created ZSTD_compress2() and ZSTD_compressStream2()

ZSTD_compress_generic() is renamed ZSTD_compressStream2().

Note that, for the time being,
the "stable" API and advanced one use different parameter planes :
setting parameters using the advanced API does not influence ZSTD_compressStream()
and using ZSTD_initCStream() does not influence parameters for ZSTD_compressStream2().

programs/benchzstd.c

@@ -223,22 +223,8 @@ static size_t local_defaultCompress(
                     void* dstBuffer, size_t dstSize,
                     void* addArgs)
 {
-    size_t moreToFlush = 1;
     ZSTD_CCtx* const cctx = (ZSTD_CCtx*)addArgs;
-    ZSTD_inBuffer in;
-    ZSTD_outBuffer out;
-    in.src = srcBuffer; in.size = srcSize; in.pos = 0;
-    out.dst = dstBuffer; out.size = dstSize; out.pos = 0;
-    while (moreToFlush) {
-        if(out.pos == out.size) {
-            return (size_t)-ZSTD_error_dstSize_tooSmall;
-        }
-        moreToFlush = ZSTD_compress_generic(cctx, &out, &in, ZSTD_e_end);
-        if (ZSTD_isError(moreToFlush)) {
-            return moreToFlush;
-        }
-    }
-    return out.pos;
+    return ZSTD_compress2(cctx, dstBuffer, dstSize, srcBuffer, srcSize);
 }
 
 /* `addArgs` is the context */

programs/fileio.c

@@ -884,7 +884,7 @@ FIO_compressZstdFrame(const cRess_t* ressPtr,
             size_t const oldIPos = inBuff.pos;
             ZSTD_outBuffer outBuff = { ress.dstBuffer, ress.dstBufferSize, 0 };
             size_t const toFlushNow = ZSTD_toFlushNow(ress.cctx);
-            CHECK_V(stillToFlush, ZSTD_compress_generic(ress.cctx, &outBuff, &inBuff, directive));
+            CHECK_V(stillToFlush, ZSTD_compressStream2(ress.cctx, &outBuff, &inBuff, directive));
 
             /* count stats */
             inputPresented++;