/**

  * $Id$

  *

  * 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 <sys/stat.h>

 #include <fcntl.h>

 #include <netinet/in.h>

 #include "gdrom/gddriver.h"

 #include "gdrom/packet.h"

 #include "ecc.h"

 static gboolean gdrom_null_check_status( 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 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 };

 gdrom_image_class_t gdrom_image_classes[] = { &cdrom_device_class, 

         &nrg_image_class, 

         &cdi_image_class, 

         &gdi_image_class, 

         NULL };

 struct cdrom_sector_header {

     uint8_t sync[12];

     uint8_t msf[3];

     uint8_t mode;

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

 };

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

 {

     gdrom_disc_t disc = (gdrom_disc_t)g_malloc0(sizeof(struct gdrom_disc));

     if( disc == NULL ) {

         return NULL;

     }

     disc->disc_type = IDE_DISC_NONE;

     disc->file = f;

     if( filename == NULL ) {

         disc->name = NULL;

     } else {

         disc->name = g_strdup(filename);

     }

 	disc->check_status = gdrom_null_check_status;

 	disc->destroy = gdrom_disc_destroy;

     return disc;

 }

 void gdrom_disc_destroy( gdrom_disc_t disc, gboolean close_fh )

 {

     int i;

     FILE *lastfile = NULL;

     if( disc->file != NULL ) {

     	if( close_fh ) {

         	fclose(disc->file);

     	}

         disc->file = NULL;

     }

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

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

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

             /* Track files (if any) are closed regardless of the value of close_fh */

             fclose(lastfile);

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

         }

     }

     if( disc->name != NULL ) {

         g_free( (gpointer)disc->name );

         disc->name = NULL;

     }

     if( disc->display_name != NULL ) {

     	g_free( (gpointer)disc->name );

     	disc->display_name = NULL;

     }

     free( disc );

 }

 /**

  * Construct a new gdrom_disc_t and initalize the vtable to the gdrom image

  * default functions.

  */

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

 {

 	gdrom_disc_t disc = gdrom_disc_new( filename, f );

 	if( disc != NULL ) {

 	    disc->read_sector = gdrom_image_read_sector;

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

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

 	}

 	return disc;

 }

 gdrom_disc_t gdrom_image_open( const gchar *inFilename )

 {

     const gchar *filename = inFilename;

     const gchar *ext = strrchr(filename, '.');

     gdrom_disc_t disc = NULL;

     int fd;

     FILE *f;

     int i;

     gdrom_image_class_t extclz = NULL;

     // Check for a url-style filename.

     char *lizard_lips = strstr( filename, "://" );

     if( lizard_lips != NULL ) {

         gchar *path = lizard_lips + 3;

         int method_len = (lizard_lips-filename);

         gchar method[method_len + 1];

         memcpy( method, filename, method_len );

         method[method_len] = '\0';

         if( strcasecmp( method, "file" ) == 0 ) {

             filename = path;

         } else if( strcasecmp( method, "dvd" ) == 0 ||

                 strcasecmp( method, "cd" ) == 0 ||

                 strcasecmp( method, "cdrom" ) ) {

             return cdrom_open_device( method, path );

         } else {

             ERROR( "Unrecognized URL method '%s' in filename '%s'", method, filename );

             return NULL;

         }

     }

     fd = open( filename, O_RDONLY | O_NONBLOCK );

     if( fd == -1 ) {

         return NULL;

     }

     f = fdopen(fd, "ro");

     /* try extensions */

     if( ext != NULL ) {

         ext++; /* Skip the '.' */

         for( i=0; gdrom_image_classes[i] != NULL; i++ ) {

             if( gdrom_image_classes[i]->extension != NULL &&

                     strcasecmp( gdrom_image_classes[i]->extension, ext ) == 0 ) {

                 extclz = gdrom_image_classes[i];

                 if( extclz->is_valid_file(f) ) {

                     disc = extclz->open_image_file(filename, f);

                     if( disc != NULL )

                         return disc;

                 }

                 break;

             }

         }

     }

     /* Okay, fall back to magic */

     gboolean recognized = FALSE;

     for( i=0; gdrom_image_classes[i] != NULL; i++ ) {

         if( gdrom_image_classes[i] != extclz &&

                 gdrom_image_classes[i]->is_valid_file(f) ) {

             recognized = TRUE;

             disc = gdrom_image_classes[i]->open_image_file(filename, f);

             if( disc != NULL )

                 return disc;

         }

     }

     fclose(f);

     return NULL;

 }

 /**

  * 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;

     }

 }

 void gdrom_set_disc_type( gdrom_disc_t disc ) 

 {

     int type = IDE_DISC_NONE, i;

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

         if( disc->track[i].mode == GDROM_CDDA ) {

             if( type == IDE_DISC_NONE )

                 type = IDE_DISC_AUDIO;

         } else if( disc->track[i].mode == GDROM_MODE1 || disc->track[i].mode == GDROM_RAW_NONXA ) {

             if( type != IDE_DISC_CDROMXA )

                 type = IDE_DISC_CDROM;

         } else {

             type = IDE_DISC_CDROMXA;

             break;

         }

     }

     disc->disc_type = type;

 }

 /**

  * 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;

 }

 /**

  * Default check media status that does nothing and always returns

  * false (unchanged).

  */

 static gboolean gdrom_null_check_status( gdrom_disc_t disc )

 {

 	return FALSE;

 }

 /**

  * 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 )

 {

     struct cdrom_sector_header secthead;

     int file_offset, read_len, track_no;

     FILE *f;

     track_no = gdrom_disc_get_track_by_lba( disc, lba );

     if( track_no == -1 ) {

         return PKT_ERR_BADREAD;

     }

     struct gdrom_track *track = &disc->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 = disc->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;

 }