Some xz command line tool improvements.

diff --git a/src/xz/args.c b/src/xz/args.c
index a2efb27..c9d1dc1 100644 (file)
--- a/src/xz/args.c
+++ b/src/xz/args.c
@@ -53,7 +53,7 @@ parse_real(args_info *args, int argc, char **argv)
                OPT_FILES0,
        };
 
-       static const char short_opts[] = "cC:dfF:hHlLkM:p:qrS:tT:vVz123456789";
+       static const char short_opts[] = "cC:defF:hHlkM:qrS:tT:vVz0123456789";
 
        static const struct option long_opts[] = {
                // Operation mode
@@ -77,11 +77,11 @@ parse_real(args_info *args, int argc, char **argv)
                // Basic compression settings
                { "format",         required_argument, NULL,  'F' },
                { "check",          required_argument, NULL,  'C' },
-               { "preset",         required_argument, NULL,  'p' },
                { "memory",         required_argument, NULL,  'M' },
                { "threads",        required_argument, NULL,  'T' },
 
-               { "fast",           no_argument,       NULL,  '1' },
+               { "extreme",        no_argument,       NULL,  'e' },
+               { "fast",           no_argument,       NULL,  '0' },
                { "best",           no_argument,       NULL,  '9' },
 
                // Filters
@@ -114,20 +114,12 @@ parse_real(args_info *args, int argc, char **argv)
        while ((c = getopt_long(argc, argv, short_opts, long_opts, NULL))
                        != -1) {
                switch (c) {
-               // gzip-like options
-
-               case '1': case '2': case '3': case '4':
+               // Compression preset (also for decompression if --format=raw)
+               case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                        coder_set_preset(c - '0');
                        break;
 
-               case 'p': {
-                       const uint64_t preset = str_to_uint64(
-                                       "preset", optarg, 1, 9);
-                       coder_set_preset(preset);
-                       break;
-               }
-
                // --memory
                case 'M':
                        // On 32-bit systems, SIZE_MAX would make more sense
@@ -162,6 +154,11 @@ parse_real(args_info *args, int argc, char **argv)
                        opt_mode = MODE_DECOMPRESS;
                        break;
 
+               // --extreme
+               case 'e':
+                       coder_set_extreme();
+                       break;
+
                // --force
                case 'f':
                        opt_force = true;

diff --git a/src/xz/message.c b/src/xz/message.c
index d973374..c2e35e8 100644 (file)
--- a/src/xz/message.c
+++ b/src/xz/message.c
@@ -891,8 +891,8 @@ message_help(bool long_help)
        }
 
        puts(_(
-"  -p, --preset=NUM    compression preset: 1-2 fast compression, 3-6 good\n"
-"                      compression, 7-9 excellent compression; default is 7"));
+"  -0 .. -9            compression preset; 0-2 fast compression, 3-5 good\n"
+"                      compression, 6-9 excellent compression; default is 6"));
 
        puts(_(
 "  -M, --memory=NUM    use roughly NUM bytes of memory at maximum; 0 indicates\n"

diff --git a/src/xz/options.c b/src/xz/options.c
index e754c26..efceba9 100644 (file)
--- a/src/xz/options.c
+++ b/src/xz/options.c
@@ -315,7 +315,7 @@ options_lzma(const char *str)
        };
 
        static const option_map opts[] = {
-               { "preset", NULL,   1, 9 },
+               { "preset", NULL,   0, 9 },
                { "dict",   NULL,   LZMA_DICT_SIZE_MIN,
                                (UINT32_C(1) << 30) + (UINT32_C(1) << 29) },
                { "lc",     NULL,   LZMA_LCLP_MIN, LZMA_LCLP_MAX },

diff --git a/src/xz/process.c b/src/xz/process.c
index 191dfc0..e6870f8 100644 (file)
--- a/src/xz/process.c
+++ b/src/xz/process.c
@@ -34,14 +34,22 @@ static lzma_filter filters[LZMA_FILTERS_MAX + 1];
 /// Number of filters. Zero indicates that we are using a preset.
 static size_t filters_count = 0;
 
-/// Number of the preset (1-9)
-static size_t preset_number = 7;
+/// Number of the preset (0-9)
+static size_t preset_number = 6;
 
-/// Indicate if no preset has been given. In that case, we will auto-adjust
-/// the compression preset so that it doesn't use too much RAM.
-// FIXME
+/// True if we should auto-adjust the compression settings to use less memory
+/// if memory usage limit is too low for the original settings.
+static bool auto_adjust = true;
+
+/// Indicate if no preset has been explicitly given. In that case, if we need
+/// to auto-adjust for lower memory usage, we won't print a warning.
 static bool preset_default = true;
 
+/// If a preset is used (no custom filter chain) and preset_extreme is true,
+/// a significantly slower compression is used to achieve slightly better
+/// compression ratio.
+static bool preset_extreme = false;
+
 /// Integrity check type
 static lzma_check check = LZMA_CHECK_CRC64;
 
@@ -64,6 +72,14 @@ coder_set_preset(size_t new_preset)
 
 
 extern void
+coder_set_extreme(void)
+{
+       preset_extreme = true;
+       return;
+}
+
+
+extern void
 coder_add_filter(lzma_vli id, void *options)
 {
        if (filters_count == LZMA_FILTERS_MAX)
@@ -77,6 +93,15 @@ coder_add_filter(lzma_vli id, void *options)
 }
 
 
+static void lzma_attribute((noreturn))
+memlimit_too_small(uint64_t memory_usage, uint64_t memory_limit)
+{
+       message_fatal(_("Memory usage limit (%" PRIu64 " MiB) is too small "
+                       "for the given filter setup (%" PRIu64 " MiB)"),
+                       memory_limit >> 20, memory_usage >> 20);
+}
+
+
 extern void
 coder_set_compression_settings(void)
 {
@@ -99,6 +124,9 @@ coder_set_compression_settings(void)
                }
 
                // Get the preset for LZMA1 or LZMA2.
+               if (preset_extreme)
+                       preset_number |= LZMA_PRESET_EXTREME;
+
                if (lzma_lzma_preset(&opt_lzma, preset_number))
                        message_bug();
 
@@ -107,6 +135,8 @@ coder_set_compression_settings(void)
                                ? LZMA_FILTER_LZMA1 : LZMA_FILTER_LZMA2;
                filters[0].options = &opt_lzma;
                filters_count = 1;
+       } else {
+               preset_default = false;
        }
 
        // Terminate the filter options array.
@@ -139,30 +169,77 @@ coder_set_compression_settings(void)
                message_fatal("Unsupported filter chain or filter options");
 
        // Print memory usage info.
-       message(V_DEBUG, _("%" PRIu64 " MiB of memory is required per thread, "
-                       "limit is %" PRIu64 " MiB"),
-                       memory_usage / (1024 * 1024),
-                       memory_limit / (1024 * 1024));
-
-       if (preset_default) {
-               // When no preset was explicitly requested, we use the default
-               // preset only if the memory usage limit allows. Otherwise we
-               // select a lower preset automatically.
-               while (memory_usage > memory_limit) {
-                       if (preset_number == 1)
-                               message_fatal(_("Memory usage limit is too "
-                                               "small for any internal "
-                                               "filter preset"));
-
-                       if (lzma_lzma_preset(&opt_lzma, --preset_number))
-                               message_bug();
+       message(V_DEBUG, _("%'" PRIu64 " MiB (%'" PRIu64 " B) of memory is "
+                       "required per thread, "
+                       "limit is %'" PRIu64 " MiB (%'" PRIu64 " B)"),
+                       memory_usage >> 20, memory_usage,
+                       memory_limit >> 20, memory_limit);
+
+       if (memory_usage > memory_limit) {
+               // If --no-auto-adjust was used or we didn't find LZMA1 or
+               // LZMA2 as the last filter, give an error immediatelly.
+               // --format=raw implies --no-auto-adjust.
+               if (!auto_adjust || opt_format == FORMAT_RAW)
+                       memlimit_too_small(memory_usage, memory_limit);
+
+               assert(opt_mode == MODE_COMPRESS);
+
+               // Look for the last filter if it is LZMA2 or LZMA1, so
+               // we can make it use less RAM. With other filters we don't
+               // know what to do.
+               size_t i = 0;
+               while (filters[i].id != LZMA_FILTER_LZMA2
+                               && filters[i].id != LZMA_FILTER_LZMA1) {
+                       if (filters[i].id == LZMA_VLI_UNKNOWN)
+                               memlimit_too_small(memory_usage, memory_limit);
+
+                       ++i;
+               }
+
+               // Decrease the dictionary size until we meet the memory
+               // usage limit. First round down to full mebibytes.
+               lzma_options_lzma *opt = filters[i].options;
+               const uint32_t orig_dict_size = opt->dict_size;
+               opt->dict_size &= ~((UINT32_C(1) << 20) - 1);
+               while (true) {
+                       // If it is below 1 MiB, auto-adjusting failed. We
+                       // could be more sophisticated and scale it down even
+                       // more, but let's see if many complain about this
+                       // version.
+                       //
+                       // FIXME: Displays the scaled memory usage instead
+                       // of the original.
+                       if (opt->dict_size < (UINT32_C(1) << 20))
+                               memlimit_too_small(memory_usage, memory_limit);
 
                        memory_usage = lzma_memusage_encoder(filters);
+                       if (memory_usage == UINT64_MAX)
+                               message_bug();
+
+                       // Accept it if it is low enough.
+                       if (memory_usage <= memory_limit)
+                               break;
+
+                       // Otherwise 1 MiB down and try again. I hope this
+                       // isn't too slow method for cases where the original
+                       // dict_size is very big.
+                       opt->dict_size -= UINT32_C(1) << 20;
                }
-       } else {
-               if (memory_usage > memory_limit)
-                       message_fatal(_("Memory usage limit is too small "
-                                       "for the given filter setup"));
+
+               // Tell the user that we decreased the dictionary size.
+               // However, omit the message if no preset or custom chain
+               // was given. FIXME: Always warn?
+               if (!preset_default)
+                       message(V_WARNING, "Adjusted LZMA%c dictionary size "
+                                       "from %'" PRIu32 " MiB to "
+                                       "%'" PRIu32 " MiB to not exceed "
+                                       "the memory usage limit of "
+                                       "%'" PRIu64 " MiB",
+                                       filters[i].id == LZMA_FILTER_LZMA2
+                                               ? '2' : '1',
+                                       orig_dict_size >> 20,
+                                       opt->dict_size >> 20,
+                                       memory_limit >> 20);
        }
 
        // Limit the number of worker threads so that memory usage
@@ -224,8 +301,8 @@ coder_init(void)
                        break;
 
                case FORMAT_RAW:
-                       // Memory usage has already been checked in args.c.
-                       // FIXME Comment
+                       // Memory usage has already been checked in
+                       // coder_set_compression_settings().
                        ret = lzma_raw_decoder(&strm, filters);
                        break;
                }

diff --git a/src/xz/process.h b/src/xz/process.h
index de23eac..3848528 100644 (file)
--- a/src/xz/process.h
+++ b/src/xz/process.h
@@ -57,6 +57,9 @@ extern void coder_set_check(lzma_check check);
 /// Set preset number
 extern void coder_set_preset(size_t new_preset);
 
+/// Enable extreme mode
+extern void coder_set_extreme(void);
+
 /// Add a filter to the custom filter chain
 extern void coder_add_filter(lzma_vli id, void *options);