maint: update copyright

[gnulib.git] / lib / unistr / u8-strchr.c

diff --git a/lib/unistr/u8-strchr.c b/lib/unistr/u8-strchr.c
index 03d6138..8e19c5f 100644 (file)
--- a/lib/unistr/u8-strchr.c
+++ b/lib/unistr/u8-strchr.c
@@ -1,5 +1,5 @@
 /* Search character in UTF-8 string.
-   Copyright (C) 1999, 2002, 2006-2007, 2009-2010 Free Software Foundation,
+   Copyright (C) 1999, 2002, 2006-2007, 2009-2014 Free Software Foundation,
    Inc.
    Written by Bruno Haible <bruno@clisp.org>, 2002.
 
@@ -62,20 +62,24 @@ u8_strchr (const uint8_t *s, ucs4_t uc)
     switch (u8_uctomb_aux (c, uc, 6))
       {
       case 2:
-        if (*s == 0)
+        if (*s == 0 || s[1] == 0)
           break;
         {
           uint8_t c0 = c[0];
           uint8_t c1 = c[1];
+          /* Search for { c0, c1 }.  */
           uint8_t s1 = s[1];
 
           for (;;)
             {
+              /* Here s[0] != 0, s[1] != 0.
+                 Test whether s[0..1] == { c0, c1 }.  */
               if (s1 == c1)
                 {
                   if (*s == c0)
                     return (uint8_t *) s;
                   else
+                    /* Skip the search at s + 1, because s[1] = c1 < c0.  */
                     goto case2_skip2;
                 }
               else
@@ -83,6 +87,7 @@ u8_strchr (const uint8_t *s, ucs4_t uc)
                   if (s1 == c0)
                     goto case2_skip1;
                   else
+                    /* Skip the search at s + 1, because s[1] != c0.  */
                     goto case2_skip2;
                 }
              case2_skip2:
@@ -96,36 +101,46 @@ u8_strchr (const uint8_t *s, ucs4_t uc)
               if (s[1] == 0)
                 break;
             }
-          return (uint8_t *) s;
         }
+        break;
 
       case 3:
-        if (*s == 0 || s[1] == 0)
+        if (*s == 0 || s[1] == 0 || s[2] == 0)
           break;
         {
           uint8_t c0 = c[0];
           uint8_t c1 = c[1];
           uint8_t c2 = c[2];
+          /* Search for { c0, c1, c2 }.  */
           uint8_t s2 = s[2];
 
           for (;;)
             {
+              /* Here s[0] != 0, s[1] != 0, s[2] != 0.
+                 Test whether s[0..2] == { c0, c1, c2 }.  */
               if (s2 == c2)
                 {
                   if (s[1] == c1 && *s == c0)
                     return (uint8_t *) s;
-                  else if (c2 == c1)
-                    goto case3_skip1;
                   else
-                    goto case3_skip3;
+                    /* If c2 != c1:
+                         Skip the search at s + 1, because s[2] == c2 != c1.
+                       Skip the search at s + 2, because s[2] == c2 < c0.  */
+                    if (c2 == c1)
+                      goto case3_skip1;
+                    else
+                      goto case3_skip3;
                 }
               else
                 {
                   if (s2 == c1)
                     goto case3_skip1;
                   else if (s2 == c0)
+                    /* Skip the search at s + 1, because s[2] != c1.  */
                     goto case3_skip2;
                   else
+                    /* Skip the search at s + 1, because s[2] != c1.
+                       Skip the search at s + 2, because s[2] != c0.  */
                     goto case3_skip3;
                 }
              case3_skip3:
@@ -145,39 +160,55 @@ u8_strchr (const uint8_t *s, ucs4_t uc)
                 break;
             }
         }
+        break;
 
       case 4:
-        if (*s == 0 || s[1] == 0 || s[2] == 0)
+        if (*s == 0 || s[1] == 0 || s[2] == 0 || s[3] == 0)
           break;
         {
           uint8_t c0 = c[0];
           uint8_t c1 = c[1];
           uint8_t c2 = c[2];
           uint8_t c3 = c[3];
+          /* Search for { c0, c1, c2, c3 }.  */
           uint8_t s3 = s[3];
 
           for (;;)
             {
+              /* Here s[0] != 0, s[1] != 0, s[2] != 0, s[3] != 0.
+                 Test whether s[0..3] == { c0, c1, c2, c3 }.  */
               if (s3 == c3)
                 {
                   if (s[2] == c2 && s[1] == c1 && *s == c0)
                     return (uint8_t *) s;
-                  else if (c3 == c2)
-                    goto case4_skip1;
-                  else if (c3 == c1)
-                    goto case4_skip2;
                   else
-                    goto case4_skip4;
+                    /* If c3 != c2:
+                         Skip the search at s + 1, because s[3] == c3 != c2.
+                       If c3 != c1:
+                         Skip the search at s + 2, because s[3] == c3 != c1.
+                       Skip the search at s + 3, because s[3] == c3 < c0.  */
+                    if (c3 == c2)
+                      goto case4_skip1;
+                    else if (c3 == c1)
+                      goto case4_skip2;
+                    else
+                      goto case4_skip4;
                 }
               else
                 {
                   if (s3 == c2)
                     goto case4_skip1;
                   else if (s3 == c1)
+                    /* Skip the search at s + 1, because s[3] != c2.  */
                     goto case4_skip2;
                   else if (s3 == c0)
+                    /* Skip the search at s + 1, because s[3] != c2.
+                       Skip the search at s + 2, because s[3] != c1.  */
                     goto case4_skip3;
                   else
+                    /* Skip the search at s + 1, because s[3] != c2.
+                       Skip the search at s + 2, because s[3] != c1.
+                       Skip the search at s + 3, because s[3] != c0.  */
                     goto case4_skip4;
                 }
              case4_skip4:
@@ -202,6 +233,7 @@ u8_strchr (const uint8_t *s, ucs4_t uc)
                 break;
             }
         }
+        break;
       }
 
   return NULL;