diff --git a/vendor/github.com/DataDog/zstd/fastcover.c b/vendor/github.com/DataDog/zstd/fastcover.c
index 5b6b941..941bb5a 100644
--- a/vendor/github.com/DataDog/zstd/fastcover.c
+++ b/vendor/github.com/DataDog/zstd/fastcover.c
@@ -287,10 +287,10 @@
  * Prepare a context for dictionary building.
  * The context is only dependent on the parameter `d` and can used multiple
  * times.
- * Returns 1 on success or zero on error.
+ * Returns 0 on success or error code on error.
  * The context must be destroyed with `FASTCOVER_ctx_destroy()`.
  */
-static int
+static size_t
 FASTCOVER_ctx_init(FASTCOVER_ctx_t* ctx,
                    const void* samplesBuffer,
                    const size_t* samplesSizes, unsigned nbSamples,
@@ -310,19 +310,19 @@
         totalSamplesSize >= (size_t)FASTCOVER_MAX_SAMPLES_SIZE) {
         DISPLAYLEVEL(1, "Total samples size is too large (%u MB), maximum size is %u MB\n",
                     (unsigned)(totalSamplesSize >> 20), (FASTCOVER_MAX_SAMPLES_SIZE >> 20));
-        return 0;
+        return ERROR(srcSize_wrong);
     }
 
     /* Check if there are at least 5 training samples */
     if (nbTrainSamples < 5) {
         DISPLAYLEVEL(1, "Total number of training samples is %u and is invalid\n", nbTrainSamples);
-        return 0;
+        return ERROR(srcSize_wrong);
     }
 
     /* Check if there's testing sample */
     if (nbTestSamples < 1) {
         DISPLAYLEVEL(1, "Total number of testing samples is %u and is invalid.\n", nbTestSamples);
-        return 0;
+        return ERROR(srcSize_wrong);
     }
 
     /* Zero the context */
@@ -347,7 +347,7 @@
     if (ctx->offsets == NULL) {
         DISPLAYLEVEL(1, "Failed to allocate scratch buffers \n");
         FASTCOVER_ctx_destroy(ctx);
-        return 0;
+        return ERROR(memory_allocation);
     }
 
     /* Fill offsets from the samplesSizes */
@@ -364,13 +364,13 @@
     if (ctx->freqs == NULL) {
         DISPLAYLEVEL(1, "Failed to allocate frequency table \n");
         FASTCOVER_ctx_destroy(ctx);
-        return 0;
+        return ERROR(memory_allocation);
     }
 
     DISPLAYLEVEL(2, "Computing frequencies\n");
     FASTCOVER_computeFrequency(ctx->freqs, ctx);
 
-    return 1;
+    return 0;
 }
 
 
@@ -435,7 +435,6 @@
   return tail;
 }
 
-
 /**
  * Parameters for FASTCOVER_tryParameters().
  */
@@ -464,6 +463,7 @@
   U16* segmentFreqs = (U16 *)calloc(((U64)1 << ctx->f), sizeof(U16));
   /* Allocate space for hash table, dict, and freqs */
   BYTE *const dict = (BYTE * const)malloc(dictBufferCapacity);
+  COVER_dictSelection_t selection = COVER_dictSelectionError(ERROR(GENERIC));
   U32 *freqs = (U32*) malloc(((U64)1 << ctx->f) * sizeof(U32));
   if (!segmentFreqs || !dict || !freqs) {
     DISPLAYLEVEL(1, "Failed to allocate buffers: out of memory\n");
@@ -473,27 +473,24 @@
   memcpy(freqs, ctx->freqs, ((U64)1 << ctx->f) * sizeof(U32));
   /* Build the dictionary */
   { const size_t tail = FASTCOVER_buildDictionary(ctx, freqs, dict, dictBufferCapacity,
-                                                  parameters, segmentFreqs);
+                                                    parameters, segmentFreqs);
+
     const unsigned nbFinalizeSamples = (unsigned)(ctx->nbTrainSamples * ctx->accelParams.finalize / 100);
-    dictBufferCapacity = ZDICT_finalizeDictionary(
-        dict, dictBufferCapacity, dict + tail, dictBufferCapacity - tail,
-        ctx->samples, ctx->samplesSizes, nbFinalizeSamples, parameters.zParams);
-    if (ZDICT_isError(dictBufferCapacity)) {
-      DISPLAYLEVEL(1, "Failed to finalize dictionary\n");
+    selection = COVER_selectDict(dict + tail, dictBufferCapacity - tail,
+         ctx->samples, ctx->samplesSizes, nbFinalizeSamples, ctx->nbTrainSamples, ctx->nbSamples, parameters, ctx->offsets,
+         totalCompressedSize);
+
+    if (COVER_dictSelectionIsError(selection)) {
+      DISPLAYLEVEL(1, "Failed to select dictionary\n");
       goto _cleanup;
     }
   }
-  /* Check total compressed size */
-  totalCompressedSize = COVER_checkTotalCompressedSize(parameters, ctx->samplesSizes,
-                                                       ctx->samples, ctx->offsets,
-                                                       ctx->nbTrainSamples, ctx->nbSamples,
-                                                       dict, dictBufferCapacity);
 _cleanup:
-  COVER_best_finish(data->best, totalCompressedSize, parameters, dict,
-                    dictBufferCapacity);
+  free(dict);
+  COVER_best_finish(data->best, parameters, selection);
   free(data);
   free(segmentFreqs);
-  free(dict);
+  COVER_dictSelectionFree(selection);
   free(freqs);
 }
 
@@ -508,6 +505,7 @@
     coverParams->nbThreads = fastCoverParams.nbThreads;
     coverParams->splitPoint = fastCoverParams.splitPoint;
     coverParams->zParams = fastCoverParams.zParams;
+    coverParams->shrinkDict = fastCoverParams.shrinkDict;
 }
 
 
@@ -524,6 +522,7 @@
     fastCoverParams->f = f;
     fastCoverParams->accel = accel;
     fastCoverParams->zParams = coverParams.zParams;
+    fastCoverParams->shrinkDict = coverParams.shrinkDict;
 }
 
 
@@ -550,11 +549,11 @@
     if (!FASTCOVER_checkParameters(coverParams, dictBufferCapacity, parameters.f,
                                    parameters.accel)) {
       DISPLAYLEVEL(1, "FASTCOVER parameters incorrect\n");
-      return ERROR(GENERIC);
+      return ERROR(parameter_outOfBound);
     }
     if (nbSamples == 0) {
       DISPLAYLEVEL(1, "FASTCOVER must have at least one input file\n");
-      return ERROR(GENERIC);
+      return ERROR(srcSize_wrong);
     }
     if (dictBufferCapacity < ZDICT_DICTSIZE_MIN) {
       DISPLAYLEVEL(1, "dictBufferCapacity must be at least %u\n",
@@ -564,11 +563,14 @@
     /* Assign corresponding FASTCOVER_accel_t to accelParams*/
     accelParams = FASTCOVER_defaultAccelParameters[parameters.accel];
     /* Initialize context */
-    if (!FASTCOVER_ctx_init(&ctx, samplesBuffer, samplesSizes, nbSamples,
+    {
+      size_t const initVal = FASTCOVER_ctx_init(&ctx, samplesBuffer, samplesSizes, nbSamples,
                             coverParams.d, parameters.splitPoint, parameters.f,
-                            accelParams)) {
-      DISPLAYLEVEL(1, "Failed to initialize context\n");
-      return ERROR(GENERIC);
+                            accelParams);
+      if (ZSTD_isError(initVal)) {
+        DISPLAYLEVEL(1, "Failed to initialize context\n");
+        return initVal;
+      }
     }
     COVER_warnOnSmallCorpus(dictBufferCapacity, ctx.nbDmers, g_displayLevel);
     /* Build the dictionary */
@@ -616,6 +618,7 @@
         (1 + (kMaxD - kMinD) / 2) * (1 + (kMaxK - kMinK) / kStepSize);
     const unsigned f = parameters->f == 0 ? DEFAULT_F : parameters->f;
     const unsigned accel = parameters->accel == 0 ? DEFAULT_ACCEL : parameters->accel;
+    const unsigned shrinkDict = 0;
     /* Local variables */
     const int displayLevel = parameters->zParams.notificationLevel;
     unsigned iteration = 1;
@@ -627,19 +630,19 @@
     /* Checks */
     if (splitPoint <= 0 || splitPoint > 1) {
       LOCALDISPLAYLEVEL(displayLevel, 1, "Incorrect splitPoint\n");
-      return ERROR(GENERIC);
+      return ERROR(parameter_outOfBound);
     }
     if (accel == 0 || accel > FASTCOVER_MAX_ACCEL) {
       LOCALDISPLAYLEVEL(displayLevel, 1, "Incorrect accel\n");
-      return ERROR(GENERIC);
+      return ERROR(parameter_outOfBound);
     }
     if (kMinK < kMaxD || kMaxK < kMinK) {
       LOCALDISPLAYLEVEL(displayLevel, 1, "Incorrect k\n");
-      return ERROR(GENERIC);
+      return ERROR(parameter_outOfBound);
     }
     if (nbSamples == 0) {
       LOCALDISPLAYLEVEL(displayLevel, 1, "FASTCOVER must have at least one input file\n");
-      return ERROR(GENERIC);
+      return ERROR(srcSize_wrong);
     }
     if (dictBufferCapacity < ZDICT_DICTSIZE_MIN) {
       LOCALDISPLAYLEVEL(displayLevel, 1, "dictBufferCapacity must be at least %u\n",
@@ -666,11 +669,14 @@
       /* Initialize the context for this value of d */
       FASTCOVER_ctx_t ctx;
       LOCALDISPLAYLEVEL(displayLevel, 3, "d=%u\n", d);
-      if (!FASTCOVER_ctx_init(&ctx, samplesBuffer, samplesSizes, nbSamples, d, splitPoint, f, accelParams)) {
-        LOCALDISPLAYLEVEL(displayLevel, 1, "Failed to initialize context\n");
-        COVER_best_destroy(&best);
-        POOL_free(pool);
-        return ERROR(GENERIC);
+      {
+        size_t const initVal = FASTCOVER_ctx_init(&ctx, samplesBuffer, samplesSizes, nbSamples, d, splitPoint, f, accelParams);
+        if (ZSTD_isError(initVal)) {
+          LOCALDISPLAYLEVEL(displayLevel, 1, "Failed to initialize context\n");
+          COVER_best_destroy(&best);
+          POOL_free(pool);
+          return initVal;
+        }
       }
       if (!warned) {
         COVER_warnOnSmallCorpus(dictBufferCapacity, ctx.nbDmers, displayLevel);
@@ -687,7 +693,7 @@
           COVER_best_destroy(&best);
           FASTCOVER_ctx_destroy(&ctx);
           POOL_free(pool);
-          return ERROR(GENERIC);
+          return ERROR(memory_allocation);
         }
         data->ctx = &ctx;
         data->best = &best;
@@ -697,6 +703,7 @@
         data->parameters.d = d;
         data->parameters.splitPoint = splitPoint;
         data->parameters.steps = kSteps;
+        data->parameters.shrinkDict = shrinkDict;
         data->parameters.zParams.notificationLevel = g_displayLevel;
         /* Check the parameters */
         if (!FASTCOVER_checkParameters(data->parameters, dictBufferCapacity,