/*

   *  LZO1X Compressor from LZO

   *

   *  Copyright (C) 1996-2012 Markus F.X.J. Oberhumer <markus@oberhumer.com>

   *
   *  The full LZO package can be found at:
   *  http://www.oberhumer.com/opensource/lzo/
   *

   *  Changed for Linux kernel use by:

   *  Nitin Gupta <nitingupta910@gmail.com>
   *  Richard Purdie <rpurdie@openedhand.com>
   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>

  #include <asm/unaligned.h>

  #include <linux/lzo.h>

  #include "lzodefs.h"
  
  static noinline size_t

  lzo1x_1_do_compress(const unsigned char *in, size_t in_len,
  		    unsigned char *out, size_t *out_len,
  		    size_t ti, void *wrkmem)

  {

  	const unsigned char *ip;
  	unsigned char *op;

  	const unsigned char * const in_end = in + in_len;

  	const unsigned char * const ip_end = in + in_len - 20;
  	const unsigned char *ii;
  	lzo_dict_t * const dict = (lzo_dict_t *) wrkmem;

  	op = out;
  	ip = in;
  	ii = ip;
  	ip += ti < 4 ? 4 - ti : 0;

  
  	for (;;) {

  		const unsigned char *m_pos;
  		size_t t, m_len, m_off;
  		u32 dv;

  literal:

  		ip += 1 + ((ip - ii) >> 5);
  next:

  		if (unlikely(ip >= ip_end))
  			break;

  		dv = get_unaligned_le32(ip);
  		t = ((dv * 0x1824429d) >> (32 - D_BITS)) & D_MASK;
  		m_pos = in + dict[t];
  		dict[t] = (lzo_dict_t) (ip - in);
  		if (unlikely(dv != get_unaligned_le32(m_pos)))
  			goto literal;

  		ii -= ti;
  		ti = 0;
  		t = ip - ii;
  		if (t != 0) {

  			if (t <= 3) {
  				op[-2] |= t;

  				COPY4(op, ii);
  				op += t;
  			} else if (t <= 16) {

  				*op++ = (t - 3);

  				COPY8(op, ii);
  				COPY8(op + 8, ii + 8);
  				op += t;

  			} else {

  				if (t <= 18) {
  					*op++ = (t - 3);
  				} else {
  					size_t tt = t - 18;

  					*op++ = 0;

  					while (unlikely(tt > 255)) {
  						tt -= 255;
  						*op++ = 0;
  					}
  					*op++ = tt;

  				}

  				do {
  					COPY8(op, ii);
  					COPY8(op + 8, ii + 8);
  					op += 16;
  					ii += 16;
  					t -= 16;
  				} while (t >= 16);
  				if (t > 0) do {
  					*op++ = *ii++;
  				} while (--t > 0);

  			}

  		}

  		m_len = 4;
  		{
  #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ64)
  		u64 v;
  		v = get_unaligned((const u64 *) (ip + m_len)) ^
  		    get_unaligned((const u64 *) (m_pos + m_len));
  		if (unlikely(v == 0)) {
  			do {
  				m_len += 8;
  				v = get_unaligned((const u64 *) (ip + m_len)) ^
  				    get_unaligned((const u64 *) (m_pos + m_len));
  				if (unlikely(ip + m_len >= ip_end))
  					goto m_len_done;
  			} while (v == 0);
  		}
  #  if defined(__LITTLE_ENDIAN)
  		m_len += (unsigned) __builtin_ctzll(v) / 8;
  #  elif defined(__BIG_ENDIAN)
  		m_len += (unsigned) __builtin_clzll(v) / 8;
  #  else
  #    error "missing endian definition"
  #  endif
  #elif defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ32)
  		u32 v;
  		v = get_unaligned((const u32 *) (ip + m_len)) ^
  		    get_unaligned((const u32 *) (m_pos + m_len));
  		if (unlikely(v == 0)) {
  			do {
  				m_len += 4;
  				v = get_unaligned((const u32 *) (ip + m_len)) ^
  				    get_unaligned((const u32 *) (m_pos + m_len));
  				if (v != 0)
  					break;
  				m_len += 4;
  				v = get_unaligned((const u32 *) (ip + m_len)) ^
  				    get_unaligned((const u32 *) (m_pos + m_len));
  				if (unlikely(ip + m_len >= ip_end))
  					goto m_len_done;
  			} while (v == 0);
  		}
  #  if defined(__LITTLE_ENDIAN)
  		m_len += (unsigned) __builtin_ctz(v) / 8;
  #  elif defined(__BIG_ENDIAN)
  		m_len += (unsigned) __builtin_clz(v) / 8;
  #  else
  #    error "missing endian definition"
  #  endif
  #else
  		if (unlikely(ip[m_len] == m_pos[m_len])) {
  			do {
  				m_len += 1;
  				if (ip[m_len] != m_pos[m_len])
  					break;
  				m_len += 1;
  				if (ip[m_len] != m_pos[m_len])
  					break;
  				m_len += 1;
  				if (ip[m_len] != m_pos[m_len])
  					break;
  				m_len += 1;
  				if (ip[m_len] != m_pos[m_len])
  					break;
  				m_len += 1;
  				if (ip[m_len] != m_pos[m_len])
  					break;
  				m_len += 1;
  				if (ip[m_len] != m_pos[m_len])
  					break;
  				m_len += 1;
  				if (ip[m_len] != m_pos[m_len])
  					break;
  				m_len += 1;
  				if (unlikely(ip + m_len >= ip_end))
  					goto m_len_done;
  			} while (ip[m_len] == m_pos[m_len]);
  		}
  #endif
  		}
  m_len_done:

  		m_off = ip - m_pos;
  		ip += m_len;
  		ii = ip;
  		if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) {
  			m_off -= 1;
  			*op++ = (((m_len - 1) << 5) | ((m_off & 7) << 2));
  			*op++ = (m_off >> 3);
  		} else if (m_off <= M3_MAX_OFFSET) {
  			m_off -= 1;
  			if (m_len <= M3_MAX_LEN)

  				*op++ = (M3_MARKER | (m_len - 2));

  			else {
  				m_len -= M3_MAX_LEN;
  				*op++ = M3_MARKER | 0;
  				while (unlikely(m_len > 255)) {
  					m_len -= 255;
  					*op++ = 0;
  				}
  				*op++ = (m_len);

  			}

  			*op++ = (m_off << 2);
  			*op++ = (m_off >> 6);

  		} else {

  			m_off -= 0x4000;
  			if (m_len <= M4_MAX_LEN)
  				*op++ = (M4_MARKER | ((m_off >> 11) & 8)

  						| (m_len - 2));

  			else {
  				m_len -= M4_MAX_LEN;
  				*op++ = (M4_MARKER | ((m_off >> 11) & 8));
  				while (unlikely(m_len > 255)) {
  					m_len -= 255;
  					*op++ = 0;

  				}

  				*op++ = (m_len);

  			}

  			*op++ = (m_off << 2);

  			*op++ = (m_off >> 6);
  		}

  		goto next;

  	}

  	*out_len = op - out;

  	return in_end - (ii - ti);

  }

  int lzo1x_1_compress(const unsigned char *in, size_t in_len,
  		     unsigned char *out, size_t *out_len,
  		     void *wrkmem)

  {

  	const unsigned char *ip = in;

  	unsigned char *op = out;

  	size_t l = in_len;
  	size_t t = 0;

  	while (l > 20) {
  		size_t ll = l <= (M4_MAX_OFFSET + 1) ? l : (M4_MAX_OFFSET + 1);
  		uintptr_t ll_end = (uintptr_t) ip + ll;
  		if ((ll_end + ((t + ll) >> 5)) <= ll_end)
  			break;
  		BUILD_BUG_ON(D_SIZE * sizeof(lzo_dict_t) > LZO1X_1_MEM_COMPRESS);
  		memset(wrkmem, 0, D_SIZE * sizeof(lzo_dict_t));
  		t = lzo1x_1_do_compress(ip, ll, op, out_len, t, wrkmem);
  		ip += ll;

  		op += *out_len;

  		l  -= ll;

  	}

  	t += l;

  
  	if (t > 0) {

  		const unsigned char *ii = in + in_len - t;

  
  		if (op == out && t <= 238) {
  			*op++ = (17 + t);
  		} else if (t <= 3) {
  			op[-2] |= t;
  		} else if (t <= 18) {
  			*op++ = (t - 3);
  		} else {
  			size_t tt = t - 18;

  			*op++ = 0;
  			while (tt > 255) {
  				tt -= 255;
  				*op++ = 0;
  			}

  			*op++ = tt;
  		}

  		if (t >= 16) do {
  			COPY8(op, ii);
  			COPY8(op + 8, ii + 8);
  			op += 16;
  			ii += 16;
  			t -= 16;
  		} while (t >= 16);
  		if (t > 0) do {

  			*op++ = *ii++;
  		} while (--t > 0);
  	}
  
  	*op++ = M4_MARKER | 1;
  	*op++ = 0;
  	*op++ = 0;
  
  	*out_len = op - out;
  	return LZO_E_OK;
  }
  EXPORT_SYMBOL_GPL(lzo1x_1_compress);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("LZO1X-1 Compressor");