[poppler] poppler/strtok_r.cpp
Albert Astals Cid
aacid at kemper.freedesktop.org
Fri Nov 19 15:53:53 PST 2010
poppler/strtok_r.cpp | 137 ---------------------------------------------------
1 file changed, 1 insertion(+), 136 deletions(-)
New commits:
commit 4faaff893515c80cb69b02e431a0f8483274a497
Author: Hib Eris <hib at hiberis.nl>
Date: Fri Nov 19 23:53:35 2010 +0000
[win32] Simplify strtok_r implementation
The previous implementation did not compile with mingw64.
diff --git a/poppler/strtok_r.cpp b/poppler/strtok_r.cpp
index 900bc8c..30e2196 100644
--- a/poppler/strtok_r.cpp
+++ b/poppler/strtok_r.cpp
@@ -42,143 +42,8 @@
#ifdef __MINGW32__
#include <string.h>
-#include <stdlib.h>
-#define LONG_MAX_32_BITS 2147483647
-
-#ifndef LONG_MAX
-#define LONG_MAX LONG_MAX_32_BITS
-#endif
-
-#define __ptr_t char*
-
-/* Find the first occurrence of C in S. */
-static char * __rawmemchr (const void * 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)
- return (__ptr_t) 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. */
-
- if (sizeof (longword) != 4 && sizeof (longword) != 8)
- abort ();
-
-#if LONG_MAX <= LONG_MAX_32_BITS
- magic_bits = 0x7efefeff;
-#else
- magic_bits = ((unsigned long int) 0x7efefefe << 32) | 0xfefefeff;
-#endif
-
- /* Set up a longword, each of whose bytes is C. */
- charmask = c | (c << 8);
- charmask |= charmask << 16;
-#if LONG_MAX > LONG_MAX_32_BITS
- charmask |= charmask << 32;
-#endif
-
- /* 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. */
- while (1)
- {
- /* 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, not 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++ ^ charmask;
-
- /* 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)
- {
- /* Which of the bytes was C? If none of them were, it was
- a misfire; continue the search. */
-
- const unsigned char *cp = (const unsigned char *) (longword_ptr - 1);
-
- if (cp[0] == c)
- return (__ptr_t) cp;
- if (cp[1] == c)
- return (__ptr_t) &cp[1];
- if (cp[2] == c)
- return (__ptr_t) &cp[2];
- if (cp[3] == c)
- return (__ptr_t) &cp[3];
-#if LONG_MAX > 2147483647
- if (cp[4] == c)
- return (__ptr_t) &cp[4];
- if (cp[5] == c)
- return (__ptr_t) &cp[5];
- if (cp[6] == c)
- return (__ptr_t) &cp[6];
- if (cp[7] == c)
- return (__ptr_t) &cp[7];
-#endif
- }
- }
-}
+#define __rawmemchr strchr
char * strtok_r (char *s, const char *delim, char **save_ptr)
{
More information about the poppler
mailing list