ICU-511.25.tar.gz

[apple/icu.git] / icuSources / common / utf_impl.c

diff --git a/icuSources/common/utf_impl.c b/icuSources/common/utf_impl.c
index 7ff990b18a5e168bd1d3939c1ec5225ba541f4b2..ce65e14d4a3b5d0d06fe1a5747ee49406b1e1414 100644 (file)
--- a/icuSources/common/utf_impl.c
+++ b/icuSources/common/utf_impl.c
@@ -1,7 +1,7 @@
 /*
 ******************************************************************************
 *
 /*
 ******************************************************************************
 *

-*   Copyright (C) 1999-2011, International Business Machines
+*   Copyright (C) 1999-2012, International Business Machines

 *   Corporation and others.  All Rights Reserved.
 *
 ******************************************************************************
 *   Corporation and others.  All Rights Reserved.
 *
 ******************************************************************************


@@ -86,13 +86,31 @@ utf8_errorValue[6]={
     0x3ffffff, 0x7fffffff
 };
 
     0x3ffffff, 0x7fffffff
 };
 

+static UChar32
+errorValue(int32_t count, int8_t strict) {
+    if(strict>=0) {
+        return utf8_errorValue[count];
+    } else if(strict==-3) {
+        return 0xfffd;
+    } else {
+        return U_SENTINEL;
+    }
+}
+

 /*
 /*

- * Handle the non-inline part of the U8_NEXT() macro and its obsolete sibling
- * UTF8_NEXT_CHAR_SAFE().
+ * Handle the non-inline part of the U8_NEXT() and U8_NEXT_FFFD() macros
+ * and their obsolete sibling UTF8_NEXT_CHAR_SAFE().
+ *
+ * U8_NEXT() supports NUL-terminated strings indicated via length<0.

  *
  * The "strict" parameter controls the error behavior:
  *
  * The "strict" parameter controls the error behavior:

- * <0  "Safe" behavior of U8_NEXT(): All illegal byte sequences yield a negative
- *     code point result.
+ * <0  "Safe" behavior of U8_NEXT():
+ *     -1: All illegal byte sequences yield U_SENTINEL=-1.
+ *     -2: Same as -1, except for lenient treatment of surrogate code points as legal.
+ *         Some implementations use this for roundtripping of
+ *         Unicode 16-bit strings that are not well-formed UTF-16, that is, they
+ *         contain unpaired surrogates.
+ *     -3: All illegal byte sequences yield U+FFFD.

  *  0  Obsolete "safe" behavior of UTF8_NEXT_CHAR_SAFE(..., FALSE):
  *     All illegal byte sequences yield a positive code point such that this
  *     result code point would be encoded with the same number of bytes as
  *  0  Obsolete "safe" behavior of UTF8_NEXT_CHAR_SAFE(..., FALSE):
  *     All illegal byte sequences yield a positive code point such that this
  *     result code point would be encoded with the same number of bytes as


@@ -101,102 +119,64 @@ utf8_errorValue[6]={
  *     Same as the obsolete "safe" behavior, but non-characters are also treated
  *     like illegal sequences.
  *
  *     Same as the obsolete "safe" behavior, but non-characters are also treated
  *     like illegal sequences.
  *

- * The special negative (<0) value -2 is used for lenient treatment of surrogate
- * code points as legal. Some implementations use this for roundtripping of
- * Unicode 16-bit strings that are not well-formed UTF-16, that is, they
- * contain unpaired surrogates.
- *

  * Note that a UBool is the same as an int8_t.
  */
 U_CAPI UChar32 U_EXPORT2
 utf8_nextCharSafeBody(const uint8_t *s, int32_t *pi, int32_t length, UChar32 c, UBool strict) {
     int32_t i=*pi;
     uint8_t count=U8_COUNT_TRAIL_BYTES(c);
  * Note that a UBool is the same as an int8_t.
  */
 U_CAPI UChar32 U_EXPORT2
 utf8_nextCharSafeBody(const uint8_t *s, int32_t *pi, int32_t length, UChar32 c, UBool strict) {
     int32_t i=*pi;
     uint8_t count=U8_COUNT_TRAIL_BYTES(c);

-    U_ASSERT(count >= 0 && count <= 5); /* U8_COUNT_TRAIL_BYTES returns value 0...5 */
-    if((i)+count<=(length)) {
-        uint8_t trail, illegal=0;
+    U_ASSERT(count <= 5); /* U8_COUNT_TRAIL_BYTES returns value 0...5 */
+    if(i+count<=length || length<0) {
+        uint8_t trail;

 
 

-        U8_MASK_LEAD_BYTE((c), count);
-        /* count==0 for illegally leading trail bytes and the illegal bytes 0xfe and 0xff */
+        U8_MASK_LEAD_BYTE(c, count);
+        /* support NUL-terminated strings: do not read beyond the first non-trail byte */

         switch(count) {
         /* each branch falls through to the next one */
         switch(count) {
         /* each branch falls through to the next one */

+        case 0:
+            /* count==0 for illegally leading trail bytes and the illegal bytes 0xfe and 0xff */

         case 5:
         case 4:
             /* count>=4 is always illegal: no more than 3 trail bytes in Unicode's UTF-8 */
         case 5:
         case 4:
             /* count>=4 is always illegal: no more than 3 trail bytes in Unicode's UTF-8 */

-            illegal=1;

             break;
         case 3:
             break;
         case 3:

-            trail=s[(i)++];
-            (c)=((c)<<6)|(trail&0x3f);
-            if(c<0x110) {
-                illegal|=(trail&0xc0)^0x80;
-            } else {
-                /* code point>0x10ffff, outside Unicode */
-                illegal=1;
-                break;
-            }
+            trail=s[i++]-0x80;
+            c=(c<<6)|trail;
+            /* c>=0x110 would result in code point>0x10ffff, outside Unicode */
+            if(c>=0x110 || trail>0x3f) { break; }

         case 2:
         case 2:

-            trail=s[(i)++];
-            (c)=((c)<<6)|(trail&0x3f);
-            illegal|=(trail&0xc0)^0x80;
+            trail=s[i++]-0x80;
+            c=(c<<6)|trail;
+            /*
+             * test for a surrogate d800..dfff unless we are lenient:
+             * before the last (c<<6), a surrogate is c=360..37f
+             */
+            if(((c&0xffe0)==0x360 && strict!=-2) || trail>0x3f) { break; }

         case 1:
         case 1:

-            trail=s[(i)++];
-            (c)=((c)<<6)|(trail&0x3f);
-            illegal|=(trail&0xc0)^0x80;
-            break;
-        case 0:
-            if(strict>=0) {
-                return UTF8_ERROR_VALUE_1;
-            } else {
-                return U_SENTINEL;
+            trail=s[i++]-0x80;
+            c=(c<<6)|trail;
+            if(trail>0x3f) { break; }
+            /* correct sequence - all trail bytes have (b7..b6)==(10) */
+            if(c>=utf8_minLegal[count] &&
+                    /* strict: forbid non-characters like U+fffe */
+                    (strict<=0 || !U_IS_UNICODE_NONCHAR(c))) {
+                *pi=i;
+                return c;

             }
         /* no default branch to optimize switch()  - all values are covered */
         }
             }
         /* no default branch to optimize switch()  - all values are covered */
         }

+    } else {
+        /* too few bytes left */
+        count=length-i;
+    }

 
 

-        /*
-         * All the error handling should return a value
-         * that needs count bytes so that UTF8_GET_CHAR_SAFE() works right.
-         *
-         * Starting with Unicode 3.0.1, non-shortest forms are illegal.
-         * Starting with Unicode 3.2, surrogate code points must not be
-         * encoded in UTF-8, and there are no irregular sequences any more.
-         *
-         * U8_ macros (new in ICU 2.4) return negative values for error conditions.
-         */
-
-        /* correct sequence - all trail bytes have (b7..b6)==(10)? */
-        /* illegal is also set if count>=4 */
-        if(illegal || (c)<utf8_minLegal[count] || (U_IS_SURROGATE(c) && strict!=-2)) {
-            /* error handling */
-            uint8_t errorCount=count;
-            /* don't go beyond this sequence */
-            i=*pi;
-            while(count>0 && U8_IS_TRAIL(s[i])) {
-                ++(i);
-                --count;
-            }
-            if(strict>=0) {
-                c=utf8_errorValue[errorCount-count];
-            } else {
-                c=U_SENTINEL;
-            }
-        } else if((strict)>0 && U_IS_UNICODE_NONCHAR(c)) {
-            /* strict: forbid non-characters like U+fffe */
-            c=utf8_errorValue[count];
-        }
-    } else /* too few bytes left */ {
-        /* error handling */
-        int32_t i0=i;
-        /* don't just set (i)=(length) in case there is an illegal sequence */
-        while((i)<(length) && U8_IS_TRAIL(s[i])) {
-            ++(i);
-        }
-        if(strict>=0) {
-            c=utf8_errorValue[i-i0];
-        } else {
-            c=U_SENTINEL;
-        }
+    /* error handling */
+    i=*pi;
+    while(count>0 && U8_IS_TRAIL(s[i])) {
+        ++i;
+        --count;

     }
     }

+    c=errorValue(i-*pi, strict);

     *pi=i;
     return c;
 }
     *pi=i;
     return c;
 }


@@ -251,18 +231,15 @@ utf8_prevCharSafeBody(const uint8_t *s, int32_t start, int32_t *pi, UChar32 c, U
     int32_t i=*pi;
     uint8_t b, count=1, shift=6;
 
     int32_t i=*pi;
     uint8_t b, count=1, shift=6;
 

+    if(!U8_IS_TRAIL(c)) { return errorValue(0, strict); }
+

     /* extract value bits from the last trail byte */
     c&=0x3f;
 
     for(;;) {
         if(i<=start) {
             /* no lead byte at all */
     /* extract value bits from the last trail byte */
     c&=0x3f;
 
     for(;;) {
         if(i<=start) {
             /* no lead byte at all */

-            if(strict>=0) {
-                return UTF8_ERROR_VALUE_1;
-            } else {
-                return U_SENTINEL;
-            }
-            /*break;*/
+            return errorValue(0, strict);

         }
 
         /* read another previous byte */
         }
 
         /* read another previous byte */


@@ -282,11 +259,7 @@ utf8_prevCharSafeBody(const uint8_t *s, int32_t start, int32_t *pi, UChar32 c, U
                         if(count>=4) {
                             count=3;
                         }
                         if(count>=4) {
                             count=3;
                         }

-                        if(strict>=0) {
-                            c=utf8_errorValue[count];
-                        } else {
-                            c=U_SENTINEL;
-                        }
+                        c=errorValue(count, strict);

                     } else {
                         /* exit with correct c */
                     }
                     } else {
                         /* exit with correct c */
                     }


@@ -296,17 +269,9 @@ utf8_prevCharSafeBody(const uint8_t *s, int32_t start, int32_t *pi, UChar32 c, U
                        include the trail byte that we started with */
                     if(count<shouldCount) {
                         *pi=i;
                        include the trail byte that we started with */
                     if(count<shouldCount) {
                         *pi=i;

-                        if(strict>=0) {
-                            c=utf8_errorValue[count];
-                        } else {
-                            c=U_SENTINEL;
-                        }
+                        c=errorValue(count, strict);

                     } else {
                     } else {

-                        if(strict>=0) {
-                            c=UTF8_ERROR_VALUE_1;
-                        } else {
-                            c=U_SENTINEL;
-                        }
+                        c=errorValue(0, strict);

                     }
                 }
                 break;
                     }
                 }
                 break;


@@ -317,20 +282,12 @@ utf8_prevCharSafeBody(const uint8_t *s, int32_t start, int32_t *pi, UChar32 c, U
                 shift+=6;
             } else {
                 /* more than 5 trail bytes is illegal */
                 shift+=6;
             } else {
                 /* more than 5 trail bytes is illegal */

-                if(strict>=0) {
-                    c=UTF8_ERROR_VALUE_1;
-                } else {
-                    c=U_SENTINEL;
-                }
+                c=errorValue(0, strict);

                 break;
             }
         } else {
             /* single-byte character precedes trailing bytes */
                 break;
             }
         } else {
             /* single-byte character precedes trailing bytes */

-            if(strict>=0) {
-                c=UTF8_ERROR_VALUE_1;
-            } else {
-                c=U_SENTINEL;
-            }
+            c=errorValue(0, strict);

             break;
         }
     }
             break;
         }
     }