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author | 2015-11-08 12:56:12 +0100 | |
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committer | 2015-11-08 12:56:12 +0100 | |
commit | 7c19aac60e12d6f5ea301bdb34d7826a01e0b06f (patch) | |
tree | f310d86aa2c6bfc19d115307dedde4eb0cd52dad /src/lib/formats/cgen_cas.cpp | |
parent | a57b46ae933badd7441ce1644711dbb851e2b504 (diff) |
Rename *.c -> *.cpp in our source (nw)
Diffstat (limited to 'src/lib/formats/cgen_cas.cpp')
-rw-r--r-- | src/lib/formats/cgen_cas.cpp | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/src/lib/formats/cgen_cas.cpp b/src/lib/formats/cgen_cas.cpp new file mode 100644 index 00000000000..d9165441618 --- /dev/null +++ b/src/lib/formats/cgen_cas.cpp @@ -0,0 +1,152 @@ +// license:BSD-3-Clause +// copyright-holders:Wilbert Pol +/******************************************************************** + +Support for EACA Colour Genie .cas cassette images + +Current state: Not working. Only the sync signal and 0x66 byte get + recognized. + +********************************************************************/ + +#include <assert.h> + +#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 |