From d1dc5192d9cf6b439133606cca3a11ea434dee11 Mon Sep 17 00:00:00 2001
From: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Date: Sat, 25 May 2019 00:00:23 +0200
Subject: Add options for lzma2 compressor
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
---
lib/comp/xz.c | 261 ++++++++++++++++++++++++++++++++++++++++++++++++++++++----
1 file 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);
}
--
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