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ext/zstd/programs/datagen.c  view on Meta::CPAN

/*
 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under both the BSD-style license (found in the
 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
 * in the COPYING file in the root directory of this source tree).
 * You may select, at your option, one of the above-listed licenses.
 */



/*-************************************
*  Dependencies
**************************************/
#include "datagen.h"
#include "platform.h"  /* SET_BINARY_MODE */
#include <stdlib.h>    /* malloc, free */
#include <stdio.h>     /* FILE, fwrite, fprintf */
#include <string.h>    /* memcpy */
#include "mem.h"       /* U32 */


/*-************************************
*  Macros
**************************************/
#define KB *(1 <<10)
#define MIN(a,b)  ( (a) < (b) ? (a) : (b) )

#define RDG_DEBUG 0
#define TRACE(...)   if (RDG_DEBUG) fprintf(stderr, __VA_ARGS__ )


/*-************************************
*  Local constants
**************************************/
#define LTLOG 13
#define LTSIZE (1<<LTLOG)
#define LTMASK (LTSIZE-1)


/*-*******************************************************
*  Local Functions
*********************************************************/
#define RDG_rotl32(x,r) ((x << r) | (x >> (32 - r)))
static U32 RDG_rand(U32* src)
{
    static const U32 prime1 = 2654435761U;
    static const U32 prime2 = 2246822519U;
    U32 rand32 = *src;
    rand32 *= prime1;
    rand32 ^= prime2;
    rand32  = RDG_rotl32(rand32, 13);
    *src = rand32;
    return rand32 >> 5;
}

typedef U32 fixedPoint_24_8;

static void RDG_fillLiteralDistrib(BYTE* ldt, fixedPoint_24_8 ld)
{
    BYTE const firstChar = (ld<=0.0) ?   0 : '(';
    BYTE const lastChar  = (ld<=0.0) ? 255 : '}';
    BYTE character = (ld<=0.0) ? 0 : '0';
    U32 u;

    if (ld<=0) ld = 0;
    for (u=0; u<LTSIZE; ) {
        U32 const weight = (((LTSIZE - u) * ld) >> 8) + 1;
        U32 const end = MIN ( u + weight , LTSIZE);
        while (u < end) ldt[u++] = character;
        character++;
        if (character > lastChar) character = firstChar;
    }
}


static BYTE RDG_genChar(U32* seed, const BYTE* ldt)
{
    U32 const id = RDG_rand(seed) & LTMASK;
    return ldt[id];  /* memory-sanitizer fails here, stating "uninitialized value" when table initialized with P==0.0. Checked : table is fully initialized */
}


static U32 RDG_rand15Bits (U32* seedPtr)