Files
mozjpeg/jconfigint.h.in
DRC fa2b6ea092 Eliminate duplicate copies of jpeg_nbits_table
ef9a4e05ba (libjpeg-turbo 1.4.x), which
was based on
https://bug815473.bmoattachments.org/attachment.cgi?id=692126
(https://bugzilla.mozilla.org/show_bug.cgi?id=815473), modified the C
baseline Huffman encoder so that it precomputes jpeg_nbits_table, in
order to facilitate sharing the table among multiple processes.
However, libjpeg-turbo never shared the table, and because the table was
implemented as a static array, f3a8684cd1
(libjpeg-turbo 1.5.x) and 37bae1a0e9
(libjpeg-turbo 2.0.x) each introduced a duplicate copy of the table for
(respectively) the SSE2 baseline Huffman encoder and the C progressive
Huffman encoder.

This commit does the following:
- Move the duplicated code in jchuff.c and jcphuff.c, originally
  introduced in 0cfc4c17b7 and
  37bae1a0e9, into a header
  (jpeg_nbits.h).
- Credit the co-author of 0cfc4c17b7.
  (Refer to https://sourceforge.net/p/libjpeg-turbo/patches/57).
- Modify the SSE2 baseline Huffman encoder so that the C Huffman
  encoders can share its definition of jpeg_nbits_table.
- Move the definition of jpeg_nbits_table into a C source file
  (jpeg_nbits.c) rather than a header, and define the table only if
  USE_CLZ_INTRINSIC is undefined and the SSE2 baseline Huffman encoder
  will not be built.
- Apply hidden symbol visibility to the shared definition of
  jpeg_nbits_table, if the compiler supports the necessary attribute.
  (In practice, only Visual C++ doesn't.)

Closes #114

See also:
https://bugzilla.mozilla.org/show_bug.cgi?id=1501523
2024-01-16 17:33:30 -05:00

77 lines
1.8 KiB
C

/* libjpeg-turbo build number */
#define BUILD "@BUILD@"
/* How to hide global symbols. */
#define HIDDEN @HIDDEN@
/* Compiler's inline keyword */
#undef inline
/* How to obtain function inlining. */
#define INLINE @INLINE@
/* How to obtain thread-local storage */
#define THREAD_LOCAL @THREAD_LOCAL@
/* Define to the full name of this package. */
#define PACKAGE_NAME "@CMAKE_PROJECT_NAME@"
/* Version number of package */
#define VERSION "@VERSION@"
/* The size of `size_t', as computed by sizeof. */
#define SIZEOF_SIZE_T @SIZE_T@
/* Define if your compiler has __builtin_ctzl() and sizeof(unsigned long) == sizeof(size_t). */
#cmakedefine HAVE_BUILTIN_CTZL
/* Define to 1 if you have the <intrin.h> header file. */
#cmakedefine HAVE_INTRIN_H
#if defined(_MSC_VER) && defined(HAVE_INTRIN_H)
#if (SIZEOF_SIZE_T == 8)
#define HAVE_BITSCANFORWARD64
#elif (SIZEOF_SIZE_T == 4)
#define HAVE_BITSCANFORWARD
#endif
#endif
#if defined(__has_attribute)
#if __has_attribute(fallthrough)
#define FALLTHROUGH __attribute__((fallthrough));
#else
#define FALLTHROUGH
#endif
#else
#define FALLTHROUGH
#endif
/*
* Define BITS_IN_JSAMPLE as either
* 8 for 8-bit sample values (the usual setting)
* 12 for 12-bit sample values
* Only 8 and 12 are legal data precisions for lossy JPEG according to the
* JPEG standard, and the IJG code does not support anything else!
*/
#ifndef BITS_IN_JSAMPLE
#define BITS_IN_JSAMPLE 8 /* use 8 or 12 */
#endif
#undef C_ARITH_CODING_SUPPORTED
#undef D_ARITH_CODING_SUPPORTED
#undef WITH_SIMD
#if BITS_IN_JSAMPLE == 8
/* Support arithmetic encoding */
#cmakedefine C_ARITH_CODING_SUPPORTED 1
/* Support arithmetic decoding */
#cmakedefine D_ARITH_CODING_SUPPORTED 1
/* Use accelerated SIMD routines. */
#cmakedefine WITH_SIMD 1
#endif