| /* lzo1x_oo.ch -- LZO1X compressed data optimizer |
| |
| This file is part of the LZO real-time data compression library. |
| |
| Copyright (C) 1996-2014 Markus Franz Xaver Johannes Oberhumer |
| All Rights Reserved. |
| |
| The LZO library 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. |
| |
| The LZO library 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 the LZO library; see the file COPYING. |
| If not, write to the Free Software Foundation, Inc., |
| 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
| |
| Markus F.X.J. Oberhumer |
| <markus@oberhumer.com> |
| http://www.oberhumer.com/opensource/lzo/ |
| */ |
| |
| |
| #define TEST_IP (ip < ip_end) |
| #define TEST_OP (op <= op_end) |
| #define TEST_IP_AND_TEST_OP (TEST_IP && TEST_OP) |
| |
| #define NO_LIT LZO_UINT_MAX |
| |
| |
| /*********************************************************************** |
| // |
| ************************************************************************/ |
| |
| static void copy2(lzo_bytep ip, const lzo_bytep m_pos, lzo_uint off) |
| { |
| assert(off > 0); |
| ip[0] = m_pos[0]; |
| if (off == 1) |
| ip[1] = m_pos[0]; |
| else |
| ip[1] = m_pos[1]; |
| } |
| |
| |
| static void copy3(lzo_bytep ip, const lzo_bytep m_pos, lzo_uint off) |
| { |
| assert(off > 0); |
| ip[0] = m_pos[0]; |
| if (off == 1) |
| { |
| ip[2] = ip[1] = m_pos[0]; |
| } |
| else if (off == 2) |
| { |
| ip[1] = m_pos[1]; |
| ip[2] = m_pos[0]; |
| } |
| else |
| { |
| ip[1] = m_pos[1]; |
| ip[2] = m_pos[2]; |
| } |
| } |
| |
| |
| /*********************************************************************** |
| // optimize a block of data. |
| ************************************************************************/ |
| |
| LZO_PUBLIC(int) |
| DO_OPTIMIZE ( lzo_bytep in , lzo_uint in_len, |
| lzo_bytep out, lzo_uintp out_len, |
| lzo_voidp wrkmem ) |
| { |
| lzo_bytep op; |
| lzo_bytep ip; |
| lzo_uint t; |
| lzo_bytep m_pos; |
| lzo_bytep const ip_end = in + in_len; |
| lzo_bytep const op_end = out + *out_len; |
| lzo_bytep litp = NULL; |
| lzo_uint lit = 0; |
| lzo_uint next_lit = NO_LIT; |
| lzo_uint nl; |
| unsigned long o_m1_a = 0, o_m1_b = 0, o_m2 = 0, o_m3_a = 0, o_m3_b = 0; |
| |
| LZO_UNUSED(wrkmem); |
| |
| *out_len = 0; |
| |
| op = out; |
| ip = in; |
| |
| assert(in_len >= 3); |
| if (*ip > 17) |
| { |
| t = *ip++ - 17; |
| if (t < 4) |
| goto match_next; |
| goto first_literal_run; |
| } |
| assert(*ip < 16 || (*ip == 17 && in_len == 3)); |
| |
| while (TEST_IP_AND_TEST_OP) |
| { |
| t = *ip++; |
| if (t >= 16) |
| goto match; |
| /* a literal run */ |
| litp = ip - 1; |
| if (t == 0) |
| { |
| t = 15; |
| while (*ip == 0) |
| t += 255, ip++; |
| t += *ip++; |
| } |
| lit = t + 3; |
| /* copy literals */ |
| copy_literal_run: |
| *op++ = *ip++; *op++ = *ip++; *op++ = *ip++; |
| first_literal_run: |
| do *op++ = *ip++; while (--t > 0); |
| |
| |
| t = *ip++; |
| |
| if (t >= 16) |
| goto match; |
| #if defined(LZO1X) |
| m_pos = op - 1 - 0x800; |
| #elif defined(LZO1Y) |
| m_pos = op - 1 - 0x400; |
| #endif |
| m_pos -= t >> 2; |
| m_pos -= *ip++ << 2; |
| *op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos++; |
| lit = 0; |
| goto match_done; |
| |
| |
| /* handle matches */ |
| do { |
| if (t < 16) /* a M1 match */ |
| { |
| m_pos = op - 1; |
| m_pos -= t >> 2; |
| m_pos -= *ip++ << 2; |
| |
| if (litp == NULL) |
| goto copy_m1; |
| |
| /* assert that there was a match just before */ |
| assert(lit >= 1 && lit <= 3); |
| assert(litp == ip - 2 - lit - 2); |
| assert((lzo_uint)(*litp & 3) == lit); |
| nl = ip[-2] & 3; |
| /* test if a match follows */ |
| if (nl == 0 && lit == 1 && ip[0] >= 16) |
| { |
| next_lit = nl; |
| /* adjust length of previous short run */ |
| lit += 2; |
| *litp = LZO_BYTE((*litp & ~3) | lit); |
| /* copy over the 2 literals that replace the match */ |
| copy2(ip-2,m_pos,pd(op,m_pos)); |
| o_m1_a++; |
| } |
| /* test if a literal run follows */ |
| else if (nl == 0 && ip[0] < 16 && ip[0] != 0 && |
| (lit + 2 + ip[0] < 16)) |
| { |
| t = *ip++; |
| /* remove short run */ |
| *litp &= ~3; |
| /* copy over the 2 literals that replace the match */ |
| copy2(ip-3+1,m_pos,pd(op,m_pos)); |
| /* move literals 1 byte ahead */ |
| litp += 2; |
| if (lit > 0) |
| lzo_memmove(litp+1,litp,lit); |
| /* insert new length of long literal run */ |
| lit += 2 + t + 3; assert(lit <= 18); |
| *litp = LZO_BYTE(lit - 3); |
| |
| o_m1_b++; |
| *op++ = *m_pos++; *op++ = *m_pos++; |
| goto copy_literal_run; |
| } |
| copy_m1: |
| *op++ = *m_pos++; *op++ = *m_pos++; |
| } |
| else |
| { |
| match: |
| if (t >= 64) /* a M2 match */ |
| { |
| m_pos = op - 1; |
| #if defined(LZO1X) |
| m_pos -= (t >> 2) & 7; |
| m_pos -= *ip++ << 3; |
| t = (t >> 5) - 1; |
| #elif defined(LZO1Y) |
| m_pos -= (t >> 2) & 3; |
| m_pos -= *ip++ << 2; |
| t = (t >> 4) - 3; |
| #endif |
| if (litp == NULL) |
| goto copy_m; |
| |
| nl = ip[-2] & 3; |
| /* test if in beetween two long literal runs */ |
| if (t == 1 && lit > 3 && nl == 0 && |
| ip[0] < 16 && ip[0] != 0 && (lit + 3 + ip[0] < 16)) |
| { |
| assert(*litp == lit - 3); |
| t = *ip++; |
| /* copy over the 3 literals that replace the match */ |
| copy3(ip-1-2,m_pos,pd(op,m_pos)); |
| /* set new length of previous literal run */ |
| lit += 3 + t + 3; assert(lit <= 18); |
| *litp = LZO_BYTE(lit - 3); |
| o_m2++; |
| *op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos++; |
| goto copy_literal_run; |
| } |
| } |
| else |
| { |
| if (t >= 32) /* a M3 match */ |
| { |
| t &= 31; |
| if (t == 0) |
| { |
| t = 31; |
| while (*ip == 0) |
| t += 255, ip++; |
| t += *ip++; |
| } |
| m_pos = op - 1; |
| m_pos -= *ip++ >> 2; |
| m_pos -= *ip++ << 6; |
| } |
| else /* a M4 match */ |
| { |
| m_pos = op; |
| m_pos -= (t & 8) << 11; |
| t &= 7; |
| if (t == 0) |
| { |
| t = 7; |
| while (*ip == 0) |
| t += 255, ip++; |
| t += *ip++; |
| } |
| m_pos -= *ip++ >> 2; |
| m_pos -= *ip++ << 6; |
| if (m_pos == op) |
| goto eof_found; |
| m_pos -= 0x4000; |
| } |
| if (litp == NULL) |
| goto copy_m; |
| |
| nl = ip[-2] & 3; |
| /* test if in beetween two matches */ |
| if (t == 1 && lit == 0 && nl == 0 && ip[0] >= 16) |
| { |
| assert(litp == ip - 3 - lit - 2); |
| assert((lzo_uint)(*litp & 3) == lit); |
| next_lit = nl; |
| /* make a previous short run */ |
| lit += 3; |
| *litp = LZO_BYTE((*litp & ~3) | lit); |
| /* copy over the 3 literals that replace the match */ |
| copy3(ip-3,m_pos,pd(op,m_pos)); |
| o_m3_a++; |
| } |
| /* test if a literal run follows */ |
| else if (t == 1 && lit <= 3 && nl == 0 && |
| ip[0] < 16 && ip[0] != 0 && (lit + 3 + ip[0] < 16)) |
| { |
| assert(litp == ip - 3 - lit - 2); |
| assert((lzo_uint)(*litp & 3) == lit); |
| t = *ip++; |
| /* remove short run */ |
| *litp &= ~3; |
| /* copy over the 3 literals that replace the match */ |
| copy3(ip-4+1,m_pos,pd(op,m_pos)); |
| /* move literals 1 byte ahead */ |
| litp += 2; |
| if (lit > 0) |
| lzo_memmove(litp+1,litp,lit); |
| /* insert new length of long literal run */ |
| lit += 3 + t + 3; assert(lit <= 18); |
| *litp = LZO_BYTE(lit - 3); |
| |
| o_m3_b++; |
| *op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos++; |
| goto copy_literal_run; |
| } |
| } |
| copy_m: |
| *op++ = *m_pos++; *op++ = *m_pos++; |
| do *op++ = *m_pos++; while (--t > 0); |
| } |
| |
| match_done: |
| if (next_lit == NO_LIT) |
| { |
| t = ip[-2] & 3; |
| lit = t; |
| litp = ip - 2; |
| } |
| else |
| t = next_lit; |
| assert(t <= 3); |
| next_lit = NO_LIT; |
| if (t == 0) |
| break; |
| /* copy literals */ |
| match_next: |
| do *op++ = *ip++; while (--t > 0); |
| t = *ip++; |
| } while (TEST_IP_AND_TEST_OP); |
| } |
| |
| /* no EOF code was found */ |
| *out_len = pd(op, out); |
| return LZO_E_EOF_NOT_FOUND; |
| |
| eof_found: |
| assert(t == 1); |
| #if 0 |
| printf("optimize: %5lu %5lu %5lu %5lu %5lu\n", |
| o_m1_a, o_m1_b, o_m2, o_m3_a, o_m3_b); |
| #endif |
| LZO_UNUSED(o_m1_a); LZO_UNUSED(o_m1_b); LZO_UNUSED(o_m2); |
| LZO_UNUSED(o_m3_a); LZO_UNUSED(o_m3_b); |
| *out_len = pd(op, out); |
| return (ip == ip_end ? LZO_E_OK : |
| (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN)); |
| } |
| |
| |
| /* |
| vi:ts=4:et |
| */ |
| |
