/*
 * Bobbi January-February 2020
 *
 * TODO: Use segment to make more memory available
 * TODO: Handle storage type $5 - files with resource fork
 * TODO: Check no disk blocks are used more than once
 * TODO: Recursive / whole volume mode - check all unused blocks are free
 * TODO: Fix mode
 * TODO: Tool for 'extending' volume dir to more than 4 blocks
 * TODO: Tool for lower/upper/camel casing filenames
 * TODO: Legacy/extended date format conversion
 * TODO: Trimming unused directory blocks
 * TODO: Improve output and user interface
 */

#pragma debug 25	/* Enable stack checking */
#pragma lint -1
#pragma stacksize 16384
#pragma memorymodel 0

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <orca.h>
#include <gsos.h>
#include <prodos.h>


#undef DEBUG            /* Enable additional debug printout */
#define CHECK		/* Perform additional integrity checking */

typedef unsigned char uchar;
typedef unsigned int uint;

#define NMLEN 15	/* Length of filename */
#define MAXFILES 1000	/* Max files per directory */

/*
 * ProDOS directory header
 * See ProDOS-8 Tech Ref pp. 152
 */
struct pd_dirhdr {
	uchar	typ_len;
	char	name[NMLEN];
	char	reserved[8];
	uchar	ctime[4];
	uchar	vers;
	uchar	minvers;
	uchar	access;
	uchar	entlen;
	uchar	entperblk;
	uchar	filecnt[2];
	uchar	parptr[2];	/* Bitmap pointer in volume dir */
	uchar	parentry;	/* Total blocks LSB in volume dir */
	uchar	parentlen;	/* Total blocks MSB in volume dir */
};

/*
 * ProDOS file entry
 * See ProDOS-8 Tech Ref pp. 155
 */
struct pd_dirent {
	uchar	typ_len;
	char	name[NMLEN];
	uchar 	type;
	uchar	keyptr[2];
	uchar	blksused[2];
	uchar	eof[3];
	uchar	ctime[4];
	uchar	vers;
	uchar	minvers;
	uchar	access;
	uchar	auxtype[2];
	uchar	mtime[4];
	uchar	hdrptr[2];
};

#define BLKSZ 512	/* 512 byte blocks */
#define PTRSZ 4		/* 4 bytes of pointers at beginning of each blk */

/*
 * Linked list of directory blocks read from disk
 * Original directory block is stored in data[]
 * Directory block for sorted directory is stored in sorteddata[]
 */
struct block {
	char data[BLKSZ];         /* Original contents of block */
	char sorteddata[BLKSZ];   /* Content block for sorted dir */
	uint blocknum;            /* Block number on disk */
	struct block *next;
};

/*
 * Entry for array of filenames used by qsort()
 */
struct fileent {
	char  name[NMLEN+1];/* Name converted to upper/lower case */
	uchar type;         /* ProDOS file type */
	uint  order;        /* Hack to make qsort() stable */
	uchar blockidx;     /* Index of dir block (1,2,3 ...)  */
	uchar entrynum;	    /* Entry within the block */
};

/* Globals */
static uchar freelist[8096];     /* 1 bit for each of 64K blocks */
static uchar flloaded = 0;
static struct block *blocks = NULL;
static struct fileent filelist[MAXFILES];
static uint numfiles = 0;
static uchar entsz;              /* Bytes per file entry */
static uchar entperblk;          /* Number of entries per block */
static char buf[BLKSZ];          /* General purpose scratch buffer */
static char buf2[BLKSZ];         /* General purpose scratch buffer */
static uchar dowrite = 0;
static uchar doverbose = 0;
static char sortopts[5] = "n";

static uint stack; // DEBUG

//#define STACK(msg) asm {tsc; sta stack }; fputs(msg, stdout); fputs(" ", stdout); pr_int(stack); putchar('\n');

/* Prototypes */
void prerr(char *s);
void reverse(char *s);
void itoa(int n, char s[]);
void uitoa(uint n, char s[]);
void pr_int(int a);
void pr_uint(uint a);
void print_uint(uint i);
int  readdiskblock(uchar device, uint blocknum, char *buf);
int  writediskblock(uchar device, uint blocknum, char *buf);
void fixcase(char *in, char *out, uchar minvers, uchar vers);
int  readfreelist(uchar device);
int  isfree(uint blk);
int  saplingblocks(uchar device, uint keyblk, uint *blkcnt);
int  treeblocks(uchar device, uint keyblk, uint *blkcnt);
int  readdir(uint device, uint blocknum);
int  cmp_name_asc(const void *a, const void *b);
int  cmp_name_desc(const void *a, const void *b);
int  cmp_type_asc(const void *a, const void *b);
int  cmp_type_desc(const void *a, const void *b);
int  cmp_dir_beg(const void *a, const void *b);
int  cmp_dir_end(const void *a, const void *b);
void sortlist(char s);
void printlist(void);
void copyent(uint srcblk, uint srcent, uint dstblk, uint dstent, uint device);
void sortblocks(uint device);
int  writedir(uchar device);
void freeblocks(void);
void usage(void);

/* Print error string to stderr */
void prerr(char *s) {
	fputs(s, stderr);
	fputs("\n", stderr);
}

/* Reverse the characters of the string s */
void reverse(char *s) {
	char buf[10];
	int l = strlen(s);
	for (int i=0; i<l; ++i)
		buf[i] = s[i];
	for (int i=0; i<l; ++i)
		s[i] = buf[l-i-1];
}

/* Stolen from K&R 2nd Ed. pp 64 */
void itoa(int n, char s[]) {
	int i, sign;

	if ((sign = n) < 0)
		n = -1;
	i = 0;
	do {
		s[i++] = n % 10 + '0';
	} while ((n /= 10) > 0);
	if (sign < 0)
		s[i++] = '-';
	s[i] = '\0';
	reverse(s);
}

/* Unsigned verson of itoa() */
void uitoa(uint n, char s[]) {
	int i;

	i = 0;
	do {
		s[i++] = n % 10 + '0';
	} while ((n /= 10) > 0);
	s[i] = '\0';
	reverse(s);
}

/* Print an integer */
void pr_int(int a) {
	char buf[10];
	itoa(a, buf);
	fputs(buf, stdout);
}

/* Print an unsigned integer */
void pr_uint(unsigned int a) {
	char buf[10];
	uitoa(a, buf);
	fputs(buf, stdout);
}

/*
 * Read block from disk using ProDOS call
 * buf must point to buffer with at least 512 bytes
 */
int readdiskblock(uchar device, uint blocknum, char *buf) {
#ifdef DEBUG
	fputs("Reading dev ", stdout);
	pr_int(device);
	fputs(" block ", stdout);
	pr_uint(blocknum);
	putchar('\n');
#endif
#ifdef CHECK
	if (flloaded)
		if (isfree(blocknum))
			printf("  1)Block %u is marked free!\n",
			        blocknum);
#endif
	BlockRec br;
	br.blockDevNum = device;
	br.blockDataBuffer = buf;
	br.blockNum = blocknum;
	READ_BLOCK(&br);
	int rc = toolerror();
	if (rc) {
		printf("  READ_BLOCK failed, err=%x\n", rc);
		return -1;
	}
	return 0;
}

/*
 * Write block from disk using ProDOS call
 * buf must point to buffer with at least 512 bytes
 */
int writediskblock(uchar device, uint blocknum, char *buf) {
#ifdef DEBUG
	fputs("Writing dev ", stdout);
	pr_int(device);
	fputs(" block ", stdout);
	pr_uint(blocknum);
	putchar('\n');
#endif
	DIORecGS dr;
	dr.pCount = 6;
	dr.devNum = device;
	dr.buffer = buf;
	dr.requestCount = BLKSZ;
	dr.startingBlock = blocknum;
	dr.blockSize = BLKSZ;
	DWriteGS(&dr);
	if (dr.transferCount != BLKSZ)
		return -1;
	return 0;
}

/*
 * Uses the vers and minvers fields of the directory entry
 * as a bitmap representing which characters are upper and which are
 * lowercase
 */
void fixcase(char *in, char *out, uchar minvers, uchar vers) {
	uchar idx = 0;
	if (!(vers&0x80)) {
		for (idx=0; idx<NMLEN; ++idx)
			out[idx] = in[idx];
		return;
	}
	vers <<= 1;
	for (int i=0; i<7; ++i) {
		out[idx++] = ((vers&0x80) ? tolower(in[idx]) : in[idx]);
		vers <<= 1;
	}
	for (int i=0; i<8; ++i) {
		out[idx++] = ((minvers&0x80) ? tolower(in[idx]) : in[idx]);
		minvers <<= 1;
	}
}

/*
 * Read the first block of a directory and deduce the device ID and block
 * number of the first block of the directory.
 */
uchar firstblk(char *dirname, uchar *device, uint *block) {
	int fp;
	uchar rv = 0;

	fp = open(dirname, O_RDONLY);
	if (!fp) {
		printf("Error opening dir %s\n", dirname);
		rv = 1;
		goto ret;
	}

	ssize_t len = read(fp, buf, BLKSZ);
	if (len != BLKSZ) {
		printf("Error reading first block of dir %s", dirname);
		rv = 1;
		goto ret;
	}

	struct stat st;
	if (stat(dirname, &st) == -1) {
		printf("Can't stat %s\n", dirname);
		exit(1);
	}

	if (!S_ISDIR(st.st_mode)) {
		printf("%s is not a directory\n", dirname);
		exit(1);
	}

	*device = st.st_dev;

	struct pd_dirhdr *hdr = (struct pd_dirhdr*)(buf + PTRSZ);

	/* Detect & handle volume directory */
	if ((hdr->typ_len & 0xf0) == 0xf0) {
		*block = 2;
		goto ret;
	}

#ifdef CHECK
	if ((hdr->typ_len & 0xf0) != 0xe0) {
		puts("Bad storage type");
		rv = 1;
		goto ret;
	}
#endif

	/* Handle subdirectory */
	uint parentblk    = hdr->parptr[0] + 256U * hdr->parptr[1];
	uint parententry  = hdr->parentry;
	uint parententlen = hdr->parentlen;

	/* Read parent directory block */
	if (readdiskblock(*device, parentblk, buf) == -1) {
		printf("Can't read parent directory for %s", dirname);
		rv = 1;
		goto ret;
	}

	struct pd_dirent *ent =
	  (struct pd_dirent *)(buf + PTRSZ + (parententry-1) * parententlen);

	*block = ent->keyptr[0] + 256U * ent->keyptr[1];

ret:
	if (fp)
		close(fp);
	return rv;
}

/*
 * Read the free list
 */
int readfreelist(uchar device) {
	bzero(freelist, 8096);
	if (readdiskblock(device, 2, buf) == -1) {
		puts("Error reading volume dir");
		return -1;
	}
	uint flblk = (uint)buf[0x27] + 256U * (uint)buf[0x28];
	uint totblks = (uint)buf[0x29] + 256U * (uint)buf[0x2a];
	printf("Volume has %u blocks\n", totblks);
	uint flsize = totblks / 4096U;
	if ((flsize % 4096) >0)
		++flsize;
	char *p = (char*)freelist;
	for (uint i=0; i<flsize; ++i) {
		if (readdiskblock(device, flblk++, p) == -1) {
			puts("Error reading free list");
			return -1;
		}
		p += BLKSZ;
	}
#if 0
	for (uint i=0; i<8096; ++i) {
		pr_uint(freelist[i]);
		putchar(' ');
	}
#endif
	flloaded = 1;
	return 0;
}

/*
 * Determine if block blk is free or not
 */
int isfree(uint blk) {
	uint idx = blk / 8;
	uint bit = blk % 8;
	//printf("freelist[%u]=%u\n",idx,freelist[idx]);
	return (freelist[idx] >> bit) & 0x01 ? 1 : 0;
}

/*
 * Count the blocks in a sapling file
 */
int saplingblocks(uchar device, uint keyblk, uint *blkcnt) {
	if (readdiskblock(device, keyblk, buf) == -1) {
		printf("  Error reading blk %u\n", keyblk);
		return -1;
	}
	*blkcnt = 1;
	for (uint i=0; i<256; ++i) {
		uint p = (uchar)buf[i] + 256U * (uchar)buf[i+256];
		if (p) {
			if (isfree(p))
				printf("  2)Block %u is marked free!\n", p);
			++(*blkcnt);
		}
	}
	return 0;
}

/*
 * Count the blocks in a tree file
 */
int treeblocks(uchar device, uint keyblk, uint *blkcnt) {
	if (readdiskblock(device, keyblk, buf2) == -1) {
		printf("  Error reading blk %u\n", keyblk);
		return -1;
	}
	*blkcnt = 1;
	for (uint i=0; i<256; ++i) {
		uint p = (uchar)buf2[i] + 256U * (uchar)buf2[i+256];
		if (p) {
			if (isfree(p))
				printf("  4)Block %u is marked free!\n", p);
			uint b;
			if (saplingblocks(device, p, &b) == 0)
				*blkcnt += b;
			else
				return -1;
		}
	}
	return 0;
}

/*
 * Read a directory, store the raw directory blocks in a linked list
 * and build filelist[] in preparation for sorting. 
 * device is the device number containing the directory
 * blocknum is the block number of the first block of the directory
 */
int readdir(uint device, uint blocknum) {
	uint blkcnt = 1;
	uint hdrblknum = blocknum;

	blocks = (struct block*)malloc(sizeof(struct block));
	if (!blocks) {
		puts("Unable to allocate memory");
		return 1;
	}
	struct block *curblk = blocks;
	curblk->next = NULL;
	curblk->blocknum = blocknum;

	if (readdiskblock(device, blocknum, curblk->data) == -1) {
		printf("Error reading dir block %d\n", blkcnt);
		return 1;
	}

	struct pd_dirhdr *hdr = (struct pd_dirhdr*)(curblk->data + PTRSZ);

	entsz           = hdr->entlen;
	entperblk       = hdr->entperblk;
	uint filecount  = hdr->filecnt[0] + 256U * hdr->filecnt[1];

	/* Copy pointers and header to sorteddata[], zero the rest */
	bzero(curblk->sorteddata, BLKSZ);
	memcpy(curblk->sorteddata, curblk->data, PTRSZ + entsz);


#ifdef DEBUG
	fputs("entsz=", stdout);
	pr_uint(entsz);
	putchar('\n');
	fputs("entperblk=", stdout);
	pr_uint(entperblk);
	putchar('\n');
	fputs("filecount=", stdout);
	pr_uint(filecount);
	putchar('\n');
#endif

#ifdef CHECK
	if (entsz != 0x27) {
		puts("Error - bad entry size");
		return 1;
	}
	if (entperblk != 0x0d) {
		puts("Error - bad entries/block");
		return 1;
	}
#endif
	uint idx = entsz + PTRSZ; /* Skip header */
	uchar blkentries = 2;
	uchar entries = 0;

	static char namebuf[NMLEN];

	while (1) {
		struct pd_dirent *ent = (struct pd_dirent*)(curblk->data + idx);
		if (ent->typ_len != 0) {
			fixcase(ent->name, namebuf, ent->vers, ent->minvers);
#ifdef CHECK
			printf("File: %s\n", namebuf);
#endif
			for (uchar i=0; i<NMLEN+1; ++i)
				filelist[numfiles].name[i] = '\0';
			for (uchar i=0; i<(ent->typ_len & 0x0f); ++i)
				filelist[numfiles].name[i] = namebuf[i];
			filelist[numfiles].type = ent->type;
			filelist[numfiles].blockidx = blkcnt;
			filelist[numfiles].entrynum = blkentries;
#ifdef CHECK
			uint keyblk = ent->keyptr[0] + 256U * ent->keyptr[1];
			uint hdrblk = ent->hdrptr[0] + 256U * ent->hdrptr[1];
			if (hdrblk != hdrblknum) {
				printf("  Header ptr %u should be %u\n",
				       hdrblk, hdrblknum);
			}
			if (isfree(keyblk))
				printf("  Keyblock %u is marked free!\n",
				       keyblk);
			uint blks = ent->blksused[0] + 256U * ent->blksused[1];
			uint count;
			switch (ent->typ_len & 0xf0) {
			case 0xd0:
				/* Subdirectory */
				if (readdiskblock(device, keyblk, buf) == -1) {
					printf("  Error reading keyblock %u\n",
					       keyblk);
					return 1;
				}
				hdr = (struct pd_dirhdr*)(buf + PTRSZ);
				uchar parentry = hdr->parentry;
				uchar parentlen = hdr->parentlen;
				uint parblk =
				  hdr->parptr[0] + 256U * hdr->parptr[1];

				if (parblk != blocknum) {
					printf("  Bad parent block %u", parblk);
					printf(", should be %u\n", blocknum);
				}
				if (parentry != blkentries) {
					printf("  Bad parent block entry %u",
					       parentry);
					printf(", should be %u\n", blkentries);
				}
				if (parentlen != 0x27)
					puts("  Bad parent entry length");
				char *dirname = buf + 0x05;
				if (strncmp(dirname, ent->name, NMLEN))
					puts("  Subdirectory name mismatch");

				//
				// TODO: COUNT DIRECTORY BLOCKS
				//
				count = 0;
				break;
			case 0x10:
				/* Seedling */
				count = 1;
				break;
			case 0x20:
				/* Sapling */
				saplingblocks(device, keyblk, &count);
				break;
			case 0x30:
				/* Tree */
				treeblocks(device, keyblk, &count);
				break;
			case 0x40:
				/* Pascal area */
				puts(" Pascal area!!");
				count = 0;
				break;
			default:
				printf(  "%s: unexpected storage type 0x%x\n",
				       namebuf, ent->typ_len & 0xf0);
				count = 0;
			}
			if (blks != count) {
				if (count != 0) {
					printf("  Size %u is incorrect", blks);
					printf(", should be %u\n", blkcnt);
				}
			}
#endif
			++numfiles;
			if (numfiles == MAXFILES) {
				puts("Too many files!");
				return 1;
			}
			++entries;
		}
		if (blkentries == entperblk) {
			blocknum =
			  curblk->data[0x02] + 256U*curblk->data[0x03];
			if (blocknum == 0) {
				break;
			}
			curblk->next =
			  (struct block*)malloc(sizeof(struct block));
			if (!curblk->next) {
				puts("Unable to allocate memory");
				return 1;
			}
			curblk = curblk->next;
			curblk->next = NULL;
			curblk->blocknum = blocknum;
			++blkcnt;
			if (
			  readdiskblock(device, blocknum, curblk->data) == -1) {
				printf("Error reading dir block %d\n", blkcnt);
				return 1;
			}
			/* Copy ptrs to sorteddata[], zero the rest */
			bzero(curblk->sorteddata, BLKSZ);
			memcpy(curblk->sorteddata, curblk->data, PTRSZ);
			blkentries = 1;
			idx = PTRSZ;
		} else {
			++blkentries;
			idx += entsz;
		}
	}
	if (filecount != entries)
		printf("Filecount %u wrong, should be %u\n", filecount, entries);
	return 0;
}

/*
 * Compare - filename sort in ascending order
 */
int cmp_name_asc(const void *a, const void *b) {
	return strncmp(((struct fileent*)a)->name,
	             ((struct fileent*)b)->name, NMLEN);
}

/*
 * Compare - filename sort in descending order
 */
int cmp_name_desc(const void *a, const void *b) {
	return strncmp(((struct fileent*)b)->name,
	               ((struct fileent*)a)->name, NMLEN);
}

/*
 * Compare - type sort in ascending order
 * Uses the order field to make qsort() stable
 */
int cmp_type_asc(const void *a, const void *b) {
	struct fileent *aa = (struct fileent*)a;
	struct fileent *bb = (struct fileent*)b;
	int rc = aa->type - bb->type;
	return rc != 0 ? rc : aa->order - bb->order;
}
/*
 * Compare - type sort in descending order
 * Uses the order field to make qsort() stable
 */
int cmp_type_desc(const void *a, const void *b) {
	struct fileent *aa = (struct fileent*)a;
	struct fileent *bb = (struct fileent*)b;
	int rc = bb->type - aa->type;
	return rc != 0 ? rc : aa->order - bb->order;
}

/*
 * Compare - sort with directories at the beginning
 * Uses the order field to make qsort() stable
 */
int cmp_dir_beg(const void *a, const void *b) {
	struct fileent *aa = (struct fileent*)a;
	struct fileent *bb = (struct fileent*)b;
	if ((aa->type == 0x0f) && (bb->type != 0x0f))
		return -1;
	if ((bb->type == 0x0f) && (aa->type != 0x0f))
		return 1;
	return aa->order - bb->order;
}

/*
 * Compare - sort with directories at the end
 * Uses the order field to make qsort() stable
 */
int cmp_dir_end(const void *a, const void *b) {
	struct fileent *aa = (struct fileent*)a;
	struct fileent *bb = (struct fileent*)b;
	if ((aa->type == 0x0f) && (bb->type != 0x0f))
		return 1;
	if ((bb->type == 0x0f) && (aa->type != 0x0f))
		return -1;
	return aa->order - bb->order;
}

/*
 * Sort filelist[]
 * s defines the field to sort on
 */
void sortlist(char s) {
	for(uint i=0; i<numfiles; ++i) {
		filelist[i].order = i;
	}
	switch (s) {
	case 'n':
		qsort(filelist, numfiles, sizeof(struct fileent),
		      cmp_name_asc);
		break;
	case 'N':
		qsort(filelist, numfiles, sizeof(struct fileent),
		      cmp_name_desc);
		break;
	case 't':
		qsort(filelist, numfiles, sizeof(struct fileent),
		      cmp_type_asc);
		break;
	case 'T':
		qsort(filelist, numfiles, sizeof(struct fileent),
		      cmp_type_desc);
		break;
	case 'd':
		qsort(filelist, numfiles, sizeof(struct fileent),
		      cmp_dir_beg);
		break;
	case 'D':
		qsort(filelist, numfiles, sizeof(struct fileent),
		      cmp_dir_end);
		break;
	default:
		puts("Invalid sort option");
		exit(2);
	}
}

/*
 * Print the file info stored in filelist[]
 */
void printlist(void) {
	puts("----------------------------------------------------");
	printf("numfiles=%u\n", numfiles);
	puts("Dirblk Entry Type : Name");
	for(uint i=0; i<numfiles; ++i)
		printf("   %03u    %02u   %02x : %s\n",
		       filelist[i].blockidx,
		       filelist[i].entrynum,
		       filelist[i].type,
		       filelist[i].name);
	puts("----------------------------------------------------");
}

/*
 * Copy a file entry from one srcblk, srcent to dstblk, dstent
 * All indices are 1-based.
 */
void copyent(uint srcblk, uint srcent, uint dstblk, uint dstent, uint device) {

	if (doverbose) {
		fputs("  from blk ", stdout);
		pr_uint(srcblk);
		fputs(" entry ", stdout);
		pr_uint(srcent);
		putchar('\n');
		fputs("  to blk ", stdout);
		pr_uint(dstblk);
		fputs(" entry ", stdout);
		pr_uint(dstent);
		putchar('\n');
	}

	struct block *source = blocks;
	struct block *dest   = blocks;
	while (--srcblk > 0)
		source = source->next;
	while (--dstblk > 0)
		dest = dest->next;
	char *srcptr =  source->data + PTRSZ + (srcent-1) * entsz;
	char *dstptr =  dest->sorteddata + PTRSZ + (dstent-1) * entsz;
	memcpy(dstptr, srcptr, entsz);

	/* For directories, update the parent dir entry number */
	struct pd_dirent *ent = (struct pd_dirent*)dstptr;
	if ((ent->typ_len & 0xf0) == 0xd0) {
		uint block = ent->keyptr[0] + 256U * ent->keyptr[1];
		if (readdiskblock(device, block, buf) == -1) {
			puts("Can't read subdirectory");
			exit(1);
		}
		struct pd_dirhdr *hdr = (struct pd_dirhdr*)(buf + PTRSZ);
		hdr->parentry = dstent;
		if (dowrite) {
			if (writediskblock(device, block, buf) == -1) {
				puts("Can't write subdirectory");
				exit(1);
			}
		} else {
			if (doverbose)
				puts("Not writing updated subdir to disk");
		}
	}
}

/*
 * Use the sorted list in filelist[] to create a sorted set of directory
 * blocks.  Note that the block and entry numbers are 1-based indices.
 */
void sortblocks(uint device) {
	uchar destblk = 1;
	uchar destentry = 2; /* Skip header on first block */
	for(uint i=0; i<numfiles; ++i) {
		puts(filelist[i].name);
		copyent(filelist[i].blockidx, filelist[i].entrynum,
		        destblk, destentry, device);
		if (destentry++ == entperblk) {
			++destblk;
			destentry = 1;
		}
	}
}

/*
 * Write out the sorted directory
 */
int writedir(uchar device) {
	struct block *i = blocks;
	while (i) {
		if(writediskblock(device, i->blocknum, i->sorteddata) == -1) {
			printf("Can't write block %u\n", i->blocknum);
			return 1;
		}
		i = i->next;
	}
	return 0;
}

/*
 * Walk through the linked list freeing memory
 */
void freeblocks(void) {
	struct block *i = blocks, *j;
	while (i) {
		j = i->next;
		free(i);
		i = j;
	}
}

void usage(void) {
	prerr("usage: sortdir [-s xxx] [-rwv] path\n");
	prerr("  Options: -s xxx  Directory sort options");
	prerr("           -w      Enable writing to disk");
	prerr("           -v      Verbose output");
	prerr("           -h      This help");
	prerr("");
	prerr("Directory sort options xxx, is a list of fields on which to");
	prerr("sort. The sort options are processed left-to-right.");
	prerr("  n  sort by filename ascending");
	prerr("  N  sort by filename descending");
	prerr("  t  sort by type ascending");
	prerr("  T  sort by type descending");
	prerr("  d  sort directories to top");
	prerr("  D  sort directories to bottom");
	prerr("");
	prerr("e.g.: sortdir -w -s nd .");
	prerr("Will sort the current directory first by name (ascending),");
	prerr("then sort directories to the top, and will write the sorted");
	prerr("directory to disk.");
	exit(2);
}

int main(int argc, char *argv[]) {
	if (argc < 2) {
		usage();
		exit(1);
	}
	int opt;
	while ((opt = getopt(argc, argv, "hwvs:")) != -1) {
		switch (opt) {
		case 's':
			strncpy(sortopts, optarg, 5);
			break;
		case 'w':
			dowrite = 1;
			break;
		case 'v':
			doverbose = 1;
			break;
		case 'h':
		default:
			usage();
		}
	}

	if (optind >= argc)
		usage();
	
	uchar dev;
	uint blk;
	if (firstblk(argv[optind], &dev, &blk) != 0) {
		exit(1);
	}
	readfreelist(dev);
	uchar err = readdir(dev, blk);
	if (!err) {
		if (doverbose)
			printlist();
		for (uchar i=0; i<strlen(sortopts); ++i)
			sortlist(sortopts[i]);
		sortblocks(dev);
		if (doverbose)
			printlist();
		if (dowrite)
			err = writedir(dev);
		else
			if (doverbose)
				puts("Not writing to disk");
	}
	freeblocks();
	return err;
}