journal: add missing compress.[ch]

src/journal/compress.c

@@ -0,0 +1,208 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2011 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <lzma.h>
+
+#include "compress.h"
+
+bool compress_blob(const void *src, uint64_t src_size, void *dst, uint64_t *dst_size) {
+        lzma_stream s = LZMA_STREAM_INIT;
+        lzma_ret ret;
+        bool b = false;
+
+        assert(src);
+        assert(src_size > 0);
+        assert(dst);
+        assert(dst_size);
+
+        /* Returns false if we couldn't compress the data or the
+         * compressed result is longer than the original */
+
+        ret = lzma_easy_encoder(&s, LZMA_PRESET_DEFAULT, LZMA_CHECK_NONE);
+        if (ret != LZMA_OK)
+                return false;
+
+        s.next_in = src;
+        s.avail_in = src_size;
+        s.next_out = dst;
+        s.avail_out = src_size;
+
+        /* Does it fit? */
+        if (lzma_code(&s, LZMA_FINISH) != LZMA_STREAM_END)
+                goto fail;
+
+        /* Is it actually shorter? */
+        if (s.avail_out == 0)
+                goto fail;
+
+        *dst_size = src_size - s.avail_out;
+        b = true;
+
+fail:
+        lzma_end(&s);
+
+        return b;
+}
+
+bool uncompress_blob(const void *src, uint64_t src_size,
+                     void **dst, uint64_t *dst_alloc_size, uint64_t* dst_size) {
+
+        lzma_stream s = LZMA_STREAM_INIT;
+        lzma_ret ret;
+        bool b = false;
+
+        assert(src);
+        assert(src_size > 0);
+        assert(dst);
+        assert(dst_alloc_size);
+        assert(dst_size);
+        assert(*dst_alloc_size == 0 || *dst);
+
+        ret = lzma_stream_decoder(&s, UINT64_MAX, 0);
+        if (ret != LZMA_OK)
+                return false;
+
+        if (*dst_alloc_size <= src_size) {
+                void *p;
+
+                p = realloc(*dst, src_size*2);
+                if (!p)
+                        return false;
+
+                *dst = p;
+                *dst_alloc_size = src_size*2;
+        }
+
+        s.next_in = src;
+        s.avail_in = src_size;
+
+        s.next_out = *dst;
+        s.avail_out = *dst_alloc_size;
+
+        for (;;) {
+                void *p;
+
+                ret = lzma_code(&s, LZMA_FINISH);
+
+                if (ret == LZMA_STREAM_END)
+                        break;
+
+                if (ret != LZMA_OK)
+                        goto fail;
+
+                p = realloc(*dst, *dst_alloc_size*2);
+                if (!p)
+                        goto fail;
+
+                s.next_out = (uint8_t*) p + ((uint8_t*) s.next_out - (uint8_t*) *dst);
+                s.avail_out += *dst_alloc_size;
+
+                *dst = p;
+                *dst_alloc_size *= 2;
+        }
+
+        *dst_size = *dst_alloc_size - s.avail_out;
+        b = true;
+
+fail:
+        lzma_end(&s);
+
+        return b;
+}
+
+bool uncompress_startswith(const void *src, uint64_t src_size,
+                           void **buffer, uint64_t *buffer_size,
+                           const void *prefix, uint64_t prefix_len,
+                           uint8_t extra) {
+
+        lzma_stream s = LZMA_STREAM_INIT;
+        lzma_ret ret;
+        bool b = false;
+
+        /* Checks whether the uncompressed blob starts with the
+         * mentioned prefix. The byte extra needs to follow the
+         * prefix */
+
+        assert(src);
+        assert(src_size > 0);
+        assert(buffer);
+        assert(buffer_size);
+        assert(prefix);
+        assert(*buffer_size == 0 || *buffer);
+
+        ret = lzma_stream_decoder(&s, UINT64_MAX, 0);
+        if (ret != LZMA_OK)
+                return false;
+
+        if (*buffer_size <= prefix_len) {
+                void *p;
+
+                p = realloc(*buffer, prefix_len*2);
+                if (!p)
+                        return false;
+
+                *buffer = p;
+                *buffer_size = prefix_len*2;
+        }
+
+        s.next_in = src;
+        s.avail_in = src_size;
+
+        s.next_out = *buffer;
+        s.avail_out = *buffer_size;
+
+        for (;;) {
+                void *p;
+
+                ret = lzma_code(&s, LZMA_FINISH);
+
+                if (ret != LZMA_STREAM_END && ret != LZMA_OK)
+                        goto fail;
+
+                if ((*buffer_size - s.avail_out > prefix_len) &&
+                    memcmp(*buffer, prefix, prefix_len) == 0 &&
+                    ((const uint8_t*) *buffer)[prefix_len] == extra)
+                        break;
+
+                if (ret == LZMA_STREAM_END)
+                        goto fail;
+
+                p = realloc(*buffer, *buffer_size*2);
+                if (!p)
+                        goto fail;
+
+                s.next_out = (uint8_t*) p + ((uint8_t*) s.next_out - (uint8_t*) *buffer);
+                s.avail_out += *buffer_size;
+
+                *buffer = p;
+                *buffer_size *= 2;
+        }
+
+        b = true;
+
+fail:
+        lzma_end(&s);
+
+        return b;
+}

src/journal/compress.h

@@ -0,0 +1,38 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#ifndef foocompresshfoo
+#define foocompresshfoo
+
+/***
+  This file is part of systemd.
+
+  Copyright 2011 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <inttypes.h>
+#include <stdbool.h>
+
+bool compress_blob(const void *src, uint64_t src_size, void *dst, uint64_t *dst_size);
+
+bool uncompress_blob(const void *src, uint64_t src_size,
+                     void **dst, uint64_t *dst_alloc_size, uint64_t* dst_size);
+
+bool uncompress_startswith(const void *src, uint64_t src_size,
+                           void **buffer, uint64_t *buffer_size,
+                           const void *prefix, uint64_t prefix_len,
+                           uint8_t extra);
+
+#endif