ywkaras commented on a change in pull request #8245:
URL: https://github.com/apache/trafficserver/pull/8245#discussion_r688848379
##########
File path: src/tscore/fastlz.c
##########
@@ -24,512 +21,615 @@
THE SOFTWARE.
*/
-#if !defined(FASTLZ__COMPRESSOR) && !defined(FASTLZ_DECOMPRESSOR)
+#include "tscore/fastlz.h"
+
+#include <stdint.h>
/*
* Always check for bound when decompressing.
* Generally it is best to leave it defined.
*/
#define FASTLZ_SAFE
+#if defined(FASTLZ_USE_SAFE_DECOMPRESSOR) && (FASTLZ_USE_SAFE_DECOMPRESSOR ==
0)
+#undef FASTLZ_SAFE
+#endif
/*
* Give hints to the compiler for branch prediction optimization.
*/
-#if defined(__GNUC__) && (__GNUC__ > 2)
-#define FASTLZ_EXPECT_CONDITIONAL(c) (__builtin_expect((c), 1))
-#define FASTLZ_UNEXPECT_CONDITIONAL(c) (__builtin_expect((c), 0))
+#if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ > 2))
+#define FASTLZ_LIKELY(c) (__builtin_expect(!!(c), 1))
+#define FASTLZ_UNLIKELY(c) (__builtin_expect(!!(c), 0))
#else
-#define FASTLZ_EXPECT_CONDITIONAL(c) (c)
-#define FASTLZ_UNEXPECT_CONDITIONAL(c) (c)
+#define FASTLZ_LIKELY(c) (c)
+#define FASTLZ_UNLIKELY(c) (c)
#endif
/*
- * Use inlined functions for supported systems.
+ * Specialize custom 64-bit implementation for speed improvements.
*/
-#if defined(__GNUC__) || defined(__DMC__) || defined(__POCC__) ||
defined(__WATCOMC__) || defined(__SUNPRO_C)
-#define FASTLZ_INLINE inline
-#elif defined(__BORLANDC__) || defined(_MSC_VER) || defined(__LCC__)
-#define FASTLZ_INLINE __inline
-#else
-#define FASTLZ_INLINE
+#if defined(__x86_64__) || defined(_M_X64)
+#define FLZ_ARCH64
#endif
-/*
- * Prevent accessing more than 8-bit at once, except on x86 architectures.
- */
-#if !defined(FASTLZ_STRICT_ALIGN)
-#define FASTLZ_STRICT_ALIGN
-#if defined(__i386__) || defined(__386) /* GNU C, Sun Studio */
-#undef FASTLZ_STRICT_ALIGN
-#elif defined(__i486__) || defined(__i586__) || defined(__i686__) /* GNU C */
-#undef FASTLZ_STRICT_ALIGN
-#elif defined(_M_IX86) /* Intel, MSVC */
-#undef FASTLZ_STRICT_ALIGN
-#elif defined(__386)
-#undef FASTLZ_STRICT_ALIGN
-#elif defined(_X86_) /* MinGW */
-#undef FASTLZ_STRICT_ALIGN
-#elif defined(__I86__) /* Digital Mars */
-#undef FASTLZ_STRICT_ALIGN
-#endif
+#if defined(FASTLZ_SAFE)
+#define FASTLZ_BOUND_CHECK(cond) \
+ if (FASTLZ_UNLIKELY(!(cond))) \
+ return 0;
+#else
+#define FASTLZ_BOUND_CHECK(cond) \
+ do { \
+ } while (0)
#endif
-/*
- * FIXME: use preprocessor magic to set this on different platforms!
- */
-typedef unsigned char flzuint8;
-typedef unsigned short flzuint16;
-typedef unsigned int flzuint32;
+#if defined(FASTLZ_USE_MEMMOVE) && (FASTLZ_USE_MEMMOVE == 0)
-/* prototypes */
-int fastlz_compress(const void *input, int length, void *output);
-int fastlz_compress_level(int level, const void *input, int length, void
*output);
-int fastlz_decompress(const void *input, int length, void *output, int maxout);
+static void
+fastlz_memmove(uint8_t *dest, const uint8_t *src, uint32_t count)
+{
+ do {
+ *dest++ = *src++;
+ } while (--count);
+}
-#define MAX_COPY 32
-#define MAX_LEN 264 /* 256 + 8 */
-#define MAX_DISTANCE 8192
+static void
+fastlz_memcpy(uint8_t *dest, const uint8_t *src, uint32_t count)
+{
+ return fastlz_memmove(dest, src, count);
+}
-#if !defined(FASTLZ_STRICT_ALIGN)
-#define FASTLZ_READU16(p) *((const flzuint16 *)(p))
#else
-#define FASTLZ_READU16(p) ((p)[0] | (p)[1] << 8)
+
+#include <string.h>
+
+static void
+fastlz_memmove(uint8_t *dest, const uint8_t *src, uint32_t count)
+{
+ if ((count > 4) && (dest >= src + count)) {
+ memmove(dest, src, count);
+ } else {
+ switch (count) {
+ default:
+ do {
+ *dest++ = *src++;
+ } while (--count);
+ break;
+ case 3:
+ *dest++ = *src++;
Review comment:
https://en.cppreference.com/w/cpp/language/attributes/fallthrough
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