1 files changed, 456 insertions, 0 deletions
diff --git a/src/io/stream/gzipstream.cpp b/src/io/stream/gzipstream.cpp
new file mode 100644
index 0000000..60d17f9
--- /dev/null
+++ b/src/io/stream/gzipstream.cpp
@@ -0,0 +1,456 @@
+// SPDX-License-Identifier: LGPL-2.1-or-later
+/** @file
+ * Zlib-enabled input and output streams
+ *//*
+ * Authors:
+ * see git history
+ * Bob Jamison <rjamison@titan.com>
+ * 
+ *
+ * Copyright (C) 2018 Authors
+ * Released under GNU LGPL v2.1+, read the file 'COPYING' for more information.
+ */
+/*
+ * This is a thin wrapper of libz calls, in order
+ * to provide a simple interface to our developers
+ * for gzip input and output.
+ */
+
+#include "gzipstream.h"
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <string>
+
+namespace Inkscape
+{
+namespace IO
+{
+
+//#########################################################################
+//# G Z I P    I N P U T    S T R E A M
+//#########################################################################
+
+#define OUT_SIZE 4000
+
+/**
+ *
+ */ 
+GzipInputStream::GzipInputStream(InputStream &sourceStream)
+                    : BasicInputStream(sourceStream),
+                      loaded(false),
+                      outputBuf(nullptr),
+                      srcBuf(nullptr),
+                      crc(0),
+                      srcCrc(0),
+                      srcSiz(0),
+                      srcLen(0),
+                      outputBufPos(0),
+                      outputBufLen(0)
+{
+    memset( &d_stream, 0, sizeof(d_stream) );
+}
+
+/**
+ *
+ */ 
+GzipInputStream::~GzipInputStream()
+{
+    close();
+    if ( srcBuf ) {
+      delete[] srcBuf;
+      srcBuf = nullptr;
+    }
+    if ( outputBuf ) {
+        delete[] outputBuf;
+        outputBuf = nullptr;
+    }
+}
+
+/**
+ * Returns the number of bytes that can be read (or skipped over) from
+ * this input stream without blocking by the next caller of a method for
+ * this input stream.
+ */ 
+int GzipInputStream::available()
+{
+    if (closed || !outputBuf)
+        return 0;
+    return outputBufLen - outputBufPos;
+}
+
+    
+/**
+ *  Closes this input stream and releases any system resources
+ *  associated with the stream.
+ */ 
+void GzipInputStream::close()
+{
+    if (closed)
+        return;
+
+    int zerr = inflateEnd(&d_stream);
+    if (zerr != Z_OK) {
+        printf("inflateEnd: Some kind of problem: %d\n", zerr);
+    }
+
+    if ( srcBuf ) {
+      delete[] srcBuf;
+      srcBuf = nullptr;
+    }
+    if ( outputBuf ) {
+        delete[] outputBuf;
+        outputBuf = nullptr;
+    }
+    closed = true;
+}
+    
+/**
+ * Reads the next byte of data from the input stream.  -1 if EOF
+ */ 
+int GzipInputStream::get()
+{
+    int ch = -1;
+    if (closed) {
+        // leave return value -1
+    }
+    else if (!loaded && !load()) {
+        closed=true;
+    } else {
+        loaded = true;
+
+        if ( outputBufPos >= outputBufLen ) {
+            // time to read more, if we can
+            fetchMore();
+        }
+
+        if ( outputBufPos < outputBufLen ) {
+            ch = (int)outputBuf[outputBufPos++];
+        }
+    }
+
+    return ch;
+}
+
+#define FTEXT 0x01
+#define FHCRC 0x02
+#define FEXTRA 0x04
+#define FNAME 0x08
+#define FCOMMENT 0x10
+
+bool GzipInputStream::load()
+{
+    crc = crc32(0L, Z_NULL, 0);
+    
+    std::vector<Byte> inputBuf;
+    while (true)
+        {
+        int ch = source.get();
+        if (ch<0)
+            break;
+        inputBuf.push_back(static_cast<Byte>(ch & 0xff));
+        }
+    long inputBufLen = inputBuf.size();
+    
+    if (inputBufLen < 19) //header + tail + 1
+        {
+        return false;
+        }
+
+    srcLen = inputBuf.size();
+    srcBuf = new (std::nothrow) Byte [srcLen];
+    if (!srcBuf) {
+        return false;
+    }
+
+    outputBuf = new (std::nothrow) unsigned char [OUT_SIZE];
+    if ( !outputBuf ) {
+        delete[] srcBuf;
+        srcBuf = nullptr;
+        return false;
+    }
+    outputBufLen = 0; // Not filled in yet
+
+    std::vector<unsigned char>::iterator iter;
+    Bytef *p = srcBuf;
+    for (iter=inputBuf.begin() ; iter != inputBuf.end() ; ++iter)
+	{
+        *p++ = *iter;
+	}
+
+    int headerLen = 10;
+
+    //Magic
+    //int val = (int)srcBuf[0];
+    ////printf("val:%x\n", val);
+    //val = (int)srcBuf[1];
+    ////printf("val:%x\n", val);
+
+    ////Method
+    //val = (int)srcBuf[2];
+    ////printf("val:%x\n", val);
+
+    //flags
+    int flags = static_cast<int>(srcBuf[3]);
+
+    ////time
+    //val = (int)srcBuf[4];
+    //val = (int)srcBuf[5];
+    //val = (int)srcBuf[6];
+    //val = (int)srcBuf[7];
+
+    ////xflags
+    //val = (int)srcBuf[8];
+    ////OS
+    //val = (int)srcBuf[9];
+
+//     if ( flags & FEXTRA ) {
+//         headerLen += 2;
+//         int xlen = 
+//         TODO deal with optional header parts
+//     }
+    if ( flags & FNAME ) {
+        int cur = 10;
+        while ( srcBuf[cur] )
+        {
+            cur++;
+            headerLen++;
+        }
+        headerLen++;
+    }
+
+
+    srcCrc = ((0x0ff & srcBuf[srcLen - 5]) << 24)
+           | ((0x0ff & srcBuf[srcLen - 6]) << 16)
+           | ((0x0ff & srcBuf[srcLen - 7]) <<  8)
+           | ((0x0ff & srcBuf[srcLen - 8]) <<  0);
+    //printf("srcCrc:%lx\n", srcCrc);
+    
+    srcSiz = ((0x0ff & srcBuf[srcLen - 1]) << 24)
+           | ((0x0ff & srcBuf[srcLen - 2]) << 16)
+           | ((0x0ff & srcBuf[srcLen - 3]) <<  8)
+           | ((0x0ff & srcBuf[srcLen - 4]) <<  0);
+    //printf("srcSiz:%lx/%ld\n", srcSiz, srcSiz);
+    
+    //outputBufLen = srcSiz + srcSiz/100 + 14;
+    
+    unsigned char *data = srcBuf + headerLen;
+    unsigned long dataLen = srcLen - (headerLen + 8);
+    //printf("%x %x\n", data[0], data[dataLen-1]);
+    
+    d_stream.zalloc    = (alloc_func)nullptr;
+    d_stream.zfree     = (free_func)nullptr;
+    d_stream.opaque    = (voidpf)nullptr;
+    d_stream.next_in   = data;
+    d_stream.avail_in  = dataLen;
+    d_stream.next_out  = outputBuf;
+    d_stream.avail_out = OUT_SIZE;
+    
+    int zerr = inflateInit2(&d_stream, -MAX_WBITS);
+    if ( zerr == Z_OK )
+    {
+        zerr = fetchMore();
+    } else {
+        printf("inflateInit2: Some kind of problem: %d\n", zerr);
+    }
+
+        
+    return (zerr == Z_OK) || (zerr == Z_STREAM_END);
+}
+
+
+int GzipInputStream::fetchMore()
+{
+    // TODO assumes we aren't called till the buffer is empty
+    d_stream.next_out  = outputBuf;
+    d_stream.avail_out = OUT_SIZE;
+    outputBufLen = 0;
+    outputBufPos = 0;
+
+    int zerr = inflate( &d_stream, Z_SYNC_FLUSH );
+    if ( zerr == Z_OK || zerr == Z_STREAM_END ) {
+        outputBufLen = OUT_SIZE - d_stream.avail_out;
+        if ( outputBufLen ) {
+            crc = crc32(crc, const_cast<const Bytef *>(outputBuf), outputBufLen);
+        }
+        //printf("crc:%lx\n", crc);
+//     } else if ( zerr != Z_STREAM_END ) {
+//         // TODO check to be sure this won't happen for partial end reads
+//         printf("inflate: Some kind of problem: %d\n", zerr);
+    }
+
+    return zerr;
+}
+
+//#########################################################################
+//# G Z I P   O U T P U T    S T R E A M
+//#########################################################################
+
+/**
+ *
+ */ 
+GzipOutputStream::GzipOutputStream(OutputStream &destinationStream)
+                     : BasicOutputStream(destinationStream)
+{
+
+    totalIn         = 0;
+    totalOut        = 0;
+    crc             = crc32(0L, Z_NULL, 0);
+
+    //Gzip header
+    destination.put(0x1f);
+    destination.put(0x8b);
+
+    //Say it is compressed
+    destination.put(Z_DEFLATED);
+
+    //flags
+    destination.put(0);
+
+    //time
+    destination.put(0);
+    destination.put(0);
+    destination.put(0);
+    destination.put(0);
+
+    //xflags
+    destination.put(0);
+
+    //OS code - from zutil.h
+    //destination.put(OS_CODE);
+    //apparently, we should not explicitly include zutil.h
+    destination.put(0);
+
+}
+
+/**
+ *
+ */ 
+GzipOutputStream::~GzipOutputStream()
+{
+    close();
+}
+
+/**
+ * Closes this output stream and releases any system resources
+ * associated with this stream.
+ */ 
+void GzipOutputStream::close()
+{
+    if (closed)
+        return;
+
+    flush();
+
+    //# Send the CRC
+    uLong outlong = crc;
+    for (int n = 0; n < 4; n++)
+        {
+        destination.put(static_cast<char>(outlong & 0xff));
+        outlong >>= 8;
+        }
+    //# send the file length
+    outlong = totalIn & 0xffffffffL;
+    for (int n = 0; n < 4; n++)
+        {
+        destination.put(static_cast<char>(outlong & 0xff));
+        outlong >>= 8;
+        }
+
+    destination.close();
+    closed = true;
+}
+    
+/**
+ *  Flushes this output stream and forces any buffered output
+ *  bytes to be written out.
+ */ 
+void GzipOutputStream::flush()
+{
+    if (closed || inputBuf.empty())
+	{
+        return;
+    }
+	
+    uLong srclen = inputBuf.size();
+    Bytef *srcbuf = new (std::nothrow) Bytef [srclen];
+    if (!srcbuf)
+        {
+        return;
+        }
+        
+    uLong destlen = srclen;
+    Bytef *destbuf = new (std::nothrow) Bytef [(destlen + (srclen/100) + 13)];
+    if (!destbuf)
+        {
+        delete[] srcbuf;
+        return;
+        }
+        
+    std::vector<unsigned char>::iterator iter;
+    Bytef *p = srcbuf;
+    for (iter=inputBuf.begin() ; iter != inputBuf.end() ; ++iter)
+        *p++ = *iter;
+        
+    crc = crc32(crc, const_cast<const Bytef *>(srcbuf), srclen);
+    
+    int zerr = compress(destbuf, static_cast<uLongf *>(&destlen), srcbuf, srclen);
+    if (zerr != Z_OK)
+        {
+        printf("Some kind of problem\n");
+        }
+
+    totalOut += destlen;
+    //skip the redundant zlib header and checksum
+    for (uLong i=2; i<destlen-4 ; i++)
+        {
+        destination.put((int)destbuf[i]);
+        }
+        
+    destination.flush();
+
+    inputBuf.clear();
+    delete[] srcbuf;
+    delete[] destbuf;
+}
+
+
+
+/**
+ * Writes the specified byte to this output stream.
+ */ 
+int GzipOutputStream::put(char ch)
+{
+    if (closed)
+        {
+        //probably throw an exception here
+        return -1;
+        }
+
+
+    //Add char to buffer
+    inputBuf.push_back(ch);
+    totalIn++;
+    return 1;
+}
+
+
+
+} // namespace IO
+} // namespace Inkscape
+
+
+//#########################################################################
+//# E N D    O F    F I L E
+//#########################################################################
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :