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/*
datagen.c - compressible data generator test tool
Copyright (C) Yann Collet 2012-2016
GPL v2 License
This program 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.
This program 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 this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
You can contact the author at :
- LZ4 source repository : https://github.com/lz4/lz4
- Public forum : https://groups.google.com/forum/#!forum/lz4c
*/
/**************************************
* Includes
**************************************/
#include "platform.h" /* Compiler options, SET_BINARY_MODE */
#include "util.h" /* U32 */
#include <stdlib.h> /* malloc */
#include <stdio.h> /* FILE, fwrite */
#include <string.h> /* memcpy */
#include <assert.h>
/**************************************
* Constants
**************************************/
#define KB *(1 <<10)
#define PRIME1 2654435761U
#define PRIME2 2246822519U
/**************************************
* Local types
**************************************/
#define LTLOG 13
#define LTSIZE (1<<LTLOG)
#define LTMASK (LTSIZE-1)
typedef BYTE litDistribTable[LTSIZE];
/*********************************************************
* Local Functions
*********************************************************/
#define MIN(a,b) ( (a) < (b) ? (a) :(b) )
#define RDG_rotl32(x,r) ((x << r) | (x >> (32 - r)))
static unsigned int RDG_rand(U32* src)
{
U32 rand32 = *src;
rand32 *= PRIME1;
rand32 ^= PRIME2;
rand32 = RDG_rotl32(rand32, 13);
*src = rand32;
return rand32;
}
static void RDG_fillLiteralDistrib(litDistribTable lt, double ld)
{
BYTE const firstChar = ld <= 0.0 ? 0 : '(';
BYTE const lastChar = ld <= 0.0 ? 255 : '}';
BYTE character = ld <= 0.0 ? 0 : '0';
U32 u = 0;
while (u<LTSIZE) {
U32 const weight = (U32)((double)(LTSIZE - u) * ld) + 1;
U32 const end = MIN(u+weight, LTSIZE);
while (u < end) {
assert(u<LTSIZE); /* try to ease static analyzer. u < end <= LTSIZE */
lt[u++] = character;
}
character++;
if (character > lastChar) character = firstChar;
}
}
static BYTE RDG_genChar(U32* seed, const litDistribTable lt)
{
U32 id = RDG_rand(seed) & LTMASK;
return (lt[id]);
}
#define RDG_DICTSIZE (32 KB)
#define RDG_RAND15BITS ((RDG_rand(seed) >> 3) & 32767)
#define RDG_RANDLENGTH ( ((RDG_rand(seed) >> 7) & 7) ? (RDG_rand(seed) & 15) : (RDG_rand(seed) & 511) + 15)
void RDG_genBlock(void* buffer, size_t buffSize, size_t prefixSize, double matchProba, litDistribTable lt, unsigned* seedPtr)
{
BYTE* buffPtr = (BYTE*)buffer;
const U32 matchProba32 = (U32)(32768 * matchProba);
size_t pos = prefixSize;
U32* seed = seedPtr;
/* special case */
while (matchProba >= 1.0) {
size_t size0 = RDG_rand(seed) & 3;
size0 = (size_t)1 << (16 + size0 * 2);
size0 += RDG_rand(seed) & (size0-1); /* because size0 is power of 2*/
if (buffSize < pos + size0) {
memset(buffPtr+pos, 0, buffSize-pos);
return;
}
memset(buffPtr+pos, 0, size0);
pos += size0;
buffPtr[pos-1] = RDG_genChar(seed, lt);
}
/* init */
if (pos==0) {
buffPtr[0] = RDG_genChar(seed, lt);
pos=1;
}
/* Generate compressible data */
while (pos < buffSize) {
/* Select : Literal (char) or Match (within 32K) */
if (RDG_RAND15BITS < matchProba32) {
/* Copy (within 32K) */
size_t match;
size_t d;
int length = RDG_RANDLENGTH + 4;
U32 offset = RDG_RAND15BITS + 1;
if (offset > pos) offset = (U32)pos;
match = pos - offset;
d = pos + length;
if (d > buffSize) d = buffSize;
while (pos < d) buffPtr[pos++] = buffPtr[match++];
} else {
/* Literal (noise) */
size_t d;
size_t length = RDG_RANDLENGTH;
d = pos + length;
if (d > buffSize) d = buffSize;
while (pos < d) buffPtr[pos++] = RDG_genChar(seed, lt);
}
}
}
void RDG_genBuffer(void* buffer, size_t size, double matchProba, double litProba, unsigned seed)
{
litDistribTable lt;
if (litProba==0.0) litProba = matchProba / 4.5;
RDG_fillLiteralDistrib(lt, litProba);
RDG_genBlock(buffer, size, 0, matchProba, lt, &seed);
}
#define RDG_BLOCKSIZE (128 KB)
void RDG_genOut(unsigned long long size, double matchProba, double litProba, unsigned seed)
{
BYTE buff[RDG_DICTSIZE + RDG_BLOCKSIZE];
U64 total = 0;
size_t genBlockSize = RDG_BLOCKSIZE;
litDistribTable lt;
/* init */
if (litProba==0.0) litProba = matchProba / 4.5;
RDG_fillLiteralDistrib(lt, litProba);
SET_BINARY_MODE(stdout);
/* Generate dict */
RDG_genBlock(buff, RDG_DICTSIZE, 0, matchProba, lt, &seed);
/* Generate compressible data */
while (total < size) {
RDG_genBlock(buff, RDG_DICTSIZE+RDG_BLOCKSIZE, RDG_DICTSIZE, matchProba, lt, &seed);
if (size-total < RDG_BLOCKSIZE) genBlockSize = (size_t)(size-total);
total += genBlockSize;
fwrite(buff, 1, genBlockSize, stdout); /* should check potential write error */
/* update dict */
memcpy(buff, buff + RDG_BLOCKSIZE, RDG_DICTSIZE);
}
}
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