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authorLasse Collin <lasse.collin@tukaani.org>2009-11-25 12:52:56 +0200
committerLasse Collin <lasse.collin@tukaani.org>2009-11-25 12:52:56 +0200
commit1f196909143b888e062bd9a0c4ba8c34d3019bfa (patch)
treedf2c1aeea3f3a39db0ab43112f5336d76bb01c3a /src
parentCreate sparse files by default when decompressing into (diff)
downloadxz-1f196909143b888e062bd9a0c4ba8c34d3019bfa.tar.xz
Index decoder fixes.
The Index decoder code didn't perfectly match the API docs, which said that *i will be set to point to the decoded Index only after decoding has succeeded. The docs were a bit unclear too. Now the decoder will initially set *i to NULL. *i will be set to point to the decoded Index once decoding has succeeded. This simplifies applications too, since it avoids dangling pointers.
Diffstat (limited to '')
-rw-r--r--src/liblzma/api/lzma/index.h23
-rw-r--r--src/liblzma/common/index_decoder.c26
2 files changed, 32 insertions, 17 deletions
diff --git a/src/liblzma/api/lzma/index.h b/src/liblzma/api/lzma/index.h
index da9a622a..3490e4c6 100644
--- a/src/liblzma/api/lzma/index.h
+++ b/src/liblzma/api/lzma/index.h
@@ -317,12 +317,13 @@ extern LZMA_API(lzma_ret) lzma_index_encoder(lzma_stream *strm, lzma_index *i)
* \brief Initialize .xz Index decoder
*
* \param strm Pointer to properly prepared lzma_stream
- * \param i Pointer to a pointer that will be made to point
- * to the final decoded Index once lzma_code() has
- * returned LZMA_STREAM_END. That is,
- * lzma_index_decoder() always takes care of
- * allocating a new lzma_index structure, and *i
- * doesn't need to be initialized by the caller.
+ * \param i The decoded Index will be made available via
+ * this pointer. Initially this function will
+ * set *i to NULL (the old value is ignored). If
+ * decoding succeeds (lzma_code() returns
+ * LZMA_STREAM_END), *i will be set to point
+ * to the decoded Index, which the application
+ * has to later free with lzma_index_end().
* \param memlimit How much memory the resulting Index is allowed
* to require.
*
@@ -373,11 +374,11 @@ extern LZMA_API(lzma_ret) lzma_index_buffer_encode(lzma_index *i,
/**
* \brief Single-call .xz Index decoder
*
- * \param i Pointer to a pointer that will be made to point
- * to the final decoded Index if decoding is
- * successful. That is, lzma_index_buffer_decode()
- * always takes care of allocating a new
- * lzma_index structure, and *i doesn't need to be
+ * \param i If decoding succeeds, *i will point to the
+ * decoded Index, which the application has to
+ * later free with lzma_index_end(). If an error
+ * occurs, *i will be NULL. The old value of *i
+ * is always ignored and thus doesn't need to be
* initialized by the caller.
* \param memlimit Pointer to how much memory the resulting Index
* is allowed to require. The value pointed by
diff --git a/src/liblzma/common/index_decoder.c b/src/liblzma/common/index_decoder.c
index 51e9de38..258bf023 100644
--- a/src/liblzma/common/index_decoder.c
+++ b/src/liblzma/common/index_decoder.c
@@ -32,6 +32,10 @@ struct lzma_coder_s {
/// Target Index
lzma_index *index;
+ /// Pointer give by the application, which is set after
+ /// successful decoding.
+ lzma_index **index_ptr;
+
/// Number of Records left to decode.
lzma_vli count;
@@ -174,6 +178,10 @@ index_decode(lzma_coder *coder, lzma_allocator *allocator,
} while (++coder->pos < 4);
+ // Decoding was successful, now we can let the application
+ // see the decoded Index.
+ *coder->index_ptr = coder->index;
+
// Make index NULL so we don't free it unintentionally.
coder->index = NULL;
@@ -222,15 +230,21 @@ static lzma_ret
index_decoder_reset(lzma_coder *coder, lzma_allocator *allocator,
lzma_index **i, uint64_t memlimit)
{
+ // Remember the pointer given by the application. We will set it
+ // to point to the decoded Index only if decoding is successful.
+ // Before that, keep it NULL so that applications can always safely
+ // pass it to lzma_index_end() no matter did decoding succeed or not.
+ coder->index_ptr = i;
+ *i = NULL;
+
// We always allocate a new lzma_index.
- *i = lzma_index_init(NULL, allocator);
- if (*i == NULL)
+ coder->index = lzma_index_init(NULL, allocator);
+ if (coder->index == NULL)
return LZMA_MEM_ERROR;
// Initialize the rest.
coder->sequence = SEQ_INDICATOR;
coder->memlimit = memlimit;
- coder->index = *i;
coder->count = 0; // Needs to be initialized due to _memconfig().
coder->pos = 0;
coder->crc32 = 0;
@@ -282,7 +296,8 @@ lzma_index_buffer_decode(
const uint8_t *in, size_t *in_pos, size_t in_size)
{
// Sanity checks
- if (i == NULL || in == NULL || in_pos == NULL || *in_pos > in_size)
+ if (i == NULL || memlimit == NULL
+ || in == NULL || in_pos == NULL || *in_pos > in_size)
return LZMA_PROG_ERROR;
// Initialize the decoder.
@@ -302,8 +317,7 @@ lzma_index_buffer_decode(
} else {
// Something went wrong, free the Index structure and restore
// the input position.
- lzma_index_end(*i, allocator);
- *i = NULL;
+ lzma_index_end(coder.index, allocator);
*in_pos = in_start;
if (ret == LZMA_OK) {