Remove inputBuffer from Context, Work Around its Absence

diff --git a/lib/lz4hc.c b/lib/lz4hc.c
index e09d8e0..dff42f0 100644 (file)
--- a/lib/lz4hc.c
+++ b/lib/lz4hc.c
@@ -999,8 +999,8 @@ int LZ4_resetStreamStateHC(void* state, char* inputBuffer)
 {
     LZ4HC_CCtx_internal *ctx = &((LZ4_streamHC_t*)state)->internal_donotuse;
     if ((((size_t)state) & (sizeof(void*)-1)) != 0) return 1;   /* Error : pointer is not aligned for pointer (32 or 64 bits) */
+    LZ4_resetStreamHC((LZ4_streamHC_t*)state, ((LZ4_streamHC_t*)state)->internal_donotuse.compressionLevel);
     LZ4HC_init(ctx, (const BYTE*)inputBuffer);
-    ctx->inputBuffer = inputBuffer;
     return 0;
 }
 
@@ -1008,9 +1008,8 @@ void* LZ4_createHC (const char* inputBuffer)
 {
     LZ4_streamHC_t* hc4 = (LZ4_streamHC_t*)ALLOC(sizeof(LZ4_streamHC_t));
     if (hc4 == NULL) return NULL;   /* not enough memory */
+    LZ4_resetStreamHC(hc4, 0 /* compressionLevel */);
     LZ4HC_init (&hc4->internal_donotuse, (const BYTE*)inputBuffer);
-    assert(sizeof(size_t) == sizeof(void*));
-    hc4->internal_donotuse.inputBuffer = (void*)(size_t)inputBuffer;   /* ugly hack, circumvent -Wcast-qual */
     return hc4;
 }
 
@@ -1032,9 +1031,11 @@ int LZ4_compressHC2_limitedOutput_continue (void* LZ4HC_Data, const char* src, c
 
 char* LZ4_slideInputBufferHC(void* LZ4HC_Data)
 {
-    LZ4HC_CCtx_internal* const hc4 = &((LZ4_streamHC_t*)LZ4HC_Data)->internal_donotuse;
-    int const dictSize = LZ4_saveDictHC((LZ4_streamHC_t*)LZ4HC_Data, (char*)(hc4->inputBuffer), 64 KB);
-    return (char*)(hc4->inputBuffer) + dictSize;
+    LZ4_streamHC_t *ctx = (LZ4_streamHC_t*)LZ4HC_Data;
+    const BYTE *bufferStart = ctx->internal_donotuse.base + ctx->internal_donotuse.lowLimit;
+    LZ4_resetStreamHC_fast(ctx, ctx->internal_donotuse.compressionLevel);
+    /* avoid const char * -> char * conversion warning :( */
+    return (char *)(uptrval)bufferStart;
 }
 
 

diff --git a/lib/lz4hc.h b/lib/lz4hc.h
index 3b0d0d3..cfc5d9e 100644 (file)
--- a/lib/lz4hc.h
+++ b/lib/lz4hc.h
@@ -149,7 +149,6 @@ struct LZ4HC_CCtx_internal
     const uint8_t* end;         /* next block here to continue on current prefix */
     const uint8_t* base;        /* All index relative to this position */
     const uint8_t* dictBase;    /* alternate base for extDict */
-    void*      inputBuffer;     /* deprecated */
     uint32_t   dictLimit;       /* below that point, need extDict */
     uint32_t   lowLimit;        /* below that point, no more dict */
     uint32_t   nextToUpdate;    /* index from which to continue dictionary update */
@@ -167,7 +166,6 @@ struct LZ4HC_CCtx_internal
     const unsigned char* end;        /* next block here to continue on current prefix */
     const unsigned char* base;       /* All index relative to this position */
     const unsigned char* dictBase;   /* alternate base for extDict */
-    void*          inputBuffer;      /* deprecated */
     unsigned int   dictLimit;        /* below that point, need extDict */
     unsigned int   lowLimit;         /* below that point, no more dict */
     unsigned int   nextToUpdate;     /* index from which to continue dictionary update */
@@ -210,7 +208,14 @@ LZ4_DEPRECATED("use LZ4_compress_HC_extStateHC() instead") LZ4LIB_API int LZ4_co
 LZ4_DEPRECATED("use LZ4_compress_HC_continue() instead") LZ4LIB_API int LZ4_compressHC_continue               (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize);
 LZ4_DEPRECATED("use LZ4_compress_HC_continue() instead") LZ4LIB_API int LZ4_compressHC_limitedOutput_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize, int maxOutputSize);
 
-/* Deprecated Streaming functions; should no longer be used */
+/* Obsolete streaming functions; degraded functionality; do not use!
+ *
+ * In order to perform streaming compression, these functions depended on data
+ * that is no longer tracked in the state. They have been preserved as well as
+ * possible: using them will still produce a correct output. However, use of
+ * LZ4_slideInputBufferHC() will truncate the history of the stream, rather
+ * than preserve a window-sized chunk of history.
+ */
 LZ4_DEPRECATED("use LZ4_createStreamHC() instead") LZ4LIB_API void* LZ4_createHC (const char* inputBuffer);
 LZ4_DEPRECATED("use LZ4_saveDictHC() instead") LZ4LIB_API     char* LZ4_slideInputBufferHC (void* LZ4HC_Data);
 LZ4_DEPRECATED("use LZ4_freeStreamHC() instead") LZ4LIB_API   int   LZ4_freeHC (void* LZ4HC_Data);