Merge pull request #1109 from lz4/staticSizes

refactor interface for static state allocation

5 files changed, 38 insertions, 95 deletions

diff --git a/lib/lz4.c b/lib/lz4.c
index 7374f6e..3f468d7 100644
--- a/lib/lz4.c
+++ b/lib/lz4.c
@@ -686,7 +686,7 @@ typedef enum { noDictIssue = 0, dictSmall } dictIssue_directive;
 int LZ4_versionNumber (void) { return LZ4_VERSION_NUMBER; }
 const char* LZ4_versionString(void) { return LZ4_VERSION_STRING; }
 int LZ4_compressBound(int isize)  { return LZ4_COMPRESSBOUND(isize); }
-int LZ4_sizeofState(void) { return LZ4_STREAMSIZE; }
+int LZ4_sizeofState(void) { return sizeof(LZ4_stream_t); }
 
 
 /*-****************************************
@@ -1443,7 +1443,7 @@ int LZ4_compress_destSize(const char* src, char* dst, int* srcSizePtr, int targe
 LZ4_stream_t* LZ4_createStream(void)
 {
     LZ4_stream_t* const lz4s = (LZ4_stream_t*)ALLOC(sizeof(LZ4_stream_t));
-    LZ4_STATIC_ASSERT(LZ4_STREAMSIZE >= sizeof(LZ4_stream_t_internal));    /* A compilation error here means LZ4_STREAMSIZE is not large enough */
+    LZ4_STATIC_ASSERT(sizeof(LZ4_stream_t) >= sizeof(LZ4_stream_t_internal));
     DEBUGLOG(4, "LZ4_createStream %p", lz4s);
     if (lz4s == NULL) return NULL;
     LZ4_initStream(lz4s, sizeof(*lz4s));
@@ -2323,9 +2323,8 @@ int LZ4_decompress_fast_doubleDict(const char* source, char* dest, int originalS
 
 LZ4_streamDecode_t* LZ4_createStreamDecode(void)
 {
-    LZ4_streamDecode_t* lz4s = (LZ4_streamDecode_t*) ALLOC_AND_ZERO(sizeof(LZ4_streamDecode_t));
-    LZ4_STATIC_ASSERT(LZ4_STREAMDECODESIZE >= sizeof(LZ4_streamDecode_t_internal));    /* A compilation error here means LZ4_STREAMDECODESIZE is not large enough */
-    return lz4s;
+    LZ4_STATIC_ASSERT(sizeof(LZ4_streamDecode_t) >= sizeof(LZ4_streamDecode_t_internal));
+    return (LZ4_streamDecode_t*) ALLOC_AND_ZERO(sizeof(LZ4_streamDecode_t));
 }
 
 int LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream)
@@ -2550,7 +2549,7 @@ int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize,
 
 /* Obsolete Streaming functions */
 
-int LZ4_sizeofStreamState(void) { return LZ4_STREAMSIZE; }
+int LZ4_sizeofStreamState(void) { return sizeof(LZ4_stream_t); }
 
 int LZ4_resetStreamState(void* state, char* inputBuffer)
 {
diff --git a/lib/lz4.h b/lib/lz4.h
index 1bd7d26..a8c6d1e 100644
--- a/lib/lz4.h
+++ b/lib/lz4.h
@@ -107,10 +107,10 @@ extern "C" {
 #define LZ4_LIB_VERSION LZ4_VERSION_MAJOR.LZ4_VERSION_MINOR.LZ4_VERSION_RELEASE
 #define LZ4_QUOTE(str) #str
 #define LZ4_EXPAND_AND_QUOTE(str) LZ4_QUOTE(str)
-#define LZ4_VERSION_STRING LZ4_EXPAND_AND_QUOTE(LZ4_LIB_VERSION)
+#define LZ4_VERSION_STRING LZ4_EXPAND_AND_QUOTE(LZ4_LIB_VERSION)  /* requires v1.7.3+ */
 
-LZ4LIB_API int LZ4_versionNumber (void);  /**< library version number; useful to check dll version */
-LZ4LIB_API const char* LZ4_versionString (void);   /**< library version string; useful to check dll version */
+LZ4LIB_API int LZ4_versionNumber (void);  /**< library version number; useful to check dll version; requires v1.3.0+ */
+LZ4LIB_API const char* LZ4_versionString (void);   /**< library version string; useful to check dll version; requires v1.7.5+ */
 
 
 /*-************************************
@@ -604,6 +604,12 @@ LZ4LIB_STATIC_API void LZ4_attach_dictionary(LZ4_stream_t* workingStream, const
   typedef unsigned int   LZ4_u32;
 #endif
 
+/*! LZ4_stream_t :
+ *  Never ever use below internal definitions directly !
+ *  These definitions are not API/ABI safe, and may change in future versions.
+ *  If you need static allocation, declare or allocate an LZ4_stream_t object.
+**/
+
 typedef struct LZ4_stream_t_internal LZ4_stream_t_internal;
 struct LZ4_stream_t_internal {
     LZ4_u32 hashTable[LZ4_HASH_SIZE_U32];
@@ -614,42 +620,9 @@ struct LZ4_stream_t_internal {
     LZ4_u32 dictSize;
 };
 
-typedef struct {
-    const LZ4_byte* externalDict;
-    size_t extDictSize;
-    const LZ4_byte* prefixEnd;
-    size_t prefixSize;
-} LZ4_streamDecode_t_internal;
-
-
-/*! LZ4_stream_t :
- *  Do not use below internal definitions directly !
- *  Declare or allocate an LZ4_stream_t instead.
- *  LZ4_stream_t can also be created using LZ4_createStream(), which is recommended.
- *  The structure definition can be convenient for static allocation
- *  (on stack, or as part of larger structure).
- *  Init this structure with LZ4_initStream() before first use.
- *  note : only use this definition in association with static linking !
- *  this definition is not API/ABI safe, and may change in future versions.
- *  Note : OS400 pointers are 16 bytes and the compiler adds 8 bytes of padding after
- *  tableType and 12 bytes after dictSize to ensure the structure is word aligned:
- *  |=========================================================
- *  |      Offset       |      Length       | Member Name
- *  |=========================================================
- *  |       0           |   16384           |  hashTable[4096]
- *  |   16384           |       4           |  currentOffset
- *  |   16388           |       4           |  tableType
- *  |   16392           |       8           |  ***PADDING***
- *  |   16400           |      16           |  dictionary
- *  |   16416           |      16           |  dictCtx
- *  |   16432           |       4           |  dictSize
- *  |   16436           |      12           |  ***PADDING***
- *  ==========================================================
- */
-#define LZ4_STREAMSIZE       ((1UL << LZ4_MEMORY_USAGE) + ((sizeof(void*)==16) ? 64 : 32))  /* static size, for inter-version compatibility */
-#define LZ4_STREAMSIZE_VOIDP (LZ4_STREAMSIZE / sizeof(void*))
+#define LZ4_STREAM_MINSIZE  ((1UL << LZ4_MEMORY_USAGE) + 32)  /* static size, for inter-version compatibility */
 union LZ4_stream_u {
-    void* table[LZ4_STREAMSIZE_VOIDP];
+    char minStateSize[LZ4_STREAM_MINSIZE];
     LZ4_stream_t_internal internal_donotuse;
 }; /* previously typedef'd to LZ4_stream_t */
 
@@ -672,28 +645,20 @@ LZ4LIB_API LZ4_stream_t* LZ4_initStream (void* buffer, size_t size);
 
 
 /*! LZ4_streamDecode_t :
- *  information structure to track an LZ4 stream during decompression.
- *  init this structure  using LZ4_setStreamDecode() before first use.
- *  note : only use in association with static linking !
- *         this definition is not API/ABI safe,
- *         and may change in a future version !
- *  Note : Same story as LZ4_STREAMSIZE for OS400 in terms of additional padding to 
- *         ensure pointers start on and structures finish on 16 byte boundaries
- *         |=========================================================
- *         |      Offset       |      Length       | Member Name
- *         |=========================================================
- *         |       0           |      16           |    externalDict 
- *         |      16           |       4           |    extDictSize  
- *         |      20           |      12           |    ***PADDING***
- *         |      32           |      16           |    prefixEnd    
- *         |      48           |       4           |    prefixSize   
- *         |      52           |      12           |    ***PADDING***
- *         ==========================================================
- */
-#define LZ4_STREAMDECODESIZE_U64 (4 + ((sizeof(void*)==16) ? 4 : 0))
-#define LZ4_STREAMDECODESIZE     (LZ4_STREAMDECODESIZE_U64 * sizeof(unsigned long long))
+ *  Never ever use below internal definitions directly !
+ *  These definitions are not API/ABI safe, and may change in future versions.
+ *  If you need static allocation, declare or allocate an LZ4_streamDecode_t object.
+**/
+typedef struct {
+    const LZ4_byte* externalDict;
+    size_t extDictSize;
+    const LZ4_byte* prefixEnd;
+    size_t prefixSize;
+} LZ4_streamDecode_t_internal;
+
+#define LZ4_STREAMDECODE_MINSIZE 32
 union LZ4_streamDecode_u {
-    unsigned long long table[LZ4_STREAMDECODESIZE_U64];
+    char minStateSize[LZ4_STREAMDECODE_MINSIZE];
     LZ4_streamDecode_t_internal internal_donotuse;
 } ;   /* previously typedef'd to LZ4_streamDecode_t */
 
diff --git a/lib/lz4hc.c b/lib/lz4hc.c
index 99650a6..77b4767 100644
--- a/lib/lz4hc.c
+++ b/lib/lz4hc.c
@@ -1005,8 +1005,6 @@ int LZ4_freeStreamHC (LZ4_streamHC_t* LZ4_streamHCPtr)
 LZ4_streamHC_t* LZ4_initStreamHC (void* buffer, size_t size)
 {
     LZ4_streamHC_t* const LZ4_streamHCPtr = (LZ4_streamHC_t*)buffer;
-    /* if compilation fails here, LZ4_STREAMHCSIZE must be increased */
-    LZ4_STATIC_ASSERT(sizeof(LZ4HC_CCtx_internal) <= LZ4_STREAMHCSIZE);
     DEBUGLOG(4, "LZ4_initStreamHC(%p, %u)", buffer, (unsigned)size);
     /* check conditions */
     if (buffer == NULL) return NULL;
@@ -1205,7 +1203,7 @@ int LZ4_compressHC_limitedOutput_continue (LZ4_streamHC_t* ctx, const char* src,
 
 
 /* Deprecated streaming functions */
-int LZ4_sizeofStreamStateHC(void) { return LZ4_STREAMHCSIZE; }
+int LZ4_sizeofStreamStateHC(void) { return sizeof(LZ4_streamHC_t); }
 
 /* state is presumed correctly sized, aka >= sizeof(LZ4_streamHC_t)
  * @return : 0 on success, !=0 if error */
diff --git a/lib/lz4hc.h b/lib/lz4hc.h
index 6176457..61e228d 100644
--- a/lib/lz4hc.h
+++ b/lib/lz4hc.h
@@ -198,6 +198,9 @@ LZ4LIB_API int LZ4_saveDictHC (LZ4_streamHC_t* streamHCPtr, char* safeBuffer, in
 #define LZ4HC_HASH_MASK (LZ4HC_HASHTABLESIZE - 1)
 
 
+/* Never ever use these definitions directly !
+ * Declare or allocate an LZ4_streamHC_t instead.
+**/
 typedef struct LZ4HC_CCtx_internal LZ4HC_CCtx_internal;
 struct LZ4HC_CCtx_internal
 {
@@ -216,38 +219,15 @@ struct LZ4HC_CCtx_internal
     const LZ4HC_CCtx_internal* dictCtx;
 };
 
-
-/* Do not use these definitions directly !
- * Declare or allocate an LZ4_streamHC_t instead.
- * Note : OS400 uses 16 byte pointers and so the structure size is larger than other
- *        platforms
- *        |===========================================================
- *        |      Offset       |      Length       | Member Name       
- *        |===========================================================
- *        |       0           |  131072           |  hashTable[32768] 
- *        |  131072           |  131072           |  chainTable[65536]
- *        |  262144           |      16           |  end              
- *        |  262160           |      16           |  base             
- *        |  262176           |      16           |  dictBase         
- *        |  262192           |       4           |  dictLimit        
- *        |  262196           |       4           |  lowLimit         
- *        |  262200           |       4           |  nextToUpdate     
- *        |  262204           |       2           |  compressionLevel 
- *        |  262206           |       1           |  favorDecSpeed    
- *        |  262207           |       1           |  dirty            
- *        |  262208           |      16           |  dictCtx           
- *        ============================================================
- */
-#define LZ4_STREAMHCSIZE       (262200 + ((sizeof(void*)==16) ? 24 : 0)) /* static size, for inter-version compatibility */
-#define LZ4_STREAMHCSIZE_VOIDP (LZ4_STREAMHCSIZE / sizeof(void*))
+#define LZ4_STREAMHC_MINSIZE  262200  /* static size, for inter-version compatibility */
 union LZ4_streamHC_u {
-    void* table[LZ4_STREAMHCSIZE_VOIDP];
+    char minStateSize[LZ4_STREAMHC_MINSIZE];
     LZ4HC_CCtx_internal internal_donotuse;
 }; /* previously typedef'd to LZ4_streamHC_t */
 
 /* LZ4_streamHC_t :
  * This structure allows static allocation of LZ4 HC streaming state.
- * This can be used to allocate statically, on state, or as part of a larger structure.
+ * This can be used to allocate statically on stack, or as part of a larger structure.
  *
  * Such state **must** be initialized using LZ4_initStreamHC() before first use.
  *
@@ -262,7 +242,7 @@ union LZ4_streamHC_u {
  * Required before first use of a statically allocated LZ4_streamHC_t.
  * Before v1.9.0 : use LZ4_resetStreamHC() instead
  */
-LZ4LIB_API LZ4_streamHC_t* LZ4_initStreamHC (void* buffer, size_t size);
+LZ4LIB_API LZ4_streamHC_t* LZ4_initStreamHC(void* buffer, size_t size);
 
 
 /*-************************************
diff --git a/tests/abiTest.c b/tests/abiTest.c
index 91e4e79..e46004a 100644
--- a/tests/abiTest.c
+++ b/tests/abiTest.c
@@ -202,6 +202,7 @@ int main(int argCount, const char** argv)
 {
     const char* const exeName = argv[0];
     int argNb = 1;
+    // Note : LZ4_VERSION_STRING requires >= v1.7.3+
     MSG("abiTest, built binary based on API %s \n", LZ4_VERSION_STRING);
     // Note : LZ4_versionString() requires >= v1.7.5+
     MSG("currently linked to dll %s \n", LZ4_versionString());