[PATCH 0/5] unistr/u*-chr, unistr/u*-strchr: improve test coverage, optimize

[bonzini]

From: Paolo Bonzini <address@hidden>

Hi,

this series introduces more optimizations (basically a Boyer-Moore
algorithm without the table) in the u8_strchr and u8_chr functions.
The algorithm introduces a heavy slow-down on UTF-16.  This is probably
due to the nature of the test, but I decided it is not worth optimizing
that case a lot.

While doing this I also improved the coverage of the functions.

Here are the timings:

                test-u8-chr         test-u8-strchr
   before       1:00                1:07
   after        0:46                0:42

The timings are obtained by modifying test-chr.h and test-strchr.h to
always search starting from the beginning of the input string (removing
the "prev" stuff, basically).

The patch series includes only the u8-chr.c changes, as I have to figure
out how to make u8_strchr safe for invalid characters while keeping the
optimization.

Some changes are just to make the code more similar between u8-chr.c and 
u8-strchr.c, or between the various character lengths.

Paolo Bonzini (5):
  unistr/u*-strchr: add tests
  unistr/u*-chr, unistr/u*-strchr: prepare for multibyte tests
  unistr/u*-chr, unistr/u*-strchr: test multibyte sequences
  unistr/u*-chr, unistr/u*-strchr: test multibyte sequences more
  unistr/u8-chr: use Boyer-Moore like algorithm.

 lib/unistr/u8-chr.c             |  129 ++++++++++++++++++++++++++------------
 lib/unistr/u8-strchr.c          |   96 ++++++++++++++++++++++-------
 modules/unistr/u16-chr-tests    |    1 +
 modules/unistr/u16-strchr-tests |   23 +++++++
 modules/unistr/u32-strchr-tests |   22 +++++++
 modules/unistr/u8-chr-tests     |    1 +
 modules/unistr/u8-strchr-tests  |   23 +++++++
 tests/unistr/test-chr.h         |   67 +++++++++++++++-----
 tests/unistr/test-strchr.h      |  127 ++++++++++++++++++++++++++++++++++++++
 tests/unistr/test-u16-chr.c     |    2 +
 tests/unistr/test-u16-strchr.c  |   33 ++++++++++
 tests/unistr/test-u32-chr.c     |    2 +
 tests/unistr/test-u32-strchr.c  |   33 ++++++++++
 tests/unistr/test-u8-chr.c      |    2 +
 tests/unistr/test-u8-strchr.c   |   33 ++++++++++
 15 files changed, 513 insertions(+), 81 deletions(-)
 create mode 100644 modules/unistr/u16-strchr-tests
 create mode 100644 modules/unistr/u32-strchr-tests
 create mode 100644 modules/unistr/u8-strchr-tests
 create mode 100644 tests/unistr/test-strchr.h
 create mode 100644 tests/unistr/test-u16-strchr.c
 create mode 100644 tests/unistr/test-u32-strchr.c
 create mode 100644 tests/unistr/test-u8-strchr.c