1 files changed, 183 insertions, 0 deletions
diff --git a/src/streaming/stream-compression/compression.h b/src/streaming/stream-compression/compression.h
new file mode 100644
index 000000000..37f589b85
--- /dev/null
+++ b/src/streaming/stream-compression/compression.h
@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef NETDATA_RRDPUSH_COMPRESSION_H
+#define NETDATA_RRDPUSH_COMPRESSION_H 1
+
+#include "libnetdata/libnetdata.h"
+
+// signature MUST end with a newline
+
+#if COMPRESSION_MAX_MSG_SIZE >= (COMPRESSION_MAX_CHUNK - COMPRESSION_MAX_OVERHEAD)
+#error "COMPRESSION_MAX_MSG_SIZE >= (COMPRESSION_MAX_CHUNK - COMPRESSION_MAX_OVERHEAD)"
+#endif
+
+typedef uint32_t rrdpush_signature_t;
+#define RRDPUSH_COMPRESSION_SIGNATURE ((rrdpush_signature_t)('z' | 0x80) | (0x80 << 8) | (0x80 << 16) | ('\n' << 24))
+#define RRDPUSH_COMPRESSION_SIGNATURE_MASK ((rrdpush_signature_t) 0xffU | (0x80U << 8) | (0x80U << 16) | (0xffU << 24))
+#define RRDPUSH_COMPRESSION_SIGNATURE_SIZE sizeof(rrdpush_signature_t)
+
+static inline rrdpush_signature_t rrdpush_compress_encode_signature(size_t compressed_data_size) {
+    rrdpush_signature_t len = ((compressed_data_size & 0x7f) | 0x80 | (((compressed_data_size & (0x7f << 7)) << 1) | 0x8000)) << 8;
+    return len | RRDPUSH_COMPRESSION_SIGNATURE;
+}
+
+typedef enum {
+    COMPRESSION_ALGORITHM_NONE  = 0,
+    COMPRESSION_ALGORITHM_ZSTD,
+    COMPRESSION_ALGORITHM_LZ4,
+    COMPRESSION_ALGORITHM_GZIP,
+    COMPRESSION_ALGORITHM_BROTLI,
+
+    // terminator
+    COMPRESSION_ALGORITHM_MAX,
+} compression_algorithm_t;
+
+extern int rrdpush_compression_levels[COMPRESSION_ALGORITHM_MAX];
+
+// this defines the order the algorithms will be selected by the receiver (parent)
+#define RRDPUSH_COMPRESSION_ALGORITHMS_ORDER "zstd lz4 brotli gzip"
+
+// ----------------------------------------------------------------------------
+
+typedef struct simple_ring_buffer {
+    const char *data;
+    size_t size;
+    size_t read_pos;
+    size_t write_pos;
+} SIMPLE_RING_BUFFER;
+
+static inline void simple_ring_buffer_reset(SIMPLE_RING_BUFFER *b) {
+    b->read_pos = b->write_pos = 0;
+}
+
+static inline void simple_ring_buffer_make_room(SIMPLE_RING_BUFFER *b, size_t size) {
+    if(b->write_pos + size > b->size) {
+        if(!b->size)
+            b->size = COMPRESSION_MAX_CHUNK;
+        else
+            b->size *= 2;
+
+        if(b->write_pos + size > b->size)
+            b->size += size;
+
+        b->data = (const char *)reallocz((void *)b->data, b->size);
+    }
+}
+
+static inline void simple_ring_buffer_append_data(SIMPLE_RING_BUFFER *b, const void *data, size_t size) {
+    simple_ring_buffer_make_room(b, size);
+    memcpy((void *)(b->data + b->write_pos), data, size);
+    b->write_pos += size;
+}
+
+static inline void simple_ring_buffer_destroy(SIMPLE_RING_BUFFER *b) {
+    freez((void *)b->data);
+    b->data = NULL;
+    b->read_pos = b->write_pos = b->size = 0;
+}
+
+// ----------------------------------------------------------------------------
+
+struct compressor_state {
+    bool initialized;
+    compression_algorithm_t algorithm;
+
+    SIMPLE_RING_BUFFER input;
+    SIMPLE_RING_BUFFER output;
+
+    int level;
+    void *stream;
+
+    struct {
+        size_t total_compressed;
+        size_t total_uncompressed;
+        size_t total_compressions;
+    } sender_locked;
+};
+
+void rrdpush_compressor_init(struct compressor_state *state);
+void rrdpush_compressor_destroy(struct compressor_state *state);
+size_t rrdpush_compress(struct compressor_state *state, const char *data, size_t size, const char **out);
+
+// ----------------------------------------------------------------------------
+
+struct decompressor_state {
+    bool initialized;
+    compression_algorithm_t algorithm;
+    size_t signature_size;
+
+    size_t total_compressed;
+    size_t total_uncompressed;
+    size_t total_compressions;
+
+    SIMPLE_RING_BUFFER output;
+
+    void *stream;
+};
+
+void rrdpush_decompressor_destroy(struct decompressor_state *state);
+void rrdpush_decompressor_init(struct decompressor_state *state);
+size_t rrdpush_decompress(struct decompressor_state *state, const char *compressed_data, size_t compressed_size);
+
+static inline size_t rrdpush_decompress_decode_signature(const char *data, size_t data_size) {
+    if (unlikely(!data || !data_size))
+        return 0;
+
+    if (unlikely(data_size != RRDPUSH_COMPRESSION_SIGNATURE_SIZE))
+        return 0;
+
+    rrdpush_signature_t sign = *(rrdpush_signature_t *)data;
+    if (unlikely((sign & RRDPUSH_COMPRESSION_SIGNATURE_MASK) != RRDPUSH_COMPRESSION_SIGNATURE))
+        return 0;
+
+    size_t length = ((sign >> 8) & 0x7f) | ((sign >> 9) & (0x7f << 7));
+    return length;
+}
+
+static inline size_t rrdpush_decompressor_start(struct decompressor_state *state, const char *header, size_t header_size) {
+    if(unlikely(state->output.read_pos != state->output.write_pos))
+        fatal("RRDPUSH DECOMPRESS: asked to decompress new data, while there are unread data in the decompression buffer!");
+
+    return rrdpush_decompress_decode_signature(header, header_size);
+}
+
+static inline size_t rrdpush_decompressed_bytes_in_buffer(struct decompressor_state *state) {
+    if(unlikely(state->output.read_pos > state->output.write_pos))
+        fatal("RRDPUSH DECOMPRESS: invalid read/write stream positions");
+
+    return state->output.write_pos - state->output.read_pos;
+}
+
+static inline size_t rrdpush_decompressor_get(struct decompressor_state *state, char *dst, size_t size) {
+    if (unlikely(!state || !size || !dst))
+        return 0;
+
+    size_t remaining = rrdpush_decompressed_bytes_in_buffer(state);
+
+    if(unlikely(!remaining))
+        return 0;
+
+    size_t bytes_to_return = size;
+    if(bytes_to_return > remaining)
+        bytes_to_return = remaining;
+
+    memcpy(dst, state->output.data + state->output.read_pos, bytes_to_return);
+    state->output.read_pos += bytes_to_return;
+
+    if(unlikely(state->output.read_pos > state->output.write_pos))
+        fatal("RRDPUSH DECOMPRESS: invalid read/write stream positions");
+
+    return bytes_to_return;
+}
+
+// ----------------------------------------------------------------------------
+
+#include "../rrdpush.h"
+
+bool rrdpush_compression_initialize(struct sender_state *s);
+bool rrdpush_decompression_initialize(struct receiver_state *rpt);
+void rrdpush_parse_compression_order(struct receiver_state *rpt, const char *order);
+void rrdpush_select_receiver_compression_algorithm(struct receiver_state *rpt);
+void rrdpush_compression_deactivate(struct sender_state *s);
+
+#endif // NETDATA_RRDPUSH_COMPRESSION_H 1