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author | Alyssa Milburn | 2016-12-09 09:34:59 +0100 |
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committer | Alyssa Milburn | 2016-12-09 09:34:59 +0100 |
commit | 2a01424f0e94e40f697bf748fad6e69a3ee4baa3 (patch) | |
tree | ce9ed38f7180a5018086a2a248c8b8da8d9ab1f7 /engines/adl/disk.cpp | |
parent | 301ab51735cf8c8aac88a3df7e3f8d87b4122bc7 (diff) | |
download | scummvm-rg350-2a01424f0e94e40f697bf748fad6e69a3ee4baa3.tar.gz scummvm-rg350-2a01424f0e94e40f697bf748fad6e69a3ee4baa3.tar.bz2 scummvm-rg350-2a01424f0e94e40f697bf748fad6e69a3ee4baa3.zip |
ADL: Support wrapped sectors in NIB files.
Diffstat (limited to 'engines/adl/disk.cpp')
-rw-r--r-- | engines/adl/disk.cpp | 66 |
1 files changed, 49 insertions, 17 deletions
diff --git a/engines/adl/disk.cpp b/engines/adl/disk.cpp index d429556670..0de740eaec 100644 --- a/engines/adl/disk.cpp +++ b/engines/adl/disk.cpp @@ -39,11 +39,13 @@ static Common::SeekableReadStream *readImage(const Common::String &filename) { return f; } +const uint trackLen = 256 * 26; + // 4-and-4 encoding (odd-even) -static uint8 read44(Common::SeekableReadStream &f) { +static uint8 read44(byte *buffer, uint &pos) { // 1s in the other fields, so we can just AND - uint8 ret = f.readByte(); - return ((ret << 1) | 1) & f.readByte(); + uint8 ret = buffer[pos++ % trackLen]; + return ((ret << 1) | 1) & buffer[pos++ % trackLen]; } static Common::SeekableReadStream *readImage_NIB(const Common::String &filename) { @@ -70,15 +72,27 @@ static Common::SeekableReadStream *readImage_NIB(const Common::String &filename) uint8 volNo, track, sector; bool newStyle; - while (f.pos() < f.size()) { + byte buffer[trackLen]; + uint firstGoodTrackPos = 0; + uint pos = trackLen; // force read + + while (true) { + if (pos >= trackLen+firstGoodTrackPos) { + if (f.pos() == f.size()) + break; + f.read(buffer, sizeof(buffer)); + firstGoodTrackPos = 0; + pos = 0; + sawAddress = false; + } + // Read until we find two sync bytes. - if (f.readByte() != 0xd5 || f.readByte() != 0xaa) + if (buffer[pos++ % trackLen] != 0xd5 || buffer[pos++ % trackLen] != 0xaa) continue; - byte prologue = f.readByte(); + byte prologue = buffer[pos++ % trackLen]; if (sawAddress && (prologue == 0xb5 || prologue == 0x96)) { - warning("NIB: data for %02x/%02x/%02x missing", volNo, track, sector); sawAddress = false; } @@ -91,18 +105,24 @@ static Common::SeekableReadStream *readImage_NIB(const Common::String &filename) // Accept a DOS 3.3(?) header at the start. if (prologue == 0x96) { newStyle = true; + } else if (prologue == 0xad || prologue == 0xfd) { + sawAddress = false; + continue; } else { error("unknown NIB field prologue %02x", prologue); } } - volNo = read44(f); - track = read44(f); - sector = read44(f); - uint8 checksum = read44(f); + volNo = read44(buffer, pos); + track = read44(buffer, pos); + sector = read44(buffer, pos); + uint8 checksum = read44(buffer, pos); if ((volNo ^ track ^ sector) != checksum) error("invalid NIB checksum"); + if (!firstGoodTrackPos) + firstGoodTrackPos = pos; + // Epilogue is de/aa plus a gap, but we don't care. continue; } @@ -121,7 +141,13 @@ static Common::SeekableReadStream *readImage_NIB(const Common::String &filename) // 6-and-2 uses 342 on-disk bytes byte inbuffer[342]; - f.read(inbuffer, 342); + uint z = trackLen - (pos % trackLen); + if (z < 342) { + memcpy(inbuffer, buffer + (pos % trackLen), z); + memcpy(inbuffer + z, buffer, 342 - z); + } else + memcpy(inbuffer, buffer + (pos % trackLen), 342); + pos += 342; byte oldVal = 0; for (uint n = 0; n < 342; ++n) { @@ -136,7 +162,7 @@ static Common::SeekableReadStream *readImage_NIB(const Common::String &filename) inbuffer[n] = oldVal; } - byte checksum = f.readByte(); + byte checksum = buffer[pos++ % trackLen]; if (checksum < 0x96 || oldVal != c_6and2_lookup[checksum - 0x96]) warning("NIB: checksum mismatch @ (%x, %x)", track, sector); @@ -156,7 +182,13 @@ static Common::SeekableReadStream *readImage_NIB(const Common::String &filename) } else { // 5-and-3 uses 410 on-disk bytes, decoding to just over 256 bytes byte inbuffer[410]; - f.read(inbuffer, 410); + uint z = trackLen - (pos % trackLen); + if (z < 410) { + memcpy(inbuffer, buffer + (pos % trackLen), z); + memcpy(inbuffer + z, buffer, 410 - z); + } else + memcpy(inbuffer, buffer + (pos % trackLen), 410); + pos += 410; bool truncated = false; byte oldVal = 0; @@ -166,7 +198,7 @@ static Common::SeekableReadStream *readImage_NIB(const Common::String &filename) if (inbuffer[n] == 0xd5) { // Early end of block. truncated = true; - f.seek(-(410 - n), SEEK_CUR); + pos -= (410 - n); warning("NIB: early end of block @ 0x%x (%x, %x)", f.pos(), track, sector); break; } @@ -175,7 +207,7 @@ static Common::SeekableReadStream *readImage_NIB(const Common::String &filename) // Badly-encoded nibbles, stop trying to decode here. truncated = true; warning("NIB: bad nibble %02x @ 0x%x (%x, %x)", inbuffer[n], f.pos(), track, sector); - f.seek(-(410 - n), SEEK_CUR); + pos -= (410 - n); break; } // undo checksum @@ -183,7 +215,7 @@ static Common::SeekableReadStream *readImage_NIB(const Common::String &filename) inbuffer[n] = oldVal; } if (!truncated) { - byte checksum = f.readByte(); + byte checksum = buffer[pos++ % trackLen]; if (checksum < 0xaa || oldVal != c_5and3_lookup[checksum - 0xaa]) warning("NIB: checksum mismatch @ (%x, %x)", track, sector); } |