From b2e56d82bf73f50484c9cf71e81c1af4ebe3cc0b Mon Sep 17 00:00:00 2001 From: Yann Collet Date: Wed, 5 Sep 2018 16:04:05 -0700 Subject: Introduced constants LZ4F_INIT_* to simplify initialization of lz4frame.h structures. Partially in response to #546. --- lib/lz4frame.h | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) (limited to 'lib') diff --git a/lib/lz4frame.h b/lib/lz4frame.h index fb434ff7..2a67c69e 100644 --- a/lib/lz4frame.h +++ b/lib/lz4frame.h @@ -33,7 +33,7 @@ */ /* LZ4F is a stand-alone API to create LZ4-compressed frames - * conformant with specification v1.5.1. + * conformant with specification v1.6.1. * It also offers streaming capabilities. * lz4.h is not required when using lz4frame.h. * */ @@ -159,8 +159,9 @@ typedef LZ4F_contentChecksum_t contentChecksum_t; /*! LZ4F_frameInfo_t : * makes it possible to set or read frame parameters. - * It's not required to set all fields, as long as the structure was initially memset() to zero. - * For all fields, 0 sets it to default value */ + * Structure must be first init to 0, using memset() or LZ4F_INIT_FRAMEINFO, + * setting all parameters to default. + * It's then possible to update selectively some parameters */ typedef struct { LZ4F_blockSizeID_t blockSizeID; /* max64KB, max256KB, max1MB, max4MB; 0 == default */ LZ4F_blockMode_t blockMode; /* LZ4F_blockLinked, LZ4F_blockIndependent; 0 == default */ @@ -171,24 +172,30 @@ typedef struct { LZ4F_blockChecksum_t blockChecksumFlag; /* 1: each block followed by a checksum of block's compressed data; 0: disabled (default) */ } LZ4F_frameInfo_t; +#define LZ4F_INIT_FRAMEINFO { 0, 0, 0, 0, 0, 0, 0 } + /*! LZ4F_preferences_t : - * makes it possible to supply detailed compression parameters to the stream interface. - * Structure is presumed initially memset() to zero, representing default settings. + * makes it possible to supply advanced compression instructions to streaming interface. + * Structure must be first init to 0, using memset() or LZ4F_INIT_PREFERENCES, + * setting all parameters to default. * All reserved fields must be set to zero. */ typedef struct { LZ4F_frameInfo_t frameInfo; int compressionLevel; /* 0: default (fast mode); values > LZ4HC_CLEVEL_MAX count as LZ4HC_CLEVEL_MAX; values < 0 trigger "fast acceleration" */ - unsigned autoFlush; /* 1: always flush, to reduce usage of internal buffers */ - unsigned favorDecSpeed; /* 1: parser favors decompression speed vs compression ratio. Only works for high compression modes (>= LZ4LZ4HC_CLEVEL_OPT_MIN) */ /* >= v1.8.2 */ + unsigned autoFlush; /* 1: always flush; reduces usage of internal buffers */ + unsigned favorDecSpeed; /* 1: parser favors decompression speed vs compression ratio. Only works for high compression modes (>= LZ4HC_CLEVEL_OPT_MIN) */ /* >= v1.8.2 */ unsigned reserved[3]; /* must be zero for forward compatibility */ } LZ4F_preferences_t; -LZ4FLIB_API int LZ4F_compressionLevel_max(void); +#define LZ4F_INIT_PREFERENCES { LZ4F_INIT_FRAMEINFO, 0, 0, 0, { 0, 0, 0 } } /*-********************************* * Simple compression function ***********************************/ + +LZ4FLIB_API int LZ4F_compressionLevel_max(void); + /*! LZ4F_compressFrameBound() : * Returns the maximum possible compressed size with LZ4F_compressFrame() given srcSize and preferences. * `preferencesPtr` is optional. It can be replaced by NULL, in which case, the function will assume default preferences. @@ -222,8 +229,9 @@ typedef struct { /*--- Resource Management ---*/ -#define LZ4F_VERSION 100 +#define LZ4F_VERSION 100 /* API version, signal an API breaking change */ LZ4FLIB_API unsigned LZ4F_getVersion(void); + /*! LZ4F_createCompressionContext() : * The first thing to do is to create a compressionContext object, which will be used in all compression operations. * This is achieved using LZ4F_createCompressionContext(), which takes as argument a version. -- cgit v1.2.3