/* ucl_init.c -- initialization of the UCL library

   This file is part of the UCL data compression library.

   Copyright (C) 1996-2004 Markus Franz Xaver Johannes Oberhumer
   All Rights Reserved.

   The UCL 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 UCL 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 UCL library; see the file COPYING.
   If not, write to the Free Software Foundation, Inc.,
   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

   Markus F.X.J. Oberhumer
   <markus@oberhumer.com>
   http://www.oberhumer.com/opensource/ucl/
 */


#include "ucl_conf.h"


/***********************************************************************
// Runtime check of the assumptions about the size of builtin types,
// memory model, byte order and other low-level constructs.
//
// We are really paranoid here - UCL should either fail
// at startup or not at all.
//
// Because of inlining much of this evaluates to nothing at compile time.
//
// And while many of the tests seem highly obvious and redundant they are
// here to catch compiler/optimizer bugs. Yes, these do exist.
************************************************************************/

static ucl_bool schedule_insns_bug(void);   /* avoid inlining */
static ucl_bool strength_reduce_bug(int *); /* avoid inlining */


#if 0 || defined(UCL_DEBUG)
#include <stdio.h>
static ucl_bool __ucl_assert_fail(const char *s, unsigned line)
{
#if defined(__palmos__)
    printf("UCL assertion failed in line %u: '%s'\n",line,s);
#else
    fprintf(stderr,"UCL assertion failed in line %u: '%s'\n",line,s);
#endif
    return 0;
}
#  define __ucl_assert(x)   ((x) ? 1 : __ucl_assert_fail(#x,__LINE__))
#else
#  define __ucl_assert(x)   ((x) ? 1 : 0)
#endif


/***********************************************************************
// basic_check - compile time assertions
************************************************************************/

#if 1

#undef ACCCHK_ASSERT
#define ACCCHK_ASSERT(expr)     ACC_COMPILE_TIME_ASSERT_HEADER(expr)

#include "acc/acc_chk.ch"

    ACCCHK_ASSERT_IS_SIGNED_T(ucl_int)
    ACCCHK_ASSERT_IS_UNSIGNED_T(ucl_uint)

    ACCCHK_ASSERT_IS_SIGNED_T(ucl_int32)
    ACCCHK_ASSERT_IS_UNSIGNED_T(ucl_uint32)
    ACCCHK_ASSERT((UCL_UINT32_C(1) << (int)(8*sizeof(UCL_UINT32_C(1))-1)) > 0)

    ACCCHK_ASSERT_IS_UNSIGNED_T(ucl_uintptr_t)
    ACCCHK_ASSERT(sizeof(ucl_uintptr_t) >= sizeof(ucl_voidp))

#endif
#undef ACCCHK_ASSERT


/***********************************************************************
//
************************************************************************/

static ucl_bool ptr_check(void)
{
    ucl_bool r = 1;
    int i;
    unsigned char _wrkmem[10 * sizeof(ucl_bytep) + sizeof(ucl_align_t)];
    ucl_bytep wrkmem;
    ucl_bytepp dict;
    unsigned char x[4 * sizeof(ucl_align_t)];
    long d;
    ucl_align_t a;

    for (i = 0; i < (int) sizeof(x); i++)
        x[i] = UCL_BYTE(i);

    memset(_wrkmem,0xff,sizeof(_wrkmem));
    wrkmem = UCL_PTR_ALIGN_UP((ucl_bytep)_wrkmem, sizeof(ucl_align_t));

    dict = (ucl_bytepp) (ucl_voidp) wrkmem;

    d = (long) ((const ucl_bytep) dict - (const ucl_bytep) _wrkmem);
    r &= __ucl_assert(d >= 0);
    r &= __ucl_assert(d < (long) sizeof(ucl_align_t));

    /* this may seem obvious, but some compilers incorrectly inline memset */
    memset(&a,0xff,sizeof(a));
    r &= __ucl_assert(a.a_ushort == USHRT_MAX);
    r &= __ucl_assert(a.a_uint == UINT_MAX);
    r &= __ucl_assert(a.a_ulong == ULONG_MAX);
    r &= __ucl_assert(a.a_ucl_uint == UCL_UINT_MAX);

    /* sanity check of the memory model */
    if (r == 1)
    {
        for (i = 0; i < 8; i++)
            r &= __ucl_assert((const ucl_voidp) (&dict[i]) == (const ucl_voidp) (&wrkmem[i * sizeof(ucl_bytep)]));
    }

    /* check that NULL == 0 */
    memset(&a,0,sizeof(a));
    r &= __ucl_assert(a.a_char_p == NULL);
    r &= __ucl_assert(a.a_ucl_bytep == NULL);

    /* check that the pointer constructs work as expected */
    if (r == 1)
    {
        unsigned k = 1;
        const unsigned n = (unsigned) sizeof(ucl_uint32);
        ucl_bytep p0;
        ucl_bytep p1;

        k += __ucl_align_gap(&x[k],n);
        p0 = (ucl_bytep) &x[k];
#if defined(PTR_LINEAR)
        r &= __ucl_assert((PTR_LINEAR(p0) & (n-1)) == 0);
#else
        r &= __ucl_assert(n == 4);
        r &= __ucl_assert(PTR_ALIGNED_4(p0));
#endif

        r &= __ucl_assert(k >= 1);
        p1 = (ucl_bytep) &x[1];
        r &= __ucl_assert(PTR_GE(p0,p1));

        r &= __ucl_assert(k < 1u+n);
        p1 = (ucl_bytep) &x[1+n];
        r &= __ucl_assert(PTR_LT(p0,p1));

        /* now check that aligned memory access doesn't core dump */
        if (r == 1)
        {
            ucl_uint32 v0, v1;
            v0 = * (ucl_uint32p) (ucl_voidp) &x[k];
            v1 = * (ucl_uint32p) (ucl_voidp) &x[k+n];
            r &= __ucl_assert(v0 > 0);
            r &= __ucl_assert(v1 > 0);
        }
    }

    return r;
}


/***********************************************************************
//
************************************************************************/

UCL_PUBLIC(int)
_ucl_config_check(void)
{
    ucl_bool r = 1;
    int i;
    union {
        ucl_uint32 a;
        unsigned short b;
        ucl_uint32 aa[4];
        unsigned char x[4*sizeof(ucl_align_t)];
    } u;

    u.a = 0; u.b = 0;
    for (i = 0; i < (int) sizeof(u.x); i++)
        u.x[i] = UCL_BYTE(i);

#if defined(ACC_ENDIAN_BIG_ENDIAN) || defined(ACC_ENDIAN_LITTLE_ENDIAN)
    if (r == 1)
    {
#  if defined(ACC_ENDIAN_BIG_ENDIAN)
        ucl_uint32 a = u.a >> (8 * sizeof(u.a) - 32);
        unsigned short b = u.b >> (8 * sizeof(u.b) - 16);
        r &= __ucl_assert(a == UCL_UINT32_C(0x00010203));
        r &= __ucl_assert(b == 0x0001);
#  endif
#  if defined(ACC_ENDIAN_LITTLE_ENDIAN)
        ucl_uint32 a = (ucl_uint32) (u.a & UCL_UINT32_C(0xffffffff));
        unsigned short b = (unsigned short) (u.b & 0xffff);
        r &= __ucl_assert(a == UCL_UINT32_C(0x03020100));
        r &= __ucl_assert(b == 0x0100);
#  endif
    }
#endif

    /* check that unaligned memory access works as expected */
#if defined(UA_GET2)
    if (r == 1)
    {
        unsigned short b[4];
        for (i = 0; i < 4; i++)
            b[i] = UA_GET2(&u.x[i]);
#  if defined(ACC_ENDIAN_LITTLE_ENDIAN)
        r &= __ucl_assert(b[0] == 0x0100);
        r &= __ucl_assert(b[1] == 0x0201);
        r &= __ucl_assert(b[2] == 0x0302);
        r &= __ucl_assert(b[3] == 0x0403);
#  endif
#  if defined(ACC_ENDIAN_BIG_ENDIAN)
        r &= __ucl_assert(b[0] == 0x0001);
        r &= __ucl_assert(b[1] == 0x0102);
        r &= __ucl_assert(b[2] == 0x0203);
        r &= __ucl_assert(b[3] == 0x0304);
#  endif
        ACC_UNUSED(b);
    }
#endif

#if defined(UA_GET4)
    if (r == 1)
    {
        ucl_uint32 a[4];
        for (i = 0; i < 4; i++)
            a[i] = UA_GET4(&u.x[i]);
#  if defined(ACC_ENDIAN_LITTLE_ENDIAN)
        r &= __ucl_assert(a[0] == UCL_UINT32_C(0x03020100));
        r &= __ucl_assert(a[1] == UCL_UINT32_C(0x04030201));
        r &= __ucl_assert(a[2] == UCL_UINT32_C(0x05040302));
        r &= __ucl_assert(a[3] == UCL_UINT32_C(0x06050403));
#  endif
#  if defined(ACC_ENDIAN_BIG_ENDIAN)
        r &= __ucl_assert(a[0] == UCL_UINT32_C(0x00010203));
        r &= __ucl_assert(a[1] == UCL_UINT32_C(0x01020304));
        r &= __ucl_assert(a[2] == UCL_UINT32_C(0x02030405));
        r &= __ucl_assert(a[3] == UCL_UINT32_C(0x03040506));
#  endif
        ACC_UNUSED(a);
    }
#endif

    /* check the ucl_adler32() function */
    if (r == 1)
    {
        ucl_uint32 adler;
        adler = ucl_adler32(0, NULL, 0);
        adler = ucl_adler32(adler, ucl_copyright(), 195);
        r &= __ucl_assert(adler == UCL_UINT32_C(0x52ca3a75));
    }

    /* check for the gcc schedule-insns optimization bug */
    if (r == 1)
    {
        r &= __ucl_assert(!schedule_insns_bug());
    }

    /* check for the gcc strength-reduce optimization bug */
    if (r == 1)
    {
        static int x[3];
        static unsigned xn = 3;
        register unsigned j;

        for (j = 0; j < xn; j++)
            x[j] = (int)j - 3;
        r &= __ucl_assert(!strength_reduce_bug(x));
    }

    /* now for the low-level pointer checks */
    if (r == 1)
    {
        r &= ptr_check();
    }

    ACC_UNUSED(u);
    return r == 1 ? UCL_E_OK : UCL_E_ERROR;
}


static ucl_bool schedule_insns_bug(void)
{
#if defined(__UCL_CHECKER)
    /* for some reason checker complains about uninitialized memory access */
    return 0;
#else
    const int clone[] = {1, 2, 0};
    const int *q;
    q = clone;
    return (*q) ? 0 : 1;
#endif
}


static ucl_bool strength_reduce_bug(int *x)
{
#if 1 && (ACC_CC_DMC || ACC_CC_SYMANTECC || ACC_CC_ZORTECHC)
    return 0;
#else
    return x[0] != -3 || x[1] != -2 || x[2] != -1;
#endif
}


/***********************************************************************
//
************************************************************************/

int __ucl_init_done = 0;

UCL_PUBLIC(int)
__ucl_init2(ucl_uint32 v, int s1, int s2, int s3, int s4, int s5,
                          int s6, int s7, int s8, int s9)
{
    int r;

#if (ACC_CC_MSC && ((_MSC_VER) < 700))
#else
#include "acc/acc_chk.ch"
#undef ACCCHK_ASSERT
#endif

    __ucl_init_done = 1;

    if (v == 0)
        return UCL_E_ERROR;

    r = (s1 == -1 || s1 == (int) sizeof(short)) &&
        (s2 == -1 || s2 == (int) sizeof(int)) &&
        (s3 == -1 || s3 == (int) sizeof(long)) &&
        (s4 == -1 || s4 == (int) sizeof(ucl_uint32)) &&
        (s5 == -1 || s5 == (int) sizeof(ucl_uint)) &&
        (s6 == -1 || s6 > 0) &&
        (s7 == -1 || s7 == (int) sizeof(char *)) &&
        (s8 == -1 || s8 == (int) sizeof(ucl_voidp)) &&
        (s9 == -1 || s9 == (int) sizeof(ucl_compress_t));
    if (!r)
        return UCL_E_ERROR;

    r = _ucl_config_check();
    if (r != UCL_E_OK)
        return r;

    return r;
}


#include "ucl_dll.ch"


/*
vi:ts=4:et
*/
