Add support for writing the PCLm subset of PDF (Issue #99)

CHANGES.md

@@ -10,6 +10,7 @@ v1.5.0 - YYYY-MM-DD
   (Issue #10)
 - Added `pdfioFileGetModDate()` API (Issue #88)
 - Added support for using libpng to embed PNG images in PDF output (Issue #90)
+- Added support for writing the PCLm subset of PDF (Issue #99)
 - Now support opening damaged PDF files (Issue #45)
 - Updated the pdf2txt example to support font encodings.
 

doc/pdfio.3

@@ -1,4 +1,4 @@
-.TH pdfio 3 "pdf read/write library" "2025-02-13" "pdf read/write library"
+.TH pdfio 3 "pdf read/write library" "2025-02-20" "pdf read/write library"
 .SH NAME
 pdfio \- pdf read/write library
 .SH Introduction
@@ -3561,7 +3561,8 @@ This function creates a new PDF file.  The "filename" argument specifies the
 name of the PDF file to create.
 .PP
 The "version" argument specifies the PDF version number for the file or
-\fBNULL\fR for the default ("2.0").
+\fBNULL\fR for the default ("2.0").  The value "PCLm-1.0" can be specified to
+produce the PCLm subset of PDF.
 .PP
 The "media_box" and "crop_box" arguments specify the default MediaBox and
 CropBox for pages in the PDF file - if \fBNULL\fR then a default "Universal" size
@@ -3643,8 +3644,19 @@ This function embeds a TrueType/OpenType font into a PDF file.  The
 characters (potentially full Unicode, but more typically a subset)
 or to only support the Windows CP1252 (ISO-8859-1 with additional
 characters such as the Euro symbol) subset of Unicode.
+.SS pdfioFileCreateICCObjFromData
+Add ICC profile data to a PDF file.
+.PP
+.nf
+pdfio_obj_t * pdfioFileCreateICCObjFromData (
+    pdfio_file_t *pdf,
+    const unsigned char *data,
+    size_t datalen,
+    size_t num_colors
+);
+.fi
 .SS pdfioFileCreateICCObjFromFile
-Add an ICC profile object to a PDF file.
+Add an ICC profile file to a PDF file.
 .PP
 .nf
 pdfio_obj_t * pdfioFileCreateICCObjFromFile (
@@ -3767,7 +3779,9 @@ written:
 .fi
 
 The "version" argument specifies the PDF version number for the file or
-\fBNULL\fR for the default ("2.0").
+\fBNULL\fR for the default ("2.0").  Unlike \fIpdfioFileCreate\fR and
+\fIpdfioFileCreateTemporary\fR, it is generally not safe to pass the
+"PCLm-1.0" version string.
 .PP
 The "media_box" and "crop_box" arguments specify the default MediaBox and
 CropBox for pages in the PDF file - if \fBNULL\fR then a default "Universal" size

doc/pdfio.html

@@ -400,6 +400,7 @@ span.string {
 <li><a href="#pdfioFileCreateArrayObj">pdfioFileCreateArrayObj</a></li>
 <li><a href="#pdfioFileCreateFontObjFromBase">pdfioFileCreateFontObjFromBase</a></li>
 <li><a href="#pdfioFileCreateFontObjFromFile">pdfioFileCreateFontObjFromFile</a></li>
+<li><a href="#pdfioFileCreateICCObjFromData">pdfioFileCreateICCObjFromData</a></li>
 <li><a href="#pdfioFileCreateICCObjFromFile">pdfioFileCreateICCObjFromFile</a></li>
 <li><a href="#pdfioFileCreateImageObjFromData">pdfioFileCreateImageObjFromData</a></li>
 <li><a href="#pdfioFileCreateImageObjFromFile">pdfioFileCreateImageObjFromFile</a></li>
@@ -3814,7 +3815,8 @@ have been iterated.</p>
 name of the PDF file to create.<br>
 <br>
 The &quot;version&quot; argument specifies the PDF version number for the file or
-<code>NULL</code> for the default (&quot;2.0&quot;).<br>
+<code>NULL</code> for the default (&quot;2.0&quot;).  The value &quot;PCLm-1.0&quot; can be specified to
+produce the PCLm subset of PDF.<br>
 <br>
 The &quot;media_box&quot; and &quot;crop_box&quot; arguments specify the default MediaBox and
 CropBox for pages in the PDF file - if <code>NULL</code> then a default &quot;Universal&quot; size
@@ -3909,8 +3911,25 @@ Unicode.</p>
 characters (potentially full Unicode, but more typically a subset)
 or to only support the Windows CP1252 (ISO-8859-1 with additional
 characters such as the Euro symbol) subset of Unicode.</p>
+<h3 class="function"><a id="pdfioFileCreateICCObjFromData">pdfioFileCreateICCObjFromData</a></h3>
+<p class="description">Add ICC profile data to a PDF file.</p>
+<p class="code">
+<a href="#pdfio_obj_t">pdfio_obj_t</a> *pdfioFileCreateICCObjFromData(<a href="#pdfio_file_t">pdfio_file_t</a> *pdf, <span class="reserved">const</span> <span class="reserved">unsigned</span> <span class="reserved">char</span> *data, size_t datalen, size_t num_colors);</p>
+<h4 class="parameters">Parameters</h4>
+<table class="list"><tbody>
+<tr><th>pdf</th>
+<td class="description">PDF file</td></tr>
+<tr><th>data</th>
+<td class="description">ICC profile buffer</td></tr>
+<tr><th>datalen</th>
+<td class="description">Length of ICC profile</td></tr>
+<tr><th>num_colors</th>
+<td class="description">Number of color components (1, 3, or 4)</td></tr>
+</tbody></table>
+<h4 class="returnvalue">Return Value</h4>
+<p class="description">Object</p>
 <h3 class="function"><a id="pdfioFileCreateICCObjFromFile">pdfioFileCreateICCObjFromFile</a></h3>
-<p class="description">Add an ICC profile object to a PDF file.</p>
+<p class="description">Add an ICC profile file to a PDF file.</p>
 <p class="code">
 <a href="#pdfio_obj_t">pdfio_obj_t</a> *pdfioFileCreateICCObjFromFile(<a href="#pdfio_file_t">pdfio_file_t</a> *pdf, <span class="reserved">const</span> <span class="reserved">char</span> *filename, size_t num_colors);</p>
 <h4 class="parameters">Parameters</h4>
@@ -4071,7 +4090,9 @@ output_cb(void *output_cbdata, const void *buffer, size_t bytes)
 </pre>
 
 The &quot;version&quot; argument specifies the PDF version number for the file or
-<code>NULL</code> for the default (&quot;2.0&quot;).<br>
+<code>NULL</code> for the default (&quot;2.0&quot;).  Unlike <a href="#pdfioFileCreate"><code>pdfioFileCreate</code></a> and
+<a href="#pdfioFileCreateTemporary"><code>pdfioFileCreateTemporary</code></a>, it is generally not safe to pass the
+&quot;PCLm-1.0&quot; version string.<br>
 <br>
 The &quot;media_box&quot; and &quot;crop_box&quot; arguments specify the default MediaBox and
 CropBox for pages in the PDF file - if <code>NULL</code> then a default &quot;Universal&quot; size
@@ -4139,8 +4160,19 @@ You must call <a href="#pdfioObjClose"><code>pdfioObjClose</code></a> to write t
 <p class="description">Create a temporary PDF file.</p>
 <p class="discussion">This function creates a PDF file with a unique filename in the current
 temporary directory.  The temporary file is stored in the string &quot;buffer&quot; an
-will have a &quot;.pdf&quot; extension.  Otherwise, this function works the same as
+will have a &quot;.pdf&quot; extension.<br>
-the <a href="#pdfioFileCreate"><code>pdfioFileCreate</code></a> function.
+<br>
+The &quot;version&quot; argument specifies the PDF version number for the file or
+<code>NULL</code> for the default (&quot;2.0&quot;).  The value &quot;PCLm-1.0&quot; can be specified to
+produce the PCLm subset of PDF.<br>
+<br>
+The &quot;media_box&quot; and &quot;crop_box&quot; arguments specify the default MediaBox and
+CropBox for pages in the PDF file - if <code>NULL</code> then a default &quot;Universal&quot; size
+of 8.27x11in (the intersection of US Letter and ISO A4) is used.<br>
+<br>
+The &quot;error_cb&quot; and &quot;error_cbdata&quot; arguments specify an error handler callback
+and its data pointer - if <code>NULL</code> the default error handler is used that
+writes error messages to <code>stderr</code>.
 
 </p>
 <h3 class="function"><a id="pdfioFileFindObj">pdfioFileFindObj</a></h3>

pdfio-file.c

@@ -165,7 +165,8 @@ pdfioFileClose(pdfio_file_t *pdf)	// I - PDF file
 // name of the PDF file to create.
 //
 // The "version" argument specifies the PDF version number for the file or
-// `NULL` for the default ("2.0").
+// `NULL` for the default ("2.0").  The value "PCLm-1.0" can be specified to
+// produce the PCLm subset of PDF.
 //
 // The "media_box" and "crop_box" arguments specify the default MediaBox and
 // CropBox for pages in the PDF file - if `NULL` then a default "Universal" size
@@ -397,7 +398,9 @@ _pdfioFileCreateObj(
 // ```
 //
 // The "version" argument specifies the PDF version number for the file or
-// `NULL` for the default ("2.0").
+// `NULL` for the default ("2.0").  Unlike @link pdfioFileCreate@ and
+// @link pdfioFileCreateTemporary@, it is generally not safe to pass the
+// "PCLm-1.0" version string.
 //
 // The "media_box" and "crop_box" arguments specify the default MediaBox and
 // CropBox for pages in the PDF file - if `NULL` then a default "Universal" size
@@ -532,8 +535,19 @@ pdfioFileCreateStringObj(
 //
 // This function creates a PDF file with a unique filename in the current
 // temporary directory.  The temporary file is stored in the string "buffer" an
-// will have a ".pdf" extension.  Otherwise, this function works the same as
+// will have a ".pdf" extension.
-// the @link pdfioFileCreate@ function.
+//
+// The "version" argument specifies the PDF version number for the file or
+// `NULL` for the default ("2.0").  The value "PCLm-1.0" can be specified to
+// produce the PCLm subset of PDF.
+//
+// The "media_box" and "crop_box" arguments specify the default MediaBox and
+// CropBox for pages in the PDF file - if `NULL` then a default "Universal" size
+// of 8.27x11in (the intersection of US Letter and ISO A4) is used.
+//
+// The "error_cb" and "error_cbdata" arguments specify an error handler callback
+// and its data pointer - if `NULL` the default error handler is used that
+// writes error messages to `stderr`.
 //
 // @since PDFio v1.1@
 //
@@ -1396,7 +1410,7 @@ create_common(
   pdf->output_cb   = output_cb;
   pdf->output_ctx  = output_cbdata;
   pdf->filename    = strdup(filename);
-  pdf->version     = strdup(version);
+  pdf->version     = strdup(!strncmp(version, "PCLm-", 5) ? "1.4" : version);
   pdf->mode        = _PDFIO_MODE_WRITE;
   pdf->error_cb    = error_cb;
   pdf->error_data  = error_cbdata;
@@ -1427,8 +1441,15 @@ create_common(
   }
 
   // Write a standard PDF header...
-  if (!_pdfioFilePrintf(pdf, "%%PDF-%s\n%%\342\343\317\323\n", version))
+  if (!strncmp(version, "PCLm-", 5))
+  {
+    if (!_pdfioFilePrintf(pdf, "%%PDF-1.4\n%%%s\n", version))
+      goto error;
+  }
+  else if (!_pdfioFilePrintf(pdf, "%%PDF-%s\n%%\342\343\317\323\n", version))
+  {
     goto error;
+  }
 
   // Create the pages object...
   if ((dict = pdfioDictCreate(pdf)) == NULL)
@@ -2364,8 +2385,7 @@ write_trailer(pdfio_file_t *pdf)	// I - PDF file
   // Write the xref table...
   xref_offset = _pdfioFileTell(pdf);
 
-  // TODO: Figure out how to do xref streams with encrypted output
+  if (strcmp(pdf->version, "1.5") >= 0 && !pdf->output_cb)
-  if (strcmp(pdf->version, "1.5") >= 0 && !pdf->output_cb && !pdf->encrypt_obj)
   {
     // Write a cross-reference stream...
     pdfio_dict_t	*xref_dict;	// Object dictionary
@@ -2374,6 +2394,11 @@ write_trailer(pdfio_file_t *pdf)	// I - PDF file
     pdfio_stream_t	*xref_st;	// Stream
     int			offsize;	// Size of object offsets
     unsigned char	buffer[10];	// Buffer entry
+    pdfio_encryption_t	encryption;	// PDF encryption mode
+
+    // Disable encryption while we write the xref stream...
+    encryption      = pdf->encryption;
+    pdf->encryption = PDFIO_ENCRYPTION_NONE;
 
     // Figure out how many bytes are needed for the object numbers
     if (xref_offset < 0xff)
@@ -2416,13 +2441,14 @@ write_trailer(pdfio_file_t *pdf)	// I - PDF file
     pdfioDictSetNumber(xref_dict, "Size", pdf->num_objs + 2);
     pdfioDictSetArray(xref_dict, "W", w_array);
     pdfioDictSetName(xref_dict, "Filter", "FlateDecode");
+    pdfioDictSetObj(xref_dict, "Info", pdf->info_obj);
+    pdfioDictSetObj(xref_dict, "Root", pdf->root_obj);
 
     if (pdf->encrypt_obj)
       pdfioDictSetObj(xref_dict, "Encrypt", pdf->encrypt_obj);
+
     if (pdf->id_array)
       pdfioDictSetArray(xref_dict, "ID", pdf->id_array);
-    pdfioDictSetObj(xref_dict, "Info", pdf->info_obj);
-    pdfioDictSetObj(xref_dict, "Root", pdf->root_obj);
 
     if ((xref_obj = pdfioFileCreateObj(pdf, xref_dict)) == NULL)
     {
@@ -2514,6 +2540,8 @@ write_trailer(pdfio_file_t *pdf)	// I - PDF file
     }
 
     pdfioStreamClose(xref_st);
+
+    pdf->encryption = encryption;
   }
   else
   {

pdfio-object.c

@@ -1,7 +1,7 @@
 //
 // PDF object functions for PDFio.
 //
-// Copyright © 2021-2024 by Michael R Sweet.
+// Copyright © 2021-2025 by Michael R Sweet.
 //
 // Licensed under Apache License v2.0.  See the file "LICENSE" for more
 // information.
@@ -10,13 +10,6 @@
 #include "pdfio-private.h"
 
 
-//
-// Local functions...
-//
-
-static bool	write_obj_header(pdfio_obj_t *obj);
-
-
 //
 // 'pdfioObjClose()' - Close an object, writing any data as needed to the PDF
 //                     file.
@@ -42,7 +35,7 @@ pdfioObjClose(pdfio_obj_t *obj)		// I - Object
   if (!obj->offset)
   {
     // Write the object value
-    if (!write_obj_header(obj))
+    if (!_pdfioObjWriteHeader(obj))
       return (false);
 
     // Write the "endobj" line...
@@ -195,7 +188,7 @@ pdfioObjCreateStream(
     }
   }
 
-  if (!write_obj_header(obj))
+  if (!_pdfioObjWriteHeader(obj))
     return (NULL);
 
   if (!_pdfioFilePuts(obj->pdf, "stream\n"))
@@ -205,7 +198,7 @@ pdfioObjCreateStream(
   obj->pdf->current_obj = obj;
 
   // Return the new stream...
-  return (_pdfioStreamCreate(obj, length_obj, filter));
+  return (_pdfioStreamCreate(obj, length_obj, 0, filter));
 }
 
 
@@ -582,11 +575,11 @@ _pdfioObjSetExtension(
 
 
 //
-// 'write_obj_header()' - Write the object header...
+// '_pdfioObjWriteHeader()' - Write the object header...
 //
 
-static bool				// O - `true` on success, `false` on failure
+bool					// O - `true` on success, `false` on failure
-write_obj_header(pdfio_obj_t *obj)	// I - Object
+_pdfioObjWriteHeader(pdfio_obj_t *obj)	// I - Object
 {
   obj->offset = _pdfioFileTell(obj->pdf);
 

pdfio-private.h

@@ -1,7 +1,7 @@
 //
 // Private header file for PDFio.
 //
-// Copyright © 2021-2024 by Michael R Sweet.
+// Copyright © 2021-2025 by Michael R Sweet.
 //
 // Licensed under Apache License v2.0.  See the file "LICENSE" for more
 // information.
@@ -107,7 +107,7 @@ typedef enum _pdfio_mode_e		// Read/write mode
 typedef enum _pdfio_predictor_e		// PNG predictor constants
 {
   _PDFIO_PREDICTOR_NONE = 1,		// No predictor (default)
-  _PDFIO_PREDICTOR_TIFF2 = 2,		// TIFF2 predictor (???)
+  _PDFIO_PREDICTOR_TIFF2 = 2,		// TIFF predictor 2 (difference from left neighbor)
   _PDFIO_PREDICTOR_PNG_NONE = 10,	// PNG None predictor (same as `_PDFIO_PREDICTOR_NONE`)
   _PDFIO_PREDICTOR_PNG_SUB = 11,	// PNG Sub predictor
   _PDFIO_PREDICTOR_PNG_UP = 12,		// PNG Up predictor
@@ -313,8 +313,9 @@ struct _pdfio_stream_s			// Stream
   z_stream	flate;			// Flate filter state
   _pdfio_predictor_t predictor;		// Predictor function, if any
   size_t	pbpixel,		// Size of a pixel in bytes
-		pbsize;			// Predictor buffer size, if any
+		pbsize,			// Predictor buffer size, if any
-  unsigned char	cbuffer[4096],		// Compressed data buffer
+		cbsize;			// Compressed data buffer size
+  unsigned char	*cbuffer,		// Compressed data buffer
 		*prbuffer,		// Raw buffer (previous line), as needed
 		*psbuffer;		// PNG filter buffer, as needed
   _pdfio_crypto_cb_t crypto_cb;		// Encryption/descryption callback, if any
@@ -383,8 +384,9 @@ extern void		_pdfioObjDelete(pdfio_obj_t *obj) _PDFIO_INTERNAL;
 extern void		*_pdfioObjGetExtension(pdfio_obj_t *obj) _PDFIO_INTERNAL;
 extern bool		_pdfioObjLoad(pdfio_obj_t *obj) _PDFIO_INTERNAL;
 extern void		_pdfioObjSetExtension(pdfio_obj_t *obj, void *data, _pdfio_extfree_t datafree) _PDFIO_INTERNAL;
+extern bool		_pdfioObjWriteHeader(pdfio_obj_t *obj) _PDFIO_INTERNAL;
 
-extern pdfio_stream_t	*_pdfioStreamCreate(pdfio_obj_t *obj, pdfio_obj_t *length_obj, pdfio_filter_t compression) _PDFIO_INTERNAL;
+extern pdfio_stream_t	*_pdfioStreamCreate(pdfio_obj_t *obj, pdfio_obj_t *length_obj, size_t cbsize, pdfio_filter_t compression) _PDFIO_INTERNAL;
 extern pdfio_stream_t	*_pdfioStreamOpen(pdfio_obj_t *obj, bool decode) _PDFIO_INTERNAL;
 
 extern bool		_pdfioStringIsAllocated(pdfio_file_t *pdf, const char *s) _PDFIO_INTERNAL;

pdfio-stream.c

@@ -50,7 +50,7 @@ pdfioStreamClose(pdfio_stream_t *st)	// I - Stream
 
       while ((status = deflate(&st->flate, Z_FINISH)) != Z_STREAM_END)
       {
-        size_t	bytes = sizeof(st->cbuffer) - st->flate.avail_out,
+        size_t	bytes = st->cbsize - st->flate.avail_out,
 					// Bytes to write
 		outbytes;		// Actual bytes written
 
@@ -89,13 +89,13 @@ pdfioStreamClose(pdfio_stream_t *st)	// I - Stream
         }
 
 	st->flate.next_out  = (Bytef *)st->cbuffer + bytes;
-	st->flate.avail_out = (uInt)(sizeof(st->cbuffer) - bytes);
+	st->flate.avail_out = (uInt)(st->cbsize - bytes);
       }
 
-      if (st->flate.avail_out < (uInt)sizeof(st->cbuffer))
+      if (st->flate.avail_out < (uInt)st->cbsize)
       {
         // Write any residuals...
-        size_t bytes = sizeof(st->cbuffer) - st->flate.avail_out;
+        size_t bytes = st->cbsize - st->flate.avail_out;
 					// Bytes to write
 
 	if (st->crypto_cb)
@@ -172,6 +172,7 @@ pdfioStreamClose(pdfio_stream_t *st)	// I - Stream
 
   st->pdf->current_obj = NULL;
 
+  free(st->cbuffer);
   free(st->prbuffer);
   free(st->psbuffer);
   free(st);
@@ -190,6 +191,7 @@ pdfio_stream_t *			// O - Stream or `NULL` on error
 _pdfioStreamCreate(
     pdfio_obj_t    *obj,		// I - Object
     pdfio_obj_t    *length_obj,		// I - Length object, if any
+    size_t         cbsize,		// I - Size of compression buffer
     pdfio_filter_t compression)		// I - Compression to apply
 {
   pdfio_stream_t	*st;		// Stream
@@ -302,8 +304,21 @@ _pdfioStreamCreate(
     else
       st->predictor = _PDFIO_PREDICTOR_NONE;
 
+    if (cbsize == 0)
+      cbsize = 4096;
+
+    st->cbsize = cbsize;
+    if ((st->cbuffer = malloc(cbsize)) == NULL)
+    {
+      _pdfioFileError(st->pdf, "Unable to allocate %lu bytes for Flate output buffer: %s", (unsigned long)cbsize, strerror(errno));
+      free(st->prbuffer);
+      free(st->psbuffer);
+      free(st);
+      return (NULL);
+    }
+
     st->flate.next_out  = (Bytef *)st->cbuffer;
-    st->flate.avail_out = (uInt)sizeof(st->cbuffer);
+    st->flate.avail_out = (uInt)cbsize;
 
     if ((status = deflateInit(&(st->flate), 9)) != Z_OK)
     {
@@ -567,11 +582,21 @@ _pdfioStreamOpen(pdfio_obj_t *obj,	// I - Object
       else
         st->predictor = _PDFIO_PREDICTOR_NONE;
 
+      st->cbsize = 4096;
+      if ((st->cbuffer = malloc(st->cbsize)) == NULL)
+      {
+	_pdfioFileError(st->pdf, "Unable to allocate %lu bytes for Flate compression buffer.", (unsigned long)st->cbsize);
+	free(st->prbuffer);
+	free(st->psbuffer);
+	free(st);
+	return (NULL);
+      }
+
       PDFIO_DEBUG("_pdfioStreamOpen: pos=%ld\n", (long)_pdfioFileTell(st->pdf));
-      if (sizeof(st->cbuffer) > st->remaining)
+      if (st->cbsize > st->remaining)
 	rbytes = _pdfioFileRead(st->pdf, st->cbuffer, st->remaining);
       else
-	rbytes = _pdfioFileRead(st->pdf, st->cbuffer, sizeof(st->cbuffer));
+	rbytes = _pdfioFileRead(st->pdf, st->cbuffer, st->cbsize);
 
       if (rbytes <= 0)
       {
@@ -1045,10 +1070,10 @@ stream_read(pdfio_stream_t *st,		// I - Stream
       if (st->flate.avail_in == 0)
       {
 	// Read more from the file...
-	if (sizeof(st->cbuffer) > st->remaining)
+	if (st->cbsize > st->remaining)
 	  rbytes = _pdfioFileRead(st->pdf, st->cbuffer, st->remaining);
 	else
-	  rbytes = _pdfioFileRead(st->pdf, st->cbuffer, sizeof(st->cbuffer));
+	  rbytes = _pdfioFileRead(st->pdf, st->cbuffer, st->cbsize);
 
 	if (rbytes <= 0)
 	  return (-1);			// End of file...
@@ -1101,10 +1126,10 @@ stream_read(pdfio_stream_t *st,		// I - Stream
 	if (st->flate.avail_in == 0)
 	{
 	  // Read more from the file...
-	  if (sizeof(st->cbuffer) > st->remaining)
+	  if (st->cbsize > st->remaining)
 	    rbytes = _pdfioFileRead(st->pdf, st->cbuffer, st->remaining);
 	  else
-	    rbytes = _pdfioFileRead(st->pdf, st->cbuffer, sizeof(st->cbuffer));
+	    rbytes = _pdfioFileRead(st->pdf, st->cbuffer, st->cbsize);
 
 	  if (rbytes <= 0)
 	    return (-1);		// End of file...
@@ -1171,10 +1196,10 @@ stream_read(pdfio_stream_t *st,		// I - Stream
 	if (st->flate.avail_in == 0)
 	{
 	  // Read more from the file...
-	  if (sizeof(st->cbuffer) > st->remaining)
+	  if (st->cbsize > st->remaining)
 	    rbytes = _pdfioFileRead(st->pdf, st->cbuffer, st->remaining);
 	  else
-	    rbytes = _pdfioFileRead(st->pdf, st->cbuffer, sizeof(st->cbuffer));
+	    rbytes = _pdfioFileRead(st->pdf, st->cbuffer, st->cbsize);
 
 	  if (rbytes <= 0)
 	    return (-1);		// End of file...
@@ -1278,10 +1303,10 @@ stream_write(pdfio_stream_t *st,	// I - Stream
 
   while (st->flate.avail_in > 0)
   {
-    if (st->flate.avail_out < (sizeof(st->cbuffer) / 8))
+    if (st->flate.avail_out < (st->cbsize / 8))
     {
       // Flush the compression buffer...
-      size_t	cbytes = sizeof(st->cbuffer) - st->flate.avail_out,
+      size_t	cbytes = st->cbsize - st->flate.avail_out,
 		outbytes;
 
       if (st->crypto_cb)
@@ -1310,7 +1335,7 @@ stream_write(pdfio_stream_t *st,	// I - Stream
       }
 
       st->flate.next_out  = (Bytef *)st->cbuffer + cbytes;
-      st->flate.avail_out = (uInt)(sizeof(st->cbuffer) - cbytes);
+      st->flate.avail_out = (uInt)(st->cbsize - cbytes);
     }
 
     // Deflate what we can this time...