1 files changed, 135 insertions, 0 deletions
diff --git a/src/base/lnav.gzip.cc b/src/base/lnav.gzip.cc
new file mode 100644
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+++ b/src/base/lnav.gzip.cc
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+/**
+ * Copyright (c) 2021, Timothy Stack
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * * Neither the name of Timothy Stack nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @file lnav.gzip.cc
+ */
+
+#include "lnav.gzip.hh"
+
+#include <zlib.h>
+
+#include "config.h"
+#include "fmt/format.h"
+
+namespace lnav {
+namespace gzip {
+
+bool
+is_gzipped(const char* buffer, size_t len)
+{
+    return len > 2 && buffer[0] == '\037' && buffer[1] == '\213';
+}
+
+Result<auto_buffer, std::string>
+compress(const void* input, size_t len)
+{
+    auto retval = auto_buffer::alloc(len + 4096);
+
+    z_stream zs;
+    zs.zalloc = Z_NULL;
+    zs.zfree = Z_NULL;
+    zs.opaque = Z_NULL;
+    zs.avail_in = (uInt) len;
+    zs.next_in = (Bytef*) input;
+    zs.avail_out = (uInt) retval.capacity();
+    zs.next_out = (Bytef*) retval.in();
+    zs.total_out = 0;
+
+    auto rc = deflateInit2(
+        &zs, Z_DEFAULT_COMPRESSION, Z_DEFLATED, 15 | 16, 8, Z_DEFAULT_STRATEGY);
+    if (rc != Z_OK) {
+        return Err(fmt::format(
+            FMT_STRING("unable to initialize compressor -- {}"), zError(rc)));
+    }
+    rc = deflate(&zs, Z_FINISH);
+    if (rc != Z_STREAM_END) {
+        return Err(fmt::format(FMT_STRING("unable to compress data -- {}"),
+                               zError(rc)));
+    }
+    rc = deflateEnd(&zs);
+    if (rc != Z_OK) {
+        return Err(fmt::format(
+            FMT_STRING("unable to finalize compression -- {}"), zError(rc)));
+    }
+    return Ok(std::move(retval.resize(zs.total_out)));
+}
+
+Result<auto_buffer, std::string>
+uncompress(const std::string& src, const void* buffer, size_t size)
+{
+    auto uncomp = auto_buffer::alloc(size * 2);
+    z_stream strm;
+    int err;
+
+    strm.next_in = (Bytef*) buffer;
+    strm.msg = Z_NULL;
+    strm.avail_in = size;
+    strm.total_in = 0;
+    strm.total_out = 0;
+    strm.zalloc = Z_NULL;
+    strm.zfree = Z_NULL;
+
+    if ((err = inflateInit2(&strm, (16 + MAX_WBITS))) != Z_OK) {
+        return Err(fmt::format(FMT_STRING("invalid gzip data: {} -- {}"),
+                               src,
+                               strm.msg ? strm.msg : zError(err)));
+    }
+
+    bool done = false;
+
+    while (!done) {
+        if (strm.total_out >= uncomp.size()) {
+            uncomp.expand_by(size / 2);
+        }
+
+        strm.next_out = (Bytef*) (uncomp.in() + strm.total_out);
+        strm.avail_out = uncomp.capacity() - strm.total_out;
+
+        // Inflate another chunk.
+        err = inflate(&strm, Z_SYNC_FLUSH);
+        if (err == Z_STREAM_END) {
+            done = true;
+        } else if (err != Z_OK) {
+            inflateEnd(&strm);
+            return Err(fmt::format(FMT_STRING("unable to uncompress: {} -- {}"),
+                                   src,
+                                   strm.msg ? strm.msg : zError(err)));
+        }
+    }
+
+    if (inflateEnd(&strm) != Z_OK) {
+        return Err(fmt::format(FMT_STRING("unable to uncompress: {} -- {}"),
+                               src,
+                               strm.msg ? strm.msg : zError(err)));
+    }
+
+    return Ok(std::move(uncomp.resize(strm.total_out)));
+}
+
+}  // namespace gzip
+}  // namespace lnav