commit aafe97b67d30ec79609fac5ab4b228e89cda016b
author Nick Terrell <terrelln@fb.com> Wed Apr 10 16:50:35 2019 -0700
committer Nick Terrell <terrelln@fb.com> Wed Apr 10 16:50:35 2019 -0700
tree 1c0522a90873b0b3d182312f2d5b3261c2385dc7
parent 50b9c41196f77c3ff89cfd1d4cd4a81372b80c64

[libzstd] Switch dictUses to an enum

lib/decompress/zstd_decompress.c

diff --git a/lib/decompress/zstd_decompress.c b/lib/decompress/zstd_decompress.c
index bd955d6..4f29227 100644
--- a/lib/decompress/zstd_decompress.c
+++ b/lib/decompress/zstd_decompress.c
@@ -106,7 +106,7 @@
     dctx->ddictLocal  = NULL;
     dctx->dictEnd     = NULL;
     dctx->ddictIsCold = 0;
-    dctx->dictUsesRemaining = 0;
+    dctx->dictUses = ZSTD_dont_use;
     dctx->inBuff      = NULL;
     dctx->inBuffSize  = 0;
     dctx->outBuffSize = 0;
@@ -153,7 +153,7 @@
     ZSTD_freeDDict(dctx->ddictLocal);
     dctx->ddictLocal = NULL;
     dctx->ddict = NULL;
-    dctx->dictUsesRemaining = 0;
+    dctx->dictUses = ZSTD_dont_use;
 }
 
 size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx)
@@ -796,15 +796,19 @@
 
 static ZSTD_DDict const* ZSTD_getDDict(ZSTD_DCtx* dctx)
 {
-    if (dctx->dictUsesRemaining == 0) {
+    switch (dctx->dictUses) {
+    default:
+        assert(0 /* Impossible */);
+        /* fall-through */
+    case ZSTD_dont_use:
         ZSTD_clearDict(dctx);
         return NULL;
-    }
-    if (dctx->dictUsesRemaining < 0) {
+    case ZSTD_use_indefinitely:
+        return dctx->ddict;
+    case ZSTD_use_once:
+        dctx->dictUses = ZSTD_dont_use;
         return dctx->ddict;
     }
-    --dctx->dictUsesRemaining;
-    return dctx->ddict;
 }
 
 size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
@@ -1261,7 +1265,7 @@
         dctx->ddictLocal = ZSTD_createDDict_advanced(dict, dictSize, dictLoadMethod, dictContentType, dctx->customMem);
         RETURN_ERROR_IF(dctx->ddictLocal == NULL, memory_allocation);
         dctx->ddict = dctx->ddictLocal;
-        dctx->dictUsesRemaining = -1;
+        dctx->dictUses = ZSTD_use_indefinitely;
     }
     return 0;
 }
@@ -1279,7 +1283,7 @@
 size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType)
 {
     FORWARD_IF_ERROR(ZSTD_DCtx_loadDictionary_advanced(dctx, prefix, prefixSize, ZSTD_dlm_byRef, dictContentType));
-    dctx->dictUsesRemaining = 1;
+    dctx->dictUses = ZSTD_use_once;
     return 0;
 }
 
@@ -1333,7 +1337,7 @@
     ZSTD_clearDict(dctx);
     if (ddict) {
         dctx->ddict = ddict;
-        dctx->dictUsesRemaining = -1;
+        dctx->dictUses = ZSTD_use_indefinitely;
     }
     return 0;
 }

lib/decompress/zstd_decompress_internal.h

diff --git a/lib/decompress/zstd_decompress_internal.h b/lib/decompress/zstd_decompress_internal.h
index ea07243..ccbdfa0 100644
--- a/lib/decompress/zstd_decompress_internal.h
+++ b/lib/decompress/zstd_decompress_internal.h
@@ -89,6 +89,12 @@
 typedef enum { zdss_init=0, zdss_loadHeader,
                zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage;
 
+typedef enum {
+    ZSTD_use_indefinitely = -1,  /* Use the dictionary indefinitely */
+    ZSTD_dont_use = 0,           /* Do not use the dictionary (if one exists free it) */
+    ZSTD_use_once = 1            /* Use the dictionary once and set to ZSTD_dont_use */
+} ZSTD_dictUses_e;
+
 struct ZSTD_DCtx_s
 {
     const ZSTD_seqSymbol* LLTptr;
@@ -123,9 +129,7 @@
     const ZSTD_DDict* ddict;     /* set by ZSTD_initDStream_usingDDict(), or ZSTD_DCtx_refDDict() */
     U32 dictID;
     int ddictIsCold;             /* if == 1 : dictionary is "new" for working context, and presumed "cold" (not in cpu cache) */
-    int dictUsesRemaining;       /* if == 1 : dictionary should be used once.
-                                  * if == 0 : dictionary should be forgotten now.
-                                  * if < 0 : dictionary should be used indefinitely. */
+    ZSTD_dictUses_e dictUses;
 
     /* streaming */
     ZSTD_dStreamStage streamStage;