/**

  * $Id$

  *

  * GD-Rom image-file common functions. 

  *

  * Copyright (c) 2005 Nathan Keynes.

  *

  * 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.

  */

 #include <assert.h>

 #include <stdlib.h>

 #include <string.h>

 #include <ctype.h>

 #include <sys/types.h>

 #include <netinet/in.h>

 #include "gdrom/gddriver.h"

 #include "gdrom/packet.h"

 #include "ecc.h"

 #include "bootstrap.h"

 static void gdrom_image_destroy( gdrom_disc_t disc );

 static gdrom_error_t gdrom_image_read_sector( gdrom_disc_t disc, uint32_t lba, int mode, 

                                               unsigned char *buf, uint32_t *readlength );

 static gdrom_error_t gdrom_image_read_toc( gdrom_disc_t disc, unsigned char *buf );

 static gdrom_error_t gdrom_image_read_session( gdrom_disc_t disc, int session, unsigned char *buf );

 static gdrom_error_t gdrom_image_read_position( gdrom_disc_t disc, uint32_t lba, unsigned char *buf );

 static int gdrom_image_drive_status( gdrom_disc_t disc );

 static uint8_t gdrom_default_sync[12] = { 0, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 0 };

 #define SECTOR_HEADER_SIZE 16

 #define SECTOR_SUBHEADER_SIZE 8

 /* Data offset (from start of raw sector) by sector mode */

 static int gdrom_data_offset[] = { 16, 16, 16, 24, 24, 0, 8, 0, 0 };

 struct cdrom_sector_header {

     uint8_t sync[12];

     uint8_t msf[3];

     uint8_t mode;

     uint8_t subhead[8]; // Mode-2 XA sectors only

 };

 /**

  * Initialize a gdrom_disc structure with the gdrom_image_* methods

  */

 void gdrom_image_init( gdrom_disc_t disc )

 {

     memset( disc, 0, sizeof(struct gdrom_disc) ); /* safety */

     disc->read_sector = gdrom_image_read_sector;

     disc->read_toc = gdrom_image_read_toc;

     disc->read_session = gdrom_image_read_session;

     disc->read_position = gdrom_image_read_position;

     disc->drive_status = gdrom_image_drive_status;

     disc->play_audio = NULL; /* not supported yet */

     disc->run_time_slice = NULL; /* not needed */

     disc->close = gdrom_image_destroy;

 }

 gdrom_disc_t gdrom_image_new( const gchar *filename, FILE *f )

 {

     gdrom_image_t image = (gdrom_image_t)g_malloc0(sizeof(struct gdrom_image));

     if( image == NULL ) {

         return NULL;

     }

     image->disc_type = IDE_DISC_CDROMXA;

     image->file = f;

     gdrom_disc_t disc = (gdrom_disc_t)image;

     gdrom_image_init(disc);

     if( filename == NULL ) {

         disc->name = NULL;

     } else {

         disc->name = g_strdup(filename);

     }

     return disc;

 }

 static void gdrom_image_destroy( gdrom_disc_t disc )

 {

     int i;

     FILE *lastfile = NULL;

     gdrom_image_t img = (gdrom_image_t)disc;

     if( img->file != NULL ) {

         fclose(img->file);

         img->file = NULL;

     }

     for( i=0; i<img->track_count; i++ ) {

         if( img->track[i].file != NULL && img->track[i].file != lastfile ) {

             lastfile = img->track[i].file;

             fclose(lastfile);

             img->track[i].file = NULL;

         }

     }

     if( disc->name != NULL ) {

         g_free( (gpointer)disc->name );

         disc->name = NULL;

     }

     free( disc );

 }

 void gdrom_image_destroy_no_close( gdrom_disc_t disc )

 {

     int i;

     FILE *lastfile = NULL;

     gdrom_image_t img = (gdrom_image_t)disc;

     if( img->file != NULL ) {

         img->file = NULL;

     }

     for( i=0; i<img->track_count; i++ ) {

         if( img->track[i].file != NULL && img->track[i].file != lastfile ) {

             lastfile = img->track[i].file;

             fclose(lastfile);

             img->track[i].file = NULL;

         }

     }

     if( disc->name != NULL ) {

         g_free( (gpointer)disc->name );

         disc->name = NULL;

     }

     free( disc );

 }

 int gdrom_image_get_track_by_lba( gdrom_image_t image, uint32_t lba )

 {

     int i;

     for( i=0; i<image->track_count; i++ ) {

         if( image->track[i].lba <= lba && 

                 lba < (image->track[i].lba + image->track[i].sector_count) ) {

             return i+1;

         }

     }

     return -1;

 }

 /**

  * Read a block from an image file, handling negative file offsets

  * with 0-fill.

  */

 static gboolean gdrom_read_block( unsigned char *buf, int file_offset, int length, FILE *f )

 {

     if( file_offset < 0 ) {

         int size = -file_offset;

         if( size >= length ) {

             memset( buf, 0, length );

             return TRUE;

         } else {

             memset( buf, 0, size );

             file_offset = 0;

             length -= size;

         }

     }

     fseek( f, file_offset, SEEK_SET );

     return fread( buf, length, 1, f ) == 1;

 }

 static void gdrom_build_sector_header( unsigned char *buf, uint32_t lba, 

                                        gdrom_track_mode_t sector_mode )

 {

     memcpy( buf, gdrom_default_sync, 12 );

     cd_build_address( buf, sector_mode, lba );

 }

 /**

  * Return TRUE if the given read mode + track modes are compatible,

  * otherwise FALSE.

  * @param track_mode one of the GDROM_MODE* constants

  * @param read_mode the READ_CD_MODE from the read request

  */

 static gboolean gdrom_is_compatible_read_mode( int track_mode, int read_mode )

 {

     switch( read_mode ) {

     case READ_CD_MODE_ANY:

         return TRUE;

     case READ_CD_MODE_CDDA:

         return track_mode == GDROM_CDDA;

     case READ_CD_MODE_1:

         return track_mode == GDROM_MODE1 || track_mode == GDROM_MODE2_FORM1;

     case READ_CD_MODE_2_FORM_1:

         return track_mode == GDROM_MODE1 || track_mode == GDROM_MODE2_FORM1;

     case READ_CD_MODE_2_FORM_2:

         return track_mode == GDROM_MODE2_FORM2;

     case READ_CD_MODE_2:

         return track_mode == GDROM_MODE2_FORMLESS;

     default:

         return FALSE;

     }

 }

 /**

  * Determine the start position in a raw sector, and the amount of data to read

  * in bytes, for a given combination of sector mode and read mode.

  */ 

 static void gdrom_get_read_bounds( int sector_mode, int read_mode, int *start, int *size )

 {

     if( READ_CD_RAW(read_mode) ) {

         // whole sector

         *start = 0;

         *size = 2352;

     } else {

         *size = 0;

         if( READ_CD_DATA(read_mode) ) {

             *start = gdrom_data_offset[sector_mode];

             *size = gdrom_sector_size[sector_mode];

         }

         if( READ_CD_SUBHEAD(read_mode) && 

                 (sector_mode == GDROM_MODE2_FORM1 || sector_mode == GDROM_MODE2_FORM2) ) {

             *start = SECTOR_HEADER_SIZE;

             *size += SECTOR_SUBHEADER_SIZE;

         }

         if( READ_CD_HEADER(read_mode) ) {

             *size += SECTOR_HEADER_SIZE;

             *start = 0;

         }

     }

 }

 void gdrom_extract_raw_data_sector( char *sector_data, int channels, unsigned char *buf, uint32_t *length )

 {

     int sector_mode;

     int start, size;

     struct cdrom_sector_header *secthead = (struct cdrom_sector_header *)sector_data;

     if( secthead->mode == 1 ) {

         sector_mode = GDROM_MODE1;

     } else {

         sector_mode = ((secthead->subhead[2] & 0x20) == 0 ) ? GDROM_MODE2_FORM1 : GDROM_MODE2_FORM2;

     }

     gdrom_get_read_bounds( sector_mode, channels, &start, &size );

     memcpy( buf, sector_data+start, size );

     *length = size;

 }

 /**

  * Read a single sector from a disc image. If you thought this would be simple, 

  * I have just one thing to say to you: Bwahahahahahahahah.

  *

  * Once we've decided that there's a real sector at the requested lba, there's 

  * really two things we need to care about:

  *   1. Is the sector mode compatible with the requested read mode

  *   2. Which parts of the sector do we need to return? 

  *      (header/subhead/data/raw sector)

  *

  * Also note that the disc image may supply us with just the data (most common 

  * case), or may have the full raw sector. In the former case we may need to 

  * generate the missing data on the fly, for which we use libedc to compute the

  * data correction codes.

  */

 static gdrom_error_t gdrom_image_read_sector( gdrom_disc_t disc, uint32_t lba,

                                               int mode, unsigned char *buf, uint32_t *length )

 {

     gdrom_image_t image = (gdrom_image_t)disc;

     struct cdrom_sector_header secthead;

     int file_offset, read_len, track_no;

     FILE *f;

     track_no = gdrom_image_get_track_by_lba( image, lba );

     if( track_no == -1 ) {

         return PKT_ERR_BADREAD;

     }

     struct gdrom_track *track = &image->track[track_no-1];

     file_offset = track->offset + track->sector_size * (lba - track->lba);

     read_len = track->sector_size;

     if( track->file != NULL ) {

         f = track->file;

     } else {

         f = image->file;

     }

     /* First figure out what the real sector mode is for raw/semiraw sectors */

     int sector_mode;

     switch( track->mode ) {

     case GDROM_RAW_NONXA:

         gdrom_read_block( (unsigned char *)(&secthead), file_offset, sizeof(secthead), f );

         sector_mode = (secthead.mode == 1) ? GDROM_MODE1 : GDROM_MODE2_FORMLESS;

         break;

     case GDROM_RAW_XA:

         gdrom_read_block( (unsigned char *)(&secthead), file_offset, sizeof(secthead), f );

         if( secthead.mode == 1 ) {

             sector_mode = GDROM_MODE1;

         } else {

             sector_mode = ((secthead.subhead[2] & 0x20) == 0 ) ? GDROM_MODE2_FORM1 : GDROM_MODE2_FORM2;

         }

         break;

     case GDROM_SEMIRAW_MODE2:

         gdrom_read_block( secthead.subhead, file_offset, 8, f );

         sector_mode = ((secthead.subhead[2] & 0x20) == 0 ) ? GDROM_MODE2_FORM1 : GDROM_MODE2_FORM2;

         break;

     default:

         /* In the other cases, the track mode completely defines the sector mode */

         sector_mode = track->mode;

         break;

     }

     if( !gdrom_is_compatible_read_mode(sector_mode, READ_CD_MODE(mode)) ) {

         return PKT_ERR_BADREADMODE;

     }

     /* Ok, we've got a valid sector, check what parts of the sector we need to

      * return - header | subhead | data | everything

      */

     int channels = READ_CD_CHANNELS(mode);

     if( channels == 0 ) {

         // legal, if weird

         *length = 0;

         return PKT_ERR_OK;

     } else if( channels == 0xA0 && 

             (sector_mode == GDROM_MODE2_FORM1 || sector_mode == GDROM_MODE2_FORM2 )) {

         // caller requested a non-contiguous region

         return PKT_ERR_BADFIELD;

     } else if( READ_CD_RAW(channels) ) {

         channels = 0xF0; // implies everything

     }

     read_len = 0;

     int start, size;

     switch( track->mode ) {

     case GDROM_CDDA:

         // audio is nice and simple (assume perfect reads for now)

         *length = 2352;

         gdrom_read_block( buf, file_offset, track->sector_size, f );

         return PKT_ERR_OK;

     case GDROM_RAW_XA:

     case GDROM_RAW_NONXA:

         gdrom_get_read_bounds( sector_mode, channels, &start, &size );

         gdrom_read_block( buf, file_offset+start, size, f );

         read_len = size;

         break;

     case GDROM_SEMIRAW_MODE2:

         gdrom_get_read_bounds( sector_mode, channels, &start, &size );

         if( READ_CD_HEADER(channels) ) {

             gdrom_build_sector_header( buf, lba, sector_mode );

             read_len += SECTOR_HEADER_SIZE;

             size -= SECTOR_HEADER_SIZE;

         } else {

             start -= SECTOR_HEADER_SIZE;

         }

         gdrom_read_block( buf + read_len, file_offset+start, size, f );

         read_len += size;

         break;

     default: // Data track w/ data only in file

         if( READ_CD_RAW(channels) ) {

             gdrom_read_block( buf + gdrom_data_offset[track->mode], file_offset, 

                     track->sector_size, f );

             do_encode_L2( buf, sector_mode, lba );

             read_len = 2352;

         } else {

             if( READ_CD_HEADER(channels) ) {

                 gdrom_build_sector_header( buf, lba, sector_mode );

                 read_len += SECTOR_HEADER_SIZE;

             }

             if( READ_CD_SUBHEAD(channels) && 

                     (sector_mode == GDROM_MODE2_FORM1 || sector_mode == GDROM_MODE2_FORM2) ) {

                 if( sector_mode == GDROM_MODE2_FORM1 ) {

                     *((uint32_t *)(buf+read_len)) = 0;

                     *((uint32_t *)(buf+read_len+4)) = 0;

                 } else {

                     *((uint32_t *)(buf+read_len)) = 0x00200000;

                     *((uint32_t *)(buf+read_len+4)) = 0x00200000;

                 }

                 read_len += 8;

             }

             if( READ_CD_DATA(channels) ) {

                 gdrom_read_block( buf+read_len, file_offset, track->sector_size, f );

                 read_len += track->sector_size;

             }

         }

     }

     *length = read_len;

     return PKT_ERR_OK;

 }

 static gdrom_error_t gdrom_image_read_toc( gdrom_disc_t disc, unsigned char *buf ) 

 {

     gdrom_image_t image = (gdrom_image_t)disc;

     struct gdrom_toc *toc = (struct gdrom_toc *)buf;

     int i;

     for( i=0; i<image->track_count; i++ ) {

         toc->track[i] = htonl( image->track[i].lba ) | image->track[i].flags;

     }

     toc->first = 0x0100 | image->track[0].flags;

     toc->last = (image->track_count<<8) | image->track[i-1].flags;

     toc->leadout = htonl(image->track[i-1].lba + image->track[i-1].sector_count) |

     image->track[i-1].flags;

     for( ;i<99; i++ )

         toc->track[i] = 0xFFFFFFFF;

     return PKT_ERR_OK;

 }

 static gdrom_error_t gdrom_image_read_session( gdrom_disc_t disc, int session, unsigned char *buf )

 {

     gdrom_image_t image = (gdrom_image_t)disc;

     struct gdrom_track *last_track = &image->track[image->track_count-1];

     unsigned int end_of_disc = last_track->lba + last_track->sector_count;

     int i;

     buf[0] = 0x01; /* Disc status? */

     buf[1] = 0;

     if( session == 0 ) {

         buf[2] = last_track->session+1; /* last session */

         buf[3] = (end_of_disc >> 16) & 0xFF;

         buf[4] = (end_of_disc >> 8) & 0xFF;

         buf[5] = end_of_disc & 0xFF;

         return PKT_ERR_OK;

     } else {

         session--;

         for( i=0; i<image->track_count; i++ ) {

             if( image->track[i].session == session ) {

                 buf[2] = i+1; /* first track of session */

                 buf[3] = (image->track[i].lba >> 16) & 0xFF;

                 buf[4] = (image->track[i].lba >> 8) & 0xFF;

                 buf[5] = image->track[i].lba & 0xFF;

                 return PKT_ERR_OK;

             }

         }

         return PKT_ERR_BADFIELD; /* No such session */

     }

 }

 static gdrom_error_t gdrom_image_read_position( gdrom_disc_t disc, uint32_t lba, unsigned char *buf )

 {

     gdrom_image_t image = (gdrom_image_t)disc;

     int track_no = gdrom_image_get_track_by_lba( image, lba );

     if( track_no == -1 ) {

         track_no = 1;

         lba = 150;

     }

     struct gdrom_track *track = &image->track[track_no-1];

     uint32_t offset = lba - track->lba;

     buf[4] = track->flags;

     buf[5] = track_no;

     buf[6] = 0x01; /* ?? */

     buf[7] = (offset >> 16) & 0xFF;

     buf[8] = (offset >> 8) & 0xFF;

     buf[9] = offset & 0xFF;

     buf[10] = 0;

     buf[11] = (lba >> 16) & 0xFF;

     buf[12] = (lba >> 8) & 0xFF;

     buf[13] = lba & 0xFF;

     return PKT_ERR_OK;

 }

 static int gdrom_image_drive_status( gdrom_disc_t disc ) 

 {

     gdrom_image_t image = (gdrom_image_t)disc;

     if( image->disc_type == IDE_DISC_NONE ) {

         return IDE_DISC_NONE;

     } else {

         return image->disc_type | IDE_DISC_READY;

     }

 }

 gdrom_device_t gdrom_device_new( const gchar *name, const gchar *dev_name )

 {

     struct gdrom_device *dev = g_malloc0( sizeof(struct gdrom_device) );

     dev->name = g_strdup(name);

     dev->device_name = g_strdup(dev_name);

     return dev;

 }

 void gdrom_device_destroy( gdrom_device_t dev )

 {

     if( dev->name != NULL ) {

         g_free( dev->name );

         dev->name = NULL;

     }

     if( dev->device_name != NULL ) {

         g_free( dev->device_name );

         dev->device_name = NULL;

     }

     g_free( dev );

 }

 /**

  * Check the disc for a useable DC bootstrap, and update the disc

  * with the title accordingly.

  * @return TRUE if we found a bootstrap, otherwise FALSE.

  */

 gboolean gdrom_image_read_info( gdrom_disc_t d ) {

     gdrom_image_t disc = (gdrom_image_t)d;

     if( disc->track_count > 0 ) {

         /* Find the first data track of the last session */

         int last_session = disc->track[disc->track_count-1].session;

         int i, boot_track = -1;

         for( i=disc->track_count-1; i>=0 && disc->track[i].session == last_session; i-- ) {

             if( disc->track[i].flags & TRACK_DATA ) {

                 boot_track = i;

             }

         }

         if( boot_track != -1 ) {

             unsigned char boot_sector[MAX_SECTOR_SIZE];

             uint32_t length = sizeof(boot_sector);

             if( d->read_sector( d, disc->track[boot_track].lba, 0x28,

                     boot_sector, &length ) == PKT_ERR_OK ) {

                 if( memcmp( boot_sector, "SEGA SEGAKATANA SEGA ENTERPRISES", 32) == 0 ) {

                     /* Got magic */

                     memcpy( d->title, boot_sector+128, 128 );

                     for( i=127; i>=0; i-- ) {

                         if( !isspace(d->title[i]) ) 

                             break;

                     }

                     d->title[i+1] = '\0';

                 }

                 bootstrap_dump(boot_sector, FALSE);

                 return TRUE;

             }

         }

     }

     return FALSE;

 }