#endif

/**
 * Interface: FX_FILEAVAIL
 *          Interface for checking whether the section of the file is available.
 */
typedef struct _FX_FILEAVAIL {
    /**
     * Version number of the interface. Currently must be 1.
     */
    int version;

    /**
     * Method: IsDataAvail
     *      Report whether the specified data section is available. A section is available only if all bytes in the section is available.
     * Interface Version:
     *      1
     * Implementation Required:
     *      Yes
     * Parameters:
     *      pThis       -   Pointer to the interface structure itself.
     *      offset      -   The offset of the data section in the file.
     *      size        -   The size of the data section
     * Return Value:
     *      true means the specified data section is available.
     * Comments:
     *      Called by Foxit SDK to check whether the data section is ready.
     */
    FPDF_BOOL (*IsDataAvail)(struct _FX_FILEAVAIL* pThis, size_t offset, size_t size);
} FX_FILEAVAIL;

typedef void* FPDF_AVAIL;

/**
* Function: FPDFAvail_Create
*           Create a document availability provider.
*
* Parameters:
*           file_avail  -   Pointer to file availability interface to check availability of file data.
*           file        -   Pointer to a file access interface for reading data from file.
* Return value:
*           A handle to the document availability provider. NULL for error.
* Comments:
*           Application must call FPDFAvail_Destroy when done with the availability provider.
*/
DLLEXPORT FPDF_AVAIL STDCALL FPDFAvail_Create(FX_FILEAVAIL* file_avail, FPDF_FILEACCESS* file);

/**
* Function: FPDFAvail_Destroy
*           Destroy a document availibity provider.
*
* Parameters:
*           avail       -   Handle to document availability provider returned by FPDFAvail_Create
* Return Value:
*           None.
*/
DLLEXPORT void STDCALL FPDFAvail_Destroy(FPDF_AVAIL avail);

/**
 * Interface: FX_DOWNLOADHINTS
 *          Download hints interface. Used to receive hints for further downloading.
 */
typedef struct _FX_DOWNLOADHINTS {
    /**
     * Version number of the interface. Currently must be 1.
     */
    int version;

    /**
     * Method: AddSegment
     *      Add a section to be downloaded.
     * Interface Version:
     *      1
     * Implementation Required:
     *      Yes
     * Parameters:
     *      pThis       -   Pointer to the interface structure itself.
     *      offset      -   The offset of the hint reported to be downloaded.
     *      size        -   The size of the hint reported to be downloaded.
     * Return Value:
     *      None.
     * Comments:
     *      Called by Foxit SDK to report some downloading hints for download manager.
     *      The position and size of section may be not accurate, part of the section might be already available.
     *      The download manager must deal with that to maximize download efficiency.
     */
    void (*AddSegment)(struct _FX_DOWNLOADHINTS* pThis, size_t offset, size_t size);
} FX_DOWNLOADHINTS;

/**
* Function: FPDFAvail_IsDocAvail
*           Check whether the document is ready for loading, if not, get download hints.
*
* Parameters:
*           avail       -   Handle to document availability provider returned by FPDFAvail_Create
*           hints       -   Pointer to a download hints interface, receiving generated hints
* Return value:
*           Non-zero for page is fully available, 0 for page not yet available.
* Comments:
*           The application should call this function whenever new data arrived, and process all the
*           generated download hints if any, until the function returns non-zero value. Then the
*           application can call FPDFAvail_GetDocument() to get a document handle.
*/
DLLEXPORT int STDCALL FPDFAvail_IsDocAvail(FPDF_AVAIL avail, FX_DOWNLOADHINTS* hints);

/**
* Function: FPDFAvail_GetDocument
*           Get document from the availability provider.
*
* Parameters:
*           avail       -   Handle to document availability provider returned by FPDFAvail_Create
*     password  -   Optional password for decrypting the PDF file.
* Return value:
*           Handle to the document.
* Comments:
*           After FPDFAvail_IsDocAvail() returns TRUE, the application should call this function to
*           get the document handle. To close the document, use FPDF_CloseDocument function.
*/
DLLEXPORT FPDF_DOCUMENT STDCALL FPDFAvail_GetDocument(FPDF_AVAIL avail,
                                                      FPDF_BYTESTRING password);

/**
* Function: FPDFAvail_GetFirstPageNum
*           Get page number for the first available page in a linearized PDF
*
* Parameters:
*           doc         -   A document handle returned by FPDFAvail_GetDocument
* Return Value:
*           Zero-based index for the first available page.
* Comments:
*           For most linearized PDFs, the first available page would be just the first page, however,
*           some PDFs might make other page to be the first available page.
*           For non-linearized PDF, this function will always return zero.
*/
DLLEXPORT int STDCALL FPDFAvail_GetFirstPageNum(FPDF_DOCUMENT doc);

/**
* Function: FPDFAvail_IsPageAvail
*           Check whether a page is ready for loading, if not, get download hints.
*
* Parameters:
*           avail       -   Handle to document availability provider returned by FPDFAvail_Create
*           page_index  -   Index number of the page. 0 for the first page.
*           hints       -   Pointer to a download hints interface, receiving generated hints
* Return value:
*           Non-zero for page is fully available, 0 for page not yet available.
* Comments:
*           This function call be called only after FPDFAvail_GetDocument if called.
*           The application should call this function whenever new data arrived, and process all the
*           generated download hints if any, until the function returns non-zero value. Then the
*           application can perform page loading.
*/
DLLEXPORT int STDCALL FPDFAvail_IsPageAvail(FPDF_AVAIL avail, int page_index, FX_DOWNLOADHINTS* hints);

/**
* Function: FPDFAvail_ISFormAvail
*           Check whether Form data is ready for init, if not, get download hints.
*
* Parameters:
*           avail       -   Handle to document availability provider returned by FPDFAvail_Create
*           hints       -   Pointer to a download hints interface, receiving generated hints
* Return value:
*           Non-zero for Form data is fully available, 0 for Form data not yet available.
*           Details: -1 - error, the input parameter not correct, such as hints is null.
*                    0  - data not available
*                    1  - data available
*                    2  - no form data.
* Comments:
*           This function call be called only after FPDFAvail_GetDocument if called.
*           The application should call this function whenever new data arrived, and process all the
*           generated download hints if any, until the function returns non-zero value. Then the
*           application can perform page loading. Recommend to call FPDFDOC_InitFormFillEnvironment
*           after the function returns non-zero value.
*/
DLLEXPORT int STDCALL FPDFAvail_IsFormAvail(FPDF_AVAIL avail, FX_DOWNLOADHINTS* hints);

/**
* Function: FPDFAvail_IsLinearized
*           To check whether a document is Linearized PDF file.
*
* Parameters:
*           avail       -   Handle to document availability provider returned by FPDFAvail_Create
* Return value:
*           return TRUE means the document is linearized PDF else not.
*           FSDK_IS_LINEARIZED is a linearize file.
*           FSDK_NOT_LINEARIZED is not a linearize file.
*           FSDK_UNKNOW_LINEARIZED don't know whether the file is a linearize file.
* Comments:
*           It return TRUE/FALSE as soon as we have first 1K data.  If the file's size less than
*           1K,we don't known whether the PDF is a linearized file.
*
*/
DLLEXPORT FPDF_BOOL STDCALL FPDFAvail_IsLinearized(FPDF_AVAIL avail);

#ifdef __cplusplus
}
#endif

#endif  // PUBLIC_FPDF_DATAAVAIL_H_