Expose internal types to remove strict aliasing

1 files changed, 48 insertions, 69 deletions

diff --git a/lib/lz4.c b/lib/lz4.c
index f86e6f8..04183e6 100644
--- a/lib/lz4.c
+++ b/lib/lz4.c
@@ -371,10 +371,6 @@ static unsigned LZ4_count(const BYTE* pIn, const BYTE* pMatch, const BYTE* pInLi
 /*-************************************
 *  Local Constants
 **************************************/
-#define LZ4_HASHLOG   (LZ4_MEMORY_USAGE-2)
-#define HASHTABLESIZE (1 << LZ4_MEMORY_USAGE)
-#define HASH_SIZE_U32 (1 << LZ4_HASHLOG)       /* required as macro for static allocation */
-
 static const int LZ4_64Klimit = ((64 KB) + (MFLIMIT-1));
 static const U32 LZ4_skipTrigger = 6;  /* Increase this value ==> compression run slower on incompressible data */
 
@@ -382,15 +378,6 @@ static const U32 LZ4_skipTrigger = 6;  /* Increase this value ==> compression ru
 /*-************************************
 *  Local Structures and types
 **************************************/
-typedef struct {
-    U32 hashTable[HASH_SIZE_U32];
-    U32 currentOffset;
-    U32 initCheck;
-    const BYTE* dictionary;
-    BYTE* bufferStart;   /* obsolete, used for slideInputBuffer */
-    U32 dictSize;
-} LZ4_stream_t_internal;
-
 typedef enum { notLimited = 0, limitedOutput = 1 } limitedOutput_directive;
 typedef enum { byPtr, byU32, byU16 } tableType_t;
 
@@ -470,7 +457,7 @@ FORCE_INLINE const BYTE* LZ4_getPosition(const BYTE* p, void* tableBase, tableTy
 /** LZ4_compress_generic() :
     inlined, to ensure branches are decided at compilation time */
 FORCE_INLINE int LZ4_compress_generic(
-                 void* const ctx,
+                 LZ4_stream_t_internal* const dictPtr,
                  const char* const source,
                  char* const dest,
                  const int inputSize,
@@ -481,8 +468,6 @@ FORCE_INLINE int LZ4_compress_generic(
                  const dictIssue_directive dictIssue,
                  const U32 acceleration)
 {
-    LZ4_stream_t_internal* const dictPtr = (LZ4_stream_t_internal*)ctx;
-
     const BYTE* ip = (const BYTE*) source;
     const BYTE* base;
     const BYTE* lowLimit;
@@ -523,7 +508,7 @@ FORCE_INLINE int LZ4_compress_generic(
     if (inputSize<LZ4_minLength) goto _last_literals;                  /* Input too small, no compression (all literals) */
 
     /* First Byte */
-    LZ4_putPosition(ip, ctx, tableType, base);
+    LZ4_putPosition(ip, dictPtr->hashTable, tableType, base);
     ip++; forwardH = LZ4_hashPosition(ip, tableType);
 
     /* Main Loop */
@@ -543,7 +528,7 @@ FORCE_INLINE int LZ4_compress_generic(
 
                 if (unlikely(forwardIp > mflimit)) goto _last_literals;
 
-                match = LZ4_getPositionOnHash(h, ctx, tableType, base);
+                match = LZ4_getPositionOnHash(h, dictPtr->hashTable, tableType, base);
                 if (dict==usingExtDict) {
                     if (match < (const BYTE*)source) {
                         refDelta = dictDelta;
@@ -553,7 +538,7 @@ FORCE_INLINE int LZ4_compress_generic(
                         lowLimit = (const BYTE*)source;
                 }   }
                 forwardH = LZ4_hashPosition(forwardIp, tableType);
-                LZ4_putPositionOnHash(ip, h, ctx, tableType, base);
+                LZ4_putPositionOnHash(ip, h, dictPtr->hashTable, tableType, base);
 
             } while ( ((dictIssue==dictSmall) ? (match < lowRefLimit) : 0)
                 || ((tableType==byU16) ? 0 : (match + MAX_DISTANCE < ip))
@@ -626,10 +611,10 @@ _next_match:
         if (ip > mflimit) break;
 
         /* Fill table */
-        LZ4_putPosition(ip-2, ctx, tableType, base);
+        LZ4_putPosition(ip-2, dictPtr->hashTable, tableType, base);
 
         /* Test next position */
-        match = LZ4_getPosition(ip, ctx, tableType, base);
+        match = LZ4_getPosition(ip, dictPtr->hashTable, tableType, base);
         if (dict==usingExtDict) {
             if (match < (const BYTE*)source) {
                 refDelta = dictDelta;
@@ -638,7 +623,7 @@ _next_match:
                 refDelta = 0;
                 lowLimit = (const BYTE*)source;
         }   }
-        LZ4_putPosition(ip, ctx, tableType, base);
+        LZ4_putPosition(ip, dictPtr->hashTable, tableType, base);
         if ( ((dictIssue==dictSmall) ? (match>=lowRefLimit) : 1)
             && (match+MAX_DISTANCE>=ip)
             && (LZ4_read32(match+refDelta)==LZ4_read32(ip)) )
@@ -673,19 +658,20 @@ _last_literals:
 
 int LZ4_compress_fast_extState(void* state, const char* source, char* dest, int inputSize, int maxOutputSize, int acceleration)
 {
+    LZ4_stream_t_internal* ctx = &((LZ4_stream_t*)state)->internal_donotuse;
     LZ4_resetStream((LZ4_stream_t*)state);
     if (acceleration < 1) acceleration = ACCELERATION_DEFAULT;
 
     if (maxOutputSize >= LZ4_compressBound(inputSize)) {
         if (inputSize < LZ4_64Klimit)
-            return LZ4_compress_generic(state, source, dest, inputSize,             0,    notLimited,                        byU16, noDict, noDictIssue, acceleration);
+            return LZ4_compress_generic(ctx, source, dest, inputSize,             0,    notLimited,                        byU16, noDict, noDictIssue, acceleration);
         else
-            return LZ4_compress_generic(state, source, dest, inputSize,             0,    notLimited, LZ4_64bits() ? byU32 : byPtr, noDict, noDictIssue, acceleration);
+            return LZ4_compress_generic(ctx, source, dest, inputSize,             0,    notLimited, LZ4_64bits() ? byU32 : byPtr, noDict, noDictIssue, acceleration);
     } else {
         if (inputSize < LZ4_64Klimit)
-            return LZ4_compress_generic(state, source, dest, inputSize, maxOutputSize, limitedOutput,                        byU16, noDict, noDictIssue, acceleration);
+            return LZ4_compress_generic(ctx, source, dest, inputSize, maxOutputSize, limitedOutput,                        byU16, noDict, noDictIssue, acceleration);
         else
-            return LZ4_compress_generic(state, source, dest, inputSize, maxOutputSize, limitedOutput, LZ4_64bits() ? byU32 : byPtr, noDict, noDictIssue, acceleration);
+            return LZ4_compress_generic(ctx, source, dest, inputSize, maxOutputSize, limitedOutput, LZ4_64bits() ? byU32 : byPtr, noDict, noDictIssue, acceleration);
     }
 }
 
@@ -722,9 +708,9 @@ int LZ4_compress_fast_force(const char* source, char* dest, int inputSize, int m
     LZ4_resetStream(&ctx);
 
     if (inputSize < LZ4_64Klimit)
-        return LZ4_compress_generic(&ctx, source, dest, inputSize, maxOutputSize, limitedOutput, byU16,                        noDict, noDictIssue, acceleration);
+        return LZ4_compress_generic(&ctx.internal_donotuse, source, dest, inputSize, maxOutputSize, limitedOutput, byU16,                        noDict, noDictIssue, acceleration);
     else
-        return LZ4_compress_generic(&ctx, source, dest, inputSize, maxOutputSize, limitedOutput, LZ4_64bits() ? byU32 : byPtr, noDict, noDictIssue, acceleration);
+        return LZ4_compress_generic(&ctx.internal_donotuse, source, dest, inputSize, maxOutputSize, limitedOutput, LZ4_64bits() ? byU32 : byPtr, noDict, noDictIssue, acceleration);
 }
 
 
@@ -733,7 +719,7 @@ int LZ4_compress_fast_force(const char* source, char* dest, int inputSize, int m
 ********************************/
 
 static int LZ4_compress_destSize_generic(
-                       void* const ctx,
+                       LZ4_stream_t_internal* const ctx,
                  const char* const src,
                        char* const dst,
                        int*  const srcSizePtr,
@@ -765,7 +751,7 @@ static int LZ4_compress_destSize_generic(
 
     /* First Byte */
     *srcSizePtr = 0;
-    LZ4_putPosition(ip, ctx, tableType, base);
+    LZ4_putPosition(ip, ctx->hashTable, tableType, base);
     ip++; forwardH = LZ4_hashPosition(ip, tableType);
 
     /* Main Loop */
@@ -786,9 +772,9 @@ static int LZ4_compress_destSize_generic(
 
                 if (unlikely(forwardIp > mflimit)) goto _last_literals;
 
-                match = LZ4_getPositionOnHash(h, ctx, tableType, base);
+                match = LZ4_getPositionOnHash(h, ctx->hashTable, tableType, base);
                 forwardH = LZ4_hashPosition(forwardIp, tableType);
-                LZ4_putPositionOnHash(ip, h, ctx, tableType, base);
+                LZ4_putPositionOnHash(ip, h, ctx->hashTable, tableType, base);
 
             } while ( ((tableType==byU16) ? 0 : (match + MAX_DISTANCE < ip))
                 || (LZ4_read32(match) != LZ4_read32(ip)) );
@@ -847,11 +833,11 @@ _next_match:
         if (op > oMaxSeq) break;
 
         /* Fill table */
-        LZ4_putPosition(ip-2, ctx, tableType, base);
+        LZ4_putPosition(ip-2, ctx->hashTable, tableType, base);
 
         /* Test next position */
-        match = LZ4_getPosition(ip, ctx, tableType, base);
-        LZ4_putPosition(ip, ctx, tableType, base);
+        match = LZ4_getPosition(ip, ctx->hashTable, tableType, base);
+        LZ4_putPosition(ip, ctx->hashTable, tableType, base);
         if ( (match+MAX_DISTANCE>=ip)
             && (LZ4_read32(match)==LZ4_read32(ip)) )
         { token=op++; *token=0; goto _next_match; }
@@ -888,17 +874,17 @@ _last_literals:
 }
 
 
-static int LZ4_compress_destSize_extState (void* state, const char* src, char* dst, int* srcSizePtr, int targetDstSize)
+static int LZ4_compress_destSize_extState (LZ4_stream_t* state, const char* src, char* dst, int* srcSizePtr, int targetDstSize)
 {
-    LZ4_resetStream((LZ4_stream_t*)state);
+    LZ4_resetStream(state);
 
     if (targetDstSize >= LZ4_compressBound(*srcSizePtr)) {  /* compression success is guaranteed */
         return LZ4_compress_fast_extState(state, src, dst, *srcSizePtr, targetDstSize, 1);
     } else {
         if (*srcSizePtr < LZ4_64Klimit)
-            return LZ4_compress_destSize_generic(state, src, dst, srcSizePtr, targetDstSize, byU16);
+            return LZ4_compress_destSize_generic(&state->internal_donotuse, src, dst, srcSizePtr, targetDstSize, byU16);
         else
-            return LZ4_compress_destSize_generic(state, src, dst, srcSizePtr, targetDstSize, LZ4_64bits() ? byU32 : byPtr);
+            return LZ4_compress_destSize_generic(&state->internal_donotuse, src, dst, srcSizePtr, targetDstSize, LZ4_64bits() ? byU32 : byPtr);
     }
 }
 
@@ -906,10 +892,10 @@ static int LZ4_compress_destSize_extState (void* state, const char* src, char* d
 int LZ4_compress_destSize(const char* src, char* dst, int* srcSizePtr, int targetDstSize)
 {
 #if (HEAPMODE)
-    void* ctx = ALLOCATOR(1, sizeof(LZ4_stream_t));   /* malloc-calloc always properly aligned */
+    LZ4_stream_t* ctx = (LZ4_stream_t*)ALLOCATOR(1, sizeof(LZ4_stream_t));   /* malloc-calloc always properly aligned */
 #else
     LZ4_stream_t ctxBody;
-    void* ctx = &ctxBody;
+    LZ4_stream_t* ctx = &ctxBody;
 #endif
 
     int result = LZ4_compress_destSize_extState(ctx, src, dst, srcSizePtr, targetDstSize);
@@ -949,7 +935,7 @@ int LZ4_freeStream (LZ4_stream_t* LZ4_stream)
 #define HASH_UNIT sizeof(size_t)
 int LZ4_loadDict (LZ4_stream_t* LZ4_dict, const char* dictionary, int dictSize)
 {
-    LZ4_stream_t_internal* dict = (LZ4_stream_t_internal*) LZ4_dict;
+    LZ4_stream_t_internal* dict = &LZ4_dict->internal_donotuse;
     const BYTE* p = (const BYTE*)dictionary;
     const BYTE* const dictEnd = p + dictSize;
     const BYTE* base;
@@ -987,7 +973,7 @@ static void LZ4_renormDictT(LZ4_stream_t_internal* LZ4_dict, const BYTE* src)
         U32 const delta = LZ4_dict->currentOffset - 64 KB;
         const BYTE* dictEnd = LZ4_dict->dictionary + LZ4_dict->dictSize;
         int i;
-        for (i=0; i<HASH_SIZE_U32; i++) {
+        for (i=0; i<LZ4_HASH_SIZE_U32; i++) {
             if (LZ4_dict->hashTable[i] < delta) LZ4_dict->hashTable[i]=0;
             else LZ4_dict->hashTable[i] -= delta;
         }
@@ -1000,7 +986,7 @@ static void LZ4_renormDictT(LZ4_stream_t_internal* LZ4_dict, const BYTE* src)
 
 int LZ4_compress_fast_continue (LZ4_stream_t* LZ4_stream, const char* source, char* dest, int inputSize, int maxOutputSize, int acceleration)
 {
-    LZ4_stream_t_internal* streamPtr = (LZ4_stream_t_internal*)LZ4_stream;
+    LZ4_stream_t_internal* streamPtr = &LZ4_stream->internal_donotuse;
     const BYTE* const dictEnd = streamPtr->dictionary + streamPtr->dictSize;
 
     const BYTE* smallest = (const BYTE*) source;
@@ -1023,9 +1009,9 @@ int LZ4_compress_fast_continue (LZ4_stream_t* LZ4_stream, const char* source, ch
     if (dictEnd == (const BYTE*)source) {
         int result;
         if ((streamPtr->dictSize < 64 KB) && (streamPtr->dictSize < streamPtr->currentOffset))
-            result = LZ4_compress_generic(LZ4_stream, source, dest, inputSize, maxOutputSize, limitedOutput, byU32, withPrefix64k, dictSmall, acceleration);
+            result = LZ4_compress_generic(streamPtr, source, dest, inputSize, maxOutputSize, limitedOutput, byU32, withPrefix64k, dictSmall, acceleration);
         else
-            result = LZ4_compress_generic(LZ4_stream, source, dest, inputSize, maxOutputSize, limitedOutput, byU32, withPrefix64k, noDictIssue, acceleration);
+            result = LZ4_compress_generic(streamPtr, source, dest, inputSize, maxOutputSize, limitedOutput, byU32, withPrefix64k, noDictIssue, acceleration);
         streamPtr->dictSize += (U32)inputSize;
         streamPtr->currentOffset += (U32)inputSize;
         return result;
@@ -1034,9 +1020,9 @@ int LZ4_compress_fast_continue (LZ4_stream_t* LZ4_stream, const char* source, ch
     /* external dictionary mode */
     {   int result;
         if ((streamPtr->dictSize < 64 KB) && (streamPtr->dictSize < streamPtr->currentOffset))
-            result = LZ4_compress_generic(LZ4_stream, source, dest, inputSize, maxOutputSize, limitedOutput, byU32, usingExtDict, dictSmall, acceleration);
+            result = LZ4_compress_generic(streamPtr, source, dest, inputSize, maxOutputSize, limitedOutput, byU32, usingExtDict, dictSmall, acceleration);
         else
-            result = LZ4_compress_generic(LZ4_stream, source, dest, inputSize, maxOutputSize, limitedOutput, byU32, usingExtDict, noDictIssue, acceleration);
+            result = LZ4_compress_generic(streamPtr, source, dest, inputSize, maxOutputSize, limitedOutput, byU32, usingExtDict, noDictIssue, acceleration);
         streamPtr->dictionary = (const BYTE*)source;
         streamPtr->dictSize = (U32)inputSize;
         streamPtr->currentOffset += (U32)inputSize;
@@ -1048,15 +1034,15 @@ int LZ4_compress_fast_continue (LZ4_stream_t* LZ4_stream, const char* source, ch
 /* Hidden debug function, to force external dictionary mode */
 int LZ4_compress_forceExtDict (LZ4_stream_t* LZ4_dict, const char* source, char* dest, int inputSize)
 {
-    LZ4_stream_t_internal* streamPtr = (LZ4_stream_t_internal*)LZ4_dict;
+    LZ4_stream_t_internal* streamPtr = &LZ4_dict->internal_donotuse;
     int result;
     const BYTE* const dictEnd = streamPtr->dictionary + streamPtr->dictSize;
 
     const BYTE* smallest = dictEnd;
     if (smallest > (const BYTE*) source) smallest = (const BYTE*) source;
-    LZ4_renormDictT((LZ4_stream_t_internal*)LZ4_dict, smallest);
+    LZ4_renormDictT(streamPtr, smallest);
 
-    result = LZ4_compress_generic(LZ4_dict, source, dest, inputSize, 0, notLimited, byU32, usingExtDict, noDictIssue, 1);
+    result = LZ4_compress_generic(streamPtr, source, dest, inputSize, 0, notLimited, byU32, usingExtDict, noDictIssue, 1);
 
     streamPtr->dictionary = (const BYTE*)source;
     streamPtr->dictSize = (U32)inputSize;
@@ -1075,7 +1061,7 @@ int LZ4_compress_forceExtDict (LZ4_stream_t* LZ4_dict, const char* source, char*
  */
 int LZ4_saveDict (LZ4_stream_t* LZ4_dict, char* safeBuffer, int dictSize)
 {
-    LZ4_stream_t_internal* const dict = (LZ4_stream_t_internal*) LZ4_dict;
+    LZ4_stream_t_internal* const dict = &LZ4_dict->internal_donotuse;
     const BYTE* const previousDictEnd = dict->dictionary + dict->dictSize;
 
     if ((U32)dictSize > 64 KB) dictSize = 64 KB;   /* useless to define a dictionary > 64 KB */
@@ -1280,13 +1266,6 @@ int LZ4_decompress_fast(const char* source, char* dest, int originalSize)
 
 /*===== streaming decompression functions =====*/
 
-typedef struct {
-    const BYTE* externalDict;
-    size_t extDictSize;
-    const BYTE* prefixEnd;
-    size_t prefixSize;
-} LZ4_streamDecode_t_internal;
-
 /*
  * If you prefer dynamic allocation methods,
  * LZ4_createStreamDecode()
@@ -1313,7 +1292,7 @@ int LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream)
  */
 int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dictionary, int dictSize)
 {
-    LZ4_streamDecode_t_internal* lz4sd = (LZ4_streamDecode_t_internal*) LZ4_streamDecode;
+    LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse;
     lz4sd->prefixSize = (size_t) dictSize;
     lz4sd->prefixEnd = (const BYTE*) dictionary + dictSize;
     lz4sd->externalDict = NULL;
@@ -1330,7 +1309,7 @@ int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dicti
 */
 int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int compressedSize, int maxOutputSize)
 {
-    LZ4_streamDecode_t_internal* lz4sd = (LZ4_streamDecode_t_internal*) LZ4_streamDecode;
+    LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse;
     int result;
 
     if (lz4sd->prefixEnd == (BYTE*)dest) {
@@ -1356,7 +1335,7 @@ int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const ch
 
 int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int originalSize)
 {
-    LZ4_streamDecode_t_internal* lz4sd = (LZ4_streamDecode_t_internal*) LZ4_streamDecode;
+    LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse;
     int result;
 
     if (lz4sd->prefixEnd == (BYTE*)dest) {
@@ -1442,29 +1421,29 @@ int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize,
 
 int LZ4_sizeofStreamState() { return LZ4_STREAMSIZE; }
 
-static void LZ4_init(LZ4_stream_t_internal* lz4ds, BYTE* base)
+static void LZ4_init(LZ4_stream_t* lz4ds, BYTE* base)
 {
-    MEM_INIT(lz4ds, 0, LZ4_STREAMSIZE);
-    lz4ds->bufferStart = base;
+    MEM_INIT(lz4ds, 0, sizeof(LZ4_stream_t));
+    lz4ds->internal_donotuse.bufferStart = base;
 }
 
 int LZ4_resetStreamState(void* state, char* inputBuffer)
 {
     if ((((size_t)state) & 3) != 0) return 1;   /* Error : pointer is not aligned on 4-bytes boundary */
-    LZ4_init((LZ4_stream_t_internal*)state, (BYTE*)inputBuffer);
+    LZ4_init((LZ4_stream_t*)state, (BYTE*)inputBuffer);
     return 0;
 }
 
 void* LZ4_create (char* inputBuffer)
 {
-    void* lz4ds = ALLOCATOR(8, LZ4_STREAMSIZE_U64);
-    LZ4_init ((LZ4_stream_t_internal*)lz4ds, (BYTE*)inputBuffer);
+    LZ4_stream_t* lz4ds = (LZ4_stream_t*)ALLOCATOR(8, sizeof(LZ4_stream_t));
+    LZ4_init (lz4ds, (BYTE*)inputBuffer);
     return lz4ds;
 }
 
 char* LZ4_slideInputBuffer (void* LZ4_Data)
 {
-    LZ4_stream_t_internal* ctx = (LZ4_stream_t_internal*)LZ4_Data;
+    LZ4_stream_t_internal* ctx = &((LZ4_stream_t*)LZ4_Data)->internal_donotuse;
     int dictSize = LZ4_saveDict((LZ4_stream_t*)LZ4_Data, (char*)ctx->bufferStart, 64 KB);
     return (char*)(ctx->bufferStart + dictSize);
 }