diff --git a/src/liblzma/api/lzma/filter.h b/src/liblzma/api/lzma/filter.h index 5ec9976..41c5895 100644 --- a/src/liblzma/api/lzma/filter.h +++ b/src/liblzma/api/lzma/filter.h @@ -124,6 +124,27 @@ extern LZMA_API(lzma_ret) lzma_filters_copy( lzma_nothrow lzma_attr_warn_unused_result; +/** + * \brief Free the options in the array of lzma_filter structures + * + * This frees the filter chain options. The filters array itself is not freed. + * + * The filters array must have at most LZMA_FILTERS_MAX + 1 elements + * including the terminating element which must have .id = LZMA_VLI_UNKNOWN. + * For all elements before the terminating element: + * - options will be freed using the given lzma_allocator or, + * if allocator is NULL, using free(). + * - options will be set to NULL. + * - id will be set to LZMA_VLI_UNKNOWN. + * + * If filters is NULL, this does nothing but remember that this never frees + * the filters array itself. + */ +extern LZMA_API(void) lzma_filters_free( + lzma_filter *filters, const lzma_allocator *allocator) + lzma_nothrow; + + /** * \brief Calculate approximate memory requirements for raw encoder * diff --git a/src/liblzma/common/filter_common.c b/src/liblzma/common/filter_common.c index 0113035..a803b4c 100644 --- a/src/liblzma/common/filter_common.c +++ b/src/liblzma/common/filter_common.c @@ -205,6 +205,32 @@ error: } +extern LZMA_API(void) +lzma_filters_free(lzma_filter *filters, const lzma_allocator *allocator) +{ + if (filters == NULL) + return; + + for (size_t i = 0; filters[i].id != LZMA_VLI_UNKNOWN; ++i) { + if (i == LZMA_FILTERS_MAX) { + // The API says that LZMA_FILTERS_MAX + 1 is the + // maximum allowed size including the terminating + // element. Thus, we should never get here but in + // case there is a bug and we do anyway, don't go + // past the (probable) end of the array. + assert(0); + break; + } + + lzma_free(filters[i].options, allocator); + filters[i].options = NULL; + filters[i].id = LZMA_VLI_UNKNOWN; + } + + return; +} + + static lzma_ret validate_chain(const lzma_filter *filters, size_t *count) { diff --git a/src/liblzma/liblzma_generic.map b/src/liblzma/liblzma_generic.map index 7b9cec7..3e3c52d 100644 --- a/src/liblzma/liblzma_generic.map +++ b/src/liblzma/liblzma_generic.map @@ -114,4 +114,5 @@ global: lzma_file_info_decoder; lzma_stream_decoder_mt; lzma_lzip_decoder; + lzma_filters_free; } XZ_5.2; diff --git a/src/liblzma/liblzma_linux.map b/src/liblzma/liblzma_linux.map index 89719dd..7f320d8 100644 --- a/src/liblzma/liblzma_linux.map +++ b/src/liblzma/liblzma_linux.map @@ -129,4 +129,5 @@ global: lzma_file_info_decoder; lzma_stream_decoder_mt; lzma_lzip_decoder; + lzma_filters_free; } XZ_5.2;