#
# Define NATIVE_CRLF if your platform uses CRLF for line endings.
#
-# Define XDL_FAST_HASH to use an alternative line-hashing method in
-# the diff algorithm. It gives a nice speedup if your processor has
-# fast unaligned word loads. Does NOT work on big-endian systems!
-# Enabled by default on x86_64.
-#
# Define GIT_USER_AGENT if you want to change how git identifies itself during
# network interactions. The default is "git/$(GIT_VERSION)".
#
MSGFMT += --check --statistics
endif
-ifneq (,$(XDL_FAST_HASH))
- BASIC_CFLAGS += -DXDL_FAST_HASH
-endif
-
ifdef GMTIME_UNRELIABLE_ERRORS
COMPAT_OBJS += compat/gmtime.o
BASIC_CFLAGS += -DGMTIME_UNRELIABLE_ERRORS
return ha;
}
-#ifdef XDL_FAST_HASH
-
-#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
-
-#define ONEBYTES REPEAT_BYTE(0x01)
-#define NEWLINEBYTES REPEAT_BYTE(0x0a)
-#define HIGHBITS REPEAT_BYTE(0x80)
-
-/* Return the high bit set in the first byte that is a zero */
-static inline unsigned long has_zero(unsigned long a)
-{
- return ((a - ONEBYTES) & ~a) & HIGHBITS;
-}
-
-static inline long count_masked_bytes(unsigned long mask)
-{
- if (sizeof(long) == 8) {
- /*
- * Jan Achrenius on G+: microoptimized version of
- * the simpler "(mask & ONEBYTES) * ONEBYTES >> 56"
- * that works for the bytemasks without having to
- * mask them first.
- */
- /*
- * return mask * 0x0001020304050608 >> 56;
- *
- * Doing it like this avoids warnings on 32-bit machines.
- */
- long a = (REPEAT_BYTE(0x01) / 0xff + 1);
- return mask * a >> (sizeof(long) * 7);
- } else {
- /* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
- /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
- long a = (0x0ff0001 + mask) >> 23;
- /* Fix the 1 for 00 case */
- return a & mask;
- }
-}
-
-unsigned long xdl_hash_record(char const **data, char const *top, long flags)
-{
- unsigned long hash = 5381;
- unsigned long a = 0, mask = 0;
- char const *ptr = *data;
- char const *end = top - sizeof(unsigned long) + 1;
-
- if (flags & XDF_WHITESPACE_FLAGS)
- return xdl_hash_record_with_whitespace(data, top, flags);
-
- ptr -= sizeof(unsigned long);
- do {
- hash += hash << 5;
- hash ^= a;
- ptr += sizeof(unsigned long);
- if (ptr >= end)
- break;
- a = *(unsigned long *)ptr;
- /* Do we have any '\n' bytes in this word? */
- mask = has_zero(a ^ NEWLINEBYTES);
- } while (!mask);
-
- if (ptr >= end) {
- /*
- * There is only a partial word left at the end of the
- * buffer. Because we may work with a memory mapping,
- * we have to grab the rest byte by byte instead of
- * blindly reading it.
- *
- * To avoid problems with masking in a signed value,
- * we use an unsigned char here.
- */
- const char *p;
- for (p = top - 1; p >= ptr; p--)
- a = (a << 8) + *((const unsigned char *)p);
- mask = has_zero(a ^ NEWLINEBYTES);
- if (!mask)
- /*
- * No '\n' found in the partial word. Make a
- * mask that matches what we read.
- */
- mask = 1UL << (8 * (top - ptr) + 7);
- }
-
- /* The mask *below* the first high bit set */
- mask = (mask - 1) & ~mask;
- mask >>= 7;
- hash += hash << 5;
- hash ^= a & mask;
-
- /* Advance past the last (possibly partial) word */
- ptr += count_masked_bytes(mask);
-
- if (ptr < top) {
- assert(*ptr == '\n');
- ptr++;
- }
-
- *data = ptr;
-
- return hash;
-}
-
-#else /* XDL_FAST_HASH */
-
unsigned long xdl_hash_record(char const **data, char const *top, long flags) {
unsigned long ha = 5381;
char const *ptr = *data;
return ha;
}
-#endif /* XDL_FAST_HASH */
-
unsigned int xdl_hashbits(unsigned int size) {
unsigned int val = 1, bits = 0;