#include "streams-jar.h"

namespace Inkscape {

const int LOC_EXTRA = 6;  // extra bytes
const int LOC_COMP  = 8;  // compression method
const int LOC_CSIZE = 18; // compressed size
const int LOC_FNLEN = 26; // filename length
const int LOC_EFLEN = 28; // extra-field length

void JarBuffer::consume_header() throw(JarHeaderException)
{
    try {
	guint8 data[30];
	_urihandle->read(data, 4);
    	check_signature(data);
	_urihandle->read(data+4, 26);
	compressed_size = compressed_left = unpack_4bytes(data, LOC_CSIZE);
	guint16 filename_length = unpack_2bytes(data, LOC_FNLEN);
	eflen = unpack_2bytes(data, LOC_EFLEN);
	flags = unpack_2bytes(data, LOC_EXTRA);
	method = unpack_2bytes(data, LOC_COMP);
	
#ifdef DEBUG_STREAMS    
	std::printf("Compressed size is %u\n", compressed_size);
	std::printf("Filename length is %hu\n", filename_length);
	std::printf("Extra field length is %hu\n", eflen);
	std::printf("Flags are %#hx\n", flags);
	std::printf("Compression method is %#hx\n", method);
#endif
    
	//guint32 crc = check_crc(data, flags);
	gchar filename[filename_length+1];
	_urihandle->read(filename, filename_length);
	filename[filename_length] = '\0';

#ifdef DEBUG_STREAMS
	std::printf("Filename is %s\n", filename);
#endif
    }
    catch (std::exception& e) {
	throw JarHeaderException();
    }
}

void JarBuffer::check_signature(guint8 *data) throw(JarHeaderException)
{
    guint32 signature = unpack_4bytes(data, 0);

#ifdef DEBUG_STREAMS
    std::printf("signature is %x\n", signature);
#endif

    if (signature == 0x08074b50) {
	_urihandle->read(data, 12);
    } else if (signature != 0x02014b50 && signature != 0x04034b50) {
	throw JarHeaderException();
    }
}

void JarBuffer::reset()//resets zlib and buffer (also skips archived directories)
{
    bool do_reset = false;
    while (compressed_left == 0) {
	consume_header();
	do_reset = true;
    }

    if (do_reset) {
	reset_inflation();
	setg(eback(), eback(), eback());
    }
}

int JarBuffer::consume_and_inflate()
{
    int nbytes;
    
    reset();

    nbytes = compressed_left > BUFSIZE_STREAM ? BUFSIZE_STREAM 
	    : compressed_left;
    
    if (is_compressed())
	return consume_compressed(nbytes);
    else
	return consume_uncompressed(nbytes);
}

int JarBuffer::consume_compressed(int nbytes)
{
    int ret;

    if ((ret = do_consume_and_inflate(nbytes)) == EOF && eflen > 0) {
	guint8 efbuf[eflen];
	_urihandle->read(efbuf, eflen);
	return 1;
    } 

    return ret;
}

int JarBuffer::consume_uncompressed(int nbytes)
{
    guint8 data[nbytes];
    if (consume(data, nbytes) == EOF)
	return EOF;
    
    copy_to_get(data, nbytes);
    compressed_left -= nbytes;

    return nbytes;
}

GByteArray *JarBuffer::inflate(guint8 *data, const int nbytes)
{
    GByteArray *gba = do_inflate(data, nbytes);
    compressed_left -= nbytes;
    return gba;
}

guint32 JarBuffer::unpack_4bytes(guint8 *data, const int offset) 
{
    return ((guint32)data[offset] 
	    + (((guint32)data[offset + 1]) << 8)
	    + (((guint32)data[offset + 2]) << 16) 
	    + (((guint32)data[offset + 3]) << 24));
}

guint16 JarBuffer::unpack_2bytes(guint8 *data, int offset)
{
    return ((guint16)data[offset] + (((guint16)data[offset + 1]) << 8));
}

} // namespace Inkscape
