/* inffas8664.c is a hand tuned assembler version of inffast.c - fast decoding

 * version for AMD64 on Windows using Microsoft C compiler

 *

 * Copyright (C) 1995-2003 Mark Adler

 * For conditions of distribution and use, see copyright notice in zlib.h

 *

 * Copyright (C) 2003 Chris Anderson <christop@charm.net>

 * Please use the copyright conditions above.

 *

 * 2005 - Adaptation to Microsoft C Compiler for AMD64 by Gilles Vollant

 *

 * inffas8664.c call function inffas8664fnc in inffasx64.asm

 *  inffasx64.asm is automatically convert from AMD64 portion of inffas86.c

 *

 * Dec-29-2003 -- I added AMD64 inflate asm support.  This version is also

 * slightly quicker on x86 systems because, instead of using rep movsb to copy

 * data, it uses rep movsw, which moves data in 2-byte chunks instead of single

 * bytes.  I've tested the AMD64 code on a Fedora Core 1 + the x86_64 updates

 * from http://fedora.linux.duke.edu/fc1_x86_64

 * which is running on an Athlon 64 3000+ / Gigabyte GA-K8VT800M system with

 * 1GB ram.  The 64-bit version is about 4% faster than the 32-bit version,

 * when decompressing mozilla-source-1.3.tar.gz.

 *

 * Mar-13-2003 -- Most of this is derived from inffast.S which is derived from

 * the gcc -S output of zlib-1.2.0/inffast.c.  Zlib-1.2.0 is in beta release at

 * the moment.  I have successfully compiled and tested this code with gcc2.96,

 * gcc3.2, icc5.0, msvc6.0.  It is very close to the speed of inffast.S

 * compiled with gcc -DNO_MMX, but inffast.S is still faster on the P3 with MMX

 * enabled.  I will attempt to merge the MMX code into this version.  Newer

 * versions of this and inffast.S can be found at

 * http://www.eetbeetee.com/zlib/ and http://www.charm.net/~christop/zlib/

 *

 */



#include <stdio.h>

#include "zutil.h"

#include "inftrees.h"

#include "inflate.h"

#include "inffast.h"



/* Mark Adler's comments from inffast.c: */



/*

   Decode literal, length, and distance codes and write out the resulting

   literal and match bytes until either not enough input or output is

   available, an end-of-block is encountered, or a data error is encountered.

   When large enough input and output buffers are supplied to inflate(), for

   example, a 16K input buffer and a 64K output buffer, more than 95% of the

   inflate execution time is spent in this routine.



   Entry assumptions:



        state->mode == LEN

        strm->avail_in >= 6

        strm->avail_out >= 258

        start >= strm->avail_out

        state->bits < 8



   On return, state->mode is one of:



        LEN -- ran out of enough output space or enough available input

        TYPE -- reached end of block code, inflate() to interpret next block

        BAD -- error in block data



   Notes:



    - The maximum input bits used by a length/distance pair is 15 bits for the

      length code, 5 bits for the length extra, 15 bits for the distance code,

      and 13 bits for the distance extra.  This totals 48 bits, or six bytes.

      Therefore if strm->avail_in >= 6, then there is enough input to avoid

      checking for available input while decoding.



    - The maximum bytes that a single length/distance pair can output is 258

      bytes, which is the maximum length that can be coded.  inflate_fast()

      requires strm->avail_out >= 258 for each loop to avoid checking for

      output space.

 */







    typedef struct inffast_ar {

/* 64   32                               x86  x86_64 */

/* ar offset                              register */

/*  0    0 */ void *esp;                /* esp save */

/*  8    4 */ void *ebp;                /* ebp save */

/* 16    8 */ unsigned char FAR *in;    /* esi rsi  local strm->next_in */

/* 24   12 */ unsigned char FAR *last;  /*     r9   while in < last */

/* 32   16 */ unsigned char FAR *out;   /* edi rdi  local strm->next_out */

/* 40   20 */ unsigned char FAR *beg;   /*          inflate()'s init next_out */

/* 48   24 */ unsigned char FAR *end;   /*     r10  while out < end */

/* 56   28 */ unsigned char FAR *window;/*          size of window, wsize!=0 */

/* 64   32 */ code const FAR *lcode;    /* ebp rbp  local strm->lencode */

/* 72   36 */ code const FAR *dcode;    /*     r11  local strm->distcode */

/* 80   40 */ size_t /*unsigned long */hold;       /* edx rdx  local strm->hold */

/* 88   44 */ unsigned bits;            /* ebx rbx  local strm->bits */

/* 92   48 */ unsigned wsize;           /*          window size */

/* 96   52 */ unsigned write;           /*          window write index */

/*100   56 */ unsigned lmask;           /*     r12  mask for lcode */

/*104   60 */ unsigned dmask;           /*     r13  mask for dcode */

/*108   64 */ unsigned len;             /*     r14  match length */

/*112   68 */ unsigned dist;            /*     r15  match distance */

/*116   72 */ unsigned status;          /*          set when state chng*/

    } type_ar;

#ifdef ASMINF



void inflate_fast(strm, start)

z_streamp strm;

unsigned start;         /* inflate()'s starting value for strm->avail_out */

{

    struct inflate_state FAR *state;

    type_ar ar;

    void inffas8664fnc(struct inffast_ar * par);



    



#if (defined( __GNUC__ ) && defined( __amd64__ ) && ! defined( __i386 )) || (defined(_MSC_VER) && defined(_M_AMD64))

#define PAD_AVAIL_IN 6

#define PAD_AVAIL_OUT 258    

#else

#define PAD_AVAIL_IN 5

#define PAD_AVAIL_OUT 257

#endif



    /* copy state to local variables */

    state = (struct inflate_state FAR *)strm->state;



    ar.in = strm->next_in;

    ar.last = ar.in + (strm->avail_in - PAD_AVAIL_IN);

    ar.out = strm->next_out;

    ar.beg = ar.out - (start - strm->avail_out);

    ar.end = ar.out + (strm->avail_out - PAD_AVAIL_OUT);

    ar.wsize = state->wsize;

    ar.write = state->write;

    ar.window = state->window;

    ar.hold = state->hold;

    ar.bits = state->bits;

    ar.lcode = state->lencode;

    ar.dcode = state->distcode;

    ar.lmask = (1U << state->lenbits) - 1;

    ar.dmask = (1U << state->distbits) - 1;



    /* decode literals and length/distances until end-of-block or not enough

       input data or output space */



    /* align in on 1/2 hold size boundary */

    while (((size_t)(void *)ar.in & (sizeof(ar.hold) / 2 - 1)) != 0) {

        ar.hold += (unsigned long)*ar.in++ << ar.bits;

        ar.bits += 8;

    }



    inffas8664fnc(&ar);



    if (ar.status > 1) {

        if (ar.status == 2)

            strm->msg = "invalid literal/length code";

        else if (ar.status == 3)

            strm->msg = "invalid distance code";

        else

            strm->msg = "invalid distance too far back";

        state->mode = BAD;

    }

    else if ( ar.status == 1 ) {

        state->mode = TYPE;

    }



    /* return unused bytes (on entry, bits < 8, so in won't go too far back) */

    ar.len = ar.bits >> 3;

    ar.in -= ar.len;

    ar.bits -= ar.len << 3;

    ar.hold &= (1U << ar.bits) - 1;



    /* update state and return */

    strm->next_in = ar.in;

    strm->next_out = ar.out;

    strm->avail_in = (unsigned)(ar.in < ar.last ?

                                PAD_AVAIL_IN + (ar.last - ar.in) :

                                PAD_AVAIL_IN - (ar.in - ar.last));

    strm->avail_out = (unsigned)(ar.out < ar.end ?

                                 PAD_AVAIL_OUT + (ar.end - ar.out) :

                                 PAD_AVAIL_OUT - (ar.out - ar.end));

    state->hold = (unsigned long)ar.hold;

    state->bits = ar.bits;

    return;

}



#endif

