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Diffstat (limited to 'trunk/src/lib/formats/apf_apt.c')
-rw-r--r--trunk/src/lib/formats/apf_apt.c157
1 files changed, 157 insertions, 0 deletions
diff --git a/trunk/src/lib/formats/apf_apt.c b/trunk/src/lib/formats/apf_apt.c
new file mode 100644
index 00000000000..1b079919a52
--- /dev/null
+++ b/trunk/src/lib/formats/apf_apt.c
@@ -0,0 +1,157 @@
+/* .APT tape images */
+
+
+#include "formats/apf_apt.h"
+
+
+#define WAVEENTRY_LOW -32768
+#define WAVEENTRY_HIGH 32767
+#define WAVEENTRY_NULL 0
+
+/* frequency of wave */
+#define APF_WAV_FREQUENCY 11050
+
+#define APF_APT_BIT_0_LENGTH ((int)(APF_WAV_FREQUENCY*0.0005))
+#define APF_APT_BIT_1_LENGTH ((int)(APF_WAV_FREQUENCY*0.001))
+
+struct apf_t
+{
+ int cassette_length;
+};
+static apf_t apf;
+
+
+/* 500 microsecond of bit 0 and 1000 microsecond of bit 1 */
+
+static INT16 *apf_emit_level(INT16 *p, int count, INT16 wave_state)
+{
+ int i;
+
+ for (i=0; i<count; i++)
+ {
+ *(p++) = wave_state;
+ }
+ return p;
+}
+
+/* 4 periods at 1200Hz */
+static INT16* apf_output_bit(INT16 *p, UINT8 b)
+{
+ if (b)
+ {
+ p = apf_emit_level(p, (APF_APT_BIT_1_LENGTH>>1), WAVEENTRY_HIGH);
+ p = apf_emit_level(p, (APF_APT_BIT_1_LENGTH>>1), WAVEENTRY_LOW);
+ }
+ else
+ {
+ p = apf_emit_level(p, (APF_APT_BIT_0_LENGTH>>1), WAVEENTRY_HIGH);
+ p = apf_emit_level(p, (APF_APT_BIT_0_LENGTH>>1), WAVEENTRY_LOW);
+ }
+
+ return p;
+}
+
+static int apf_get_bit_size_in_samples(UINT8 b)
+{
+ if (b)
+ {
+ return APF_APT_BIT_1_LENGTH;
+ }
+
+ return APF_APT_BIT_0_LENGTH;
+}
+
+
+/*************************************************************************************/
+
+/* each bit in the data represents a "1" or "0" waveform */
+static int apf_cassette_calculate_size_in_samples(const UINT8 *bytes, int length)
+{
+ unsigned i;
+ int size;
+ int b;
+ UINT8 data;
+
+ size = 0;
+ apf.cassette_length = length;
+
+
+ for (i=0; i<length; i++)
+ {
+ data = bytes[i];
+
+ for (b=0; b<8; b++)
+ {
+ size += apf_get_bit_size_in_samples((data>>7) & 0x01);
+ data = data<<1;
+ }
+ }
+
+ return size;
+}
+
+/*************************************************************************************/
+
+static int apf_cassette_fill_wave(INT16 *buffer, int length, UINT8 *bytes)
+{
+ int i;
+ INT16 *p;
+ UINT8 data;
+ int b;
+
+ p = buffer;
+
+ for (i=0; i<apf.cassette_length; i++)
+ {
+ data = bytes[i];
+ for (b=0; b<8; b++)
+ {
+ p = apf_output_bit(p,(data>>7) & 0x01);
+ data = data<<1;
+ }
+ }
+ return p - buffer;
+}
+
+
+
+static const struct CassetteLegacyWaveFiller apf_legacy_fill_wave =
+{
+ apf_cassette_fill_wave, /* fill_wave */
+ -1, /* chunk_size */
+ 0, /* chunk_samples */
+ apf_cassette_calculate_size_in_samples, /* chunk_sample_calc */
+ APF_WAV_FREQUENCY, /* sample_frequency */
+ 0, /* header_samples */
+ 0 /* trailer_samples */
+};
+
+
+
+static casserr_t apf_apt_identify(cassette_image *cassette, struct CassetteOptions *opts)
+{
+ return cassette_legacy_identify(cassette, opts, &apf_legacy_fill_wave);
+}
+
+
+
+static casserr_t apf_apt_load(cassette_image *cassette)
+{
+ return cassette_legacy_construct(cassette, &apf_legacy_fill_wave);
+}
+
+
+
+static const struct CassetteFormat apf_apt_format =
+{
+ "apt",
+ apf_apt_identify,
+ apf_apt_load,
+ NULL
+};
+
+
+
+CASSETTE_FORMATLIST_START(apf_cassette_formats)
+ CASSETTE_FORMAT(apf_apt_format)
+CASSETTE_FORMATLIST_END