1 files changed, 108 insertions, 0 deletions

diff --git a/firmware/libc/strchr.c b/firmware/libc/strchr.c
new file mode 100644
index 0000000000..96acf5edf6
--- /dev/null
+++ b/firmware/libc/strchr.c
@@ -0,0 +1,108 @@
+/*
+FUNCTION
+        <<strchr>>---search for character in string
+
+INDEX
+        strchr
+
+ANSI_SYNOPSIS
+        #include <string.h>
+        char * strchr(const char *<[string]>, int <[c]>);
+
+TRAD_SYNOPSIS
+        #include <string.h>
+        char * strchr(<[string]>, <[c]>);
+        char *<[string]>;
+        int *<[c]>;
+
+DESCRIPTION
+        This function finds the first occurence of <[c]> (converted to
+        a char) in the string pointed to by <[string]> (including the
+        terminating null character).
+
+RETURNS
+        Returns a pointer to the located character, or a null pointer
+        if <[c]> does not occur in <[string]>.
+
+PORTABILITY
+<<strchr>> is ANSI C.
+
+<<strchr>> requires no supporting OS subroutines.
+
+QUICKREF
+        strchr ansi pure
+*/
+
+#include <string.h>
+#include <limits.h>
+
+/* Nonzero if X is not aligned on a "long" boundary.  */
+#define UNALIGNED(X) ((long)X & (sizeof (long) - 1))
+
+/* How many bytes are loaded each iteration of the word copy loop.  */
+#define LBLOCKSIZE (sizeof (long))
+
+#if LONG_MAX == 2147483647L
+#define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
+#else
+#if LONG_MAX == 9223372036854775807L
+/* Nonzero if X (a long int) contains a NULL byte. */
+#define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)
+#else
+#error long int is not a 32bit or 64bit type.
+#endif
+#endif
+
+/* DETECTCHAR returns nonzero if (long)X contains the byte used 
+   to fill (long)MASK. */
+#define DETECTCHAR(X,MASK) (DETECTNULL(X ^ MASK))
+
+char *
+_DEFUN (strchr, (s1, i),
+        _CONST char *s1 _AND
+        int i)
+{
+  _CONST unsigned char *s = (_CONST unsigned char *)s1;
+#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
+  unsigned char c = (unsigned int)i;
+
+  while (*s && *s != c)
+    {
+      s++;
+    }
+
+  if (*s != c)
+    {
+      s = NULL;
+    }
+
+  return (char *) s;
+#else
+  unsigned char c = (unsigned char)i;
+  unsigned long mask,j;
+  unsigned long *aligned_addr;
+
+  if (!UNALIGNED (s))
+    {
+      mask = 0;
+      for (j = 0; j < LBLOCKSIZE; j++)
+        mask = (mask << 8) | c;
+
+      aligned_addr = (unsigned long*)s;
+      while (!DETECTNULL (*aligned_addr) && !DETECTCHAR (*aligned_addr, mask))
+        aligned_addr++;
+
+      /* The block of bytes currently pointed to by aligned_addr
+         contains either a null or the target char, or both.  We
+         catch it using the bytewise search.  */
+
+      s = (unsigned char*)aligned_addr;
+    }
+
+  while (*s && *s != c)
+      s++;
+  if (*s == c)
+    return (char *)s;
+  return NULL;
+#endif /* not PREFER_SIZE_OVER_SPEED */
+}