/*
   * unicode.c
   *
   * PURPOSE
   *	Routines for converting between UTF-8 and OSTA Compressed Unicode.
   *      Also handles filename mangling
   *
   * DESCRIPTION
   *	OSTA Compressed Unicode is explained in the OSTA UDF specification.
   *		http://www.osta.org/
   *	UTF-8 is explained in the IETF RFC XXXX.
   *		ftp://ftp.internic.net/rfc/rfcxxxx.txt
   *
   * COPYRIGHT
   *	This file is distributed under the terms of the GNU General Public
   *	License (GPL). Copies of the GPL can be obtained from:
   *		ftp://prep.ai.mit.edu/pub/gnu/GPL
   *	Each contributing author retains all rights to their own work.
   */
  
  #include "udfdecl.h"
  
  #include <linux/kernel.h>
  #include <linux/string.h>	/* for memset */
  #include <linux/nls.h>
  #include <linux/crc-itu-t.h>
  #include <linux/slab.h>
  
  #include "udf_sb.h"
  
  static int udf_translate_to_linux(uint8_t *, uint8_t *, int, uint8_t *, int);
  
  static int udf_char_to_ustr(struct ustr *dest, const uint8_t *src, int strlen)
  {
  	if ((!dest) || (!src) || (!strlen) || (strlen > UDF_NAME_LEN - 2))
  		return 0;
  
  	memset(dest, 0, sizeof(struct ustr));
  	memcpy(dest->u_name, src, strlen);
  	dest->u_cmpID = 0x08;
  	dest->u_len = strlen;
  
  	return strlen;
  }
  
  /*
   * udf_build_ustr
   */
  int udf_build_ustr(struct ustr *dest, dstring *ptr, int size)
  {
  	int usesize;
  
  	if (!dest || !ptr || !size)
  		return -1;
  	BUG_ON(size < 2);
  
  	usesize = min_t(size_t, ptr[size - 1], sizeof(dest->u_name));
  	usesize = min(usesize, size - 2);
  	dest->u_cmpID = ptr[0];
  	dest->u_len = usesize;
  	memcpy(dest->u_name, ptr + 1, usesize);
  	memset(dest->u_name + usesize, 0, sizeof(dest->u_name) - usesize);
  
  	return 0;
  }
  
  /*
   * udf_build_ustr_exact
   */
  static int udf_build_ustr_exact(struct ustr *dest, dstring *ptr, int exactsize)
  {
  	if ((!dest) || (!ptr) || (!exactsize))
  		return -1;
  
  	memset(dest, 0, sizeof(struct ustr));
  	dest->u_cmpID = ptr[0];
  	dest->u_len = exactsize - 1;
  	memcpy(dest->u_name, ptr + 1, exactsize - 1);
  
  	return 0;
  }
  
  /*
   * udf_ocu_to_utf8
   *
   * PURPOSE
   *	Convert OSTA Compressed Unicode to the UTF-8 equivalent.
   *
   * PRE-CONDITIONS
   *	utf			Pointer to UTF-8 output buffer.
   *	ocu			Pointer to OSTA Compressed Unicode input buffer
   *				of size UDF_NAME_LEN bytes.
   * 				both of type "struct ustr *"
   *
   * POST-CONDITIONS
   *	<return>		Zero on success.
   *
   * HISTORY
   *	November 12, 1997 - Andrew E. Mileski
   *	Written, tested, and released.
   */
  int udf_CS0toUTF8(struct ustr *utf_o, const struct ustr *ocu_i)
  {
  	const uint8_t *ocu;
  	uint8_t cmp_id, ocu_len;
  	int i;
  
  	ocu_len = ocu_i->u_len;
  	if (ocu_len == 0) {
  		memset(utf_o, 0, sizeof(struct ustr));
  		return 0;
  	}
  
  	cmp_id = ocu_i->u_cmpID;
  	if (cmp_id != 8 && cmp_id != 16) {
  		memset(utf_o, 0, sizeof(struct ustr));
  		pr_err("unknown compression code (%d) stri=%s
  ",
  		       cmp_id, ocu_i->u_name);
  		return 0;
  	}
  
  	ocu = ocu_i->u_name;
  	utf_o->u_len = 0;
  	for (i = 0; (i < ocu_len) && (utf_o->u_len <= (UDF_NAME_LEN - 3));) {
  
  		/* Expand OSTA compressed Unicode to Unicode */
  		uint32_t c = ocu[i++];
  		if (cmp_id == 16)
  			c = (c << 8) | ocu[i++];
  
  		/* Compress Unicode to UTF-8 */
  		if (c < 0x80U)
  			utf_o->u_name[utf_o->u_len++] = (uint8_t)c;
  		else if (c < 0x800U) {
  			utf_o->u_name[utf_o->u_len++] =
  						(uint8_t)(0xc0 | (c >> 6));
  			utf_o->u_name[utf_o->u_len++] =
  						(uint8_t)(0x80 | (c & 0x3f));
  		} else {
  			utf_o->u_name[utf_o->u_len++] =
  						(uint8_t)(0xe0 | (c >> 12));
  			utf_o->u_name[utf_o->u_len++] =
  						(uint8_t)(0x80 |
  							  ((c >> 6) & 0x3f));
  			utf_o->u_name[utf_o->u_len++] =
  						(uint8_t)(0x80 | (c & 0x3f));
  		}
  	}
  	utf_o->u_cmpID = 8;
  
  	return utf_o->u_len;
  }
  
  /*
   *
   * udf_utf8_to_ocu
   *
   * PURPOSE
   *	Convert UTF-8 to the OSTA Compressed Unicode equivalent.
   *
   * DESCRIPTION
   *	This routine is only called by udf_lookup().
   *
   * PRE-CONDITIONS
   *	ocu			Pointer to OSTA Compressed Unicode output
   *				buffer of size UDF_NAME_LEN bytes.
   *	utf			Pointer to UTF-8 input buffer.
   *	utf_len			Length of UTF-8 input buffer in bytes.
   *
   * POST-CONDITIONS
   *	<return>		Zero on success.
   *
   * HISTORY
   *	November 12, 1997 - Andrew E. Mileski
   *	Written, tested, and released.
   */
  static int udf_UTF8toCS0(dstring *ocu, struct ustr *utf, int length)
  {
  	unsigned c, i, max_val, utf_char;
  	int utf_cnt, u_len;
  
  	memset(ocu, 0, sizeof(dstring) * length);
  	ocu[0] = 8;
  	max_val = 0xffU;
  
  try_again:
  	u_len = 0U;
  	utf_char = 0U;
  	utf_cnt = 0U;
  	for (i = 0U; i < utf->u_len; i++) {
  		c = (uint8_t)utf->u_name[i];
  
  		/* Complete a multi-byte UTF-8 character */
  		if (utf_cnt) {
  			utf_char = (utf_char << 6) | (c & 0x3fU);
  			if (--utf_cnt)
  				continue;
  		} else {
  			/* Check for a multi-byte UTF-8 character */
  			if (c & 0x80U) {
  				/* Start a multi-byte UTF-8 character */
  				if ((c & 0xe0U) == 0xc0U) {
  					utf_char = c & 0x1fU;
  					utf_cnt = 1;
  				} else if ((c & 0xf0U) == 0xe0U) {
  					utf_char = c & 0x0fU;
  					utf_cnt = 2;
  				} else if ((c & 0xf8U) == 0xf0U) {
  					utf_char = c & 0x07U;
  					utf_cnt = 3;
  				} else if ((c & 0xfcU) == 0xf8U) {
  					utf_char = c & 0x03U;
  					utf_cnt = 4;
  				} else if ((c & 0xfeU) == 0xfcU) {
  					utf_char = c & 0x01U;
  					utf_cnt = 5;
  				} else {
  					goto error_out;
  				}
  				continue;
  			} else {
  				/* Single byte UTF-8 character (most common) */
  				utf_char = c;
  			}
  		}
  
  		/* Choose no compression if necessary */
  		if (utf_char > max_val) {
  			if (max_val == 0xffU) {
  				max_val = 0xffffU;
  				ocu[0] = (uint8_t)0x10U;
  				goto try_again;
  			}
  			goto error_out;
  		}
  
  		if (max_val == 0xffffU)
  			ocu[++u_len] = (uint8_t)(utf_char >> 8);
  		ocu[++u_len] = (uint8_t)(utf_char & 0xffU);
  	}
  
  	if (utf_cnt) {
  error_out:
  		ocu[++u_len] = '?';
  		printk(KERN_DEBUG pr_fmt("bad UTF-8 character
  "));
  	}
  
  	ocu[length - 1] = (uint8_t)u_len + 1;
  
  	return u_len + 1;
  }
  
  static int udf_CS0toNLS(struct nls_table *nls, struct ustr *utf_o,
  			const struct ustr *ocu_i)
  {
  	const uint8_t *ocu;
  	uint8_t cmp_id, ocu_len;
  	int i, len;
  
  
  	ocu_len = ocu_i->u_len;
  	if (ocu_len == 0) {
  		memset(utf_o, 0, sizeof(struct ustr));
  		return 0;
  	}
  
  	cmp_id = ocu_i->u_cmpID;
  	if (cmp_id != 8 && cmp_id != 16) {
  		memset(utf_o, 0, sizeof(struct ustr));
  		pr_err("unknown compression code (%d) stri=%s
  ",
  		       cmp_id, ocu_i->u_name);
  		return 0;
  	}
  
  	ocu = ocu_i->u_name;
  	utf_o->u_len = 0;
  	for (i = 0; (i < ocu_len) && (utf_o->u_len <= (UDF_NAME_LEN - 3));) {
  		/* Expand OSTA compressed Unicode to Unicode */
  		uint32_t c = ocu[i++];
  		if (cmp_id == 16)
  			c = (c << 8) | ocu[i++];
  
  		len = nls->uni2char(c, &utf_o->u_name[utf_o->u_len],
  				    UDF_NAME_LEN - utf_o->u_len);
  		/* Valid character? */
  		if (len >= 0)
  			utf_o->u_len += len;
  		else
  			utf_o->u_name[utf_o->u_len++] = '?';
  	}
  	utf_o->u_cmpID = 8;
  
  	return utf_o->u_len;
  }
  
  static int udf_NLStoCS0(struct nls_table *nls, dstring *ocu, struct ustr *uni,
  			int length)
  {
  	int len;
  	unsigned i, max_val;
  	uint16_t uni_char;
  	int u_len;
  
  	memset(ocu, 0, sizeof(dstring) * length);
  	ocu[0] = 8;
  	max_val = 0xffU;
  
  try_again:
  	u_len = 0U;
  	for (i = 0U; i < uni->u_len; i++) {
  		len = nls->char2uni(&uni->u_name[i], uni->u_len - i, &uni_char);
  		if (!len)
  			continue;
  		/* Invalid character, deal with it */
  		if (len < 0) {
  			len = 1;
  			uni_char = '?';
  		}
  
  		if (uni_char > max_val) {
  			max_val = 0xffffU;
  			ocu[0] = (uint8_t)0x10U;
  			goto try_again;
  		}
  
  		if (max_val == 0xffffU)
  			ocu[++u_len] = (uint8_t)(uni_char >> 8);
  		ocu[++u_len] = (uint8_t)(uni_char & 0xffU);
  		i += len - 1;
  	}
  
  	ocu[length - 1] = (uint8_t)u_len + 1;
  	return u_len + 1;
  }
  
  int udf_get_filename(struct super_block *sb, uint8_t *sname, uint8_t *dname,
  		     int flen)
  {
  	struct ustr *filename, *unifilename;
  	int len = 0;
  
  	filename = kmalloc(sizeof(struct ustr), GFP_NOFS);
  	if (!filename)
  		return 0;
  
  	unifilename = kmalloc(sizeof(struct ustr), GFP_NOFS);
  	if (!unifilename)
  		goto out1;
  
  	if (udf_build_ustr_exact(unifilename, sname, flen))
  		goto out2;
  
  	if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
  		if (!udf_CS0toUTF8(filename, unifilename)) {
  			udf_debug("Failed in udf_get_filename: sname = %s
  ",
  				  sname);
  			goto out2;
  		}
  	} else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
  		if (!udf_CS0toNLS(UDF_SB(sb)->s_nls_map, filename,
  				  unifilename)) {
  			udf_debug("Failed in udf_get_filename: sname = %s
  ",
  				  sname);
  			goto out2;
  		}
  	} else
  		goto out2;
  
  	len = udf_translate_to_linux(dname, filename->u_name, filename->u_len,
  				     unifilename->u_name, unifilename->u_len);
  out2:
  	kfree(unifilename);
  out1:
  	kfree(filename);
  	return len;
  }
  
  int udf_put_filename(struct super_block *sb, const uint8_t *sname,
  		     uint8_t *dname, int flen)
  {
  	struct ustr unifilename;
  	int namelen;
  
  	if (!udf_char_to_ustr(&unifilename, sname, flen))
  		return 0;
  
  	if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
  		namelen = udf_UTF8toCS0(dname, &unifilename, UDF_NAME_LEN);
  		if (!namelen)
  			return 0;
  	} else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
  		namelen = udf_NLStoCS0(UDF_SB(sb)->s_nls_map, dname,
  					&unifilename, UDF_NAME_LEN);
  		if (!namelen)
  			return 0;
  	} else
  		return 0;
  
  	return namelen;
  }
  
  #define ILLEGAL_CHAR_MARK	'_'
  #define EXT_MARK		'.'
  #define CRC_MARK		'#'
  #define EXT_SIZE 		5
  
  static int udf_translate_to_linux(uint8_t *newName, uint8_t *udfName,
  				  int udfLen, uint8_t *fidName,
  				  int fidNameLen)
  {
  	int index, newIndex = 0, needsCRC = 0;
  	int extIndex = 0, newExtIndex = 0, hasExt = 0;
  	unsigned short valueCRC;
  	uint8_t curr;
  	const uint8_t hexChar[] = "0123456789ABCDEF";
  
  	if (udfName[0] == '.' &&
  	    (udfLen == 1 || (udfLen == 2 && udfName[1] == '.'))) {
  		needsCRC = 1;
  		newIndex = udfLen;
  		memcpy(newName, udfName, udfLen);
  	} else {
  		for (index = 0; index < udfLen; index++) {
  			curr = udfName[index];
  			if (curr == '/' || curr == 0) {
  				needsCRC = 1;
  				curr = ILLEGAL_CHAR_MARK;
  				while (index + 1 < udfLen &&
  						(udfName[index + 1] == '/' ||
  						 udfName[index + 1] == 0))
  					index++;
  			}
  			if (curr == EXT_MARK &&
  					(udfLen - index - 1) <= EXT_SIZE) {
  				if (udfLen == index + 1)
  					hasExt = 0;
  				else {
  					hasExt = 1;
  					extIndex = index;
  					newExtIndex = newIndex;
  				}
  			}
  			if (newIndex < 256)
  				newName[newIndex++] = curr;
  			else
  				needsCRC = 1;
  		}
  	}
  	if (needsCRC) {
  		uint8_t ext[EXT_SIZE];
  		int localExtIndex = 0;
  
  		if (hasExt) {
  			int maxFilenameLen;
  			for (index = 0;
  			     index < EXT_SIZE && extIndex + index + 1 < udfLen;
  			     index++) {
  				curr = udfName[extIndex + index + 1];
  
  				if (curr == '/' || curr == 0) {
  					needsCRC = 1;
  					curr = ILLEGAL_CHAR_MARK;
  					while (extIndex + index + 2 < udfLen &&
  					      (index + 1 < EXT_SIZE &&
  						(udfName[extIndex + index + 2] == '/' ||
  						 udfName[extIndex + index + 2] == 0)))
  						index++;
  				}
  				ext[localExtIndex++] = curr;
  			}
  			maxFilenameLen = 250 - localExtIndex;
  			if (newIndex > maxFilenameLen)
  				newIndex = maxFilenameLen;
  			else
  				newIndex = newExtIndex;
  		} else if (newIndex > 250)
  			newIndex = 250;
  		newName[newIndex++] = CRC_MARK;
  		valueCRC = crc_itu_t(0, fidName, fidNameLen);
  		newName[newIndex++] = hexChar[(valueCRC & 0xf000) >> 12];
  		newName[newIndex++] = hexChar[(valueCRC & 0x0f00) >> 8];
  		newName[newIndex++] = hexChar[(valueCRC & 0x00f0) >> 4];
  		newName[newIndex++] = hexChar[(valueCRC & 0x000f)];
  
  		if (hasExt) {
  			newName[newIndex++] = EXT_MARK;
  			for (index = 0; index < localExtIndex; index++)
  				newName[newIndex++] = ext[index];
  		}
  	}
  
  	return newIndex;
  }