inflate

tbeu · May 31, 2020 · b696f82 · b696f82
1 parent 1ed0690
commit b696f82
Show file tree

Hide file tree

Showing 2 changed files with 27 additions and 25 deletions.
diff --git a/src/inflate.c b/src/inflate.c
@@ -48,7 +48,7 @@ size_t
 InflateSkip(mat_t *mat, z_streamp z, int nBytes)
 {
     mat_uint8_t comp_buf[READ_BLOCK_SIZE], uncomp_buf[READ_BLOCK_SIZE];
-    int    n, err, cnt = 0;
+    int n, err, cnt = 0;
     size_t bytesread = 0;
 
     if ( nBytes < 1 )
@@ -82,11 +82,11 @@ InflateSkip(mat_t *mat, z_streamp z, int nBytes)
     while ( cnt < nBytes ) {
         if ( !z->avail_in ) {
             size_t nbytes = fread(comp_buf, 1, n, (FILE*)mat->fp);
-            bytesread += nbytes;
-            z->avail_in = (uInt)nbytes;
             if ( 0 == nbytes ) {
                 break;
             }
+            bytesread += nbytes;
+            z->avail_in = (uInt)nbytes;
             z->next_in = comp_buf;
         }
         err = inflate(z,Z_FULL_FLUSH);
@@ -105,8 +105,8 @@ InflateSkip(mat_t *mat, z_streamp z, int nBytes)
     }
 
     if ( z->avail_in ) {
-        long offset = -(long)z->avail_in;
-        (void)fseek((FILE*)mat->fp,offset,SEEK_CUR);
+        const long offset = -(long)z->avail_in;
+        (void)fseek((FILE*)mat->fp, offset, SEEK_CUR);
         bytesread -= z->avail_in;
         z->avail_in = 0;
     }
@@ -203,18 +203,19 @@ InflateRankDims(mat_t *mat, z_streamp z, void *buf, size_t nBytes, mat_uint32_t*
 
 /** @brief Inflates the data
  *
+ * buf must hold at least @c nBytes bytes
  * @ingroup mat_internal
  * @param mat Pointer to the MAT file
  * @param z zlib compression stream
- * @param buf Pointer to store the variables name
- * @param nBytes Number of characters in the name
+ * @param buf Pointer to store the uncompressed data
+ * @param nBytes Number of uncompressed bytes to inflate
  * @return Number of bytes read from the file
  */
 size_t
 Inflate(mat_t *mat, z_streamp z, void *buf, unsigned int nBytes)
 {
-    mat_uint8_t comp_buf[32];
-    int    err;
+    mat_uint8_t comp_buf[4];
+    int err;
     size_t bytesread = 0;
 
     if ( buf == NULL )
@@ -238,11 +239,11 @@ Inflate(mat_t *mat, z_streamp z, void *buf, unsigned int nBytes)
     }
     while ( z->avail_out && !z->avail_in ) {
         size_t nbytes = fread(comp_buf, 1, 1, (FILE*)mat->fp);
-        bytesread += nbytes;
-        z->avail_in = (uInt)nbytes;
         if ( 0 == nbytes ) {
             break;
         }
+        bytesread += nbytes;
+        z->avail_in = (uInt)nbytes;
         z->next_in = comp_buf;
         err = inflate(z,Z_NO_FLUSH);
         if ( err != Z_OK ) {
@@ -252,7 +253,8 @@ Inflate(mat_t *mat, z_streamp z, void *buf, unsigned int nBytes)
     }
 
     if ( z->avail_in ) {
-        (void)fseek((FILE*)mat->fp,-(int)z->avail_in,SEEK_CUR);
+        const long offset = -(long)z->avail_in;
+        (void)fseek((FILE*)mat->fp, offset, SEEK_CUR);
         bytesread -= z->avail_in;
         z->avail_in = 0;
     }
@@ -271,8 +273,8 @@ Inflate(mat_t *mat, z_streamp z, void *buf, unsigned int nBytes)
  * @ingroup mat_internal
  * @param mat Pointer to the MAT file
  * @param z zlib compression stream
- * @param buf Pointer to store the data type
- * @param nBytes Number of bytes to inflate
+ * @param buf Pointer to store the uncompressed data
+ * @param nBytes Number of uncompressed bytes to inflate
  * @return Number of bytes read from the file
  */
 size_t
@@ -317,24 +319,24 @@ InflateData(mat_t *mat, z_streamp z, void *buf, unsigned int nBytes)
         } else {
             nbytes = fread(comp_buf, 1, nBytes - bytesread, (FILE*)mat->fp);
         }
-        bytesread += nbytes;
-        z->avail_in = (uInt)nbytes;
         if ( 0 == nbytes ) {
             break;
         }
+        bytesread += nbytes;
+        z->avail_in = (uInt)nbytes;
         z->next_in = comp_buf;
         err = inflate(z,Z_FULL_FLUSH);
         if ( err == Z_STREAM_END ) {
             break;
-        } else if ( err != Z_OK && err != Z_BUF_ERROR ) {
+        } else if ( err != Z_OK ) {
             Mat_Critical("InflateData: inflate returned %s",zError(err == Z_NEED_DICT ? Z_DATA_ERROR : err));
             break;
         }
     }
 
     if ( z->avail_in ) {
         const long offset = -(long)z->avail_in;
-        (void)fseek((FILE*)mat->fp,offset,SEEK_CUR);
+        (void)fseek((FILE*)mat->fp, offset, SEEK_CUR);
         bytesread -= z->avail_in;
         z->avail_in = 0;
     }

diff --git a/src/mat.c b/src/mat.c
@@ -313,19 +313,19 @@ int SafeAdd(size_t* res, size_t a, size_t b)
  * @retval 0 on success
  */
 int
-SafeRead(void* buf, size_t size, size_t count, FILE* fp, size_t* read_bytes) {
-    const size_t read_result = fread(buf, size, count, fp);
-    int err = read_result != count;
-    if ( NULL != read_bytes ) {
-        *read_bytes += read_result*size;
+SafeRead(void* buf, size_t size, size_t count, FILE* fp, size_t* bytesread) {
+    const size_t readcount = fread(buf, size, count, fp);
+    int err = readcount != count;
+    if ( NULL != bytesread ) {
+        *bytesread += readcount*size;
     }
-    if ( err && feof(fp) && 0 == read_result) {
+    if ( err && feof(fp) && 0 == readcount) {
         err = 0;
     }
     if ( err ) {
         Mat_Critical("Read beyond EOF error: Read %"
             SIZE_T_FMTSTR " bytes, expected %"
-            SIZE_T_FMTSTR " bytes", read_result*size, count*size);
+            SIZE_T_FMTSTR " bytes", readcount*size, count*size);
     }
     return err;
 }