/*
 * support.c -  Specific support functions
 *
 * Copyright (C) 1997 Martin von Löwis
 * Copyright (C) 1997 Régis Duchesne
 * Copyright (C) 2001 Anton Altaparmakov (AIA)
 */

#include "ntfstypes.h"
#include "struct.h"
#include "support.h"

#include <stdarg.h>
#include <linux/slab.h>
#include <linux/locks.h>
#include <linux/fs.h>
#include "util.h"
#include "inode.h"
#include "macros.h"

#ifndef NLS_MAX_CHARSET_SIZE
#include <linux/nls.h>
#endif

static char print_buf[1024];

#ifdef DEBUG
#include "sysctl.h"
#include <linux/kernel.h>

/* Debugging output */
void ntfs_debug(int mask, const char *fmt, ...)
{
	va_list ap;

	/* Filter it with the debugging level required */
	if (ntdebug & mask) {
		va_start(ap,fmt);
		strcpy(print_buf, KERN_DEBUG);
		vsprintf(print_buf + 3, fmt, ap);
		printk(print_buf);
		va_end(ap);
	}
}

#ifndef ntfs_malloc
/* Verbose kmalloc */
void *ntfs_malloc(int size)
{
	void *ret;

	ret = kmalloc(size, GFP_KERNEL);
	ntfs_debug(DEBUG_MALLOC, "Allocating %x at %p\n", size, ret);

	return ret;
}
#endif

#ifndef ntfs_free
/* Verbose kfree() */
void ntfs_free(void *block)
{
        ntfs_debug(DEBUG_MALLOC, "Freeing memory at %p\n", block);
	kfree(block);
}
#endif
#else /* End of DEBUG functions. Normal ones below... */
void ntfs_debug(int mask, const char *fmt, ...)
{
}

#ifndef ntfs_malloc
void *ntfs_malloc(int size)
{
	return kmalloc(size, GFP_KERNEL);
}
#endif

#ifndef ntfs_free
void ntfs_free(void *block)
{
	kfree(block);
}
#endif
#endif /* DEBUG */

void ntfs_bzero(void *s, int n)
{
	memset(s, 0, n);
}

/* These functions deliberately return no value. It is dest, anyway,
   and not used anywhere in the NTFS code.  */

void ntfs_memcpy(void *dest, const void *src, ntfs_size_t n)
{
	memcpy(dest, src, n);
}

void ntfs_memmove(void *dest, const void *src, ntfs_size_t n)
{
	memmove(dest, src, n);
}

/* Warn that an error occurred. */
void ntfs_error(const char *fmt,...)
{
        va_list ap;

        va_start(ap, fmt);
        strcpy(print_buf, KERN_ERR);
        vsprintf(print_buf + 3, fmt, ap);
        printk(print_buf);
        va_end(ap);
}

int ntfs_read_mft_record(ntfs_volume *vol, int mftno, char *buf)
{
	int error;
	ntfs_io io;

	ntfs_debug(DEBUG_OTHER, "read_mft_record 0x%x\n", mftno);
	if (mftno == FILE_$Mft)
	{
		ntfs_memcpy(buf, vol->mft, vol->mft_record_size);
		return 0;
	}
	if (!vol->mft_ino)
	{
		printk(KERN_ERR "NTFS: mft_ino is NULL. Something is terribly "
				"wrong here!\n");
		return -ENODATA;
	}
 	io.fn_put = ntfs_put;
	io.fn_get = 0;
	io.param = buf;
	io.size = vol->mft_record_size;
	ntfs_debug(DEBUG_OTHER, "read_mft_record: calling ntfs_read_attr with: "
		"mftno = 0x%x, vol->mft_record_size_bits = 0x%x, "
		"mftno << vol->mft_record_size_bits = 0x%Lx\n", mftno,
		vol->mft_record_size_bits,
		(__s64)mftno << vol->mft_record_size_bits);
	error = ntfs_read_attr(vol->mft_ino, vol->at_data, NULL,
				(__s64)mftno << vol->mft_record_size_bits, &io);
	if (error || (io.size != vol->mft_record_size)) {
		ntfs_debug(DEBUG_OTHER, "read_mft_record: read 0x%x failed "
				   	"(%d,%d,%d)\n", mftno, error, io.size,
				   	vol->mft_record_size);
		return error ? error : -ENODATA;
	}
	ntfs_debug(DEBUG_OTHER, "read_mft_record: finished read 0x%x\n", mftno);
	if (!ntfs_check_mft_record(vol, buf)) {
		/* FIXME: This is incomplete behaviour. We might be able to
		 * recover at this stage. ntfs_check_mft_record() is too
		 * conservative at aborting it's operations. It is OK for
		 * now as we just can't handle some on disk structures
		 * this way. (AIA) */
		printk(KERN_WARNING "NTFS: Invalid MFT record for 0x%x\n", mftno);
		return -EINVAL;
	}
	ntfs_debug(DEBUG_OTHER, "read_mft_record: Done 0x%x\n", mftno);
	return 0;
}

int ntfs_getput_clusters(ntfs_volume *vol, int cluster,	ntfs_size_t start_offs,
			 ntfs_io *buf)
{
	struct super_block *sb = NTFS_SB(vol);
	struct buffer_head *bh;
	int length = buf->size;
	int error = 0;
	ntfs_size_t to_copy;

	ntfs_debug(DEBUG_OTHER, "%s_clusters %d %d %d\n", 
		   buf->do_read ? "get" : "put", cluster, start_offs, length);
	while (length) {
		if (!(bh = bread(sb->s_dev, cluster, vol->cluster_size))) {
			ntfs_debug(DEBUG_OTHER, "%s failed\n",
				   buf->do_read ? "Reading" : "Writing");
			error = -EIO;
			goto error_ret;
		}
		to_copy = min(vol->cluster_size - start_offs, length);
		lock_buffer(bh);
		if (buf->do_read) {
			buf->fn_put(buf, bh->b_data + start_offs, to_copy);
			unlock_buffer(bh);
		} else {
			buf->fn_get(bh->b_data + start_offs, buf, to_copy);
			mark_buffer_dirty(bh);
			unlock_buffer(bh);
			/*
			 * Note: We treat synchronous IO on a per volume basis
			 * disregarding flags of individual inodes. This can
			 * lead to some strange write ordering effects upon a
			 * remount with a change in the sync flag but it should
			 * not break anything. [Except if the system crashes
			 * at that point in time but there would be more thigs
			 * to worry about than that in that case...]. (AIA)
			 */
			if (sb->s_flags & MS_SYNCHRONOUS) {
				ll_rw_block(WRITE, 1, &bh);
				wait_on_buffer(bh);
				if (buffer_req(bh) && !buffer_uptodate(bh)) {
					printk(KERN_ERR "IO error syncing NTFS "
					       "cluster [%s:%i]\n",
					       bdevname(sb->s_dev), cluster);
					brelse(bh);
					error = -EIO;
					goto error_ret;
				}
			}
		}
		length -= to_copy;
		start_offs = 0;
		cluster++;
		brelse(bh);
	}
error_ret:
	return error;
}

ntfs_time64_t ntfs_now(void)
{
	return ntfs_unixutc2ntutc(CURRENT_TIME);
}

/* When printing unicode characters base64, use this table. It is not strictly
 * base64, but the Linux vfat encoding. base64 has the disadvantage of using
 * the slash. */
static char uni2esc[64] = 
	    "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz+-";

static unsigned char esc2uni(char c)
{
	if (c <  '0') return 255;
	if (c <= '9') return c - '0';
	if (c <  'A') return 255;
	if (c <= 'Z') return c - 'A' + 10;
	if (c <  'a') return 255;
	if (c <= 'z') return c - 'a' + 36;
	if (c == '+') return 62;
	if (c == '-') return 63;
	return 255;
}

int ntfs_dupuni2map(ntfs_volume *vol, ntfs_u16 *in, int in_len, char **out,
		    int *out_len)
{
	int i, o, val, chl, chi;
	char *result, *buf, charbuf[NLS_MAX_CHARSET_SIZE];
	struct nls_table* nls = vol->nls_map;

	result = ntfs_malloc(in_len + 1);
	if (!result)
		return -ENOMEM;
	*out_len = in_len;
	result[in_len] = '\0';
	for (i = o = 0; i < in_len; i++) {
		int cl, ch;
		/* FIXME: byte order? */
		cl = in[i] & 0xFF;
		ch = (in[i] >> 8) & 0xFF;
		if (!nls) {
			if (!ch) {
				result[o++] = cl;
				continue;
			}
		} else {
			/* FIXME: byte order? */
			wchar_t uni = in[i];
			if ((chl = nls->uni2char(uni, charbuf,
						NLS_MAX_CHARSET_SIZE)) > 0) {
				/* adjust result buffer */
				if (chl > 1) {
					buf = ntfs_malloc(*out_len + chl - 1);
					if (!buf) {
						ntfs_free(result);
						return -ENOMEM;
					}
					memcpy(buf, result, o);
					ntfs_free(result);
					result = buf;
					*out_len += (chl - 1);
				}
				for (chi = 0; chi < chl; chi++)
					result[o++] = charbuf[chi];
			} else
				result[o++] = '?';
			continue;
		}
		if (!(vol->nct & nct_uni_xlate))
			goto inval;
		/* realloc */
		buf = ntfs_malloc(*out_len + 3);
		if (!buf) {
			ntfs_free(result);
			return -ENOMEM;
		}
		memcpy(buf, result, o);
		ntfs_free(result);
		result = buf;
		*out_len += 3;
		result[o++] = ':';
		if (vol->nct & nct_uni_xlate_vfat) {
			val = (cl << 8) + ch;
			result[o+2] = uni2esc[val & 0x3f];
			val >>= 6;
			result[o+1] = uni2esc[val & 0x3f];
			val >>= 6;
			result[o] = uni2esc[val & 0x3f];
			o += 3;
		} else {
			val = (ch << 8) + cl;
			result[o++] = uni2esc[val & 0x3f];
			val >>= 6;
			result[o++] = uni2esc[val & 0x3f];
			val >>= 6;
			result[o++] = uni2esc[val & 0x3f];
		}
	}
	*out = result;
	return 0;
 inval:
	ntfs_free(result);
	*out = 0;
	return -EILSEQ;
}

int ntfs_dupmap2uni(ntfs_volume *vol, char* in, int in_len, ntfs_u16 **out,
		    int *out_len)
{
	int i, o;
	ntfs_u16* result;
	struct nls_table* nls = vol->nls_map;

	*out=result = ntfs_malloc(2 * in_len);
	if (!result)
		return -ENOMEM;
	*out_len = in_len;
	for (i = o = 0; i < in_len; i++, o++){
		wchar_t uni;
		if (in[i] != ':' || (vol->nct & nct_uni_xlate) == 0){
			int charlen;
			charlen = nls->char2uni(&in[i], in_len-i, &uni);
			if (charlen < 0)
				return charlen;
			*out_len -= (charlen - 1);
			i += (charlen - 1);
		} else {
			unsigned char c1, c2, c3;
			*out_len -= 3;
			c1 = esc2uni(in[++i]);
			c2 = esc2uni(in[++i]);
			c3 = esc2uni(in[++i]);
			if (c1 == 255 || c2 == 255 || c3 == 255)
				uni = 0;
			else if (vol->nct & nct_uni_xlate_vfat) {
				uni = (((c2 & 0x3) << 6) + c3) << 8 |
				      ((c1 << 4) + (c2 >> 2));
			} else {
				uni = ((c3 << 4) + (c2 >> 2)) << 8 |
				      (((c2 & 0x3) << 6) + c1);
			}
		}
		/* FIXME: byte order? */
		result[o] = uni;
		if (!result[o]) {
			ntfs_free(result);
			return -EILSEQ;
		}
	}
	return 0;
}

