diff options
| -rw-r--r-- | lib/comp/xz.c | 261 |
1 files changed, 244 insertions, 17 deletions
diff --git a/lib/comp/xz.c b/lib/comp/xz.c index 3fb3c12..b0a07ab 100644 --- a/lib/comp/xz.c +++ b/lib/comp/xz.c @@ -3,51 +3,122 @@ #include <stdlib.h> #include <string.h> #include <stdio.h> +#include <ctype.h> #include <lzma.h> #include "internal.h" +typedef enum { + XZ_FILTER_X86 = 0x01, + XZ_FILTER_POWERPC = 0x02, + XZ_FILTER_IA64 = 0x04, + XZ_FILTER_ARM = 0x08, + XZ_FILTER_ARMTHUMB = 0x10, + XZ_FILTER_SPARC = 0x20, + + XZ_FILTER_ALL = 0x3F, +} XZ_FILTER_FLAG; + typedef struct { compressor_t base; size_t block_size; + size_t dict_size; + int flags; } xz_compressor_t; +typedef struct { + uint32_t dict_size; + uint32_t flags; +} xz_options_t; + +static const struct { + const char *name; + lzma_vli filter; + int flag; +} xz_filters[] = { + { "x86", LZMA_FILTER_X86, XZ_FILTER_X86 }, + { "powerpc", LZMA_FILTER_POWERPC, XZ_FILTER_POWERPC }, + { "ia64", LZMA_FILTER_IA64, XZ_FILTER_IA64 }, + { "arm", LZMA_FILTER_ARM, XZ_FILTER_ARM }, + { "armthumb", LZMA_FILTER_ARMTHUMB, XZ_FILTER_ARMTHUMB }, + { "sparc", LZMA_FILTER_SPARC, XZ_FILTER_SPARC }, +}; + +#define XZ_NUM_FILTERS (sizeof(xz_filters) / sizeof(xz_filters[0])) + static int xz_write_options(compressor_t *base, int fd) { - (void)base; - (void)fd; - return 0; + xz_compressor_t *xz = (xz_compressor_t *)base; + xz_options_t opt; + + if (xz->flags == 0 && xz->dict_size == xz->block_size) + return 0; + + opt.dict_size = htole32(xz->dict_size); + opt.flags = htole32(xz->flags); + + return generic_write_options(fd, &opt, sizeof(opt)); } static int xz_read_options(compressor_t *base, int fd) { - (void)base; - (void)fd; - fputs("xz extra options are not yet implemented\n", stderr); - return -1; + xz_compressor_t *xz = (xz_compressor_t *)base; + xz_options_t opt; + uint32_t mask; + + if (generic_read_options(fd, &opt, sizeof(opt))) + return -1; + + opt.dict_size = le32toh(opt.dict_size); + opt.flags = le32toh(opt.flags); + + mask = opt.dict_size & (opt.dict_size - 1); + + if (mask != 0 && ((mask & (mask - 1)) != 0)) { + fputs("Invalid lzma dictionary size.\n", stderr); + return -1; + } + + if (opt.flags & ~XZ_FILTER_ALL) { + fputs("Unknown BCJ filter used.\n", stderr); + return -1; + } + + xz->flags = opt.flags; + xz->dict_size = opt.dict_size; + return 0; } -static ssize_t xz_comp_block(compressor_t *base, const uint8_t *in, - size_t size, uint8_t *out, size_t outsize) +static ssize_t compress(xz_compressor_t *xz, lzma_vli filter, + const uint8_t *in, size_t size, + uint8_t *out, size_t outsize) { - xz_compressor_t *xz = (xz_compressor_t *)base; lzma_filter filters[5]; lzma_options_lzma opt; size_t written = 0; lzma_ret ret; + int i = 0; if (lzma_lzma_preset(&opt, LZMA_PRESET_DEFAULT)) { fputs("error initializing xz options\n", stderr); return -1; } - opt.dict_size = xz->block_size; + opt.dict_size = xz->dict_size; + + if (filter != LZMA_VLI_UNKNOWN) { + filters[i].id = filter; + filters[i].options = NULL; + ++i; + } - filters[0].id = LZMA_FILTER_LZMA2; - filters[0].options = &opt; + filters[i].id = LZMA_FILTER_LZMA2; + filters[i].options = &opt; + ++i; - filters[1].id = LZMA_VLI_UNKNOWN; - filters[1].options = NULL; + filters[i].id = LZMA_VLI_UNKNOWN; + filters[i].options = NULL; + ++i; ret = lzma_stream_buffer_encode(filters, LZMA_CHECK_CRC32, NULL, in, size, out, &written, outsize); @@ -63,6 +134,40 @@ static ssize_t xz_comp_block(compressor_t *base, const uint8_t *in, return 0; } +static ssize_t xz_comp_block(compressor_t *base, const uint8_t *in, + size_t size, uint8_t *out, size_t outsize) +{ + xz_compressor_t *xz = (xz_compressor_t *)base; + lzma_vli selected = LZMA_VLI_UNKNOWN; + size_t i, smallest; + ssize_t ret; + + ret = compress(xz, LZMA_VLI_UNKNOWN, in, size, out, outsize); + if (ret < 0 || xz->flags == 0) + return ret; + + smallest = ret; + + for (i = 0; i < XZ_NUM_FILTERS; ++i) { + if (!(xz->flags & xz_filters[i].flag)) + continue; + + ret = compress(xz, xz_filters[i].filter, in, size, out, outsize); + if (ret < 0) + return -1; + + if (ret > 0 && (smallest == 0 || (size_t)ret < smallest)) { + smallest = ret; + selected = xz_filters[i].filter; + } + } + + if (smallest == 0) + return 0; + + return compress(xz, selected, in, size, out, outsize); +} + static ssize_t xz_uncomp_block(compressor_t *base, const uint8_t *in, size_t size, uint8_t *out, size_t outsize) { @@ -88,17 +193,119 @@ static void xz_destroy(compressor_t *base) free(base); } +static int process_options(char *options, size_t blocksize, + int *flags, uint64_t *dictsize) +{ + enum { + OPT_DICT = 0, + }; + char *const token[] = { + [OPT_DICT] = (char *)"dictsize", + NULL + }; + char *subopts, *value; + uint64_t mask; + size_t i; + int opt; + + subopts = options; + + while (*subopts != '\0') { + opt = getsubopt(&subopts, token, &value); + + switch (opt) { + case OPT_DICT: + if (value == NULL) + goto fail_value; + + for (i = 0; isdigit(value[i]); ++i) + ; + + if (i < 1 || i > 9) + goto fail_dict; + + *dictsize = atol(value); + + switch (value[i]) { + case '\0': + break; + case 'm': + case 'M': + *dictsize <<= 20; + break; + case 'k': + case 'K': + *dictsize <<= 10; + break; + case '%': + *dictsize = ((*dictsize) * blocksize) / 100; + break; + default: + goto fail_dict; + } + + if (*dictsize > 0x0FFFFFFFFUL) + goto fail_dict_ov; + + mask = *dictsize & (*dictsize - 1); + + if (mask != 0 && ((mask & (mask - 1)) != 0)) + goto fail_dict_pot; + break; + default: + for (i = 0; i < XZ_NUM_FILTERS; ++i) { + if (strcmp(value, xz_filters[i].name) == 0) { + *flags |= xz_filters[i].flag; + break; + } + } + if (i == XZ_NUM_FILTERS) + goto fail_opt; + break; + } + } + + return 0; +fail_dict_pot: + fputs("dictionary size must be either 2^n or 2^n + 2^(n-1)\n", stderr); + return -1; +fail_dict_ov: + fputs("dictionary size too large.\n", stderr); + return -1; +fail_dict: + fputs("dictionary size must be a number with the optional " + "suffix 'm','k' or '%'.\n", stderr); + return -1; +fail_opt: + fprintf(stderr, "Unknown option '%s'.\n", value); + return -1; +fail_value: + fprintf(stderr, "Missing value for '%s'.\n", token[opt]); + return -1; +} + compressor_t *create_xz_compressor(bool compress, size_t block_size, char *options) { - xz_compressor_t *xz = calloc(1, sizeof(*xz)); - compressor_t *base = (compressor_t *)xz; + uint64_t dictsize = block_size; + xz_compressor_t *xz; + compressor_t *base; + int flags = 0; + if (options != NULL) { + if (process_options(options, block_size, &flags, &dictsize)) + return NULL; + } + + xz = calloc(1, sizeof(*xz)); + base = (compressor_t *)xz; if (xz == NULL) { perror("creating xz compressor"); return NULL; } + xz->flags = flags; + xz->dict_size = dictsize; xz->block_size = block_size; base->destroy = xz_destroy; base->do_block = compress ? xz_comp_block : xz_uncomp_block; @@ -109,4 +316,24 @@ compressor_t *create_xz_compressor(bool compress, size_t block_size, void compressor_xz_print_help(void) { + size_t i; + + fputs( +"Available options for xz compressor:\n" +"\n" +" dictsize=<value> Dictionary size. Either a value in bytes or a\n" +" percentage of the block size. Defaults to 100%.\n" +" The suffix '%' indicates a percentage. 'K' and 'M'\n" +" can also be used for kibi and mebi bytes\n" +" respecitively.\n" +"\n" +"In additon to the options, one or more bcj filters can be specified.\n" +"If multiple filters are provided, the one yielding the best compression\n" +"ratio will be used.\n" +"\n" +"The following filters are available:\n", + stdout); + + for (i = 0; i < XZ_NUM_FILTERS; ++i) + printf("\t%s\n", xz_filters[i].name); } |