Add support for listing and extracting BAS2BOOT images.

This is a single-file image that boots an Atari BASIC program.

Makefile

@@ -34,6 +34,7 @@ SOURCES_lsatr=\
  lsatr.c\
  lssfs.c\
  lsdos.c\
+ lsextra.c\
  msg.c\
 
 CFLAGS=-O2 -Wall

src/lsatr.c

@@ -20,6 +20,7 @@
 #include "atr.h"
 #include "compat.h"
 #include "lsdos.h"
+#include "lsextra.h"
 #include "lssfs.h"
 #include "msg.h"
 #include <errno.h>
@@ -113,11 +114,11 @@ int main(int argc, char **argv)
 
     int e = sfs_read(atr, atr_name, atari_list, lower_case, extract_files);
     if( e )
-    {
         e = dos_read(atr, atr_name, atari_list, lower_case, extract_files);
-        if( e )
-            show_msg("%s: ATR image format not supported.", atr_name);
-    }
+    if( e )
+        e = extra_read(atr, atr_name, atari_list, lower_case, extract_files);
+    if( e )
+        show_msg("%s: ATR image format not supported.", atr_name);
     atr_free(atr);
 
     return e;

src/lsextra.c

@@ -0,0 +1,186 @@
+/*
+ *  Copyright (C) 2023 Daniel Serpell
+ *
+ *  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, see <http://www.gnu.org/licenses/>
+ */
+/*
+ * Extracts various simple boot formats.
+ */
+#include "lsextra.h"
+#include "msg.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+static unsigned get_name(char *name, char *aname, const uint8_t *data, int max,
+                         int lower_case)
+{
+    unsigned l = 0;
+    unsigned a = 0;
+    int dot    = 0;
+    memset(aname, ' ', max + 1);
+    aname[max + 1] = 0;
+    for( int i = 0; i < max; i++ )
+    {
+        uint8_t c = data[i];
+        if( c >= 'A' && c <= 'Z' && lower_case )
+            c = c - 'A' + 'a';
+        if( c == '.' )
+        {
+            // Store dot
+            dot       = 1;
+            name[l++] = c;
+            while( a < 8 )
+                aname[a++] = ' ';
+            continue;
+        }
+        if( c < ' ' || c == '/' || c == '.' || c == '?' || c == '\\' || c == 96 ||
+            c > 'z' )
+            c = '_';
+        else if( c == ' ' )
+            continue;
+        if( i > 7 && !dot )
+        {
+            dot        = 1;
+            name[l++]  = '.';
+            aname[a++] = ' ';
+        }
+        name[l++]  = c;
+        aname[a++] = c;
+    }
+    name[l] = 0;
+    return l;
+}
+
+static uint16_t read16(const uint8_t *p)
+{
+    return (p == NULL) ? 0 : (p[0] | (p[1] << 8));
+}
+
+static int check_bas2boot(struct atr_image *atr)
+{
+    // BAS2BOOT only supports 128 bytes per sector, and we must have
+    // at least one data sector
+    if( atr->sec_size != 128 || atr->sec_count < 2 )
+        return 0;
+
+    const uint8_t *sec1 = atr_data(atr, 1);
+    const uint8_t *sec2 = atr_data(atr, 2);
+
+    // Check boot count == 2 and load address == $700
+    if( read16(sec1) != 0x200 || read16(sec1 + 2) != 0x700 )
+        return 0;
+
+    // Check ID
+    if( memcmp(sec2 + 0x3C, "BAS2BOOT", 8) )
+        return 0;
+
+    // Ok, we have a BAS2BOOT file
+    return 1;
+}
+
+static void extract_bas2boot(struct atr_image *atr, int atari_list, int lower_case,
+                             int extract_files)
+{
+    // Get headers
+    const uint8_t *sec1 = atr_data(atr, 1);
+    const uint8_t *sec2 = atr_data(atr, 2);
+    // Get filename
+    char path[32], aname[32];
+    if( !get_name(path, aname, sec2 + 0x60, 12, lower_case) || !*path )
+    {
+        strcpy(path, "noname.bas");
+        strcpy(aname, "NONAME  BAS");
+    }
+    // Adds '.BAS' if no extension is present
+    if( !strchr(path, '.') )
+    {
+        const char *ext = lower_case ? ".bas" : ".BAS";
+        strcat(path, ext);
+        memcpy(aname + 9, ext + 1, 3);
+    }
+
+    // Get data and length
+    unsigned fsize = read16(sec1 + 8);
+    uint8_t *fdata = check_malloc(fsize < 16 ? 16 : fsize);
+
+    // Read header and undo bad conversion for certain files
+    memcpy(fdata, sec2 + 0x72, 14);
+    for( int i = 2; i < 14; i += 2 )
+    {
+        int x        = fdata[0] + fdata[1] * 256;
+        int y        = fdata[i] + fdata[i + 1] * 256 + x;
+        fdata[i]     = y & 0xFF;
+        fdata[i + 1] = y >> 8;
+    }
+    // Read rest of file
+    unsigned secnum = 3;
+    for( unsigned pos = 14; pos < fsize; pos += 128, secnum++ )
+    {
+        unsigned len     = fsize - pos < 128 ? fsize - pos : 128;
+        const uint8_t *s = atr_data(atr, secnum);
+        if( !s )
+            memset(fdata + pos, 0, len);
+        else
+            memcpy(fdata + pos, s, len);
+    }
+
+    if( extract_files )
+    {
+        struct stat st;
+        fprintf(stderr, "%s\n", path);
+        // Check if file already exists:
+        if( 0 == stat(path, &st) )
+            show_error("%s: file already exists.", path);
+        // Create new file
+        int fd = creat(path, 0666);
+        if( fd == -1 )
+            show_error("%s: can´t create file, %s", path, strerror(errno));
+        if( fsize != write(fd, fdata, fsize) )
+            show_error("%s: can´t write file, %s", path, strerror(errno));
+        if( close(fd) )
+            show_error("%s: can´t write file, %s", path, strerror(errno));
+    }
+    else if( atari_list )
+        printf("%-12s %7u\n", aname, fsize);
+    else
+        printf("%8u\t\t%s\n", fsize, path);
+
+    free(fdata);
+}
+
+int extra_read(struct atr_image *atr, const char *atr_name, int atari_list,
+               int lower_case, int extract_files)
+{
+    // Check BAS2BOOT
+    if( check_bas2boot(atr) )
+    {
+        if( atari_list )
+            printf("ATR image: %s\n"
+                   "Image size: %u sectors of %u bytes\n"
+                   "Volume: BAS2BOOT\n",
+                   atr_name, atr->sec_count, atr->sec_size);
+        else
+            printf("%s: %u sectors of %u bytes, BAS2BOOT.\n", atr_name, atr->sec_count,
+                   atr->sec_size);
+        extract_bas2boot(atr, atari_list, lower_case, extract_files);
+        return 0;
+    }
+
+    return 1;
+}

src/lsextra.h

@@ -0,0 +1,24 @@
+/*
+ *  Copyright (C) 2024 Daniel Serpell
+ *
+ *  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, see <http://www.gnu.org/licenses/>
+ */
+/*
+ * Extracts various simple boot formats.
+ */
+#pragma once
+#include "atr.h"
+
+int extra_read(struct atr_image *atr, const char *atr_name, int atari_list,
+               int lower_case, int extract_files);