1 files changed, 38 insertions, 29 deletions

diff --git a/ext/sqlite/libsqlite/src/encode.c b/ext/sqlite/libsqlite/src/encode.c
index 5614999ab9..7d959b00ca 100644
--- a/ext/sqlite/libsqlite/src/encode.c
+++ b/ext/sqlite/libsqlite/src/encode.c
@@ -18,6 +18,7 @@
 ** $Id$
 */
 #include <string.h>
+#include <assert.h>
 
 /*
 ** How This Encoder Works
@@ -26,7 +27,7 @@
 ** 0x00.  This is accomplished by using an escape character to encode
 ** 0x27 and 0x00 as a two-byte sequence.  The escape character is always
 ** 0x01.  An 0x00 is encoded as the two byte sequence 0x01 0x01.  The
-** 0x27 character is encoded as the two byte sequence 0x01 0x03.  Finally,
+** 0x27 character is encoded as the two byte sequence 0x01 0x28.  Finally,
 ** the escape character itself is encoded as the two-character sequence
 ** 0x01 0x02.
 **
@@ -34,7 +35,7 @@
 **
 **       0x00  ->  0x01 0x01
 **       0x01  ->  0x01 0x02
-**       0x27  ->  0x01 0x03
+**       0x27  ->  0x01 0x28
 **
 ** If that were all the encoder did, it would work, but in certain cases
 ** it could double the size of the encoded string.  For example, to
@@ -80,7 +81,7 @@
 **           the offset in step 7 below.
 **
 **     (6)   Convert each 0x01 0x01 sequence into a single character 0x00.
-**           Convert 0x01 0x02 into 0x01.  Convert 0x01 0x03 into 0x27.
+**           Convert 0x01 0x02 into 0x01.  Convert 0x01 0x28 into 0x27.
 **
 **     (7)   Subtract the offset value that was the first character of
 **           the encoded buffer from all characters in the output buffer.
@@ -114,13 +115,20 @@
 **
 ** The return value is the number of characters in the encoded
 ** string, excluding the "\000" terminator.
+**
+** If out==NULL then no output is generated but the routine still returns
+** the number of characters that would have been generated if out had
+** not been NULL.
 */
 int sqlite_encode_binary(const unsigned char *in, int n, unsigned char *out){
   int i, j, e, m;
+  unsigned char x;
   int cnt[256];
   if( n<=0 ){
-    out[0] = 'x';
-    out[1] = 0;
+    if( out ){
+      out[0] = 'x';
+      out[1] = 0;
+    }
     return 1;
   }
   memset(cnt, 0, sizeof(cnt));
@@ -136,24 +144,21 @@ int sqlite_encode_binary(const unsigned char *in, int n, unsigned char *out){
       if( m==0 ) break;
     }
   }
+  if( out==0 ){
+    return n+m+1;
+  }
   out[0] = e;
   j = 1;
   for(i=0; i<n; i++){
-    int c = (in[i] - e)&0xff;
-    if( c==0 ){
-      out[j++] = 1;
-      out[j++] = 1;
-    }else if( c==1 ){
+    x = in[i] - e;
+    if( x==0 || x==1 || x=='\''){
       out[j++] = 1;
-      out[j++] = 2;
-    }else if( c=='\'' ){
-      out[j++] = 1;
-      out[j++] = 3;
-    }else{
-      out[j++] = c;
+      x++;
     }
+    out[j++] = x;
   }
   out[j] = 0;
+  assert( j==n+m+1 );
   return j;
 }
 
@@ -168,38 +173,32 @@ int sqlite_encode_binary(const unsigned char *in, int n, unsigned char *out){
 ** to decode a string in place.
 */
 int sqlite_decode_binary(const unsigned char *in, unsigned char *out){
-  int i, c, e;
+  int i, e;
+  unsigned char c;
   e = *(in++);
   i = 0;
   while( (c = *(in++))!=0 ){
     if( c==1 ){
-      c = *(in++);
-      if( c==1 ){
-        c = 0;
-      }else if( c==2 ){
-        c = 1;
-      }else if( c==3 ){
-        c = '\'';
-      }else{
-        return -1;
-      }
+      c = *(in++) - 1;
     }
-    out[i++] = (c + e)&0xff;
+    out[i++] = c + e;
   }
   return i;
 }
 
 #ifdef ENCODER_TEST
+#include <stdio.h>
 /*
 ** The subroutines above are not tested by the usual test suite.  To test
 ** these routines, compile just this one file with a -DENCODER_TEST=1 option
 ** and run the result.
 */
 int main(int argc, char **argv){
-  int i, j, n, m, nOut;
+  int i, j, n, m, nOut, nByteIn, nByteOut;
   unsigned char in[30000];
   unsigned char out[33000];
 
+  nByteIn = nByteOut = 0;
   for(i=0; i<sizeof(in); i++){
     printf("Test %d: ", i+1);
     n = rand() % (i+1);
@@ -213,11 +212,17 @@ int main(int argc, char **argv){
     }else{
       for(j=0; j<n; j++) in[j] = rand() & 0xff;
     }
+    nByteIn += n;
     nOut = sqlite_encode_binary(in, n, out);
+    nByteOut += nOut;
     if( nOut!=strlen(out) ){
       printf(" ERROR return value is %d instead of %d\n", nOut, strlen(out));
       exit(1);
     }
+    if( nOut!=sqlite_encode_binary(in, n, 0) ){
+      printf(" ERROR actual output size disagrees with predicted size\n");
+      exit(1);
+    }
     m = (256*n + 1262)/253;
     printf("size %d->%d (max %d)", n, strlen(out)+1, m);
     if( strlen(out)+1>m ){
@@ -241,5 +246,9 @@ int main(int argc, char **argv){
     }
     printf(" OK\n");
   }
+  fprintf(stderr,"Finished.  Total encoding: %d->%d bytes\n",
+          nByteIn, nByteOut);
+  fprintf(stderr,"Avg size increase: %.3f%%\n",
+    (nByteOut-nByteIn)*100.0/(double)nByteIn);
 }
 #endif /* ENCODER_TEST */