Frodo4/Src/1541d64.cpp

/*
 *  1541d64.cpp - 1541 emulation in disk image files (.d64/.x64/zipcode)
 *
 *  Frodo (C) 1994-1997,2002-2003 Christian Bauer
 *  zipcode decoding routines (C) 1993-1997 Marko Mäkelä, Paul David Doherty
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/*
 *  Incompatibilities:
 *   - No support for relative files
 *   - Unimplemented commands: P
 *   - Impossible to implement: B-E, M-E
 */

#include "sysdeps.h"

#include "1541d64.h"
#include "IEC.h"
#include "Prefs.h"
#include "C64.h"
#include "main.h"


// Channel modes (IRC users listen up :-)
enum {
        CHMOD_FREE,                     // Channel free
        CHMOD_COMMAND,          // Command/error channel
        CHMOD_DIRECTORY,        // Reading directory, using large allocated buffer
        CHMOD_FILE,                     // Sequential file open, using buffer in 1541 RAM
        CHMOD_REL,                      // Relative file open, using buffer in 1541 RAM
        CHMOD_DIRECT            // Direct buffer access ('#'), using buffer in 1541 RAM
};

// Directory track
const int DIR_TRACK = 18;

// BAM structure
enum {
        BAM_DIR_TRACK = 0,              // Track...
        BAM_DIR_SECTOR = 1,             // ...and sector of first directory block (unused)
        BAM_FMT_TYPE = 2,               // Format type
        BAM_BITMAP = 4,                 // Sector allocation map
        BAM_DISK_NAME = 144,    // Disk name
        BAM_DISK_ID = 162,              // Disk ID
        BAM_FMT_CHAR = 165              // Format characters
};

// Directory structure
enum {
        DIR_NEXT_TRACK = 0,             // Track...
        DIR_NEXT_SECTOR = 1,    // ... and sector of next directory block
        DIR_ENTRIES = 2,                // Start of directory entries (8)

        DE_TYPE = 0,                    // File type/flags
        DE_TRACK = 1,                   // Track...
        DE_SECTOR = 2,                  // ...and sector of first data block
        DE_NAME = 3,                    // File name
        DE_SIDE_TRACK = 19,             // Track...
        DE_SIDE_SECTOR = 20,    // ...and sector of first side sector
        DE_REC_LEN = 21,                // Record length
        DE_OVR_TRACK = 26,              // Track...
        DE_OVR_SECTOR = 27,             // ...and sector on overwrite (@)
        DE_NUM_BLOCKS_L = 28,   // Number of blocks, LSB
        DE_NUM_BLOCKS_H = 29,   // Number of blocks, MSB

        SIZEOF_DE = 32                  // Size of directory entry
};

// Interleave of directory and data blocks
const int DIR_INTERLEAVE = 3;
const int DATA_INTERLEAVE = 10;

// Number of sectors per track, for all tracks
const int num_sectors[41] = {
        0,
        21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,
        19,19,19,19,19,19,19,
        18,18,18,18,18,18,
        17,17,17,17,17,
        17,17,17,17,17          // Tracks 36..40
};

// Accumulated number of sectors
const int accum_num_sectors[41] = {
        0,
        0,21,42,63,84,105,126,147,168,189,210,231,252,273,294,315,336,
        357,376,395,414,433,452,471,
        490,508,526,544,562,580,
        598,615,632,649,666,
        683,700,717,734,751     // Tracks 36..40
};

// Prototypes
static bool match(const uint8 *p, int p_len, const uint8 *n);


/*
 *  Constructor: Prepare emulation, open image file
 */

ImageDrive::ImageDrive(IEC *iec, const char *filepath) : Drive(iec), the_file(NULL), bam(ram + 0x700), bam_dirty(false)
{
        for (int i=0; i<18; i++) {
                ch[i].mode = CHMOD_FREE;
                ch[i].buf = NULL;
        }
        ch[15].mode = CHMOD_COMMAND;

        Reset();

        // Open image file
        if (change_image(filepath))
                Ready = true;
}


/*
 *  Destructor
 */

ImageDrive::~ImageDrive()
{
        close_image();
}


/*
 *  Close the image file
 */

void ImageDrive::close_image(void)
{
        if (the_file) {
                close_all_channels();
                if (bam_dirty) {
                        write_sector(DIR_TRACK, 0, bam);
                        bam_dirty = false;
                }
                fclose(the_file);
                the_file = NULL;
        }
}


/*
 *  Open the image file
 */

bool ImageDrive::change_image(const char *path)
{
        // Close old image file
        close_image();

        // Open new image file (try write access first, then read-only)
        write_protected = false;
        the_file = open_image_file(path, true);
        if (the_file == NULL) {
                write_protected = true;
                the_file = open_image_file(path, false);
        }
        if (the_file) {

                // Determine file type and fill in image_file_desc structure
                if (!parse_image_file(the_file, desc)) {
                        fclose(the_file);
                        the_file = false;
                        return false;
                }

                // Read BAM
                read_sector(DIR_TRACK, 0, bam);
                bam_dirty = false;
                return true;
        } else
                return false;
}


/*
 *  Open channel
 */

uint8 ImageDrive::Open(int channel, const uint8 *name, int name_len)
{
        set_error(ERR_OK);

        // Channel 15: execute file name as command
        if (channel == 15) {
                execute_cmd(name, name_len);
                return ST_OK;
        }

        if (ch[channel].mode != CHMOD_FREE) {
                set_error(ERR_NOCHANNEL);
                return ST_OK;
        }

        if (name[0] == '$')
                if (channel)
                        return open_file_ts(channel, DIR_TRACK, 0);
                else
                        return open_directory(name + 1, name_len - 1);

        if (name[0] == '#')
                return open_direct(channel, name);

        return open_file(channel, name, name_len);
}


/*
 *  Open file
 */

uint8 ImageDrive::open_file(int channel, const uint8 *name, int name_len)
{
        uint8 plain_name[NAMEBUF_LENGTH];
        int plain_name_len;
        int mode = FMODE_READ;
        int type = FTYPE_DEL;
        int rec_len = 0;
        parse_file_name(name, name_len, plain_name, plain_name_len, mode, type, rec_len);
        if (plain_name_len > 16)
                plain_name_len = 16;

        // Channel 0 is READ, channel 1 is WRITE
        if (channel == 0 || channel == 1) {
                mode = channel ? FMODE_WRITE : FMODE_READ;
                if (type == FTYPE_DEL)
                        type = FTYPE_PRG;
        }

        ch[channel].writing = (mode == FMODE_WRITE || mode == FMODE_APPEND);

        // Wildcards are only allowed on reading
        if (ch[channel].writing && (strchr((const char *)plain_name, '*') || strchr((const char *)plain_name, '?'))) {
                set_error(ERR_SYNTAX33);
                return ST_OK;
        }

        // Check for write-protection if writing
        if (ch[channel].writing && write_protected) {
                set_error(ERR_WRITEPROTECT);
                return ST_OK;
        }

        // Relative files are not supported
        if (type == FTYPE_REL) {
                set_error(ERR_UNIMPLEMENTED);
                return ST_OK;
        }

        // Find file in directory
        int dir_track, dir_sector, entry;
        if (find_first_file(plain_name, plain_name_len, dir_track, dir_sector, entry)) {

                // File exists
                ch[channel].dir_track = dir_track;
                ch[channel].dir_sector = dir_sector;
                ch[channel].entry = entry;
                uint8 *de = dir + DIR_ENTRIES + entry * SIZEOF_DE;

                // Get file type from existing file if not specified in file name
                if (type == FTYPE_DEL)
                        type = de[DE_TYPE] & 7;

                if ((de[DE_TYPE] & 7) != type) {

                        // File type doesn't match
                        set_error(ERR_FILETYPE);

                } else if (mode == FMODE_WRITE) {

                        if (name[0] == '@') {

                                // Open old file for overwriting (save-replace)
                                return create_file(channel, plain_name, plain_name_len, type, true);

                        } else {

                                // File to be written already exists, error
                                set_error(ERR_FILEEXISTS);
                        }

                } else if (mode == FMODE_APPEND) {

                        // Open old file for appending
                        open_file_ts(channel, de[DE_TRACK], de[DE_SECTOR]);

                        // Seek to end of file
                        int track = 0, sector = 0, num_blocks = 0;
                        while (ch[channel].buf[0]) {
                                if (!read_sector(track = ch[channel].buf[0], sector = ch[channel].buf[1], ch[channel].buf))
                                        return ST_OK;
                                num_blocks++;
                        }

                        // Change channel mode to writing, adjust buffer pointer
                        ch[channel].writing = true;
                        ch[channel].buf_len = ch[channel].buf[1] + 1;
                        ch[channel].buf_ptr = ch[channel].buf + ch[channel].buf_len;
                        ch[channel].track = track;
                        ch[channel].sector = sector;
                        ch[channel].num_blocks = num_blocks;

                } else if (mode == FMODE_M) {

                        // Open old file for reading, even if it is not closed
                        return open_file_ts(channel, de[DE_TRACK], de[DE_SECTOR]);

                } else {

                        // Open old file for reading, error if file is open
                        if (de[DE_TYPE] & 0x80)
                                return open_file_ts(channel, de[DE_TRACK], de[DE_SECTOR]);
                        else
                                set_error(ERR_WRITEFILEOPEN);
                }

        } else {

                // File doesn't exist
                // Set file type to SEQ if not specified in file name
                if (type == FTYPE_DEL)
                        type = FTYPE_SEQ;

                if (mode == FMODE_WRITE) {

                        // Create new file for writing
                        return create_file(channel, plain_name, plain_name_len, type);

                } else
                        set_error(ERR_FILENOTFOUND);
        }
        return ST_OK;
}


/*
 *  Open channel for reading from file given track/sector of first block
 */

uint8 ImageDrive::open_file_ts(int channel, int track, int sector)
{
        // Allocate buffer and set channel mode
        int buf = alloc_buffer(-1);
        if (buf == -1) {
                set_error(ERR_NOCHANNEL);
                return ST_OK;
        }
        ch[channel].buf_num = buf;
        ch[channel].buf = ram + 0x300 + buf * 0x100;
        ch[channel].mode = CHMOD_FILE;

        // On the next call to Read, the first block will be read
        ch[channel].buf[0] = track;
        ch[channel].buf[1] = sector;
        ch[channel].buf_len = 0;

        return ST_OK;
}


/*
 *  Create file and open channel for writing to file
 */

uint8 ImageDrive::create_file(int channel, const uint8 *name, int name_len, int type, bool overwrite)
{
        // Allocate buffer
        int buf = alloc_buffer(-1);
        if (buf == -1) {
                set_error(ERR_NOCHANNEL);
                return ST_OK;
        }
        ch[channel].buf_num = buf;
        ch[channel].buf = ram + 0x300 + buf * 0x100;

        // Allocate new directory entry if not overwriting
        if (!overwrite) {
                if (!alloc_dir_entry(ch[channel].dir_track, ch[channel].dir_sector, ch[channel].entry)) {
                        free_buffer(buf);
                        return ST_OK;
                }
        }
        uint8 *de = dir + DIR_ENTRIES + ch[channel].entry * SIZEOF_DE;

        // Allocate first data block
        ch[channel].track = DIR_TRACK - 1;
        ch[channel].sector = -DATA_INTERLEAVE;
        if (!alloc_next_block(ch[channel].track, ch[channel].sector, DATA_INTERLEAVE)) {
                free_buffer(buf);
                return ST_OK;
        }
        ch[channel].num_blocks = 1;

        // Write directory entry
        memset(de, 0, SIZEOF_DE);
        de[DE_TYPE] = type;             // bit 7 not set -> open file
        if (overwrite) {
                de[DE_OVR_TRACK] = ch[channel].track;
                de[DE_OVR_SECTOR] = ch[channel].sector;
        } else {
                de[DE_TRACK] = ch[channel].track;
                de[DE_SECTOR] = ch[channel].sector;
        }
        memset(de + DE_NAME, 0xa0, 16);
        memcpy(de + DE_NAME, name, name_len);
        write_sector(ch[channel].dir_track, ch[channel].dir_sector, dir);

        // Set channel descriptor
        ch[channel].mode = CHMOD_FILE;
        ch[channel].writing = true;
        ch[channel].buf_ptr = ch[channel].buf + 2;
        ch[channel].buf_len = 2;
        return ST_OK;
}


/*
 *  Prepare directory as BASIC program (channel 0)
 */

const char type_char_1[] = "DSPUREER";
const char type_char_2[] = "EERSELQG";
const char type_char_3[] = "LQGRL???";

uint8 ImageDrive::open_directory(const uint8 *pattern, int pattern_len)
{
        // Special treatment for "$0"
        if (pattern[0] == '0' && pattern_len == 1) {
                pattern++;
                pattern_len--;
        }

        // Skip everything before the ':' in the pattern
        uint8 *t = (uint8 *)memchr(pattern, ':', pattern_len);
        if (t) {
                t++;
                pattern_len -= t - pattern;
                pattern = t;
        }

        ch[0].mode = CHMOD_DIRECTORY;
        uint8 *p = ch[0].buf_ptr = ch[0].buf = new uint8[8192];

        // Create directory title with disk name, ID and format type
        *p++ = 0x01;    // Load address $0401 (from PET days :-)
        *p++ = 0x04;
        *p++ = 0x01;    // Dummy line link
        *p++ = 0x01;
        *p++ = 0;               // Drive number (0) as line number
        *p++ = 0;
        *p++ = 0x12;    // RVS ON
        *p++ = '\"';

        uint8 *q = bam + BAM_DISK_NAME;
        for (int i=0; i<23; i++) {
                int c;
                if ((c = *q++) == 0xa0)
                        *p++ = ' ';             // Replace 0xa0 by space
                else
                        *p++ = c;
        }
        *(p-7) = '\"';
        *p++ = 0;

        // Scan all directory blocks
        dir[DIR_NEXT_TRACK] = DIR_TRACK;
        dir[DIR_NEXT_SECTOR] = 1;

        int num_dir_blocks = 0;
        while (dir[DIR_NEXT_TRACK] && num_dir_blocks < num_sectors[DIR_TRACK]) {
                if (!read_sector(dir[DIR_NEXT_TRACK], dir[DIR_NEXT_SECTOR], dir))
                        return ST_OK;
                num_dir_blocks++;

                // Scan all 8 entries of a block
                uint8 *de = dir + DIR_ENTRIES;
                for (int j=0; j<8; j++, de+=SIZEOF_DE) {
                        if (de[DE_TYPE] && (pattern_len == 0 || match(pattern, pattern_len, de + DE_NAME))) {

                                // Dummy line link
                                *p++ = 0x01;
                                *p++ = 0x01;

                                // Line number = number of blocks
                                *p++ = de[DE_NUM_BLOCKS_L];
                                *p++ = de[DE_NUM_BLOCKS_H];

                                // Appropriate number of spaces to align file names
                                *p++ = ' ';
                                int n = (de[DE_NUM_BLOCKS_H] << 8) + de[DE_NUM_BLOCKS_L];
                                if (n<10) *p++ = ' ';
                                if (n<100) *p++ = ' ';

                                // File name enclosed in quotes
                                *p++ = '\"';
                                q = de + DE_NAME;
                                uint8 c;
                                bool m = false;
                                for (int i=0; i<16; i++) {
                                        if ((c = *q++) == 0xa0) {
                                                if (m)
                                                        *p++ = ' ';                     // Replace all 0xa0 by spaces
                                                else
                                                        m = (*p++ = '\"');      // But the first by a '"'
                                        } else
                                                *p++ = c;
                                }
                                if (m)
                                        *p++ = ' ';
                                else
                                        *p++ = '\"';                    // No 0xa0, then append a space

                                // Open files are marked by '*'
                                if (de[DE_TYPE] & 0x80)
                                        *p++ = ' ';
                                else
                                        *p++ = '*';

                                // File type
                                *p++ = type_char_1[de[DE_TYPE] & 7];
                                *p++ = type_char_2[de[DE_TYPE] & 7];
                                *p++ = type_char_3[de[DE_TYPE] & 7];

                                // Protected files are marked by '<'
                                if (de[DE_TYPE] & 0x40)
                                        *p++ = '<';
                                else
                                        *p++ = ' ';

                                // Appropriate number of spaces at the end
                                *p++ = ' ';
                                if (n >= 10) *p++ = ' ';
                                if (n >= 100) *p++ = ' ';
                                *p++ = 0;
                        }
                }
        }

        // Final line, count number of free blocks
        int n = 0;
        for (int i=1; i<=35; i++) {
                if (i != DIR_TRACK)     // exclude track 18
                        n += num_free_blocks(i);
        }

        *p++ = 0x01;            // Dummy line link
        *p++ = 0x01;
        *p++ = n & 0xff;        // Number of free blocks as line number
        *p++ = (n >> 8) & 0xff;

        *p++ = 'B';
        *p++ = 'L';
        *p++ = 'O';
        *p++ = 'C';
        *p++ = 'K';
        *p++ = 'S';
        *p++ = ' ';
        *p++ = 'F';
        *p++ = 'R';
        *p++ = 'E';
        *p++ = 'E';
        *p++ = '.';

        memset(p, ' ', 13);
        p += 13;

        *p++ = 0;
        *p++ = 0;
        *p++ = 0;

        ch[0].buf_len = p - ch[0].buf;
        return ST_OK;
}


/*
 *  Open channel for direct buffer access
 */

uint8 ImageDrive::open_direct(int channel, const uint8 *name)
{
        int buf = -1;

        if (name[1] == 0)
                buf = alloc_buffer(-1);
        else
                if ((name[1] >= '0') && (name[1] <= '3') && (name[2] == 0))
                        buf = alloc_buffer(name[1] - '0');

        if (buf == -1) {
                set_error(ERR_NOCHANNEL);
                return ST_OK;
        }

        // The buffers are in the 1541 RAM at $300 and are 256 bytes each
        ch[channel].mode = CHMOD_DIRECT;
        ch[channel].buf = ram + 0x300 + buf * 0x100;
        ch[channel].buf_num = buf;

        // Store actual buffer number in buffer
        ch[channel].buf[1] = buf + '0';
        ch[channel].buf_len = 1;
        ch[channel].buf_ptr = ch[channel].buf + 1;

        return ST_OK;
}


/*
 *  Close channel
 */

uint8 ImageDrive::Close(int channel)
{
        switch (ch[channel].mode) {
                case CHMOD_FREE:
                        break;
 
                case CHMOD_COMMAND:
                        close_all_channels();
                        break;

                case CHMOD_DIRECT:
                        free_buffer(ch[channel].buf_num);
                        ch[channel].buf = NULL;
                        ch[channel].mode = CHMOD_FREE;
                        break;

                case CHMOD_FILE:
                        if (ch[channel].writing) {

                                // Current block empty? Then write CR character
                                if (ch[channel].buf_len == 2) {
                                        ch[channel].buf[2] = 0x0d;
                                        ch[channel].buf_len++;
                                }

                                // Write last data block
                                ch[channel].buf[0] = 0;
                                ch[channel].buf[1] = ch[channel].buf_len - 1;
                                if (!write_sector(ch[channel].track, ch[channel].sector, ch[channel].buf))
                                        goto free;

                                // Close write file in directory
                                read_sector(ch[channel].dir_track, ch[channel].dir_sector, dir);
                                uint8 *de = dir + DIR_ENTRIES + ch[channel].entry * SIZEOF_DE;
                                de[DE_TYPE] |= 0x80;
                                de[DE_NUM_BLOCKS_L] = ch[channel].num_blocks & 0xff;
                                de[DE_NUM_BLOCKS_H] = ch[channel].num_blocks >> 8;
                                if (de[DE_OVR_TRACK]) {
                                        // Overwriting, free old data blocks and set pointer to new ones
                                        free_block_chain(de[DE_TRACK], de[DE_SECTOR]);
                                        de[DE_TRACK] = de[DE_OVR_TRACK];
                                        de[DE_SECTOR] = de[DE_OVR_SECTOR];
                                        de[DE_OVR_TRACK] = de[DE_OVR_SECTOR] = 0;
                                }
                                write_sector(ch[channel].dir_track, ch[channel].dir_sector, dir);
                        }
free:           free_buffer(ch[channel].buf_num);
                        ch[channel].buf = NULL;
                        ch[channel].mode = CHMOD_FREE;
                        break;

                case CHMOD_DIRECTORY:
                        delete[] ch[channel].buf;
                        ch[channel].buf = NULL;
                        ch[channel].mode = CHMOD_FREE;
                        break;
        }

        return ST_OK;
}


/*
 *  Close all channels
 */

void ImageDrive::close_all_channels()
{
        for (int i=0; i<15; i++)
                Close(i);
        Close(16);
        Close(17);

        cmd_len = 0;
}


/*
 *  Read from channel
 */

uint8 ImageDrive::Read(int channel, uint8 &byte)
{
        switch (ch[channel].mode) {
                case CHMOD_FREE:
                        if (current_error == ERR_OK)
                                set_error(ERR_FILENOTOPEN);
                        break;

                case CHMOD_COMMAND:
                        // Read error channel
                        byte = *error_ptr++;
                        if (--error_len)
                                return ST_OK;
                        else {
                                set_error(ERR_OK);
                                return ST_EOF;
                        }
                        break;

                case CHMOD_FILE:
                        if (ch[channel].writing)
                                return ST_READ_TIMEOUT;
                        if (current_error != ERR_OK)
                                return ST_READ_TIMEOUT;

                        // Read next block if necessary
                        if (ch[channel].buf_len == 0 && ch[channel].buf[0]) {
                                if (!read_sector(ch[channel].buf[0], ch[channel].buf[1], ch[channel].buf))
                                        return ST_READ_TIMEOUT;
                                ch[channel].buf_ptr = ch[channel].buf + 2;

                                // Determine block length
                                ch[channel].buf_len = ch[channel].buf[0] ? 254 : ch[channel].buf[1] - 1;
                        }

                        if (ch[channel].buf_len > 0) {
                                byte = *(ch[channel].buf_ptr)++;
                                if (--(ch[channel].buf_len) == 0 && ch[channel].buf[0] == 0)
                                        return ST_EOF;
                                else
                                        return ST_OK;
                        } else
                                return ST_READ_TIMEOUT;
                        break;

                case CHMOD_DIRECTORY:
                case CHMOD_DIRECT:
                        if (ch[channel].buf_len > 0) {
                                byte = *(ch[channel].buf_ptr)++;
                                if (--(ch[channel].buf_len))
                                        return ST_OK;
                                else
                                        return ST_EOF;
                        } else
                                return ST_READ_TIMEOUT;
                        break;
        }
        return ST_READ_TIMEOUT;
}


/*
 *  Write byte to channel
 */

uint8 ImageDrive::Write(int channel, uint8 byte, bool eoi)
{
        switch (ch[channel].mode) {
                case CHMOD_FREE:
                        if (current_error == ERR_OK)
                                set_error(ERR_FILENOTOPEN);
                        break;

                case CHMOD_COMMAND:
                        // Collect characters and execute command on EOI
                        if (cmd_len > 58) {
                                set_error(ERR_SYNTAX32);
                                return ST_TIMEOUT;
                        }

                        cmd_buf[cmd_len++] = byte;

                        if (eoi) {
                                execute_cmd(cmd_buf, cmd_len);
                                cmd_len = 0;
                        }
                        return ST_OK;

                case CHMOD_DIRECTORY:
                        set_error(ERR_WRITEFILEOPEN);
                        break;

                case CHMOD_FILE:
                        if (!ch[channel].writing)
                                return ST_TIMEOUT;
                        if (current_error != ERR_OK)
                                return ST_TIMEOUT;

                        // Buffer full?
                        if (ch[channel].buf_len >= 256) {

                                // Yes, allocate new block
                                int track = ch[channel].track, sector = ch[channel].sector;
                                if (!alloc_next_block(track, sector, DATA_INTERLEAVE))
                                        return ST_TIMEOUT;
                                ch[channel].num_blocks++;

                                // Write buffer with link to new block
                                ch[channel].buf[0] = track;
                                ch[channel].buf[1] = sector;
                                write_sector(ch[channel].track, ch[channel].sector, ch[channel].buf);

                                // Reset buffer
                                ch[channel].buf_ptr = ch[channel].buf + 2;
                                ch[channel].buf_len = 2;
                                ch[channel].track = track;
                                ch[channel].sector = sector;
                        }
                        *(ch[channel].buf_ptr)++ = byte;
                        ch[channel].buf_len++;
                        return ST_OK;

                case CHMOD_DIRECT:
                        if (ch[channel].buf_len < 256) {
                                *(ch[channel].buf_ptr)++ = byte;
                                ch[channel].buf_len++;
                                return ST_OK;
                        } else
                                return ST_TIMEOUT;
                        break;
        }
        return ST_TIMEOUT;
}


/*
 *  Reset drive
 */

void ImageDrive::Reset(void)
{
        close_all_channels();

        cmd_len = 0;
        for (int i=0; i<4; i++)
                buf_free[i] = true;

        if (bam_dirty) {
                write_sector(DIR_TRACK, 0, bam);
                bam_dirty = false;
        }

        memset(ram, 0, sizeof(ram));

        read_sector(DIR_TRACK, 0, bam);

        set_error(ERR_STARTUP);
}


/*
 *  Allocate floppy buffer
 *   -> Desired buffer number or -1
 *   <- Allocated buffer number or -1
 */

int ImageDrive::alloc_buffer(int want)
{
        if (want == -1) {
                for (want=3; want>=0; want--)
                        if (buf_free[want]) {
                                buf_free[want] = false;
                                return want;
                        }
                return -1;
        }

        if (want < 4)
                if (buf_free[want]) {
                        buf_free[want] = false;
                        return want;
                } else
                        return -1;
        else
                return -1;
}


/*
 *  Free floppy buffer
 */

void ImageDrive::free_buffer(int buf)
{
        buf_free[buf] = true;
}


/*
 *  Search file in directory, return directory track/sector and entry number
 *  false: not found, true: found
 */

// Return true if name 'n' matches pattern 'p'
static bool match(const uint8 *p, int p_len, const uint8 *n)
{
        if (p_len > 16)
                p_len = 16;

        int c = 0;
        while (p_len-- > 0) {
                if (*p == '*')  // Wildcard '*' matches all following characters
                        return true;
                if ((*p != *n) && (*p != '?'))  // Wildcard '?' matches single character
                        return false;
                p++; n++; c++;
        }

        return *n == 0xa0 || c == 16;
}

bool ImageDrive::find_file(const uint8 *pattern, int pattern_len, int &dir_track, int &dir_sector, int &entry, bool cont)
{
        // Counter to prevent cyclic directories from resulting in an infinite loop
        int num_dir_blocks = 0;

        // Pointer to current directory entry
        uint8 *de = NULL;
        if (cont)
                de = dir + DIR_ENTRIES + entry * SIZEOF_DE;
        else {
                dir[DIR_NEXT_TRACK] = DIR_TRACK;
                dir[DIR_NEXT_SECTOR] = 1;
                entry = 8;
        }

        while (num_dir_blocks < num_sectors[DIR_TRACK]) {

                // Goto next entry
                entry++; de += SIZEOF_DE;
                if (entry >= 8) {

                        // Read next directory block
                        if (dir[DIR_NEXT_TRACK] == 0)
                                return false;
                        if (!read_sector(dir_track = dir[DIR_NEXT_TRACK], dir_sector = dir[DIR_NEXT_SECTOR], dir))
                                return false;
                        num_dir_blocks++;
                        entry = 0;
                        de = dir + DIR_ENTRIES;
                }

                // Does entry match pattern?
                if (de[DE_TYPE] && match(pattern, pattern_len, de + DE_NAME))
                        return true;
        }
        return false;
}

bool ImageDrive::find_first_file(const uint8 *pattern, int pattern_len, int &dir_track, int &dir_sector, int &entry)
{
        return find_file(pattern, pattern_len, dir_track, dir_sector, entry, false);
}

bool ImageDrive::find_next_file(const uint8 *pattern, int pattern_len, int &dir_track, int &dir_sector, int &entry)
{
        return find_file(pattern, pattern_len, dir_track, dir_sector, entry, true);
}


/*
 *  Allocate new entry in directory, returns false on error (usually when
 *  all sectors of track 18 are allocated)
 *  The track/sector and entry numbers are returned
 */

bool ImageDrive::alloc_dir_entry(int &track, int &sector, int &entry)
{
        // First look for free entry in existing directory blocks
        dir[DIR_NEXT_TRACK] = DIR_TRACK;
        dir[DIR_NEXT_SECTOR] = 1;
        while (dir[DIR_NEXT_TRACK]) {
                if (!read_sector(track = dir[DIR_NEXT_TRACK], sector = dir[DIR_NEXT_SECTOR], dir))
                        return false;

                uint8 *de = dir + DIR_ENTRIES;
                for (entry=0; entry<8; entry++, de+=SIZEOF_DE) {
                        if (de[DE_TYPE] == 0)
                                return true;
                }
        }

        // No free entry found, allocate new directory block
        int last_track = track, last_sector = sector;
        if (!alloc_next_block(track, sector, DIR_INTERLEAVE))
                return false;

        // Write link to new block to last block
        dir[DIR_NEXT_TRACK] = track;
        dir[DIR_NEXT_SECTOR] = sector;
        write_sector(last_track, last_sector, dir);

        // Write new empty directory block and return first entry
        memset(dir, 0, 256);
        dir[DIR_NEXT_SECTOR] = 0xff;
        write_sector(track, sector, dir);
        entry = 0;
        return true;
}

/*
 *  Test if block is free in BAM (track/sector are not checked for validity)
 */

bool ImageDrive::is_block_free(int track, int sector)
{
        uint8 *p = bam + BAM_BITMAP + (track - 1) * 4;
        int byte = sector / 8 + 1;
        int bit = sector & 7;
        return p[byte] & (1 << bit);
}


/*
 *  Get number of free blocks on a track
 */

int ImageDrive::num_free_blocks(int track)
{
        return bam[BAM_BITMAP + (track - 1) * 4];
}


/*
 *  Clear BAM, mark all blocks as free
 */

static void clear_bam(uint8 *bam)
{
        for (int track=1; track<=35; track++) {
                static const uint8 num2bits[8] = {0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
                (bam + BAM_BITMAP)[(track-1) * 4 + 0] = num_sectors[track];
                (bam + BAM_BITMAP)[(track-1) * 4 + 1] = 0xff;
                (bam + BAM_BITMAP)[(track-1) * 4 + 2] = 0xff;
                (bam + BAM_BITMAP)[(track-1) * 4 + 3] = num2bits[num_sectors[track] - 16];
        }
}


/*
 *  Allocate block in BAM, returns error code
 */

int ImageDrive::alloc_block(int track, int sector)
{
        if (track < 1 || track > 35 || sector < 0 || sector >= num_sectors[track])
                return ERR_ILLEGALTS;

        uint8 *p = bam + BAM_BITMAP + (track - 1) * 4;
        int byte = sector / 8 + 1;
        int bit = sector & 7;

        // Block free?
        if (p[byte] & (1 << bit)) {

                // Yes, allocate and decrement free block count
                p[byte] &= ~(1 << bit);
                p[0]--;
                bam_dirty = true;
                return ERR_OK;

        } else
                return ERR_NOBLOCK;
}


/*
 *  Free block in BAM, returns error code
 */

int ImageDrive::free_block(int track, int sector)
{
        if (track < 1 || track > 35 || sector < 0 || sector >= num_sectors[track])
                return ERR_ILLEGALTS;

        uint8 *p = bam + BAM_BITMAP + (track - 1) * 4;
        int byte = sector / 8 + 1;
        int bit = sector & 7;

        // Block allocated?
        if (!(p[byte] & (1 << bit))) {

                // Yes, free and increment free block count
                p[byte] |= (1 << bit);
                p[0]++;
                bam_dirty = true;
        }
        return ERR_OK;
}


/*
 *  Allocate chain of data blocks in BAM
 */

bool ImageDrive::alloc_block_chain(int track, int sector)
{
        uint8 buf[256];
        while (alloc_block(track, sector) == ERR_OK) {
                if (!read_sector(track, sector, buf))
                        return false;
                track = buf[0];
                sector = buf[1];
        }
        return true;
}


/*
 *  Free chain of data blocks in BAM
 */

bool ImageDrive::free_block_chain(int track, int sector)
{
        uint8 buf[256];
        while (free_block(track, sector) == ERR_OK) {
                if (!read_sector(track, sector, buf))
                        return false;
                track = buf[0];
                sector = buf[1];
        }
        return true;
}


/*
 *  Search and allocate next free block, returns false if no more blocks
 *  are free (ERR_DISKFULL is also set in this case)
 *  "track" and "sector" must be set to the block where the search should
 *  begin
 */

bool ImageDrive::alloc_next_block(int &track, int &sector, int interleave)
{
        // Find track with free blocks
        bool side_changed = false;
        while (num_free_blocks(track) == 0) {
                if (track == DIR_TRACK) {       // Directory doesn't grow to other tracks
full:           track = sector = 0;
                        set_error(ERR_DISKFULL);
                        return false;
                } else if (track > DIR_TRACK) {
                        track++;
                        if (track > 35) {
                                if (!side_changed)
                                        side_changed = true;
                                else
                                        goto full;
                                track = DIR_TRACK - 1;
                                sector = 0;
                        }
                } else {
                        track--;
                        if (track < 1) {
                                if (!side_changed)
                                        side_changed = true;
                                else
                                        goto full;
                                track = DIR_TRACK + 1;
                                sector = 0;
                        }
                }
        }

        // Find next free block on track
        int num = num_sectors[track];
        sector = sector + interleave;
        if (sector >= num) {
                sector -= num;
                if (sector)
                        sector--;
        }
        while (!is_block_free(track, sector)) {
                sector++;
                if (sector >= num_sectors[track]) {
                        sector = 0;
                        while (!is_block_free(track, sector)) {
                                sector++;
                                if (sector >= num_sectors[track]) {
                                        // Something is wrong: the BAM free block count for this
                                        // track was >0, but we found no free blocks
                                        track = sector = 0;
                                        set_error(ERR_DIRERROR);
                                        return false;
                                }
                        }
                }
        }

        alloc_block(track, sector);
        return true;
}


/*
 *  Sector reading/writing routines
 */

static long offset_from_ts(const image_file_desc &desc, int track, int sector)
{
        if ((track < 1) || (track > desc.num_tracks)
         || (sector < 0) || (sector >= num_sectors[track]))
                return -1;

        return ((accum_num_sectors[track] + sector) << 8) + desc.header_size;
}

// Get number of sectors per given track
int sectors_per_track(const image_file_desc &desc, int track)
{
        return num_sectors[track];
}

// Get reference to error info byte of given track/sector
uint8 &error_info_for_sector(image_file_desc &desc, int track, int sector)
{
        return desc.error_info[accum_num_sectors[track] + sector];
}

static inline const uint8 &error_info_for_sector(const image_file_desc &desc, int track, int sector)
{
        return desc.error_info[accum_num_sectors[track] + sector];
}

const int conv_job_error[16] = {
        ERR_OK,                         // 0 -> 00 OK
        ERR_OK,                         // 1 -> 00 OK
        ERR_READ20,                     // 2 -> 20 READ ERROR
        ERR_READ21,                     // 3 -> 21 READ ERROR
        ERR_READ22,                     // 4 -> 22 READ ERROR
        ERR_READ23,                     // 5 -> 23 READ ERROR
        ERR_READ24,                     // 6 -> 24 READ ERROR (undetected by 1541)
        ERR_WRITE25,            // 7 -> 25 WRITE ERROR
        ERR_WRITEPROTECT,       // 8 -> 26 WRITE PROTECT ON
        ERR_READ27,                     // 9 -> 27 READ ERROR
        ERR_WRITE28,            // 10 -> 28 WRITE ERROR
        ERR_DISKID,                     // 11 -> 29 DISK ID MISMATCH
        ERR_OK,                         // 12 -> 00 OK
        ERR_OK,                         // 13 -> 00 OK
        ERR_OK,                         // 14 -> 00 OK
        ERR_NOTREADY            // 15 -> 74 DRIVE NOT READY
};

// Read sector, return error code
int read_sector(FILE *f, const image_file_desc &desc, int track, int sector, uint8 *buffer)
{
        // Convert track/sector to byte offset in file
        long offset = offset_from_ts(desc, track, sector);
        if (offset < 0)
                return ERR_ILLEGALTS;

        if (f == NULL)
                return ERR_NOTREADY;

        fseek(f, offset, SEEK_SET);
        if (fread(buffer, 1, 256, f) != 256)
                return ERR_READ22;
        else {
                unsigned int error = error_info_for_sector(desc, track, sector);
                return conv_job_error[error & 0x0f];
        }
}

// Write sector, return error code
int write_sector(FILE *f, const image_file_desc &desc, int track, int sector, uint8 *buffer)
{
        // Convert track/sector to byte offset in file
        long offset = offset_from_ts(desc, track, sector);
        if (offset < 0)
                return ERR_ILLEGALTS;

        if (f == NULL)
                return ERR_NOTREADY;

        fseek(f, offset, SEEK_SET);
        if (fwrite(buffer, 1, 256, f) != 256)
                return ERR_WRITE25;
        else
                return ERR_OK;
}

// Read sector and set error message, returns false on error
bool ImageDrive::read_sector(int track, int sector, uint8 *buffer)
{
        int error = ::read_sector(the_file, desc, track, sector, buffer);
        if (error)
                set_error(error, track, sector);
        return error == ERR_OK;
}

// Write sector and set error message, returns false on error
bool ImageDrive::write_sector(int track, int sector, uint8 *buffer)
{
        int error = ::write_sector(the_file, desc, track, sector, buffer);
        if (error)
                set_error(error, track, sector);
        return error == ERR_OK;
}

// Write error info back to image file
void write_back_error_info(FILE *f, const image_file_desc &desc)
{
        if (desc.type == TYPE_D64 && desc.has_error_info) {
                int num_sectors = desc.num_tracks == 40 ? NUM_SECTORS_40 : NUM_SECTORS_35;
                fseek(f, num_sectors * 256, SEEK_SET);
                fwrite(desc.error_info, num_sectors, 1, f);
        }
}

// Format disk image
bool format_image(FILE *f, image_file_desc &desc, bool lowlevel, uint8 id1, uint8 id2, const uint8 *disk_name, int disk_name_len)
{
        uint8 p[256];

        if (lowlevel) {

                // Fill buffer with 1541 empty sector pattern (4b 01 01 ...,
                // except on track 1 where it's 01 01 01 ...)
                memset(p, 1, 256);

                // Overwrite all blocks
                for (int track=1; track<=35; track++) {
                        if (track == 2)
                                p[0] = 0x4b;
                        for (int sector=0; sector<num_sectors[track]; sector++) {
                                if (write_sector(f, desc, track, sector, p) != ERR_OK)
                                        return false;
                        }
                }

                // Clear and write error info
                memset(desc.error_info, 1, sizeof(desc.error_info));
                write_back_error_info(f, desc);

                // Clear BAM
                memset(p, 0, 256);

        } else {

                // Read BAM
                if (read_sector(f, desc, DIR_TRACK, 0, p) != ERR_OK)
                        return false;
        }

        // Create and write empty BAM
        p[BAM_DIR_TRACK] = DIR_TRACK;
        p[BAM_DIR_SECTOR] = 1;
        p[BAM_FMT_TYPE] = 'A';
        clear_bam(p);
        p[BAM_BITMAP + (DIR_TRACK - 1) * 4 + 0] -= 2;   // Allocate BAM and first directory block
        p[BAM_BITMAP + (DIR_TRACK - 1) * 4 + 1] &= 0xfc;
        memset(p + BAM_DISK_NAME, 0xa0, 27);
        if (disk_name_len > 16)
                disk_name_len = 16;
        memcpy(p + BAM_DISK_NAME, disk_name, disk_name_len);
        p[BAM_DISK_ID] = id1;
        p[BAM_DISK_ID + 1] = id2;
        p[BAM_FMT_CHAR] = '2';
        p[BAM_FMT_CHAR + 1] = 'A';
        if (write_sector(f, desc, DIR_TRACK, 0, p) != ERR_OK)
                return false;

        // Create and write empty directory
        memset(p, 0, 256);
        p[1] = 255;
        return write_sector(f, desc, DIR_TRACK, 1, p) == ERR_OK;
}


/*
 *  Execute drive commands
 */

// BLOCK-READ:channel,0,track,sector
void ImageDrive::block_read_cmd(int channel, int track, int sector, bool user_cmd)
{
        if (channel >= 16 || ch[channel].mode != CHMOD_DIRECT) {
                set_error(ERR_NOCHANNEL);
                return;
        }
        if (!read_sector(track, sector, ch[channel].buf))
                return;
        if (user_cmd) {
                ch[channel].buf_len = 256;
                ch[channel].buf_ptr = ch[channel].buf;
        } else {
                ch[channel].buf_len = ch[channel].buf[0];
                ch[channel].buf_ptr = ch[channel].buf + 1;
        }
}

// BLOCK-WRITE:channel,0,track,sector
void ImageDrive::block_write_cmd(int channel, int track, int sector, bool user_cmd)
{
        if (write_protected) {
                set_error(ERR_WRITEPROTECT);
                return;
        }
        if (channel >= 16 || ch[channel].mode != CHMOD_DIRECT) {
                set_error(ERR_NOCHANNEL);
                return;
        }
        if (!user_cmd)
                ch[channel].buf[0] = ch[channel].buf_len ? ch[channel].buf_len - 1 : 1;
        if (!write_sector(track, sector, ch[channel].buf))
                return;
        if (!user_cmd) {
                ch[channel].buf_len = 1;
                ch[channel].buf_ptr = ch[channel].buf + 1;
        }
}

// BLOCK-ALLOCATE:0,track,sector
void ImageDrive::block_allocate_cmd(int track, int sector)
{
        int err = alloc_block(track, sector);
        if (err) {
                if (err == ERR_NOBLOCK) {
                        // Find next free block and return its track/sector address in the
                        // error message (only look on higher tracks)
                        for (;;) {
                                sector++;
                                if (sector >= num_sectors[track]) {
                                        track++;
                                        sector = 0;
                                        if (track > 35) {
                                                set_error(ERR_NOBLOCK, 0, 0);
                                                return;
                                        }
                                }
                                if (is_block_free(track, sector)) {
                                        set_error(ERR_NOBLOCK, track, sector);
                                        return;
                                }
                        }
                } else
                        set_error(err, track, sector);
        }
}

// BLOCK-FREE:0,track,sector
void ImageDrive::block_free_cmd(int track, int sector)
{
        int err = free_block(track, sector);
        if (err)
                set_error(err, track, sector);
}

// BUFFER-POINTER:channel,pos
void ImageDrive::buffer_pointer_cmd(int channel, int pos)
{
        if (channel >= 16 || ch[channel].mode != CHMOD_DIRECT) {
                set_error(ERR_NOCHANNEL);
                return;
        }
        ch[channel].buf_ptr = ch[channel].buf + pos;
        ch[channel].buf_len = 256 - pos;
}

// M-R<adr low><adr high>[<number>]
void ImageDrive::mem_read_cmd(uint16 adr, uint8 len)
{
        error_len = len;
        if (adr >= 0x300 && adr < 0x1000) {
                // Read from RAM
                error_ptr = (char *)ram + (adr & 0x7ff);
        } else if (adr >= 0xc000) {
                // Read from ROM
                error_ptr = (char *)(TheC64->ROM1541) + (adr - 0xc000);
        } else {
                unsupp_cmd();
                memset(error_buf, 0, len);
                error_ptr = error_buf;
        }
}

// M-W<adr low><adr high><number><data...>
void ImageDrive::mem_write_cmd(uint16 adr, uint8 len, uint8 *p)
{
        while (len) {
                if (adr >= 0x300 && adr < 0x1000) {
                        // Write to RAM
                        ram[adr & 0x7ff] = *p;
                } else if (adr < 0xc000) {
                        unsupp_cmd();
                        return;
                }
                len--; adr++; p++;
        }
}

//   COPY:new=file1,file2,...
//        ^   ^
// new_file   old_files
void ImageDrive::copy_cmd(const uint8 *new_file, int new_file_len, const uint8 *old_files, int old_files_len)
{
        // Check if destination file is already present
        int dir_track, dir_sector, entry;
        if (find_first_file(new_file, new_file_len, dir_track, dir_sector, entry)) {
                set_error(ERR_FILEEXISTS);
                return;
        }

        // Loop for all source files
        bool first = true;
        while (old_files_len > 0) {
                uint8 *comma = (uint8 *)memchr(old_files, ',', old_files_len);
                int name_len = comma ? comma - old_files : old_files_len;

                // Check if source file is present
                if (!find_first_file(old_files, name_len, dir_track, dir_sector, entry)) {
                        set_error(ERR_FILENOTFOUND);
                        Close(17);
                        return;
                }
                uint8 *de = dir + DIR_ENTRIES + entry * SIZEOF_DE;
                uint8 type = de[DE_TYPE] & 7, track = de[DE_TRACK], sector = de[DE_SECTOR];

                // If this is the first source file, open internal write channel for destination file
                if (first) {
                        create_file(17, new_file, new_file_len, type, false);
                        if (ch[17].mode == CHMOD_FREE)
                                return;
                        first = false;
                }

                // Open internal read channel for source file
                open_file_ts(16, track, sector);
                if (ch[16].mode == CHMOD_FREE) {
                        Close(17);
                        return;
                }

                // Copy file
                uint8 byte, st;
                do {
                        st = Read(16, byte);
                        Write(17, byte, false);
                } while (st == ST_OK);
                Close(16);
                if (st != ST_EOF) {
                        Close(17);
                        return;
                }

                if (comma) {
                        old_files_len -= name_len + 1;
                        old_files = comma + 1;
                } else
                        old_files_len = 0;
        }
        Close(17);
}

// RENAME:new=old
//        ^   ^
// new_file   old_file
void ImageDrive::rename_cmd(const uint8 *new_file, int new_file_len, const uint8 *old_file, int old_file_len)
{
        // Check if destination file is already present
        int dir_track, dir_sector, entry;
        if (find_first_file(new_file, new_file_len, dir_track, dir_sector, entry)) {
                set_error(ERR_FILEEXISTS);
                return;
        }

        // Check if source file is present
        if (!find_first_file(old_file, old_file_len, dir_track, dir_sector, entry)) {
                set_error(ERR_FILENOTFOUND);
                return;
        }

        // Check for write-protection
        if (write_protected) {
                set_error(ERR_WRITEPROTECT);
                return;
        }

        // Rename file in directory entry
        uint8 *p = dir + DIR_ENTRIES + entry * SIZEOF_DE;
        memset(p + DE_NAME, 0xa0, 16);
        memcpy(p + DE_NAME, new_file, new_file_len);
        write_sector(dir_track, dir_sector, dir);
}

// SCRATCH:file1,file2,...
//         ^
//         files
void ImageDrive::scratch_cmd(const uint8 *files, int files_len)
{
        // Check for write-protection
        if (write_protected) {
                set_error(ERR_WRITEPROTECT);
                return;
        }

        // Loop for all files
        int num_files = 0;
        while (files_len > 0) {
                uint8 *comma = (uint8 *)memchr(files, ',', files_len);
                int name_len = comma ? comma - files : files_len;

                int dir_track, dir_sector, entry;
                if (find_first_file(files, name_len, dir_track, dir_sector, entry)) {
                        do {
                                uint8 *de = dir + DIR_ENTRIES + entry * SIZEOF_DE;

                                // File protected? Then skip
                                if (de[DE_TYPE] & 0x40)
                                        continue;

                                // Free allocated data blocks and side sectors
                                free_block_chain(de[DE_TRACK], de[DE_SECTOR]);
                                free_block_chain(de[DE_SIDE_TRACK], de[DE_SIDE_SECTOR]);

                                // Clear file type
                                de[DE_TYPE] = 0;

                                // Write directory block back
                                write_sector(dir_track, dir_sector, dir);
                                num_files++;
                        } while (find_next_file(files, name_len, dir_track, dir_sector, entry));
                }

                if (comma) {
                        files_len -= name_len + 1;
                        files = comma + 1;
                } else
                        files_len = 0;
        }

        // Report number of files scratched
        set_error(ERR_SCRATCHED, num_files);
}

// INITIALIZE
void ImageDrive::initialize_cmd(void)
{
        // Close all channels and re-read BAM
        close_all_channels();
        if (bam_dirty) {
                write_sector(DIR_TRACK, 0, bam);
                bam_dirty = false;
        }
        read_sector(DIR_TRACK, 0, bam);
}

// NEW:name,id
//     ^   ^
//  name   comma (or NULL)
void ImageDrive::new_cmd(const uint8 *name, int name_len, const uint8 *comma)
{
        // Check for write-protection
        if (write_protected) {
                set_error(ERR_WRITEPROTECT);
                return;
        }

        // Remember current ID
        uint8 id1 = bam[BAM_DISK_ID], id2 = bam[BAM_DISK_ID + 1];

        // Formatting with ID?
        if (comma) {

                close_all_channels();

                // Clear BAM buffer
                memset(bam, 0, 256);

                // Get ID from command
                if (comma[1]) {
                        id1 = comma[1];
                        id2 = comma[2] ? comma[2] : ' ';
                } else {
                        id1 = id2 = ' ';
                }
        }

        // Format disk image
        format_image(the_file, desc, comma, id1, id2, name, name_len);

        // Re-read BAM
        read_sector(DIR_TRACK, 0, bam);
        bam_dirty = false;
}

// VALIDATE
void ImageDrive::validate_cmd(void)
{
        // Backup of old BAM in case something goes amiss
        uint8 old_bam[256];
        memcpy(old_bam, bam, 256);

        // Clear BAM
        clear_bam(bam);
        bam_dirty = true;

        // Allocate BAM and directory
        if (!alloc_block_chain(DIR_TRACK, 0)) {
                memcpy(bam, old_bam, 256);
                return;
        }

        // Allocate all file data and side sector blocks
        int dir_track, dir_sector, entry;
        if (find_first_file((uint8 *)"*", 1, dir_track, dir_sector, entry)) {
                do {
                        uint8 *de = dir + DIR_ENTRIES + entry * SIZEOF_DE;

                        if (de[DE_TYPE] & 0x80) {
                                // Closed file, allocate all file data and side sector blocks
                                if (!alloc_block_chain(de[DE_TRACK], de[DE_SECTOR]) || !alloc_block_chain(de[DE_SIDE_TRACK], de[DE_SIDE_SECTOR])) {
                                        memcpy(bam, old_bam, 256);
                                        return;
                                }
                        } else {
                                // Open file, delete it
                                de[DE_TYPE] = 0;
                                write_sector(dir_track, dir_sector, dir);
                        }
                } while (find_next_file((uint8 *)"*", 1, dir_track, dir_sector, entry));
        }
}


/*
 *  Check whether file with given header (64 bytes) and size looks like one
 *  of the file types supported by this module
 */

static bool is_d64_file(const uint8 *header, long size)
{
        return size == NUM_SECTORS_35 * 256 || size == NUM_SECTORS_35 * 257
            || size == NUM_SECTORS_40 * 256 || size == NUM_SECTORS_40 * 257;
}

static bool is_ed64_file(const uint8 *header, long size)
{
        // 35-track d64 file with header ID at the end (only used internally for
        // converted zipcode files)
        return size == NUM_SECTORS_35 * 256 + 2;
}

static bool is_x64_file(const uint8 *header, long size)
{
        return memcmp(header, "C\x15\x41\x64\x01\x02", 6) == 0;
}

static bool is_zipcode_file(const char *path)
{
#if 0
        string base, part;
        SplitPath(path, base, part);
        return part.length() > 2 && part[0] >= '1' && part[0] <= '4' && part[1] == '!';
#else
        return false;
#endif
}

bool IsImageFile(const char *path, const uint8 *header, long size)
{
        return is_d64_file(header, size) || is_x64_file(header, size) || is_zipcode_file(path);
}


#if 0
/*
 *  Convert zipcode file to extended d64 file (d64 file with header ID)
 */

static FILE *open_zipcode_file(FILE *old, int num, const string &base, string &part, uint8 &id1, uint8 &id2)
{
        if (old)
                fclose(old);
        part[0] = num + '1';
        FILE *f = fopen(AddToPath(base, part).c_str(), "rb");
        if (f == NULL)
                return NULL;
        if (fseek(f, 2, SEEK_SET) < 0) {
                fclose(f);
                return NULL;
        }
        if (num == 0) {
                id1 = getc(f);
                id2 = getc(f);
        }
        return f;
}

static FILE *convert_zipcode_to_ed64(const string &path)
{
        FILE *in = NULL, *out = NULL;
        uint8 id1, id2;

        // Split input file name
        string base, part;
        SplitPath(path, base, part);

        // Open output file
        out = tmpfile();
        if (out == NULL)
                goto error;

        // Decode all tracks
        for (int track=1; track<=35; track++) {
                int max_sect = 17 + ((track < 31) ? 1 : 0) + ((track < 25) ? 1 : 0) + ((track < 18) ? 2 : 0);

                // Select appropriate input file
                switch (track) {
                        case 1:
                                if ((in = open_zipcode_file(NULL, 0, base, part, id1, id2)) == NULL)
                                        goto error;
                                break;
                        case 9:
                                if ((in = open_zipcode_file(in, 1, base, part, id1, id2)) == NULL)
                                        goto error;
                                break;
                        case 17:
                                if ((in = open_zipcode_file(in, 2, base, part, id1, id2)) == NULL)
                                        goto error;
                                break;
                        case 26:
                                if ((in = open_zipcode_file(in, 3, base, part, id1, id2)) == NULL)
                                        goto error;
                                break;
                }

                // Clear "sector read" flags
                bool sect_flag[21];
                for (int i=0; i<max_sect; i++)
                        sect_flag[i] = false;

                // Read track
                uint8 act_track[21 * 256];
                for (int i=0; i<max_sect; i++) {

                        // Read and verify track/sector number
                        uint8 t = getc(in);
                        uint8 s = getc(in);
                        if ((t & 0x3f) != track || s >= max_sect || sect_flag[s] || feof(in))
                                goto error;
                        sect_flag[s] = true;
                        uint8 *p = act_track + s * 256;

                        // Uncompress sector
                        if (t & 0x80) {
                                // Run-length encoded sector
                                uint8 len = getc(in);
                                uint8 rep = getc(in);
                                int count = 0;
                                for (int j=0; j<len; j++) {
                                        if (feof(in))
                                                goto error;
                                        uint8 c = getc(in);
                                        if (c != rep)
                                                p[count++] = c;
                                        else {
                                                uint8 repnum = getc(in);
                                                if (feof(in))
                                                        goto error;
                                                c = getc(in);
                                                j += 2;
                                                for (int k=0; k<repnum; k++)
                                                        p[count++] = c;
                                        }
                                }
                        } else if (t & 0x40) {
                                // Sector filled with constant byte
                                if (feof(in))
                                        goto error;
                                uint8 c = getc(in);
                                memset(p, c, 256);
                        } else {
                                // Plain sector
                                if (fread(p, 1, 256, in) != 256)
                                        goto error;
                        }
                }

                // Write track
                if (fwrite(act_track, 256, max_sect, out) != (size_t)max_sect)
                        goto error;
        }

        // Write header ID
        putc(id1, out);
        putc(id2, out);

        // Done
        fclose(in);
        fseek(out, 0, SEEK_SET);
        return out;

error:
        if (in)
                fclose(in);
        if (out)
                fclose(out);
        return NULL;
}
#endif


/*
 *  Open disk image file, return file handle
 */

FILE *open_image_file(const char *path, bool write_mode)
{
#if 0
        if (is_zipcode_file(path)) {
                if (write_mode)
                        return NULL;
                else
                        return convert_zipcode_to_ed64(path);
        } else
#endif
                return fopen(path, write_mode ? "r+b" : "rb");
}


/*
 *  Parse image file and fill in image_file_desc structure
 */

static bool parse_d64_file(FILE *f, image_file_desc &desc, bool has_header_id)
{
        // .d64 files have no header
        desc.type = has_header_id ? TYPE_ED64 : TYPE_D64;
        desc.header_size = 0;

        // Determine number of tracks
        fseek(f, 0, SEEK_END);
        long size = ftell(f);
        if (size == NUM_SECTORS_40 * 256 || size == NUM_SECTORS_40 * 257)
                desc.num_tracks = 40;
        else
                desc.num_tracks = 35;

        if (has_header_id) {
                // Read header ID from image file (last 2 bytes)
                fseek(f, -2, SEEK_END);
                desc.id1 = getc(f);
                desc.id2 = getc(f);
        } else {
                // Read header ID from BAM (use error_info as buffer)
                fseek(f, accum_num_sectors[18] * 256, SEEK_SET);
                fread(desc.error_info, 1, 256, f);
                desc.id1 = desc.error_info[BAM_DISK_ID];
                desc.id2 = desc.error_info[BAM_DISK_ID + 1];
        }

        // Read error info
        memset(desc.error_info, 1, sizeof(desc.error_info));
        if (size == NUM_SECTORS_35 * 257) {
                fseek(f, NUM_SECTORS_35 * 256, SEEK_SET);
                fread(desc.error_info, NUM_SECTORS_35, 1, f);
                desc.has_error_info = true;
        } else if (size == NUM_SECTORS_40 * 257) {
                fseek(f, NUM_SECTORS_40 * 256, SEEK_SET);
                fread(desc.error_info, NUM_SECTORS_40, 1, f);
                desc.has_error_info = true;
        } else
                desc.has_error_info = false;

        return true;
}

static bool parse_x64_file(FILE *f, image_file_desc &desc)
{
        desc.type = TYPE_X64;
        desc.header_size = 64;

        // Read number of tracks
        fseek(f, 7, SEEK_SET);
        desc.num_tracks = getc(f);
        if (desc.num_tracks < 35 || desc.num_tracks > 40)
                return false;

        // Read header ID from BAM (use error_info as buffer)
        fseek(f, desc.header_size + accum_num_sectors[18] * 256, SEEK_SET);
        fread(desc.error_info, 1, 256, f);
        desc.id1 = desc.error_info[BAM_DISK_ID];
        desc.id2 = desc.error_info[BAM_DISK_ID + 1];

        // .x64 files have no error info
        memset(desc.error_info, 1, sizeof(desc.error_info));
        desc.has_error_info = false;
        return true;
}

bool parse_image_file(FILE *f, image_file_desc &desc)
{
        // Read header
        uint8 header[64];
        fread(header, 1, sizeof(header), f);

        // Determine file size
        fseek(f, 0, SEEK_END);
        long size = ftell(f);

        // Determine file type and fill in image_file_desc structure
        if (is_x64_file(header, size))
                return parse_x64_file(f, desc);
        else if (is_d64_file(header, size))
                return parse_d64_file(f, desc, false);
        else if (is_ed64_file(header, size))
                return parse_d64_file(f, desc, true);
        else
                return false;
}


/*
 *  Create new blank disk image file, returns false on error
 */

bool CreateImageFile(const char *path)
{
        // Open file for writing
        FILE *f = fopen(path, "wb");
        if (f == NULL)
                return false;

        // Create descriptor
        image_file_desc desc;
        desc.type = TYPE_D64;
        desc.header_size = 0;
        desc.num_tracks = 35;
        desc.id1 = 'F';
        desc.id1 = 'R';
        memset(desc.error_info, 1, sizeof(desc.error_info));
        desc.has_error_info = false;

        // Format image file
        if (!format_image(f, desc, true, 'F', 'R', (uint8 *)"D64 FILE", 8)) {
                fclose(f);
                remove(path);
                return false;
        }

        // Close file
        fclose(f);
        return true;
}
Revision:	1.6
Committed:	2004-01-12T14:31:57Z (20 years, 10 months ago) by cebix
Branch:	MAIN
Changes since 1.5:	+43 -43 lines
Log Message:	D64Drive -> ImageDrive