Integrated dictionary builder into zstd cli
diff --git a/programs/dibio.c b/programs/dibio.c
new file mode 100644
index 0000000..a471d54
--- /dev/null
+++ b/programs/dibio.c
@@ -0,0 +1,275 @@
+/*
+    dibio - I/O API for dictionary builder
+    Copyright (C) Yann Collet 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 :
+    - zstd homepage : http://www.zstd.net/
+*/
+
+/*-**************************************
+*  Compiler Options
+****************************************/
+/* Disable some Visual warning messages */
+#ifdef _MSC_VER
+#  define _CRT_SECURE_NO_WARNINGS                /* fopen */
+#  pragma warning(disable : 4127)                /* disable: C4127: conditional expression is constant */
+#endif
+
+/* Unix Large Files support (>4GB) */
+#define _FILE_OFFSET_BITS 64
+#if (defined(__sun__) && (!defined(__LP64__)))   /* Sun Solaris 32-bits requires specific definitions */
+#  define _LARGEFILE_SOURCE
+#elif ! defined(__LP64__)                        /* No point defining Large file for 64 bit */
+#  define _LARGEFILE64_SOURCE
+#endif
+
+
+/*-*************************************
+*  Includes
+***************************************/
+#include <stdlib.h>         /* malloc, free */
+#include <string.h>         /* memset */
+#include <stdio.h>          /* fprintf, fopen, ftello64 */
+#include <sys/types.h>      /* stat64 */
+#include <sys/stat.h>       /* stat64 */
+#include <time.h>           /* clock */
+
+#include "mem.h"            /* read */
+#include "error_private.h"
+#include "dictBuilder_static.h"
+
+/*-*************************************
+*  Compiler specifics
+***************************************/
+#if !defined(S_ISREG)
+#  define S_ISREG(x) (((x) & S_IFMT) == S_IFREG)
+#endif
+
+
+/*-*************************************
+*  Constants
+***************************************/
+#define KB *(1 <<10)
+#define MB *(1 <<20)
+#define GB *(1U<<30)
+
+#define DICTLISTSIZE 10000
+#define MEMMULT 11
+static const size_t maxMemory = (sizeof(size_t) == 4) ? (2 GB - 64 MB) : ((size_t)(512 MB) << sizeof(size_t));
+
+#define NOISELENGTH 32
+#define PRIME1   2654435761U
+#define PRIME2   2246822519U
+
+
+/*-*************************************
+*  Console display
+***************************************/
+#define DISPLAY(...)         fprintf(stderr, __VA_ARGS__)
+#define DISPLAYLEVEL(l, ...) if (g_displayLevel>=l) { DISPLAY(__VA_ARGS__); }
+static unsigned g_displayLevel = 0;   /* 0 : no display;   1: errors;   2: default;  4: full information */
+void DiB_setNotificationLevel(unsigned l) { g_displayLevel=l; ZDICT_setNotificationLevel(l); }
+
+void DiB_printHex(U32 dlevel, const void* ptr, size_t length)
+{
+    const BYTE* const b = (const BYTE*)ptr;
+    size_t u;
+    for (u=0; u<length; u++) {
+        BYTE c = b[u];
+        if (c<32 || c>126) c = '.';   /* non-printable char */
+        DISPLAYLEVEL(dlevel, "%c", c);
+    }
+}
+
+
+/*-*************************************
+*  Exceptions
+***************************************/
+#ifndef DEBUG
+#  define DEBUG 0
+#endif
+#define DEBUGOUTPUT(...) if (DEBUG) DISPLAY(__VA_ARGS__);
+#define EXM_THROW(error, ...)                                             \
+{                                                                         \
+    DEBUGOUTPUT("Error defined at %s, line %i : \n", __FILE__, __LINE__); \
+    DISPLAYLEVEL(1, "Error %i : ", error);                                \
+    DISPLAYLEVEL(1, __VA_ARGS__);                                         \
+    DISPLAYLEVEL(1, "\n");                                                \
+    exit(error);                                                          \
+}
+
+
+/* ********************************************************
+*  Helper functions
+**********************************************************/
+unsigned DiB_isError(size_t errorCode) { return ERR_isError(errorCode); }
+
+const char* DiB_getErrorName(size_t errorCode) { return ERR_getErrorName(errorCode); }
+
+
+/* ********************************************************
+*  File related operations
+**********************************************************/
+static unsigned long long DiB_getFileSize(const char* infilename)
+{
+    int r;
+#if defined(_MSC_VER)
+    struct _stat64 statbuf;
+    r = _stat64(infilename, &statbuf);
+#else
+    struct stat statbuf;
+    r = stat(infilename, &statbuf);
+#endif
+    if (r || !S_ISREG(statbuf.st_mode)) return 0;   /* No good... */
+    return (unsigned long long)statbuf.st_size;
+}
+
+
+static unsigned long long DiB_getTotalFileSize(const char** fileNamesTable, unsigned nbFiles)
+{
+    unsigned long long total = 0;
+    unsigned n;
+    for (n=0; n<nbFiles; n++)
+        total += DiB_getFileSize(fileNamesTable[n]);
+    return total;
+}
+
+
+static void DiB_loadFiles(void* buffer, size_t bufferSize,
+                          size_t* fileSizes,
+                          const char** fileNamesTable, unsigned nbFiles)
+{
+    char* buff = (char*)buffer;
+    size_t pos = 0;
+    unsigned n;
+
+    for (n=0; n<nbFiles; n++) {
+        size_t readSize;
+        unsigned long long fileSize = DiB_getFileSize(fileNamesTable[n]);
+        FILE* f = fopen(fileNamesTable[n], "rb");
+        if (f==NULL) EXM_THROW(10, "impossible to open file %s", fileNamesTable[n]);
+        DISPLAYLEVEL(2, "Loading %s...       \r", fileNamesTable[n]);
+        if (fileSize > bufferSize-pos) fileSize = 0;  /* stop there, not enough memory to load all files */
+        readSize = fread(buff+pos, 1, (size_t)fileSize, f);
+        if (readSize != (size_t)fileSize) EXM_THROW(11, "could not read %s", fileNamesTable[n]);
+        pos += readSize;
+        fileSizes[n] = (size_t)fileSize;
+        fclose(f);
+    }
+}
+
+
+/*-********************************************************
+*  Dictionary training functions
+**********************************************************/
+static size_t DiB_findMaxMem(unsigned long long requiredMem)
+{
+    size_t step = 8 MB;
+    void* testmem = NULL;
+
+    requiredMem = (((requiredMem >> 23) + 1) << 23);
+    requiredMem += 2 * step;
+    if (requiredMem > maxMemory) requiredMem = maxMemory;
+
+    while (!testmem) {
+        requiredMem -= step;
+        testmem = malloc((size_t)requiredMem);
+    }
+
+    free(testmem);
+    return (size_t)(requiredMem - step);
+}
+
+
+static void DiB_fillNoise(void* buffer, size_t length)
+{
+    unsigned acc = PRIME1;
+    size_t p=0;;
+
+    for (p=0; p<length; p++) {
+        acc *= PRIME2;
+        ((unsigned char*)buffer)[p] = (unsigned char)(acc >> 21);
+    }
+}
+
+
+static void DiB_saveDict(const char* dictFileName,
+                         const void* buff, size_t buffSize)
+{
+    FILE* f;
+    size_t n;
+
+    f = fopen(dictFileName, "wb");
+    if (f==NULL) EXM_THROW(3, "cannot open %s ", dictFileName);
+
+    n = fwrite(buff, 1, buffSize, f);
+    if (n!=buffSize) EXM_THROW(4, "%s : write error", dictFileName)
+
+    n = (size_t)fclose(f);
+    if (n!=0) EXM_THROW(5, "%s : flush error", dictFileName)
+}
+
+
+int DiB_trainFromFiles(const char* dictFileName, unsigned maxDictSize,
+                       const char** fileNamesTable, unsigned nbFiles,
+                       ZDICT_params_t params)
+{
+    void* srcBuffer;
+    size_t benchedSize;
+    size_t* fileSizes = (size_t*)malloc(nbFiles * sizeof(size_t));
+    unsigned long long totalSizeToLoad = DiB_getTotalFileSize(fileNamesTable, nbFiles);
+    void* dictBuffer = malloc(maxDictSize);
+    size_t dictSize;
+    int result = 0;
+
+    /* init */
+    benchedSize = DiB_findMaxMem(totalSizeToLoad * MEMMULT) / MEMMULT;
+    if ((unsigned long long)benchedSize > totalSizeToLoad) benchedSize = (size_t)totalSizeToLoad;
+    if (benchedSize < totalSizeToLoad)
+        DISPLAYLEVEL(1, "Not enough memory; training on %u MB only...\n", (unsigned)(benchedSize >> 20));
+
+    /* Memory allocation & restrictions */
+    srcBuffer = malloc(benchedSize+NOISELENGTH);     /* + noise */
+    if ((!fileSizes) || (!srcBuffer) || (!dictBuffer)) EXM_THROW(12, "not enough memory for DiB_trainFiles");  /* should not happen */
+
+    /* Load input buffer */
+    DiB_loadFiles(srcBuffer, benchedSize, fileSizes, fileNamesTable, nbFiles);
+    DiB_fillNoise((char*)srcBuffer + benchedSize, NOISELENGTH);   /* guard band, for end of buffer condition */
+
+    /* call buffer version */
+    dictSize = ZDICT_trainFromBuffer_unsafe(dictBuffer, maxDictSize,
+                        srcBuffer, fileSizes, nbFiles,
+                        params);
+    if (ZDICT_isError(dictSize)) {
+        DISPLAYLEVEL(1, "dictionary training failed : %s", ZDICT_getErrorName(dictSize));   /* should not happen */
+        result = 1;
+        goto _cleanup;
+    }
+
+    /* save dict */
+    DISPLAYLEVEL(2, "Save dictionary of size %u into file %s \n", (U32)dictSize, dictFileName);
+    DiB_saveDict(dictFileName, dictBuffer, dictSize);
+
+    /* clean up */
+_cleanup:
+    free(srcBuffer);
+    free(dictBuffer);
+    free(fileSizes);
+    return result;
+}