commit b8136f019a7dc50b51fc51e68cfd38bace101057
author Yann Collet <yann.collet.73@gmail.com> Sat May 27 00:03:08 2017 -0700
committer Yann Collet <yann.collet.73@gmail.com> Sat May 27 00:03:08 2017 -0700
tree 6e6c87ce78345752a000b71e3793723c7af21865
parent cdf7e82222758cecb01438f09cf1f7b08bf1688d

static dctx is incompatible with legacy support

documented, and runtime tested

doc/zstd_manual.html

diff --git a/doc/zstd_manual.html b/doc/zstd_manual.html
index a4b59bc..156e7dd 100644
--- a/doc/zstd_manual.html
+++ b/doc/zstd_manual.html
@@ -718,7 +718,8 @@
  @return : pointer to ZSTD_DCtx*, or NULL if error (size too small)
   Note : zstd will never resize nor malloc() when using a static dctx.
          If it needs more memory than available, it will simply error out.
-  Note 2 : there is no corresponding "free" function.
+  Note 2 : static dctx is incompatible with legacy support
+  Note 3 : there is no corresponding "free" function.
            Since workspace was allocated externally, it must be freed externally.
   Limitation : currently not compatible with internal DDict creation,
                such as ZSTD_initDStream_usingDict().

lib/decompress/zstd_decompress.c

diff --git a/lib/decompress/zstd_decompress.c b/lib/decompress/zstd_decompress.c
index fe7446a..a597243 100644
--- a/lib/decompress/zstd_decompress.c
+++ b/lib/decompress/zstd_decompress.c
@@ -1586,6 +1586,8 @@
             size_t decodedSize;
             size_t const frameSize = ZSTD_findFrameCompressedSizeLegacy(src, srcSize);
             if (ZSTD_isError(frameSize)) return frameSize;
+            /* legacy support is incompatible with static dctx */
+            if (dctx->staticSize) return ERROR(memory_allocation);
 
             decodedSize = ZSTD_decompressLegacy(dst, dstCapacity, src, frameSize, dict, dictSize);
 
@@ -2258,8 +2260,11 @@
     U32 someMoreWork = 1;
 
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
-    if (zds->legacyVersion)
+    if (zds->legacyVersion) {
+        /* legacy support is incompatible with static dctx */
+        if (zds->staticSize) return ERROR(memory_allocation);
         return ZSTD_decompressLegacyStream(zds->legacyContext, zds->legacyVersion, output, input);
+    }
 #endif
 
     while (someMoreWork) {
@@ -2277,6 +2282,8 @@
                     if (legacyVersion) {
                         const void* const dict = zds->ddict ? zds->ddict->dictContent : NULL;
                         size_t const dictSize = zds->ddict ? zds->ddict->dictSize : 0;
+                        /* legacy support is incompatible with static dctx */
+                        if (zds->staticSize) return ERROR(memory_allocation);
                         CHECK_F(ZSTD_initLegacyStream(&zds->legacyContext, zds->previousLegacyVersion, legacyVersion,
                                                        dict, dictSize));
                         zds->legacyVersion = zds->previousLegacyVersion = legacyVersion;

lib/zstd.h

diff --git a/lib/zstd.h b/lib/zstd.h
index b1d8eca..3bbdb76 100644
--- a/lib/zstd.h
+++ b/lib/zstd.h
@@ -844,7 +844,8 @@
  * @return : pointer to ZSTD_DCtx*, or NULL if error (size too small)
  *  Note : zstd will never resize nor malloc() when using a static dctx.
  *         If it needs more memory than available, it will simply error out.
- *  Note 2 : there is no corresponding "free" function.
+ *  Note 2 : static dctx is incompatible with legacy support
+ *  Note 3 : there is no corresponding "free" function.
  *           Since workspace was allocated externally, it must be freed externally.
  *  Limitation : currently not compatible with internal DDict creation,
  *               such as ZSTD_initDStream_usingDict().