Implement Pl_DCT pipeline

Additional testing is added in later commits to be supported by
additional changes in the library.

include/qpdf/Pl_DCT.hh

@@ -0,0 +1,70 @@
+// Copyright (c) 2005-2015 Jay Berkenbilt
+//
+// This file is part of qpdf.  This software may be distributed under
+// the terms of version 2 of the Artistic License which may be found
+// in the source distribution.  It is provided "as is" without express
+// or implied warranty.
+
+#ifndef __PL_DCT_HH__
+#define __PL_DCT_HH__
+
+#include <qpdf/Pipeline.hh>
+#include <qpdf/Pl_Buffer.hh>
+#include <jpeglib.h>
+
+class Pl_DCT: public Pipeline
+{
+  public:
+    // Constructor for decompressing image data
+    QPDF_DLL
+    Pl_DCT(char const* identifier, Pipeline* next);
+
+    class CompressConfig
+    {
+      public:
+        CompressConfig()
+        {
+        }
+        virtual ~CompressConfig()
+        {
+        }
+        virtual void apply(jpeg_compress_struct*) = 0;
+    };
+
+    // Constructor for compressing image data
+    QPDF_DLL
+    Pl_DCT(char const* identifier, Pipeline* next,
+           JDIMENSION image_width,
+           JDIMENSION image_height,
+           int components,
+           J_COLOR_SPACE color_space,
+           CompressConfig* config_callback = 0);
+
+    QPDF_DLL
+    virtual ~Pl_DCT();
+
+    QPDF_DLL
+    virtual void write(unsigned char* data, size_t len);
+    QPDF_DLL
+    virtual void finish();
+
+  private:
+    void compress(void* cinfo, PointerHolder<Buffer>);
+    void decompress(void* cinfo, PointerHolder<Buffer>);
+
+    enum action_e { a_compress, a_decompress };
+
+    action_e action;
+    Pl_Buffer buf;
+
+    // Used for compression
+    JDIMENSION image_width;
+    JDIMENSION image_height;
+    int components;
+    J_COLOR_SPACE color_space;
+
+    CompressConfig* config_callback;
+
+};
+
+#endif // __PL_DCT_HH__

libqpdf/Pl_DCT.cc

@@ -0,0 +1,204 @@
+#include <qpdf/Pl_DCT.hh>
+
+#include <qpdf/QUtil.hh>
+#include <setjmp.h>
+#include <string>
+#include <stdexcept>
+
+#if BITS_IN_JSAMPLE != 8
+# error "qpdf does not support libjpeg built with BITS_IN_JSAMPLE != 8"
+#endif
+
+struct qpdf_jpeg_error_mgr
+{
+    struct jpeg_error_mgr pub;
+    jmp_buf jmpbuf;
+    std::string msg;
+};
+
+static void
+error_handler(j_common_ptr cinfo)
+{
+    qpdf_jpeg_error_mgr* jerr =
+        reinterpret_cast<qpdf_jpeg_error_mgr*>(cinfo->err);
+    char buf[JMSG_LENGTH_MAX];
+    (*cinfo->err->format_message)(cinfo, buf);
+    jerr->msg = buf;
+    longjmp(jerr->jmpbuf, 1);
+}
+
+Pl_DCT::Pl_DCT(char const* identifier, Pipeline* next) :
+    Pipeline(identifier, next),
+    action(a_decompress),
+    buf("DCT compressed image")
+{
+}
+
+Pl_DCT::Pl_DCT(char const* identifier, Pipeline* next,
+               JDIMENSION image_width,
+               JDIMENSION image_height,
+               int components,
+               J_COLOR_SPACE color_space,
+               CompressConfig* config_callback) :
+    Pipeline(identifier, next),
+    action(a_compress),
+    buf("DCT uncompressed image"),
+    image_width(image_width),
+    image_height(image_height),
+    components(components),
+    color_space(color_space),
+    config_callback(config_callback)
+{
+}
+
+Pl_DCT::~Pl_DCT()
+{
+}
+
+void
+Pl_DCT::write(unsigned char* data, size_t len)
+{
+    this->buf.write(data, len);
+}
+
+void
+Pl_DCT::finish()
+{
+    this->buf.finish();
+    PointerHolder<Buffer> b = this->buf.getBuffer();
+
+    struct jpeg_compress_struct cinfo_compress;
+    struct jpeg_decompress_struct cinfo_decompress;
+    struct qpdf_jpeg_error_mgr jerr;
+
+    cinfo_compress.err = jpeg_std_error(&(jerr.pub));
+    cinfo_decompress.err = jpeg_std_error(&(jerr.pub));
+    jerr.pub.error_exit = error_handler;
+
+    bool error = false;
+    if (setjmp(jerr.jmpbuf) == 0)
+    {
+        if (this->action == a_compress)
+        {
+            compress(reinterpret_cast<void*>(&cinfo_compress), b);
+        }
+        else
+        {
+            decompress(reinterpret_cast<void*>(&cinfo_decompress), b);
+        }
+    }
+    else
+    {
+        error = true;
+    }
+
+    if (this->action == a_compress)
+    {
+        jpeg_destroy_compress(&cinfo_compress);
+    }
+    if (this->action == a_decompress)
+    {
+        jpeg_destroy_decompress(&cinfo_decompress);
+    }
+    if (error)
+    {
+        throw std::runtime_error(jerr.msg);
+    }
+}
+
+void
+Pl_DCT::compress(void* cinfo_p, PointerHolder<Buffer> b)
+{
+    struct jpeg_compress_struct* cinfo =
+        reinterpret_cast<jpeg_compress_struct*>(cinfo_p);
+
+#ifdef __GNUC__
+# if ((__GNUC__ * 100) + __GNUC_MINOR__) >= 406
+#       pragma GCC diagnostic push
+#       pragma GCC diagnostic ignored "-Wold-style-cast"
+# endif
+#endif
+    jpeg_create_compress(cinfo);
+#ifdef __GNUC__
+# if ((__GNUC__ * 100) + __GNUC_MINOR__) >= 406
+#       pragma GCC diagnostic pop
+# endif
+#endif
+    unsigned char* outbuffer = 0;
+    unsigned long outsize = 0;
+    jpeg_mem_dest(cinfo, &outbuffer, &outsize);
+
+    cinfo->image_width = this->image_width;
+    cinfo->image_height = this->image_height;
+    cinfo->input_components = this->components;
+    cinfo->in_color_space = this->color_space;
+    jpeg_set_defaults(cinfo);
+    if (this->config_callback)
+    {
+        this->config_callback->apply(cinfo);
+    }
+
+    jpeg_start_compress(cinfo, TRUE);
+
+    int width = cinfo->image_width * cinfo->input_components;
+    size_t expected_size =
+        cinfo->image_height * cinfo->image_width * cinfo->input_components;
+    if (b->getSize() != expected_size)
+    {
+        throw std::runtime_error(
+            "Pl_DCT: image buffer size = " +
+            QUtil::int_to_string(b->getSize()) + "; expected size = " +
+            QUtil::int_to_string(expected_size));
+    }
+    JSAMPROW row_pointer[1];
+    unsigned char* buffer = b->getBuffer();
+    while (cinfo->next_scanline < cinfo->image_height)
+    {
+        // We already verified that the buffer is big enough.
+        row_pointer[0] = &buffer[cinfo->next_scanline * width];
+        (void) jpeg_write_scanlines(cinfo, row_pointer, 1);
+    }
+    jpeg_finish_compress(cinfo);
+    this->getNext()->write(outbuffer, outsize);
+    this->getNext()->finish();
+
+    free(outbuffer);
+}
+
+void
+Pl_DCT::decompress(void* cinfo_p, PointerHolder<Buffer> b)
+{
+    struct jpeg_decompress_struct* cinfo =
+        reinterpret_cast<jpeg_decompress_struct*>(cinfo_p);
+
+#ifdef __GNUC__
+# if ((__GNUC__ * 100) + __GNUC_MINOR__) >= 406
+#       pragma GCC diagnostic push
+#       pragma GCC diagnostic ignored "-Wold-style-cast"
+# endif
+#endif
+    jpeg_create_decompress(cinfo);
+#ifdef __GNUC__
+# if ((__GNUC__ * 100) + __GNUC_MINOR__) >= 406
+#       pragma GCC diagnostic pop
+# endif
+#endif
+    jpeg_mem_src(cinfo, b->getBuffer(), b->getSize());
+
+    (void) jpeg_read_header(cinfo, TRUE);
+    (void) jpeg_calc_output_dimensions(cinfo);
+
+    int width = cinfo->output_width * cinfo->output_components;
+    JSAMPARRAY buffer = (*cinfo->mem->alloc_sarray)
+        (reinterpret_cast<j_common_ptr>(cinfo), JPOOL_IMAGE, width, 1);
+
+    (void) jpeg_start_decompress(cinfo);
+    while (cinfo->output_scanline < cinfo->output_height)
+    {
+        (void) jpeg_read_scanlines(cinfo, buffer, 1);
+        this->getNext()->write(reinterpret_cast<unsigned char*>(buffer[0]),
+                               width * sizeof(buffer[0][0]));
+    }
+    (void) jpeg_finish_decompress(cinfo);
+    this->getNext()->finish();
+}

libqpdf/build.mk

@@ -21,6 +21,7 @@ SRCS_libqpdf = \
 	libqpdf/Pl_Buffer.cc \
 	libqpdf/Pl_Concatenate.cc \
 	libqpdf/Pl_Count.cc \
+	libqpdf/Pl_DCT.cc \
 	libqpdf/Pl_Discard.cc \
 	libqpdf/Pl_Flate.cc \
 	libqpdf/Pl_LZWDecoder.cc \

libtests/build.mk

@@ -4,6 +4,8 @@ BINS_libtests = \
 	bits \
 	buffer \
 	concatenate \
+	dct_compress \
+	dct_uncompress \
 	flate \
 	hex \
 	input_source \

libtests/dct_compress.cc

@@ -0,0 +1,93 @@
+#include <qpdf/Pl_DCT.hh>
+#include <qpdf/Pl_StdioFile.hh>
+#include <qpdf/QUtil.hh>
+
+#include <stdio.h>
+#include <string.h>
+#include <iostream>
+#include <stdlib.h>
+
+static void usage()
+{
+    std::cerr << "Usage: dct_compress infile outfile width height"
+              << " {rgb|cmyk|gray}" << std::endl;
+    exit(2);
+}
+
+class Callback: public Pl_DCT::CompressConfig
+{
+  public:
+    virtual ~Callback()
+    {
+    }
+    virtual void apply(jpeg_compress_struct*);
+    bool called = false;
+};
+
+void Callback::apply(jpeg_compress_struct*)
+{
+    this->called = true;
+}
+
+int main(int argc, char* argv[])
+{
+    if (argc != 6)
+    {
+        usage();
+    }
+
+    char* infilename = argv[1];
+    char* outfilename = argv[2];
+    unsigned int width = atoi(argv[3]);
+    unsigned int height = atoi(argv[4]);
+    char* colorspace = argv[5];
+    J_COLOR_SPACE cs =
+        ((strcmp(colorspace, "rgb") == 0) ? JCS_RGB :
+         (strcmp(colorspace, "cmyk") == 0) ? JCS_CMYK :
+         (strcmp(colorspace, "gray") == 0) ? JCS_GRAYSCALE :
+         JCS_UNKNOWN);
+    int components = 0;
+    switch (cs)
+    {
+      case JCS_RGB:
+        components = 3;
+        break;
+      case JCS_CMYK:
+        components = 4;
+        break;
+      case JCS_GRAYSCALE:
+        components = 1;
+        break;
+      default:
+        usage();
+        break;
+    }
+
+    FILE* infile = QUtil::safe_fopen(infilename, "rb");
+    FILE* outfile = QUtil::safe_fopen(outfilename, "wb");
+    Pl_StdioFile out("stdout", outfile);
+    unsigned char buf[100];
+    bool done = false;
+    Callback callback;
+    Pl_DCT dct("dct", &out, width, height, components, cs, &callback);
+    while (! done)
+    {
+	size_t len = fread(buf, 1, sizeof(buf), infile);
+	if (len <= 0)
+	{
+	    done = true;
+	}
+	else
+	{
+	    dct.write(buf, len);
+	}
+    }
+    dct.finish();
+    if (! callback.called)
+    {
+        std::cout << "Callback was not called" << std::endl;
+    }
+    fclose(infile);
+    fclose(outfile);
+    return 0;
+}

libtests/dct_uncompress.cc

@@ -0,0 +1,44 @@
+#include <qpdf/Pl_DCT.hh>
+#include <qpdf/Pl_StdioFile.hh>
+#include <qpdf/QUtil.hh>
+
+#include <stdio.h>
+#include <string.h>
+#include <iostream>
+#include <stdlib.h>
+
+int main(int argc, char* argv[])
+{
+    if (argc != 3)
+    {
+	std::cerr << "Usage: dct_uncompress infile outfile"
+                  << std::endl;
+	exit(2);
+    }
+
+    char* infilename = argv[1];
+    char* outfilename = argv[2];
+
+    FILE* infile = QUtil::safe_fopen(infilename, "rb");
+    FILE* outfile = QUtil::safe_fopen(outfilename, "wb");
+    Pl_StdioFile out("stdout", outfile);
+    unsigned char buf[100];
+    bool done = false;
+    Pl_DCT dct("dct", &out);
+    while (! done)
+    {
+	size_t len = fread(buf, 1, sizeof(buf), infile);
+	if (len <= 0)
+	{
+	    done = true;
+	}
+	else
+	{
+	    dct.write(buf, len);
+	}
+    }
+    dct.finish();
+    fclose(infile);
+    fclose(outfile);
+    return 0;
+}

libtests/qtest/dct.test

@@ -0,0 +1,66 @@
+#!/usr/bin/env perl
+require 5.008;
+use warnings;
+use strict;
+
+chdir("dct") or die "chdir testdir failed: $!\n";
+
+require TestDriver;
+
+# This test suite does light verification of DCT by running some data
+# through a round trip with one encoding system. The
+# examples/pdf-create program also exercises DCT but does so more
+# fully.
+
+my $td = new TestDriver('dct');
+
+cleanup();
+
+$td->runtest("compress",
+             {$td->COMMAND => "dct_compress rawdata a.jpg 400 256 gray"},
+             {$td->STRING => "", $td->EXIT_STATUS => 0});
+$td->runtest("decompress",
+             {$td->COMMAND => "dct_uncompress a.jpg out"},
+             {$td->STRING => "", $td->EXIT_STATUS => 0});
+# Compare
+my @raw = get_data('rawdata');
+my @processed = get_data('out');
+my $checked_data = 0;
+if ($td->runtest("bytes in data",
+                 {$td->STRING => scalar(@processed)},
+                 {$td->STRING => scalar(@raw)}))
+{
+    my $mismatch = 0;
+    for (my $i = 0; $i < scalar(@raw); ++$i)
+    {
+        $checked_data = 1;
+        my $delta = abs(ord($raw[$i]) - ord($processed[$i]));
+        if ($delta > 10)
+        {
+            ++$mismatch;
+        }
+    }
+    $td->runtest("data is close enough",
+                 {$td->STRING => $mismatch},
+                 {$td->STRING => '0'});
+}
+
+cleanup();
+
+$td->report(3 + $checked_data);
+
+sub cleanup
+{
+    system("rm -f a.jpg out");
+}
+
+sub get_data
+{
+    my $file = shift;
+    local $/ = undef;
+    open(F, "<$file") || die;
+    binmode(F);
+    my $data = <F>;
+    close(F);
+    split('', $data);
+}