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tvb_lz77huff: reduce stack memory usage 

clang errs about the stack frame size being too big.

* use indexes instead of pointers
* use guint8 instead of gboolean (== int)
* remplace hard coded 512 with #define

Change-Id: Idae70677f20e88ac8bba93899573e0137b9a3d7e
Fixes: 0db39ae59a ("smb2: add support for decompression")
Reviewed-on: https://code.wireshark.org/review/33965
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
This commit is contained in:
Aurelien Aptel 2019-07-16 11:08:13 +02:00 committed by Peter Wu
parent 6a7b01255a
commit 22e74ec018
1 changed files with 18 additions and 14 deletions
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32
epan/tvbuff_lz77huff.c
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@ -25,6 +25,7 @@
#define TREE_SIZE 1024
#define ENCODED_TREE_SIZE 256
#define SYMBOL_INFO_SIZE (2*ENCODED_TREE_SIZE)
struct input {
tvbuff_t *tvb;
@ -40,11 +41,14 @@ struct prefix_code_node {
guint16 symbol;
/* Indicates whether this node is a leaf in the tree */
gboolean leaf;
guint8 leaf;
/* Points to the node’s two children. The value NIL is used to
* indicate that a particular child does not exist */
struct prefix_code_node *child[2];
/*
* Points to the node's two children. Values are indexes in
* the tree node array. The value -1 is used to indicate that
* a particular child does not exist
*/
gint16 child[2];
};
/**
@ -107,19 +111,19 @@ static int prefix_code_tree_add_leaf(struct hf_tree *tree,
while (bits > 1) {
bits = bits - 1;
child_index = (mask >> bits) & 1;
if (node->child[child_index] == NULL) {
if (node->child[child_index] < 0) {
if (i >= TREE_SIZE)
return -1;
node->child[child_index] = &tree->nodes[i];
node->child[child_index] = i;
tree->nodes[i].leaf = FALSE;
i = i + 1;
}
node = node->child[child_index];
node = tree->nodes + node->child[child_index];
if (!is_node_valid(tree, node))
return -1;
}
node->child[mask & 1] = &tree->nodes[leaf_index];
node->child[mask & 1] = leaf_index;
*out_index = i;
return 0;
@ -152,15 +156,15 @@ static int compare_symbols(const void *ve1, const void *ve2)
static int PrefixCodeTreeRebuild( struct hf_tree *tree,
const struct input *input)
{
struct prefix_code_symbol symbolInfo[512];
struct prefix_code_symbol symbolInfo[SYMBOL_INFO_SIZE];
guint32 i, j, mask, bits;
int rc;
for (i = 0; i < TREE_SIZE; i++) {
tree->nodes[i].symbol = 0;
tree->nodes[i].leaf = FALSE;
tree->nodes[i].child[0] = NULL;
tree->nodes[i].child[1] = NULL;
tree->nodes[i].child[0] = -1;
tree->nodes[i].child[1] = -1;
}
if (input->size < ENCODED_TREE_SIZE)
@ -173,10 +177,10 @@ static int PrefixCodeTreeRebuild( struct hf_tree *tree,
symbolInfo[2*i+1].length = tvb_get_guint8(input->tvb, input->offset+i) >> 4;
}
qsort(symbolInfo, 512, sizeof(symbolInfo[0]), compare_symbols);
qsort(symbolInfo, SYMBOL_INFO_SIZE, sizeof(symbolInfo[0]), compare_symbols);
i = 0;
while (i < 512 && symbolInfo[i].length == 0) {
while (i < SYMBOL_INFO_SIZE && symbolInfo[i].length == 0) {
i = i + 1;
}
@ -261,7 +265,7 @@ static int prefix_code_tree_decode_symbol(struct hf_tree *tree,
do {
bit = bitstring_lookup(bstr, 1);
bitstring_skip(bstr, 1);
node = node->child[bit];
node = tree->nodes + node->child[bit];
if (!is_node_valid(tree, node))
return -1;
} while (node->leaf == FALSE);