mirror of
https://github.com/michaelrsweet/pdfio.git
synced 2024-11-08 06:28:27 +01:00
581 lines
13 KiB
C
581 lines
13 KiB
C
//
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// PDF file functions for pdfio.
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//
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// Copyright © 2021 by Michael R Sweet.
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//
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// Licensed under Apache License v2.0. See the file "LICENSE" for more
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// information.
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//
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//
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// Include necessary headers...
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//
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#include "pdfio-private.h"
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#ifndef O_BINARY
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# define O_BINARY 0
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#endif // !O_BINARY
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//
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// Local functions...
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//
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static pdfio_obj_t *add_object(pdfio_file_t *pdf);
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static bool load_xref(pdfio_file_t *pdf, off_t xref_offset);
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static bool write_trailer(pdfio_file_t *pdf);
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//
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// 'pdfioFileClose()' - Close a PDF file and free all memory used for it.
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//
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bool // O - `true` on success and `false` on failure
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pdfioFileClose(pdfio_file_t *pdf) // I - PDF file
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{
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bool ret = true; // Return value
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size_t i; // Looping var
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// Range check input
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if (!pdf)
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return (false);
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// Close the file itself...
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if (pdf->mode == _PDFIO_MODE_WRITE)
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ret = write_trailer(pdf);
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if (close(pdf->fd) < 0)
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ret = false;
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// Free all data...
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free(pdf->filename);
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free(pdf->version);
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for (i = 0; i < pdf->num_arrays; i ++)
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_pdfioArrayDelete(pdf->arrays[i]);
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free(pdf->arrays);
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for (i = 0; i < pdf->num_dicts; i ++)
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_pdfioDictDelete(pdf->dicts[i]);
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free(pdf->dicts);
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for (i = 0; i < pdf->num_objs; i ++)
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_pdfioObjDelete(pdf->objs[i]);
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free(pdf->objs);
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free(pdf->pages);
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for (i = 0; i < pdf->num_strings; i ++)
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free(pdf->strings[i]);
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free(pdf->strings);
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free(pdf);
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return (ret);
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}
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//
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// 'pdfioFileCreate()' - Create a PDF file.
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//
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pdfio_file_t * // O - PDF file or `NULL` on error
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pdfioFileCreate(
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const char *filename, // I - Filename
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const char *version, // I - PDF version number or `NULL` for default (2.0)
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pdfio_error_cb_t error_cb, // I - Error callback or `NULL` for default
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void *error_data) // I - Error callback data, if any
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{
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pdfio_file_t *pdf; // PDF file
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// Range check input...
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if (!filename)
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return (NULL);
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if (!version)
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version = "2.0";
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if (!error_cb)
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{
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error_cb = _pdfioFileDefaultError;
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error_data = NULL;
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}
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// Allocate a PDF file structure...
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if ((pdf = (pdfio_file_t *)calloc(1, sizeof(pdfio_file_t))) == NULL)
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{
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pdfio_file_t temp; // Dummy file
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char message[8192]; // Message string
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temp.filename = (char *)filename;
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snprintf(message, sizeof(message), "Unable to allocate memory for PDF file - %s", strerror(errno));
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(error_cb)(&temp, message, error_data);
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return (NULL);
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}
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pdf->filename = strdup(filename);
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pdf->version = strdup(version);
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pdf->mode = _PDFIO_MODE_WRITE;
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pdf->error_cb = error_cb;
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pdf->error_data = error_data;
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// Create the file...
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if ((pdf->fd = open(filename, O_WRONLY | O_BINARY | O_CREAT | O_TRUNC, 0666)) < 0)
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{
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_pdfioFileError(pdf, "Unable to create file - %s", strerror(errno));
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free(pdf->filename);
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free(pdf->version);
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free(pdf);
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return (NULL);
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}
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// Write a standard PDF header...
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if (!_pdfioFilePrintf(pdf, "%%PDF-%s\n%%\342\343\317\323\n", version))
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{
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pdfioFileClose(pdf);
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unlink(filename);
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return (NULL);
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}
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return (pdf);
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}
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//
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// 'pdfioFileCreateObject()' - Create a new object in a PDF file.
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//
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pdfio_obj_t * // O - New object
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pdfioFileCreateObject(
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pdfio_file_t *pdf, // I - PDF file
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pdfio_dict_t *dict) // I - Object dictionary
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{
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pdfio_obj_t *obj; // New object
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// Range check input...
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if (!pdf || !dict)
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{
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if (pdf)
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_pdfioFileError(pdf, "Missing object dictionary.");
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return (NULL);
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}
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if (pdf->mode != _PDFIO_MODE_WRITE)
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return (NULL);
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if (dict->pdf != pdf)
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dict = pdfioDictCopy(pdf, dict); // Copy dictionary to new PDF
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// Allocate memory for the object...
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if ((obj = (pdfio_obj_t *)calloc(1, sizeof(pdfio_obj_t))) == NULL)
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{
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_pdfioFileError(pdf, "Unable to allocate memory for object - %s", strerror(errno));
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return (NULL);
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}
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// Expand the objects array as needed
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if (pdf->num_objs >= pdf->alloc_objs)
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{
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pdfio_obj_t **temp = (pdfio_obj_t **)realloc(pdf->objs, (pdf->alloc_objs + 32) * sizeof(pdfio_obj_t *));
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if (!temp)
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{
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_pdfioFileError(pdf, "Unable to allocate memory for object - %s", strerror(errno));
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free(obj);
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return (NULL);
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}
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pdf->objs = temp;
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pdf->alloc_objs += 32;
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}
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pdf->objs[pdf->num_objs ++] = obj;
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// Initialize the object...
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obj->pdf = pdf;
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obj->number = pdf->num_objs;
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obj->dict = dict;
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obj->offset = _pdfioFileTell(pdf);
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// Don't write anything just yet...
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return (obj);
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}
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//
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// 'pdfioFileCreatePage()' - Create a page in a PDF file.
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//
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pdfio_obj_t * // O - New object
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pdfioFileCreatePage(pdfio_file_t *pdf, // I - PDF file
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pdfio_dict_t *dict) // I - Page dictionary
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{
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// TODO: Implement me
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(void)pdf;
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(void)dict;
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return (NULL);
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}
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//
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// 'pdfioFileGetID()' - Get the PDF file's ID strings.
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//
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pdfio_array_t * // O - Array with binary strings
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pdfioFileGetID(pdfio_file_t *pdf) // I - PDF file
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{
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return (pdf ? pdfioDictGetArray(pdf->trailer, "ID") : NULL);
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}
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//
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// 'pdfioFileGetName()' - Get a PDF's filename.
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//
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const char * // O - Filename
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pdfioFileGetName(pdfio_file_t *pdf) // I - PDF file
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{
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return (pdf ? pdf->filename : NULL);
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}
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//
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// 'pdfioFileGetNumObjects()' - Get the number of objects in a PDF file.
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//
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size_t // O - Number of objects
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pdfioFileGetNumObjects(
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pdfio_file_t *pdf) // I - PDF file
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{
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return (pdf ? pdf->num_objs : 0);
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}
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//
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// 'pdfioFileGetNumPages()' - Get the number of pages in a PDF file.
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//
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size_t // O - Number of pages
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pdfioFileGetNumPages(pdfio_file_t *pdf) // I - PDF file
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{
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return (pdf ? pdf->num_pages : 0);
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}
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//
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// 'pdfioFileGetObject()' - Get an object from a PDF file.
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//
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pdfio_obj_t * // O - Object
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pdfioFileGetObject(pdfio_file_t *pdf, // I - PDF file
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size_t number) // I - Object number (starting at 1)
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{
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if (!pdf || number < 1 || number > pdf->num_objs)
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return (NULL);
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else
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return (pdf->objs[number - 1]);
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}
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//
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// 'pdfioFileGetPage()' - Get a page object from a PDF file.
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//
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pdfio_obj_t * // O - Object
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pdfioFileGetPage(pdfio_file_t *pdf, // I - PDF file
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size_t number) // I - Page number (starting at 1)
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{
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if (!pdf || number < 1 || number > pdf->num_pages)
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return (NULL);
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else
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return (pdf->pages[number - 1]);
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}
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//
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// 'pdfioFileGetVersion()' - Get the PDF version number for a PDF file.
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//
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const char * // O - Version number or `NULL`
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pdfioFileGetVersion(
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pdfio_file_t *pdf) // I - PDF file
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{
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return (pdf ? pdf->version : NULL);
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}
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//
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// 'pdfioFileOpen()' - Open a PDF file for reading.
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//
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pdfio_file_t * // O - PDF file
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pdfioFileOpen(
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const char *filename, // I - Filename
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pdfio_error_cb_t error_cb, // I - Error callback or `NULL` for default
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void *error_data) // I - Error callback data, if any
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{
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pdfio_file_t *pdf; // PDF file
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char line[1024], // Line from file
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*ptr; // Pointer into line
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off_t xref_offset; // Offset to xref table
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// Range check input...
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if (!filename)
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return (NULL);
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if (!error_cb)
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{
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error_cb = _pdfioFileDefaultError;
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error_data = NULL;
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}
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// Allocate a PDF file structure...
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if ((pdf = (pdfio_file_t *)calloc(1, sizeof(pdfio_file_t))) == NULL)
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{
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pdfio_file_t temp; // Dummy file
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char message[8192]; // Message string
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temp.filename = (char *)filename;
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snprintf(message, sizeof(message), "Unable to allocate memory for PDF file - %s", strerror(errno));
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(error_cb)(&temp, message, error_data);
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return (NULL);
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}
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pdf->filename = strdup(filename);
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pdf->mode = _PDFIO_MODE_READ;
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pdf->error_cb = error_cb;
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pdf->error_data = error_data;
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// Open the file...
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if ((pdf->fd = open(filename, O_RDONLY | O_BINARY)) < 0)
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{
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_pdfioFileError(pdf, "Unable to open file - %s", strerror(errno));
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free(pdf->filename);
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free(pdf);
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return (NULL);
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}
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// Read the header from the first line...
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if (!_pdfioFileGets(pdf, line, sizeof(line)))
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goto error;
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if ((strncmp(line, "%PDF-1.", 7) && strncmp(line, "%PDF-2.", 7)) || !isdigit(line[7] & 255))
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{
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// Bad header
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_pdfioFileError(pdf, "Bad header '%s'.", line);
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goto error;
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}
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// Copy the version number...
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pdf->version = strdup(line + 5);
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// Grab the last 32 characters of the file to find the start of the xref table...
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_pdfioFileSeek(pdf, -32, SEEK_END);
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if (_pdfioFileRead(pdf, line, 32) < 32)
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{
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_pdfioFileError(pdf, "Unable to read startxref data.");
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goto error;
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}
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line[32] = '\0';
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if ((ptr = strstr(line, "startxref")) == NULL)
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{
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_pdfioFileError(pdf, "Unable to find start of xref table.");
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goto error;
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}
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xref_offset = (off_t)strtol(ptr + 9, NULL, 10);
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if (!load_xref(pdf, xref_offset))
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goto error;
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return (pdf);
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// If we get here we had a fatal read error...
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error:
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pdfioFileClose(pdf);
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return (NULL);
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}
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//
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// 'add_object()' - Add an object to a PDF file.
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//
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static pdfio_obj_t * // O - New object
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add_object(pdfio_file_t *pdf) // I - PDF file
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{
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pdfio_obj_t *obj; // New object
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// Allocate memory for the object...
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if ((obj = (pdfio_obj_t *)calloc(1, sizeof(pdfio_obj_t))) == NULL)
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{
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_pdfioFileError(pdf, "Unable to allocate memory for object - %s", strerror(errno));
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return (NULL);
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}
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// Expand the objects array as needed
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if (pdf->num_objs >= pdf->alloc_objs)
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{
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pdfio_obj_t **temp = (pdfio_obj_t **)realloc(pdf->objs, (pdf->alloc_objs + 32) * sizeof(pdfio_obj_t *));
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if (!temp)
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{
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_pdfioFileError(pdf, "Unable to allocate memory for object - %s", strerror(errno));
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free(obj);
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return (NULL);
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}
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pdf->objs = temp;
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pdf->alloc_objs += 32;
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}
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pdf->objs[pdf->num_objs ++] = obj;
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return (obj);
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}
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//
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// 'load_xref()' - Load an XREF table...
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//
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static bool // O - `true` on success, `false` on failure
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load_xref(pdfio_file_t *pdf, // I - PDF file
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off_t xref_offset) // I - Offset to xref
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{
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bool done = false; // Are we done?
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char line[1024], // Line from file
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*ptr; // Pointer into line
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while (!done)
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{
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if (_pdfioFileSeek(pdf, xref_offset, SEEK_SET) != xref_offset)
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{
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_pdfioFileError(pdf, "Unable to seek to start of xref table.");
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return (false);
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}
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if (!_pdfioFileGets(pdf, line, sizeof(line)))
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{
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_pdfioFileError(pdf, "Unable to read start of xref table.");
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return (false);
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}
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if (strcmp(line, "xref"))
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{
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_pdfioFileError(pdf, "Bad xref table header '%s'.", line);
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return (false);
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}
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|
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// Read the xref tables
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while (_pdfioFileGets(pdf, line, sizeof(line)))
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{
|
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intmax_t number, // Object number
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num_objects; // Number of objects
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if (!strcmp(line, "trailer"))
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break;
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if (sscanf(line, "%jd%jd", &number, &num_objects) != 2)
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{
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_pdfioFileError(pdf, "Malformed xref table section '%s'.", line);
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return (false);
|
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}
|
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|
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// Read this group of objects...
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for (; num_objects > 0; num_objects --, number ++)
|
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{
|
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intmax_t offset; // Offset in file
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int generation; // Generation number
|
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pdfio_obj_t *obj; // Object
|
||
|
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// Read a line from the file and validate it...
|
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if (_pdfioFileRead(pdf, line, 20) != 20)
|
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return (false);
|
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|
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line[20] = '\0';
|
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|
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if (strcmp(line + 18, "\r\n") && strcmp(line + 18, " \n") && strcmp(line + 18, " \r"))
|
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{
|
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_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
|
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return (false);
|
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}
|
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line[18] = '\0';
|
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|
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// Parse the line
|
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if ((offset = strtoimax(line, &ptr, 10)) < 0)
|
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{
|
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_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
|
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return (false);
|
||
}
|
||
|
||
if ((generation = (int)strtol(ptr, &ptr, 10)) < 0 || generation > 65535)
|
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{
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_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
|
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return (false);
|
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}
|
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|
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if (*ptr != ' ')
|
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{
|
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_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
|
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return (false);
|
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}
|
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|
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ptr ++;
|
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if (*ptr != 'f' && *ptr != 'n')
|
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{
|
||
_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
|
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return (false);
|
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}
|
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|
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if (*ptr == 'f')
|
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continue; // Don't care about free objects...
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|
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// Create a placeholder for the object in memory...
|
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if ((obj = add_object(pdf)) == NULL)
|
||
return (false);
|
||
|
||
obj->number = (size_t)number;
|
||
obj->generation = (unsigned short)generation;
|
||
obj->offset = offset;
|
||
}
|
||
}
|
||
|
||
if (strcmp(line, "trailer"))
|
||
{
|
||
_pdfioFileError(pdf, "Missing trailer.");
|
||
return (false);
|
||
}
|
||
|
||
// TODO: Read trailer dict...
|
||
done = true;
|
||
}
|
||
|
||
return (true);
|
||
}
|
||
|
||
|
||
//
|
||
// 'write_trailer()' - Write the PDF catalog object, xref table, and trailer.
|
||
//
|
||
|
||
static bool // O - `true` on success, `false` on failure
|
||
write_trailer(pdfio_file_t *pdf) // I - PDF file
|
||
{
|
||
// TODO: Write trailer
|
||
(void)pdf;
|
||
|
||
return (false);
|
||
}
|