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/*
* IO layer : gzip streambuf and streams
*
* Authors:
* Johan Ceuppens <jceuppen at easynet dot be>
*
* Copyright (C) 2004 Johan Ceuppens
*
* Released under GNU LGPL, read the file 'COPYING.LIB' for more information
*/
#include "streams-gzip.h"
namespace Inkscape {
//With some inpsiration and code from libgsf, fastjar, libpng and RFC 1952
static int const GZIP_IS_ASCII = 0x01; //file contains text
static int const GZIP_HEADER_CRC = 0x02; //there is a CRC in the header
static int const GZIP_EXTRA_FIELD = 0x04; //there is an 'extra' field
static int const GZIP_ORIGINAL_NAME = 0x08; //the original is stored
static int const GZIP_HAS_COMMENT = 0x10; //There is a comment in the header
static unsigned int const GZIP_HEADER_FLAGS = (GZIP_IS_ASCII
|GZIP_HEADER_CRC
|GZIP_EXTRA_FIELD
|GZIP_ORIGINAL_NAME
|GZIP_HAS_COMMENT);
/**
* GZipBuffer
*/
void GZipBuffer::consume_header() throw(GZipHeaderException)
{
unsigned int flags;
guint8 data[4];
try {
_urihandle->read(data, 4);
check_signature(data);
check_flags(data);
flags = data[3];
_urihandle->read(data, 4);
//get_modification_time()
_urihandle->read(data, 1);
//check_extra_flags();
_urihandle->read(data, 1);
//check_OS();
if (flags & GZIP_EXTRA_FIELD) {
get_extrafield();
}
if (flags & GZIP_ORIGINAL_NAME) {
get_filename();
}
if (flags & GZIP_HAS_COMMENT) {
get_comment();
}
if (flags & GZIP_HEADER_CRC) {
get_crc();
}
}
catch(std::exception& e) {
throw GZipHeaderException();
}
}
void GZipBuffer::check_signature(guint8 *data) throw(GZipHeaderException)
{
guint8 const signature[2] = {0x1f, 0x8b};
if (memcmp(data, signature, sizeof(signature)) != 0)
throw GZipHeaderException();
}
void GZipBuffer::check_flags(guint8 *data) throw(GZipHeaderException)
{
unsigned int flags = data[3];
if (data[2] != Z_DEFLATED || (flags & ~GZIP_HEADER_FLAGS) != 0)
throw GZipHeaderException();
}
gchar *GZipBuffer::get_filename()
{
#ifdef DEBUG_STREAMS
std::cout<<"Filename is ";
#endif
return read_string();
}
gchar *GZipBuffer::get_comment()
{
#ifdef DEBUG_STREAMS
std::cout<<"Comment is "<<std::endl;
#endif
return read_string();
}
guint16 GZipBuffer::get_crc()
{
guint16 buf;
_urihandle->read(&buf, 2);
return buf;
}
void GZipBuffer::get_extrafield()
{
guint8 length_data[2];
_urihandle->read(length_data, 2);
unsigned int const length = length_data[0] | (length_data[1] << 8);
guint8 *data = new guint8[length];
_urihandle->read(data, length);
}
gchar *GZipBuffer::read_string() throw(GZipHeaderException)
{
GByteArray *gba = g_byte_array_new();
try {
guint8 byte[1];
do {
_urihandle->read(byte, 1);
g_byte_array_append(gba, byte, sizeof(byte));
#ifdef DEBUG_STREAMS
std::cout <<(char)*byte;
#endif
} while (*byte != 0);
} catch (std::exception& e) {
g_byte_array_free(gba, TRUE);
throw GZipHeaderException();
}
#ifdef DEBUG_STREAMS
std::cout<<std::endl;
#endif
gchar *ret = (gchar *)gba->data;
g_byte_array_free(gba, FALSE);
return ret;
}
} // namespace Inkscape
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :
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