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Diffstat (limited to 'trunk/src/lib/formats/cgen_cas.c')
-rw-r--r--trunk/src/lib/formats/cgen_cas.c149
1 files changed, 149 insertions, 0 deletions
diff --git a/trunk/src/lib/formats/cgen_cas.c b/trunk/src/lib/formats/cgen_cas.c
new file mode 100644
index 00000000000..b2aba94b41a
--- /dev/null
+++ b/trunk/src/lib/formats/cgen_cas.c
@@ -0,0 +1,149 @@
+/********************************************************************
+
+Support for EACA Colour Genie .cas cassette images
+
+Current state: Not working. Only the sync signal and 0x66 byte get
+ recognized.
+
+********************************************************************/
+
+#include "formats/cgen_cas.h"
+
+#define TAPE_HEADER "Colour Genie - Virtual Tape File"
+
+#define SMPLO -32768
+#define SMPHI 32767
+
+
+static int cas_size;
+static int level;
+
+
+static int cgenie_output_byte(INT16 *buffer, int sample_count, UINT8 data)
+{
+ int i;
+ int samples = 0;
+
+ for ( i = 0; i < 8; i++ )
+ {
+ /* Output bit boundary */
+ level ^= 1;
+ if ( buffer )
+ buffer[ sample_count + samples ] = level ? SMPHI : SMPLO;
+ samples++;
+
+ /* Output bit */
+ if ( data & 0x80 )
+ level ^= 1;
+ if ( buffer )
+ buffer[ sample_count + samples ] = level ? SMPHI : SMPLO;
+ samples++;
+
+ data <<= 1;
+ }
+ return samples;
+}
+
+
+static int cgenie_handle_cas(INT16 *buffer, const UINT8 *casdata)
+{
+ int i, data_pos, sample_count;
+
+ data_pos = 0;
+ sample_count = 0;
+ level = 0;
+
+ /* Check for presence of optional header */
+ if ( ! memcmp( casdata, TAPE_HEADER, sizeof(TAPE_HEADER) - 1 ) )
+ {
+ /* Search for 0x00 or end of file */
+ while ( data_pos < cas_size && casdata[data_pos] )
+ data_pos++;
+
+ /* If we're at the end of the file it's not a valid .cas file */
+ if ( data_pos == cas_size )
+ return -1;
+
+ /* Skip the 0x00 byte */
+ data_pos++;
+ }
+
+ /* If we're at the end of the file it's not a valid .cas file */
+ if ( data_pos == cas_size )
+ return -1;
+
+ /* Check for beginning of tape file marker */
+ if ( casdata[data_pos] != 0x66 )
+ return -1;
+
+ /* Create header */
+ for ( i = 0; i < 256; i++ )
+ sample_count += cgenie_output_byte( buffer, sample_count, 0xaa );
+
+ /* Start outputting data */
+ while( data_pos < cas_size )
+ {
+ sample_count += cgenie_output_byte( buffer, sample_count, casdata[data_pos] );
+ data_pos++;
+ }
+ sample_count += cgenie_output_byte( buffer, sample_count, 0x00 );
+
+ return sample_count;
+}
+
+/*******************************************************************
+ Generate samples for the tape image
+********************************************************************/
+static int cgenie_cas_fill_wave(INT16 *buffer, int sample_count, UINT8 *bytes)
+{
+ return cgenie_handle_cas( buffer, bytes );
+}
+
+
+/*******************************************************************
+ Calculate the number of samples needed for this tape image
+********************************************************************/
+static int cgenie_cas_to_wav_size(const UINT8 *casdata, int caslen)
+{
+ cas_size = caslen;
+
+ return cgenie_handle_cas( NULL, casdata );
+}
+
+static const struct CassetteLegacyWaveFiller cgenie_cas_legacy_fill_wave =
+{
+ cgenie_cas_fill_wave, /* fill_wave */
+ -1, /* chunk_size */
+ 0, /* chunk_samples */
+ cgenie_cas_to_wav_size, /* chunk_sample_calc */
+ 2400, /* sample_frequency */
+ 0, /* header_samples */
+ 0 /* trailer_samples */
+};
+
+
+static casserr_t cgenie_cas_identify(cassette_image *cassette, struct CassetteOptions *opts)
+{
+ return cassette_legacy_identify(cassette, opts, &cgenie_cas_legacy_fill_wave);
+}
+
+
+static casserr_t cgenie_cas_load(cassette_image *cassette)
+{
+ return cassette_legacy_construct(cassette, &cgenie_cas_legacy_fill_wave);
+}
+
+
+static const struct CassetteFormat cgenie_cas_format =
+{
+ "cas",
+ cgenie_cas_identify,
+ cgenie_cas_load,
+ NULL
+};
+
+
+CASSETTE_FORMATLIST_START(cgenie_cassette_formats)
+ CASSETTE_FORMAT(cgenie_cas_format)
+CASSETTE_FORMATLIST_END
+