mirror of
https://github.com/michaelrsweet/pdfio.git
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540 lines
13 KiB
C
540 lines
13 KiB
C
//
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// PDF object functions for PDFio.
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//
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// Copyright © 2021-2023 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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#include "pdfio-private.h"
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//
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// Local functions...
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//
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static bool write_obj_header(pdfio_obj_t *obj);
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//
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// 'pdfioObjClose()' - Close an object, writing any data as needed to the PDF
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// file.
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//
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bool // O - `true` on success, `false` on failure
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pdfioObjClose(pdfio_obj_t *obj) // I - Object
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{
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// Range check input
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if (!obj)
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return (false);
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// Clear the current object pointer...
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obj->pdf->current_obj = NULL;
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if (obj->pdf->mode != _PDFIO_MODE_WRITE)
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{
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// Nothing to do when reading
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return (true);
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}
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// Write what remains for the object...
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if (!obj->offset)
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{
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// Write the object value
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if (!write_obj_header(obj))
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return (false);
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// Write the "endobj" line...
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return (_pdfioFilePuts(obj->pdf, "endobj\n"));
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}
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else if (obj->stream)
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{
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// Close the stream...
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return (pdfioStreamClose(obj->stream));
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}
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else
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{
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// Already closed
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return (true);
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}
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}
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//
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// 'pdfioObjCopy()' - Copy an object to another PDF file.
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//
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pdfio_obj_t * // O - New object or `NULL` on error
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pdfioObjCopy(pdfio_file_t *pdf, // I - PDF file
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pdfio_obj_t *srcobj) // I - Object to copy
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{
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pdfio_obj_t *dstobj; // Destination object
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pdfio_stream_t *srcst, // Source stream
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*dstst; // Destination stream
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char buffer[32768]; // Copy buffer
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ssize_t bytes; // Bytes read
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PDFIO_DEBUG("pdfioObjCopy(pdf=%p, srcobj=%p(%p))\n", pdf, srcobj, srcobj ? srcobj->pdf : NULL);
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// Range check input
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if (!pdf || !srcobj)
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return (NULL);
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// Load the object value if needed...
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if (srcobj->value.type == PDFIO_VALTYPE_NONE)
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_pdfioObjLoad(srcobj);
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// Create the new object...
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if ((dstobj = _pdfioFileCreateObj(pdf, srcobj->pdf, NULL)) == NULL)
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return (NULL);
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// Add new object to the cache of copied objects...
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if (!_pdfioFileAddMappedObj(pdf, dstobj, srcobj))
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return (NULL);
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// Copy the object's value...
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if (!_pdfioValueCopy(pdf, &dstobj->value, srcobj->pdf, &srcobj->value))
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return (NULL);
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if (dstobj->value.type == PDFIO_VALTYPE_DICT)
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_pdfioDictClear(dstobj->value.value.dict, "Length");
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if (srcobj->stream_offset)
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{
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// Copy stream data...
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if ((srcst = pdfioObjOpenStream(srcobj, false)) == NULL)
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{
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pdfioObjClose(dstobj);
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return (NULL);
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}
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if ((dstst = pdfioObjCreateStream(dstobj, PDFIO_FILTER_NONE)) == NULL)
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{
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pdfioStreamClose(srcst);
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pdfioObjClose(dstobj);
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return (NULL);
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}
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while ((bytes = pdfioStreamRead(srcst, buffer, sizeof(buffer))) > 0)
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{
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if (!pdfioStreamWrite(dstst, buffer, (size_t)bytes))
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{
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bytes = -1;
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break;
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}
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}
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pdfioStreamClose(srcst);
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pdfioStreamClose(dstst);
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if (bytes < 0)
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return (NULL);
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}
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else
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pdfioObjClose(dstobj);
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return (dstobj);
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}
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//
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// 'pdfioObjCreateStream()' - Create an object (data) stream for writing.
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//
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pdfio_stream_t * // O - Stream or `NULL` on error
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pdfioObjCreateStream(
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pdfio_obj_t *obj, // I - Object
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pdfio_filter_t filter) // I - Type of compression to apply
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{
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pdfio_obj_t *length_obj = NULL; // Length object, if any
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// Range check input
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if (!obj || obj->pdf->mode != _PDFIO_MODE_WRITE || obj->value.type != PDFIO_VALTYPE_DICT)
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return (NULL);
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if (obj->offset)
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{
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_pdfioFileError(obj->pdf, "Object has already been written.");
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return (NULL);
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}
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if (filter != PDFIO_FILTER_NONE && filter != PDFIO_FILTER_FLATE)
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{
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_pdfioFileError(obj->pdf, "Unsupported filter value for PDFioObjCreateStream.");
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return (NULL);
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}
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if (obj->pdf->current_obj)
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{
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_pdfioFileError(obj->pdf, "Another object (%u) is already open.", (unsigned)obj->pdf->current_obj->number);
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return (NULL);
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}
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// Write the header...
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if (!_pdfioDictGetValue(obj->value.value.dict, "Length"))
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{
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if (obj->pdf->output_cb)
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{
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// Streaming via an output callback, so add a placeholder length object
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_pdfio_value_t length_value; // Length value
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length_value.type = PDFIO_VALTYPE_NUMBER;
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length_value.value.number = 0.0f;
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length_obj = _pdfioFileCreateObj(obj->pdf, obj->pdf, &length_value);
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pdfioDictSetObj(obj->value.value.dict, "Length", length_obj);
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}
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else
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{
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// Need a Length key for the stream, add a placeholder that we can fill in
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// later...
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pdfioDictSetNumber(obj->value.value.dict, "Length", 0.0);
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}
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}
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if (!write_obj_header(obj))
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return (NULL);
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if (!_pdfioFilePuts(obj->pdf, "stream\n"))
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return (NULL);
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obj->stream_offset = _pdfioFileTell(obj->pdf);
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obj->pdf->current_obj = obj;
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// Return the new stream...
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return (_pdfioStreamCreate(obj, length_obj, filter));
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}
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//
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// '_pdfioObjDelete()' - Free memory used by an object.
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//
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void
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_pdfioObjDelete(pdfio_obj_t *obj) // I - Object
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{
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if (obj)
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pdfioStreamClose(obj->stream);
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free(obj);
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}
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//
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// 'pdfioObjGetArray()' - Get the array associated with an object.
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//
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pdfio_array_t * // O - Array or `NULL` on error
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pdfioObjGetArray(pdfio_obj_t *obj) // I - Object
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{
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if (!obj)
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return (NULL);
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if (obj->value.type == PDFIO_VALTYPE_NONE)
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_pdfioObjLoad(obj);
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if (obj->value.type == PDFIO_VALTYPE_ARRAY)
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return (obj->value.value.array);
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else
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return (NULL);
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}
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//
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// 'pdfioObjGetDict()' - Get the dictionary associated with an object.
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//
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pdfio_dict_t * // O - Dictionary or `NULL` on error
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pdfioObjGetDict(pdfio_obj_t *obj) // I - Object
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{
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if (!obj)
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return (NULL);
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if (obj->value.type == PDFIO_VALTYPE_NONE)
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_pdfioObjLoad(obj);
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if (obj->value.type == PDFIO_VALTYPE_DICT)
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return (obj->value.value.dict);
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else
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return (NULL);
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}
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//
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// '_pdfioObjGetExtension()' - Get the extension pointer for an object.
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//
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void * // O - Extension data
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_pdfioObjGetExtension(pdfio_obj_t *obj) // I - Object
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{
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return (obj->data);
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}
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//
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// 'pdfioObjGetGeneration()' - Get the object's generation number.
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//
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unsigned short // O - Generation number (0 to 65535)
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pdfioObjGetGeneration(pdfio_obj_t *obj) // I - Object
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{
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return (obj ? obj->generation : 0);
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}
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//
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// 'pdfioObjGetLength()' - Get the length of the object's (data) stream.
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//
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size_t // O - Length in bytes or `0` for none
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pdfioObjGetLength(pdfio_obj_t *obj) // I - Object
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{
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size_t length; // Length of stream
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pdfio_obj_t *lenobj; // Length object
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// Range check input...
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if (!obj || !obj->stream_offset || obj->value.type != PDFIO_VALTYPE_DICT)
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return (0);
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// Try getting the length, directly or indirectly
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if ((length = (size_t)pdfioDictGetNumber(obj->value.value.dict, "Length")) > 0)
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{
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PDFIO_DEBUG("pdfioObjGetLength(obj=%p) returning %lu.\n", obj, (unsigned long)length);
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return (length);
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}
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if ((lenobj = pdfioDictGetObj(obj->value.value.dict, "Length")) == NULL)
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{
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_pdfioFileError(obj->pdf, "Unable to get length of stream.");
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return (0);
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}
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if (lenobj->value.type == PDFIO_VALTYPE_NONE)
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_pdfioObjLoad(lenobj);
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if (lenobj->value.type != PDFIO_VALTYPE_NUMBER || lenobj->value.value.number <= 0.0)
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{
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_pdfioFileError(obj->pdf, "Unable to get length of stream.");
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return (0);
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}
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PDFIO_DEBUG("pdfioObjGetLength(obj=%p) returning %lu.\n", obj, (unsigned long)lenobj->value.value.number);
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return ((size_t)lenobj->value.value.number);
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}
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//
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// 'pdfioObjGetNumber()' - Get the object's number.
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//
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size_t // O - Object number (1 to 9999999999)
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pdfioObjGetNumber(pdfio_obj_t *obj) // I - Object
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{
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return (obj ? obj->number : 0);
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}
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//
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// 'pdfioObjGetSubtype()' - Get an object's subtype.
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//
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const char * // O - Object subtype
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pdfioObjGetSubtype(pdfio_obj_t *obj) // I - Object
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{
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pdfio_dict_t *dict; // Object dictionary
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if ((dict = pdfioObjGetDict(obj)) == NULL)
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return (NULL);
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else
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return (pdfioDictGetName(dict, "Subtype"));
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}
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//
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// 'pdfioObjGetType()' - Get an object's type.
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//
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const char * // O - Object type
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pdfioObjGetType(pdfio_obj_t *obj) // I - Object
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{
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pdfio_dict_t *dict; // Object dictionary
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if ((dict = pdfioObjGetDict(obj)) == NULL)
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return (NULL);
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else
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return (pdfioDictGetName(dict, "Type"));
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}
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//
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// '_pdfioObjLoad()' - Load an object dictionary/value.
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//
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bool // O - `true` on success, `false` otherwise
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_pdfioObjLoad(pdfio_obj_t *obj) // I - Object
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{
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char line[64], // Line from file
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*ptr; // Pointer into line
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ssize_t bytes; // Bytes read
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_pdfio_token_t tb; // Token buffer/stack
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PDFIO_DEBUG("_pdfioObjLoad(obj=%p(%lu)), offset=%lu\n", obj, (unsigned long)obj->number, (unsigned long)obj->offset);
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// Seek to the start of the object and read its header...
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if (_pdfioFileSeek(obj->pdf, obj->offset, SEEK_SET) != obj->offset)
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{
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_pdfioFileError(obj->pdf, "Unable to seek to object %lu.", (unsigned long)obj->number);
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return (false);
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}
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if ((bytes = _pdfioFilePeek(obj->pdf, line, sizeof(line) - 1)) < 0)
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{
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_pdfioFileError(obj->pdf, "Unable to read header for object %lu.", (unsigned long)obj->number);
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return (false);
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}
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line[bytes] = '\0';
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PDFIO_DEBUG("_pdfioObjLoad: Header is '%s'.\n", line);
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if (strtoimax(line, &ptr, 10) != (intmax_t)obj->number)
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{
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_pdfioFileError(obj->pdf, "Bad header for object %lu.", (unsigned long)obj->number);
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return (false);
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}
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if (strtol(ptr, &ptr, 10) != (long)obj->generation)
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{
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_pdfioFileError(obj->pdf, "Bad header for object %lu.", (unsigned long)obj->number);
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return (false);
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}
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while (isspace(*ptr & 255))
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ptr ++;
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if (strncmp(ptr, "obj", 3) || (ptr[3] && ptr[3] != '<' && ptr[3] != '[' && !isspace(ptr[3] & 255)))
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{
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_pdfioFileError(obj->pdf, "Bad header for object %lu.", (unsigned long)obj->number);
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return (false);
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}
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ptr += 3;
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while (*ptr && isspace(*ptr & 255))
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ptr ++;
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_pdfioFileConsume(obj->pdf, (size_t)(ptr - line));
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// Then grab the object value...
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_pdfioTokenInit(&tb, obj->pdf, (_pdfio_tconsume_cb_t)_pdfioFileConsume, (_pdfio_tpeek_cb_t)_pdfioFilePeek, obj->pdf);
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if (!_pdfioValueRead(obj->pdf, obj, &tb, &obj->value, 0))
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{
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_pdfioFileError(obj->pdf, "Unable to read value for object %lu.", (unsigned long)obj->number);
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return (false);
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}
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// Now see if there is an associated stream...
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if (!_pdfioTokenGet(&tb, line, sizeof(line)))
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{
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_pdfioFileError(obj->pdf, "Early end-of-file for object %lu.", (unsigned long)obj->number);
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return (false);
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}
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PDFIO_DEBUG("_pdfioObjLoad: tb.bufptr=%p, tb.bufend=%p, tb.bufptr[0]=0x%02x, tb.bufptr[0]=0x%02x\n", tb.bufptr, tb.bufend, tb.bufptr[0], tb.bufptr[1]);
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if (tb.bufptr && tb.bufptr < tb.bufend && (tb.bufptr[0] == 0x0d || tb.bufptr[0] == 0x0a))
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tb.bufptr ++; // Skip trailing CR or LF after token
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_pdfioTokenFlush(&tb);
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if (!strcmp(line, "stream"))
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{
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// Yes, this is an embedded stream so save its location...
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obj->stream_offset = _pdfioFileTell(obj->pdf);
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PDFIO_DEBUG("_pdfioObjLoad: stream_offset=%lu.\n", (unsigned long)obj->stream_offset);
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}
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PDFIO_DEBUG("_pdfioObjLoad: ");
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PDFIO_DEBUG_VALUE(&obj->value);
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PDFIO_DEBUG("\n");
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return (true);
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}
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//
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// 'pdfioObjOpenStream()' - Open an object's (data) stream for reading.
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//
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pdfio_stream_t * // O - Stream or `NULL` on error
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pdfioObjOpenStream(pdfio_obj_t *obj, // I - Object
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bool decode) // I - Decode/decompress data?
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{
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// Range check input...
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if (!obj)
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return (NULL);
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if (obj->pdf->current_obj)
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{
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_pdfioFileError(obj->pdf, "Another object (%u) is already open.", (unsigned)obj->pdf->current_obj->number);
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return (NULL);
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}
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// Make sure we've loaded the object dictionary...
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if (!obj->value.type)
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{
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if (!_pdfioObjLoad(obj))
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return (NULL);
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}
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// No stream if there is no dict or offset to a stream...
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if (obj->value.type != PDFIO_VALTYPE_DICT || !obj->stream_offset)
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return (NULL);
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// Open the stream...
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obj->pdf->current_obj = obj;
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return (_pdfioStreamOpen(obj, decode));
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}
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//
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// '_pdfioObjSetExtension()' - Set extension data for an object.
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//
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void
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_pdfioObjSetExtension(
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pdfio_obj_t *obj, // I - Object
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void *data, // I - Data
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void (*datafree)(void *)) // I - Free function
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{
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obj->data = data;
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obj->datafree = datafree;
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}
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//
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// 'write_obj_header()' - Write the object header...
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//
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static bool // O - `true` on success, `false` on failure
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write_obj_header(pdfio_obj_t *obj) // I - Object
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{
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obj->offset = _pdfioFileTell(obj->pdf);
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if (!_pdfioFilePrintf(obj->pdf, "%lu %u obj\n", (unsigned long)obj->number, obj->generation))
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return (false);
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if (!_pdfioValueWrite(obj->pdf, obj, &obj->value, &obj->length_offset))
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return (false);
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return (_pdfioFilePuts(obj->pdf, "\n"));
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}
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