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Overview
Comment:speed-up looks_like_text(), by eliminating variable "i" and handle first character separately.
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SHA1: 204680eedc0232952480fb932897ac5947f82a4b
User & Date: jan.nijtmans 2012-10-28 20:40:55.642
Original Comment: speed-up lools_like_text(), by eliminating variable "i" and handle first character separately.
Context
2012-10-28
20:47
.. but don't forget to update j ... (check-in: 6542935c9d user: jan.nijtmans tags: trunk)
20:40
speed-up looks_like_text(), by eliminating variable "i" and handle first character separately. ... (check-in: 204680eedc user: jan.nijtmans tags: trunk)
17:28
Performance enhancement for branch name look-ups. ... (check-in: 186405ce3a user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/diff.c.
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** Returns 1, if the file appears text, and does not contain CrLf
** Returns 0 if the specified content appears to be binary or
** contains a line that is too long
** Returns -1, if the file appears text, but it contains CrLf
*/
int looks_like_text(const Blob *pContent){
  const char *z = blob_buffer(pContent);
  int n = blob_size(pContent);
  int i, j;
  int result = 1;

  /* Check individual lines.
  */
  for(i=j=0; i<n; i++, j++){
    int c = z[i];
    if( c==0 ) return 1;  /* \000 byte in a file -> binary */




    if( c=='\n' ){
      if( i>0 && z[i-1]=='\r' ){
    	  result = -1;   /* Contains CrLf, continue */
      }
      if( j>LENGTH_MASK ){
        return 0;   /* Very long line -> binary */
      }
      j = 0;
    }








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** Returns 1, if the file appears text, and does not contain CrLf
** Returns 0 if the specified content appears to be binary or
** contains a line that is too long
** Returns -1, if the file appears text, but it contains CrLf
*/
int looks_like_text(const Blob *pContent){
  const char *z = blob_buffer(pContent);
  unsigned int n = blob_size(pContent);
  int j, c;
  int result = 1;

  /* Check individual lines.
  */
  if( n==0 ) return 1;  /* Empty file -> text */
  c = *z;
  if( c==0 ) return 0;  /* \000 byte in a file -> binary */
  j = (c!='\n');
  while( --n>0 ){
    c = *++z;
    if( c==0 ) return 0;  /* \000 byte in a file -> binary */
    if( c=='\n' ){
      if( z[-1]=='\r' ){
    	  result = -1;   /* Contains CrLf, continue */
      }
      if( j>LENGTH_MASK ){
        return 0;   /* Very long line -> binary */
      }
      j = 0;
    }
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