static int szddd_read_headers(struct mspack_system *sys,
struct mspack_file *fh,
struct msszddd_header *hdr)
{
unsigned char buf[8];
/* read and check signature */
if (sys->read(fh, buf, 8) != 8) return MSPACK_ERR_READ;
if ((mspack_memcmp(buf, szdd_signature_expand, 8) == 0)) {
/* common SZDD */
hdr->format = MSSZDD_FMT_NORMAL;
/* read the rest of the header */
if (sys->read(fh, buf, 6) != 6) return MSPACK_ERR_READ;
if (buf[0] != 0x41) return MSPACK_ERR_DATAFORMAT;
hdr->missing_char = buf[1];
hdr->length = EndGetI32(&buf[2]);
}
else if ((mspack_memcmp(buf, szdd_signature_qbasic, 8) == 0)) {
/* special QBasic SZDD */
hdr->format = MSSZDD_FMT_QBASIC;
if (sys->read(fh, buf, 4) != 4) return MSPACK_ERR_READ;
hdr->missing_char = '\0';
hdr->length = EndGetI32(buf);
}
else {
return MSPACK_ERR_SIGNATURE;
}
return MSPACK_ERR_OK;
}
static int szddd_read_headers(struct mspack_system *sys,
struct mspack_file *fh,
struct msszddd_header *szdd)
{
unsigned char buf[szddhead_SIZEOF];
szdd->length = 0;
szdd->missing_char = '\0';
/* read header */
if (sys->read(fh, &buf[0], szddhead_SIZEOF) != szddhead_SIZEOF) {
return MSPACK_ERR_READ;
}
/* check signature */
if ((mspack_memcmp(&buf[szddhead_Signature], &szdd_signature[0], 8) != 0)) {
return MSPACK_ERR_SIGNATURE;
}
/* check compression method */
if (buf[szddhead_CompType] != SZDD_COMPTYPE_A) {
return MSPACK_ERR_DATAFORMAT;
}
/* read missing character from filename */
szdd->missing_char = buf[szddhead_FileChar];
/* read decompressed length of file */
szdd->length = EndGetI32(&buf[szddhead_FileLength]);
return MSPACK_ERR_OK;
}
