Documentation update for fuzz support.

git-svn-id: svn://vcs.exim.org/pcre2/code/trunk@585 6239d852-aaf2-0410-a92c-79f79f948069

1 files changed, 28 insertions, 17 deletions

diff --git a/README b/README
index 4264772..76c94f4 100644
--- a/README
+++ b/README
@@ -204,13 +204,6 @@ library. They are also documented in the pcre2build man page.
   --enable-newline-is-crlf, --enable-newline-is-anycrlf, or
   --enable-newline-is-any to the "configure" command, respectively.
 
-  If you specify --enable-newline-is-cr or --enable-newline-is-crlf, some of
-  the standard tests will fail, because the lines in the test files end with
-  LF. Even if the files are edited to change the line endings, there are likely
-  to be some failures. With --enable-newline-is-anycrlf or
-  --enable-newline-is-any, many tests should succeed, but there may be some
-  failures.
-
 . By default, the sequence \R in a pattern matches any Unicode line ending
   sequence. This is independent of the option specifying what PCRE2 considers
   to be the end of a line (see above). However, the caller of PCRE2 can
@@ -253,13 +246,13 @@ library. They are also documented in the pcre2build man page.
   sizes in the pcre2stack man page.
 
 . In the 8-bit library, the default maximum compiled pattern size is around
-  64K. You can increase this by adding --with-link-size=3 to the "configure"
-  command. PCRE2 then uses three bytes instead of two for offsets to different
-  parts of the compiled pattern. In the 16-bit library, --with-link-size=3 is
-  the same as --with-link-size=4, which (in both libraries) uses four-byte
-  offsets. Increasing the internal link size reduces performance in the 8-bit
-  and 16-bit libraries. In the 32-bit library, the link size setting is
-  ignored, as 4-byte offsets are always used.
+  64K bytes. You can increase this by adding --with-link-size=3 to the
+  "configure" command. PCRE2 then uses three bytes instead of two for offsets
+  to different parts of the compiled pattern. In the 16-bit library,
+  --with-link-size=3 is the same as --with-link-size=4, which (in both
+  libraries) uses four-byte offsets. Increasing the internal link size reduces
+  performance in the 8-bit and 16-bit libraries. In the 32-bit library, the
+  link size setting is ignored, as 4-byte offsets are always used.
 
 . You can build PCRE2 so that its internal match() function that is called from
   pcre2_match() does not call itself recursively. Instead, it uses memory
@@ -346,7 +339,8 @@ library. They are also documented in the pcre2build man page.
 
   The value must be a plain integer. The default is 20480. The amount of memory 
   used by pcre2grep is actually three times this number, to allow for "before" 
-  and "after" lines.
+  and "after" lines. If very long lines are encountered, the buffer is 
+  automatically enlarged, up to a fixed maximum size.
   
 . The default maximum size of pcre2grep's internal buffer can be set by, for 
   example:
@@ -378,6 +372,22 @@ library. They are also documented in the pcre2build man page.
   If you get error messages about missing functions tgetstr, tgetent, tputs,
   tgetflag, or tgoto, this is the problem, and linking with the ncurses library
   should fix it.
+  
+. There is a special option called --enable-fuzz-support for use by people who 
+  want to run fuzzing tests on PCRE2. At present this applies only to the 8-bit 
+  library. If set, it causes an extra library called libpcre2-fuzzsupport.a to 
+  be built, but not installed. This contains a single function called
+  LLVMFuzzerTestOneInput() whose arguments are a pointer to a string and the 
+  length of the string. When called, this function tries to compile the string 
+  as a pattern, and if that succeeds, to match it. This is done both with no 
+  options and with some random options bits that are generated from the string.
+  Setting --enable-fuzz-support also causes a binary called pcre2fuzzcheck to
+  be created. This is normally run under valgrind or used when PCRE2 is
+  compiled with address sanitizing enabled. It calls the fuzzing function and
+  outputs information about it is doing. The input strings are specified by 
+  arguments: if an argument starts with "=" the rest of it is a literal input 
+  string. Otherwise, it is assumed to be a file name, and the contents of the 
+  file are the test string.
 
 The "configure" script builds the following files for the basic C library:
 
@@ -553,7 +563,7 @@ script creates the .txt and HTML forms of the documentation from the man pages.
 
 
 Testing PCRE2
-------------
+-------------
 
 To test the basic PCRE2 library on a Unix-like system, run the RunTest script.
 There is another script called RunGrepTest that tests the pcre2grep command.
@@ -767,6 +777,7 @@ The distribution should contain the files listed below.
   src/pcre2_xclass.c       )
 
   src/pcre2_printint.c     debugging function that is used by pcre2test,
+  src/pcre2_fuzzsupport.c  function for (optional) fuzzing support 
 
   src/config.h.in          template for config.h, when built by "configure"
   src/pcre2.h.in           template for pcre2.h when built by "configure"
@@ -855,4 +866,4 @@ The distribution should contain the files listed below.
 Philip Hazel
 Email local part: ph10
 Email domain: cam.ac.uk
-Last updated: 07 October 2016
+Last updated: 01 November 2016