Merge LibCSS port to trunk.

svn path=/trunk/netsurf/; revision=8752

1 files changed, 165 insertions, 18 deletions

diff --git a/utils/utils.c b/utils/utils.c
index ad76c5e30..ae58222b9 100644
--- a/utils/utils.c
+++ b/utils/utils.c
@@ -230,6 +230,26 @@ const char *rfc1123_date(time_t t)
 }
 
 /**
+ * Returns a number of centiseconds, that increases in real time, for the
+ * purposes of measuring how long something takes in wall-clock terms.  It uses
+ * gettimeofday() for this.  Should the call to gettimeofday() fail, it returns
+ * zero.
+ *
+ * \return number of centiseconds that increases monotonically
+ */
+unsigned int wallclock(void)
+{
+	struct timeval tv;
+
+	if (gettimeofday(&tv, NULL) == -1)
+		return 0;
+
+	return ((tv.tv_sec * 100) + (tv.tv_usec / 10000));
+}
+
+#ifndef HAVE_STRCASESTR
+
+/**
  * Case insensitive strstr implementation
  *
  * \param haystack String to search in
@@ -250,24 +270,7 @@ char *strcasestr(const char *haystack, const char *needle)
 	return NULL;
 }
 
-/**
- * Returns a number of centiseconds, that increases in real time, for the
- * purposes of measuring how long something takes in wall-clock terms.  It uses
- * gettimeofday() for this.  Should the call to gettimeofday() fail, it returns
- * zero.
- *
- * \return number of centiseconds that increases monotonically
- */
-unsigned int wallclock(void)
-{
-	struct timeval tv;
-
-	if (gettimeofday(&tv, NULL) == -1)
-		return 0;
-
-	return ((tv.tv_sec * 100) + (tv.tv_usec / 10000));
-}
-
+#endif
 
 #ifndef HAVE_STRNDUP
 
@@ -293,3 +296,147 @@ char *strndup(const char *s, size_t n)
 }
 
 #endif
+
+#ifndef HAVE_STRCHRNUL
+
+/**
+ *  Find the first occurrence of C in S or the final NUL byte.
+ *
+ *  \note This implementation came from glibc 2.2.5
+ */
+char *strchrnul (const char *s, int c_in)
+{
+  const unsigned char *char_ptr;
+  const unsigned long int *longword_ptr;
+  unsigned long int longword, magic_bits, charmask;
+  unsigned char c;
+
+  c = (unsigned char) c_in;
+
+  /* Handle the first few characters by reading one character at a time.
+     Do this until CHAR_PTR is aligned on a longword boundary.  */
+  for (char_ptr = (const unsigned char *)s; ((unsigned long int) char_ptr
+		      & (sizeof (longword) - 1)) != 0;
+       ++char_ptr)
+    if (*char_ptr == c || *char_ptr == '\0')
+      return (void *) char_ptr;
+
+  /* All these elucidatory comments refer to 4-byte longwords,
+     but the theory applies equally well to 8-byte longwords.  */
+
+  longword_ptr = (unsigned long int *) char_ptr;
+
+  /* Bits 31, 24, 16, and 8 of this number are zero.  Call these bits
+     the "holes."  Note that there is a hole just to the left of
+     each byte, with an extra at the end:
+
+     bits:  01111110 11111110 11111110 11111111
+     bytes: AAAAAAAA BBBBBBBB CCCCCCCC DDDDDDDD
+
+     The 1-bits make sure that carries propagate to the next 0-bit.
+     The 0-bits provide holes for carries to fall into.  */
+  switch (sizeof (longword))
+    {
+    case 4: magic_bits = 0x7efefeffL; break;
+    case 8: magic_bits = ((0x7efefefeL << 16) << 16) | 0xfefefeffL; break;
+    default:
+      abort ();
+    }
+
+  /* Set up a longword, each of whose bytes is C.  */
+  charmask = c | (c << 8);
+  charmask |= charmask << 16;
+  if (sizeof (longword) > 4)
+    /* Do the shift in two steps to avoid a warning if long has 32 bits.  */
+    charmask |= (charmask << 16) << 16;
+  if (sizeof (longword) > 8)
+    abort ();
+
+  /* Instead of the traditional loop which tests each character,
+     we will test a longword at a time.  The tricky part is testing
+     if *any of the four* bytes in the longword in question are zero.  */
+  for (;;)
+    {
+      /* We tentatively exit the loop if adding MAGIC_BITS to
+	 LONGWORD fails to change any of the hole bits of LONGWORD.
+
+	 1) Is this safe?  Will it catch all the zero bytes?
+	 Suppose there is a byte with all zeros.  Any carry bits
+	 propagating from its left will fall into the hole at its
+	 least significant bit and stop.  Since there will be no
+	 carry from its most significant bit, the LSB of the
+	 byte to the left will be unchanged, and the zero will be
+	 detected.
+
+	 2) Is this worthwhile?  Will it ignore everything except
+	 zero bytes?  Suppose every byte of LONGWORD has a bit set
+	 somewhere.  There will be a carry into bit 8.  If bit 8
+	 is set, this will carry into bit 16.  If bit 8 is clear,
+	 one of bits 9-15 must be set, so there will be a carry
+	 into bit 16.  Similarly, there will be a carry into bit
+	 24.  If one of bits 24-30 is set, there will be a carry
+	 into bit 31, so all of the hole bits will be changed.
+
+	 The one misfire occurs when bits 24-30 are clear and bit
+	 31 is set; in this case, the hole at bit 31 is not
+	 changed.  If we had access to the processor carry flag,
+	 we could close this loophole by putting the fourth hole
+	 at bit 32!
+
+	 So it ignores everything except 128's, when they're aligned
+	 properly.
+
+	 3) But wait!  Aren't we looking for C as well as zero?
+	 Good point.  So what we do is XOR LONGWORD with a longword,
+	 each of whose bytes is C.  This turns each byte that is C
+	 into a zero.  */
+
+      longword = *longword_ptr++;
+
+      /* Add MAGIC_BITS to LONGWORD.  */
+      if ((((longword + magic_bits)
+
+	    /* Set those bits that were unchanged by the addition.  */
+	    ^ ~longword)
+
+	   /* Look at only the hole bits.  If any of the hole bits
+	      are unchanged, most likely one of the bytes was a
+	      zero.  */
+	   & ~magic_bits) != 0 ||
+
+	  /* That caught zeroes.  Now test for C.  */
+	  ((((longword ^ charmask) + magic_bits) ^ ~(longword ^ charmask))
+	   & ~magic_bits) != 0)
+	{
+	  /* Which of the bytes was C or zero?
+	     If none of them were, it was a misfire; continue the search.  */
+
+	  const unsigned char *cp = (const unsigned char *) (longword_ptr - 1);
+
+	  if (*cp == c || *cp == '\0')
+	    return (char *) cp;
+	  if (*++cp == c || *cp == '\0')
+	    return (char *) cp;
+	  if (*++cp == c || *cp == '\0')
+	    return (char *) cp;
+	  if (*++cp == c || *cp == '\0')
+	    return (char *) cp;
+	  if (sizeof (longword) > 4)
+	    {
+	      if (*++cp == c || *cp == '\0')
+		return (char *) cp;
+	      if (*++cp == c || *cp == '\0')
+		return (char *) cp;
+	      if (*++cp == c || *cp == '\0')
+		return (char *) cp;
+	      if (*++cp == c || *cp == '\0')
+		return (char *) cp;
+	    }
+	}
+    }
+
+  /* This should never happen.  */
+  return NULL;
+}
+
+#endif