From c052a188f28d6ded5eae0d98cba6f72f2020fd0e Mon Sep 17 00:00:00 2001
From: Emmanuel Marty <emmanuel@fgl.com>
Date: Thu, 19 Sep 2019 11:46:03 +0200
Subject: [PATCH] Reduce LZSA2 forward arrivals memory use

---
 src/shrink_block_v2.c | 13 -------------
 src/shrink_context.c  | 23 ++++++++++++++---------
 2 files changed, 14 insertions(+), 22 deletions(-)

diff --git a/src/shrink_block_v2.c b/src/shrink_block_v2.c
index 5b1dd0e..49bfe3e 100644
--- a/src/shrink_block_v2.c
+++ b/src/shrink_block_v2.c
@@ -302,22 +302,9 @@ static void lzsa_optimize_forward_v2(lzsa_compressor *pCompressor, const int nSt
    pCompressor->best_match[i].length = 0;
    pCompressor->best_match[i].offset = 0;
 
-   unsigned int nRepMatchOffset = 0;
-   int nEndCost = end_arrival->cost;
-
-   int *backward_cost = (int*)pCompressor->pos_data;  /* Reuse */
-   for (i = nStartOffset; i != nEndOffset; i++) {
-      backward_cost[i] = nEndCost - arrival[(i << MATCHES_PER_OFFSET_SHIFT) + 0].cost;
-   }
-
    while (end_arrival->from_slot > 0 && end_arrival->from_pos >= 0) {
       pCompressor->best_match[end_arrival->from_pos].length = end_arrival->match_len;
       pCompressor->best_match[end_arrival->from_pos].offset = end_arrival->match_offset;
-      pCompressor->repmatch_opt[end_arrival->from_pos].expected_repmatch = (end_arrival->match_len >= MIN_MATCH_SIZE_V2 && nRepMatchOffset == end_arrival->match_offset) ? 1 : 0;
-
-      if (end_arrival->match_len >= MIN_MATCH_SIZE_V2)
-         nRepMatchOffset = end_arrival->match_offset;
-
       end_arrival = &arrival[(end_arrival->from_pos << MATCHES_PER_OFFSET_SHIFT) + (end_arrival->from_slot - 1)];
    }
 }
diff --git a/src/shrink_context.c b/src/shrink_context.c
index 3eba0f4..1f9b6d7 100644
--- a/src/shrink_context.c
+++ b/src/shrink_context.c
@@ -92,21 +92,26 @@ int lzsa_compressor_init(lzsa_compressor *pCompressor, const int nMaxWindowSize,
 
                   if (pCompressor->arrival || (pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) == 0) {
                      if (pCompressor->format_version == 2) {
-                        pCompressor->selected_match = (lzsa_match *)malloc(nMaxWindowSize * NMATCHES_PER_OFFSET * sizeof(lzsa_match));
+                        pCompressor->best_match = (lzsa_match *)malloc(nMaxWindowSize * sizeof(lzsa_match));
 
-                        if (pCompressor->selected_match) {
-                           pCompressor->best_match = (lzsa_match *)malloc(nMaxWindowSize * sizeof(lzsa_match));
+                        if (pCompressor->best_match) {
+                           if ((pCompressor->flags & LZSA_FLAG_FAVOR_RATIO) == 0) {
+                              pCompressor->selected_match = (lzsa_match *)malloc(nMaxWindowSize * NMATCHES_PER_OFFSET * sizeof(lzsa_match));
 
-                           if (pCompressor->best_match) {
-                              pCompressor->slot_cost = (int *)malloc(nMaxWindowSize * NMATCHES_PER_OFFSET * sizeof(int));
+                              if (pCompressor->selected_match) {
+                                 pCompressor->slot_cost = (int *)malloc(nMaxWindowSize * NMATCHES_PER_OFFSET * sizeof(int));
 
-                              if (pCompressor->slot_cost) {
-                                 pCompressor->repmatch_opt = (lzsa_repmatch_opt *)malloc(nMaxWindowSize * sizeof(lzsa_repmatch_opt));
+                                 if (pCompressor->slot_cost) {
+                                    pCompressor->repmatch_opt = (lzsa_repmatch_opt *)malloc(nMaxWindowSize * sizeof(lzsa_repmatch_opt));
 
-                                 if (pCompressor->repmatch_opt)
-                                    return 0;
+                                    if (pCompressor->repmatch_opt)
+                                       return 0;
+                                 }
                               }
                            }
+                           else {
+                              return 0;
+                           }
                         }
                      }
                      else {