1 files changed, 186 insertions, 0 deletions
diff --git a/src/zstd/programs/datagen.c b/src/zstd/programs/datagen.c
new file mode 100644
index 000000000..4353b7ff9
--- /dev/null
+++ b/src/zstd/programs/datagen.c
@@ -0,0 +1,186 @@
+/*
+ * Copyright (c) 2016-2020, 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 "../lib/common/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)
+{
+    return RDG_rand(seedPtr) & 0x7FFF;
+}
+
+static U32 RDG_randLength(U32* seedPtr)
+{
+    if (RDG_rand(seedPtr) & 7) return (RDG_rand(seedPtr) & 0xF);   /* small length */
+    return (RDG_rand(seedPtr) & 0x1FF) + 0xF;
+}
+
+static void RDG_genBlock(void* buffer, size_t buffSize, size_t prefixSize,
+                         double matchProba, const BYTE* ldt, U32* seedPtr)
+{
+    BYTE* const buffPtr = (BYTE*)buffer;
+    U32 const matchProba32 = (U32)(32768 * matchProba);
+    size_t pos = prefixSize;
+    U32 prevOffset = 1;
+
+    /* special case : sparse content */
+    while (matchProba >= 1.0) {
+        size_t size0 = RDG_rand(seedPtr) & 3;
+        size0  = (size_t)1 << (16 + size0 * 2);
+        size0 += RDG_rand(seedPtr) & (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(seedPtr, ldt);
+        continue;
+    }
+
+    /* init */
+    if (pos==0) buffPtr[0] = RDG_genChar(seedPtr, ldt), pos=1;
+
+    /* Generate compressible data */
+    while (pos < buffSize) {
+        /* Select : Literal (char) or Match (within 32K) */
+        if (RDG_rand15Bits(seedPtr) < matchProba32) {
+            /* Copy (within 32K) */
+            U32 const length = RDG_randLength(seedPtr) + 4;
+            U32 const d = (U32) MIN(pos + length , buffSize);
+            U32 const repeatOffset = (RDG_rand(seedPtr) & 15) == 2;
+            U32 const randOffset = RDG_rand15Bits(seedPtr) + 1;
+            U32 const offset = repeatOffset ? prevOffset : (U32) MIN(randOffset , pos);
+            size_t match = pos - offset;
+            while (pos < d) { buffPtr[pos++] = buffPtr[match++];   /* correctly manages overlaps */ }
+            prevOffset = offset;
+        } else {
+            /* Literal (noise) */
+            U32 const length = RDG_randLength(seedPtr);
+            U32 const d = (U32) MIN(pos + length, buffSize);
+            while (pos < d) { buffPtr[pos++] = RDG_genChar(seedPtr, ldt); }
+    }   }
+}
+
+
+void RDG_genBuffer(void* buffer, size_t size, double matchProba, double litProba, unsigned seed)
+{
+    U32 seed32 = seed;
+    BYTE ldt[LTSIZE];
+    memset(ldt, '0', sizeof(ldt));  /* yes, character '0', this is intentional */
+    if (litProba<=0.0) litProba = matchProba / 4.5;
+    RDG_fillLiteralDistrib(ldt, (fixedPoint_24_8)(litProba * 256 + 0.001));
+    RDG_genBlock(buffer, size, 0, matchProba, ldt, &seed32);
+}
+
+
+void RDG_genStdout(unsigned long long size, double matchProba, double litProba, unsigned seed)
+{
+    U32 seed32 = seed;
+    size_t const stdBlockSize = 128 KB;
+    size_t const stdDictSize = 32 KB;
+    BYTE* const buff = (BYTE*)malloc(stdDictSize + stdBlockSize);
+    U64 total = 0;
+    BYTE ldt[LTSIZE];   /* literals distribution table */
+
+    /* init */
+    if (buff==NULL) { perror("datagen"); exit(1); }
+    if (litProba<=0.0) litProba = matchProba / 4.5;
+    memset(ldt, '0', sizeof(ldt));   /* yes, character '0', this is intentional */
+    RDG_fillLiteralDistrib(ldt, (fixedPoint_24_8)(litProba * 256 + 0.001));
+    SET_BINARY_MODE(stdout);
+
+    /* Generate initial dict */
+    RDG_genBlock(buff, stdDictSize, 0, matchProba, ldt, &seed32);
+
+    /* Generate compressible data */
+    while (total < size) {
+        size_t const genBlockSize = (size_t) (MIN (stdBlockSize, size-total));
+        RDG_genBlock(buff, stdDictSize+stdBlockSize, stdDictSize, matchProba, ldt, &seed32);
+        total += genBlockSize;
+        { size_t const unused = fwrite(buff, 1, genBlockSize, stdout); (void)unused; }
+        /* update dict */
+        memcpy(buff, buff + stdBlockSize, stdDictSize);
+    }
+
+    /* cleanup */
+    free(buff);
+}