pdfio/pdfio-object.c

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//
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// PDF object functions for pdfio.
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//
// Copyright © 2021 by Michael R Sweet.
//
// Licensed under Apache License v2.0. See the file "LICENSE" for more
// information.
//
//
// Include necessary headers...
//
#include "pdfio-private.h"
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//
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// 'pdfioObjClose()' - Close an object, writing any data as needed to the PDF
// file.
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//
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bool // O - `true` on success, `false` on failure
pdfioObjClose(pdfio_obj_t *obj) // I - Object
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{
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// TODO: Implement me
(void)obj;
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return (false);
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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
pdfioObjCreateStream(
pdfio_obj_t *obj, // I - Object
pdfio_filter_t filter) // I - Type of compression to apply
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{
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// TODO: Implement me
(void)obj;
(void)filter;
return (NULL);
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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)
pdfioStreamClose(obj->stream);
free(obj);
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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
pdfioObjGetDict(pdfio_obj_t *obj) // I - Object
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{
if (!obj)
return (NULL);
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if (obj->value.type == PDFIO_VALTYPE_NONE)
_pdfioObjLoad(obj);
if (obj->value.type == PDFIO_VALTYPE_DICT)
return (obj->value.value.dict);
else
return (NULL);
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}
//
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// 'pdfioObjGetGeneration()' - Get the object's generation number.
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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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// 'pdfioObjGetNumber()' - Get the object's number.
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//
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size_t // O - Object number (1 to 9999999999)
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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// 'pdfioObjGetType()' - Get an object's type.
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//
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const char * // O - Object type
pdfioObjGetType(pdfio_obj_t *obj) // I - Object
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{
pdfio_dict_t *dict; // Object dictionary
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if ((dict = pdfioObjGetDict(obj)) == NULL)
return (NULL);
else
return (pdfioDictGetName(dict, "Type"));
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}
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//
// '_pdfioObjLoad()' - Load an object dictionary/value.
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//
bool // O - `true` on success, `false` otherwise
_pdfioObjLoad(pdfio_obj_t *obj) // I - Object
{
char line[1024], // Line from file
*ptr; // Pointer into line
_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...
if (_pdfioFileSeek(obj->pdf, obj->offset, SEEK_SET) != obj->offset)
{
_pdfioFileError(obj->pdf, "Unable to seek to object %lu.", (unsigned long)obj->number);
return (false);
}
if (!_pdfioFileGets(obj->pdf, line, sizeof(line)))
{
_pdfioFileError(obj->pdf, "Unable to read header for object %lu.", (unsigned long)obj->number);
return (false);
}
if (strtoimax(line, &ptr, 10) != (intmax_t)obj->number)
{
_pdfioFileError(obj->pdf, "Bad header for object %lu.", (unsigned long)obj->number);
return (false);
}
if (strtol(ptr, &ptr, 10) != (long)obj->generation)
{
_pdfioFileError(obj->pdf, "Bad header for object %lu.", (unsigned long)obj->number);
return (false);
}
while (isspace(*ptr & 255))
ptr ++;
if (strcmp(ptr, "obj"))
{
_pdfioFileError(obj->pdf, "Bad header for object %lu.", (unsigned long)obj->number);
return (false);
}
// Then grab the object value...
_pdfioTokenInit(&tb, obj->pdf, (_pdfio_tconsume_cb_t)_pdfioFileConsume, (_pdfio_tpeek_cb_t)_pdfioFilePeek, obj->pdf);
if (!_pdfioValueRead(obj->pdf, &tb, &obj->value))
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{
_pdfioFileError(obj->pdf, "Unable to read value for object %lu.", (unsigned long)obj->number);
return (false);
}
// Now see if there is an associated stream...
if (!_pdfioFileGets(obj->pdf, line, sizeof(line)))
{
_pdfioFileError(obj->pdf, "Early end-of-file for object %lu.", (unsigned long)obj->number);
return (false);
}
if (!strcmp(line, "stream"))
{
// Yes, save its location...
obj->stream_offset = _pdfioFileTell(obj->pdf);
}
return (true);
}
//
// 'pdfioObjOpenStream()' - Open an object's (data) stream for reading.
//
pdfio_stream_t * // O - Stream or `NULL` on error
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pdfioObjOpenStream(pdfio_obj_t *obj, // I - Object
bool decode) // I - Decode/decompress data?
{
// Range check input...
if (!obj)
return (NULL);
// Make sure we've loaded the object dictionary...
if (!obj->value.type)
{
if (!_pdfioObjLoad(obj))
return (NULL);
}
// No stream if there is no dict or offset to a stream...
if (obj->value.type != PDFIO_VALTYPE_DICT || !obj->stream_offset)
return (NULL);
// Open the stream...
return (_pdfioStreamOpen(obj, decode));
}