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      1 // Copyright 2014 PDFium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
      6 
      7 #ifndef PUBLIC_FPDF_DATAAVAIL_H_
      8 #define PUBLIC_FPDF_DATAAVAIL_H_
      9 
     10 #include <stddef.h>
     11 
     12 // NOLINTNEXTLINE(build/include)
     13 #include "fpdfview.h"
     14 
     15 #define PDF_LINEARIZATION_UNKNOWN -1
     16 #define PDF_NOT_LINEARIZED 0
     17 #define PDF_LINEARIZED 1
     18 
     19 #define PDF_DATA_ERROR -1
     20 #define PDF_DATA_NOTAVAIL 0
     21 #define PDF_DATA_AVAIL 1
     22 
     23 #define PDF_FORM_ERROR -1
     24 #define PDF_FORM_NOTAVAIL 0
     25 #define PDF_FORM_AVAIL 1
     26 #define PDF_FORM_NOTEXIST 2
     27 
     28 #ifdef __cplusplus
     29 extern "C" {
     30 #endif  // __cplusplus
     31 
     32 // Interface for checking whether sections of the file are available.
     33 typedef struct _FX_FILEAVAIL {
     34   // Version number of the interface. Must be 1.
     35   int version;
     36 
     37   // Reports if the specified data section is currently available. A section is
     38   // available if all bytes in the section are available.
     39   //
     40   // Interface Version: 1
     41   // Implementation Required: Yes
     42   //
     43   //   pThis  - pointer to the interface structure.
     44   //   offset - the offset of the data section in the file.
     45   //   size   - the size of the data section.
     46   //
     47   // Returns true if the specified data section at |offset| of |size|
     48   // is available.
     49   FPDF_BOOL (*IsDataAvail)(struct _FX_FILEAVAIL* pThis,
     50                            size_t offset,
     51                            size_t size);
     52 } FX_FILEAVAIL;
     53 typedef void* FPDF_AVAIL;
     54 
     55 // Create a document availability provider.
     56 //
     57 //   file_avail - pointer to file availability interface.
     58 //   file       - pointer to a file access interface.
     59 //
     60 // Returns a handle to the document availability provider, or NULL on error.
     61 //
     62 // |FPDFAvail_Destroy| must be called when done with the availability provider.
     63 DLLEXPORT FPDF_AVAIL STDCALL FPDFAvail_Create(FX_FILEAVAIL* file_avail,
     64                                               FPDF_FILEACCESS* file);
     65 
     66 // Destroy the |avail| document availability provider.
     67 //
     68 //   avail - handle to document availability provider to be destroyed.
     69 DLLEXPORT void STDCALL FPDFAvail_Destroy(FPDF_AVAIL avail);
     70 
     71 // Download hints interface. Used to receive hints for further downloading.
     72 typedef struct _FX_DOWNLOADHINTS {
     73   // Version number of the interface. Must be 1.
     74   int version;
     75 
     76   // Add a section to be downloaded.
     77   //
     78   // Interface Version: 1
     79   // Implementation Required: Yes
     80   //
     81   //   pThis  - pointer to the interface structure.
     82   //   offset - the offset of the hint reported to be downloaded.
     83   //   size   - the size of the hint reported to be downloaded.
     84   //
     85   // The |offset| and |size| of the section may not be unique. Part of the
     86   // section might be already available. The download manager must deal with
     87   // overlapping sections.
     88   void (*AddSegment)(struct _FX_DOWNLOADHINTS* pThis,
     89                      size_t offset,
     90                      size_t size);
     91 } FX_DOWNLOADHINTS;
     92 
     93 // Checks if the document is ready for loading, if not, gets download hints.
     94 //
     95 //   avail - handle to document availability provider.
     96 //   hints - pointer to a download hints interface.
     97 //
     98 // Returns one of:
     99 //   PDF_DATA_ERROR: A common error is returned. Data availability unknown.
    100 //   PDF_DATA_NOTAVAIL: Data not yet available.
    101 //   PDF_DATA_AVAIL: Data available.
    102 //
    103 // Applications should call this function whenever new data arrives, and process
    104 // all the generated download hints, if any, until the function returns
    105 // |PDF_DATA_ERROR| or |PDF_DATA_AVAIL|.
    106 //
    107 // Once all data is available, call |FPDFAvail_GetDocument| to get a document
    108 // handle.
    109 DLLEXPORT int STDCALL
    110 FPDFAvail_IsDocAvail(FPDF_AVAIL avail, FX_DOWNLOADHINTS* hints);
    111 
    112 // Get document from the availability provider.
    113 //
    114 //   avail    - handle to document availability provider.
    115 //   password - password for decrypting the PDF file. Optional.
    116 //
    117 // Returns a handle to the document.
    118 //
    119 // When |FPDFAvail_IsDocAvail| returns TRUE, call |FPDFAvail_GetDocument| to
    120 // retrieve the document handle.
    121 DLLEXPORT FPDF_DOCUMENT STDCALL FPDFAvail_GetDocument(FPDF_AVAIL avail,
    122                                                       FPDF_BYTESTRING password);
    123 
    124 // Get the page number for the first available page in a linearized PDF.
    125 //
    126 //   doc - document handle.
    127 //
    128 // Returns the zero-based index for the first available page.
    129 //
    130 // For most linearized PDFs, the first available page will be the first page,
    131 // however, some PDFs might make another page the first available page.
    132 // For non-linearized PDFs, this function will always return zero.
    133 DLLEXPORT int STDCALL FPDFAvail_GetFirstPageNum(FPDF_DOCUMENT doc);
    134 
    135 // Check if |page_index| is ready for loading, if not, get the
    136 // |FX_DOWNLOADHINTS|.
    137 //
    138 //   avail      - handle to document availability provider.
    139 //   page_index - index number of the page. Zero for the first page.
    140 //   hints      - pointer to a download hints interface. Populated if
    141 //                |page_index| is not available.
    142 //
    143 // Returns one of:
    144 //   PDF_DATA_ERROR: A common error is returned. Data availability unknown.
    145 //   PDF_DATA_NOTAVAIL: Data not yet available.
    146 //   PDF_DATA_AVAIL: Data available.
    147 //
    148 // This function can be called only after |FPDFAvail_GetDocument| is called.
    149 // Applications should call this function whenever new data arrives and process
    150 // all the generated download |hints|, if any, until this function returns
    151 // |PDF_DATA_ERROR| or |PDF_DATA_AVAIL|. Applications can then perform page
    152 // loading.
    153 DLLEXPORT int STDCALL FPDFAvail_IsPageAvail(FPDF_AVAIL avail,
    154                                             int page_index,
    155                                             FX_DOWNLOADHINTS* hints);
    156 
    157 // Check if form data is ready for initialization, if not, get the
    158 // |FX_DOWNLOADHINTS|.
    159 //
    160 //   avail - handle to document availability provider.
    161 //   hints - pointer to a download hints interface. Populated if form is not
    162 //           ready for initialization.
    163 //
    164 // Returns one of:
    165 //   PDF_FORM_ERROR: A common eror, in general incorrect parameters.
    166 //   PDF_FORM_NOTAVAIL: Data not available.
    167 //   PDF_FORM_AVAIL: Data available.
    168 //   PDF_FORM_NOTEXIST: No form data.
    169 //
    170 // This function can be called only after |FPDFAvail_GetDocument| is called.
    171 // The application should call this function whenever new data arrives and
    172 // process all the generated download |hints|, if any, until the function
    173 // |PDF_FORM_ERROR|, |PDF_FORM_AVAIL| or |PDF_FORM_NOTEXIST|.
    174 // Applications can then perform page loading. It is recommend to call
    175 // |FPDFDOC_InitFormFillEnvironment| when |PDF_FORM_AVAIL| is returned.
    176 DLLEXPORT int STDCALL FPDFAvail_IsFormAvail(FPDF_AVAIL avail,
    177                                             FX_DOWNLOADHINTS* hints);
    178 
    179 // Check whether a document is a linearized PDF.
    180 //
    181 //   avail - handle to document availability provider.
    182 //
    183 // Returns one of:
    184 //   PDF_LINEARIZED
    185 //   PDF_NOT_LINEARIZED
    186 //   PDF_LINEARIZATION_UNKNOWN
    187 //
    188 // |FPDFAvail_IsLinearized| will return |PDF_LINEARIZED| or |PDF_NOT_LINEARIZED|
    189 // when we have 1k  of data. If the files size less than 1k, it returns
    190 // |PDF_LINEARIZATION_UNKNOWN| as there is insufficient information to determine
    191 // if the PDF is linearlized.
    192 DLLEXPORT int STDCALL FPDFAvail_IsLinearized(FPDF_AVAIL avail);
    193 
    194 #ifdef __cplusplus
    195 }  // extern "C"
    196 #endif  // __cplusplus
    197 
    198 #endif  // PUBLIC_FPDF_DATAAVAIL_H_
    199