Cppcheck report - MOAB: src/io/mhdf/src/util.c

/**
 * MOAB, a Mesh-Oriented datABase, is a software component for creating,
 * storing and accessing finite element mesh data.
 *
 * Copyright 2004 Sandia Corporation.  Under the terms of Contract
 * DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government
 * retains certain rights in this software.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 */

#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <ctype.h>
#include <hdf5.h>
#include "util.h"
#include "status.h"
#include "names-and-paths.h"

#ifdef VALGRIND
#include <valgrind/memcheck.h>
#else
#define VALGRIND_CHECK_MEM_IS_DEFINED( A, B )
#define VALGRIND_MAKE_MEM_UNDEFINED( A, B )
#endif

void* mhdf_malloc( size_t size, mhdf_Status* status )
{
    void* result;
    result = malloc( size );
    if( !result ) mhdf_setFail( status, "Allocation of %d bytes failed.\n", (int)size );
    return result;
}

void* mhdf_realloc( void* ptr, size_t size, mhdf_Status* status )
{
    void* result;
    result = realloc( ptr, size );
    if( !result ) mhdf_setFail( status, "Allocation of %d bytes failed.\n", (int)size );
    return result;
}

size_t mhdf_name_to_path( const char* name, char* path, size_t path_len )
{
    size_t length = 1;
    unsigned char* iter;

    if( 0 == strcmp( name, "." ) )
    {
        if( path_len >= 4 ) sprintf( path, "\\%02X", (int)*name );
        return 4;
    }

    for( iter = (unsigned char*)name; *iter; ++iter )
    {
        if( iscntrl( *iter ) || *iter == '/' || *iter == '\\' || *iter > 127 )
            length += 3;
        else
            length += 1;
    }
    if( path_len < length ) return length;

    for( iter = (unsigned char*)name; *iter; ++iter )
    {
        if( iscntrl( *iter ) || *iter == '/' || *iter == '\\' || *iter > 127 )
        {
            sprintf( path, "\\%02X", (int)( *iter ) );
            path += 3;
        }
        else
        {
            *( path++ ) = *iter;
        }
    }

    *path = '\0';
    return length;
}

static int mhdf_hex_char( int c )
{
    if( isdigit( c ) )
        return c - '0';
    else
        return toupper( c ) - ( 'A' - 10 );
}

int mhdf_path_to_name( const char* path, char* name )
{
    const char* iter;
    char c1, c2;

    for( iter = path; *iter; ++iter, ++name )
    {
        if( *iter == '\\' )
        {
            c1 = *++iter;
            c2 = *++iter;
            if( !isxdigit( c1 ) || !isxdigit( c2 ) ) return 0;

            *name = (char)( 16 * mhdf_hex_char( c1 ) + mhdf_hex_char( c2 ) );
        }
        else
        {
            *name = *iter;
        }
    }

    *name = '\0';
    return 1;
}

char* mhdf_name_to_path_copy( const char* name, mhdf_Status* status )
{
    size_t size;
    char* buffer;

    size   = mhdf_name_to_path( name, NULL, 0 );
    buffer = (char*)mhdf_malloc( size, status );
    if( !buffer ) return NULL;

    mhdf_name_to_path( name, buffer, size );
    return buffer;
}

char* mhdf_name_to_path_cat( const char* prefix, const char* name, mhdf_Status* status )
{
    size_t size, plen;
    char* buffer;

    plen   = strlen( prefix );
    size   = mhdf_name_to_path( name, NULL, 0 ) + 1;
    buffer = (char*)mhdf_malloc( size + plen, status );
    if( !buffer ) return NULL;

    memcpy( buffer, prefix, plen );
    mhdf_name_to_path( name, buffer + plen, size );
    return buffer;
}

hid_t mhdf_elem_group_from_handle( FileHandle* file_ptr, const char* elem_handle, mhdf_Status* status )
{
    char* path;
    hid_t result;

    path = mhdf_name_to_path_cat( ELEMENT_GROUP, elem_handle, status );
    if( NULL == path ) return -1;

#if defined( H5Gopen_vers ) && H5Gopen_vers > 1
    result = H5Gopen2( file_ptr->hdf_handle, path, H5P_DEFAULT );
#else
    result  = H5Gopen( file_ptr->hdf_handle, path );
#endif
    free( path );
    if( result < 0 ) mhdf_setFail( status, "Failed to open element group: \"%s\"", elem_handle );
    return result;
}

int mhdf_create_scalar_attrib( hid_t object, const char* name, hid_t type, const void* value, mhdf_Status* status )
{
    hid_t dspace_id, attr_id;
    herr_t rval;

    dspace_id = H5Screate( H5S_SCALAR );
    if( dspace_id < 0 )
    {
        mhdf_setFail( status, "Internal error calling H5Screate_simple." );
        return 0;
    }

#if defined( H5Acreate_vers ) && H5Acreate_vers > 1
    attr_id = H5Acreate2( object, name, type, dspace_id, H5P_DEFAULT, H5P_DEFAULT );
#else
    attr_id = H5Acreate( object, name, type, dspace_id, H5P_DEFAULT );
#endif
    H5Sclose( dspace_id );
    if( attr_id < 0 )
    {
        mhdf_setFail( status, "Failed to create \"%s\" attrib.", name );
        return 0;
    }

    VALGRIND_CHECK_MEM_IS_DEFINED( value, H5Tget_size( type ) );
    rval = H5Awrite( attr_id, type, value );
    H5Aclose( attr_id );
    if( rval < 0 )
    {
        mhdf_setFail( status, "Failed to write \"%s\" attrib.", name );
        return 0;
    }

    return 1;
}

int mhdf_read_scalar_attrib( hid_t object, const char* name, hid_t type, void* value, mhdf_Status* status )
{
    hid_t attr_id, type_id;
    herr_t rval;

    attr_id = H5Aopen_name( object, name );
    if( attr_id < 0 )
    {
        mhdf_setFail( status, "Failed to create \"%s\" attrib.", name );
        return 0;
    }

    if( type > 0 )
    {
        type_id = type;
    }
    else
    {
        type_id = H5Aget_type( attr_id );
        if( type_id < 0 )
        {
            H5Aclose( attr_id );
            return 0;
        }
    }

    rval = H5Aread( attr_id, type_id, value );
    H5Aclose( attr_id );
    if( type < 1 ) H5Tclose( type_id );
    if( rval < 0 )
    {
        mhdf_setFail( status, "Failed to read \"%s\" attrib.", name );
        return 0;
    }

    return 1;
}

#if defined( H5Aiterate_vers ) && H5Aiterate_vers > 1
static herr_t find_attr_by_name( hid_t handle, const char* name, const H5A_info_t* info, void* mydata )
{
    /* empty statement to remove compiler warning */
    if( info )
    {
    }
#else
static herr_t find_attr_by_name( hid_t handle, const char* name, void* mydata )
{
#endif
    /* empty statement to remove compiler warning */
    if( handle )
    {
    }
    return !strcmp( name, (const char*)mydata );
}

int mhdf_find_attribute( hid_t object, const char* attrib_name, unsigned int* index_out, mhdf_Status* status )
{
    herr_t rval;
#if defined( H5Aiterate_vers ) && H5Aiterate_vers > 1
    hsize_t idx = 0;
    rval = H5Aiterate2( object, H5_INDEX_CRT_ORDER, H5_ITER_NATIVE, &idx, &find_attr_by_name, (void*)attrib_name );
    *index_out = (unsigned int)idx;
#else
    *index_out = 0;
    rval = H5Aiterate( object, index_out, &find_attr_by_name, (void*)attrib_name );
#endif
    if( rval < 0 ) mhdf_setFail( status, "Internal error calling H5Aiterate." );
    return (int)rval;
}

static herr_t find_link_by_name( hid_t handle, const char* name, void* mydata )
{
    /* empty statement to remove compiler warning */
    if( handle )
    {
    }
    return !strcmp( name, (const char*)mydata );
}

int mhdf_is_in_group( hid_t group, const char* name, mhdf_Status* status )
{
    int rval;
    rval = H5Giterate( group, ".", NULL, &find_link_by_name, (void*)name );
    if( rval < 0 ) mhdf_setFail( status, "Internal error in H5Giterate." );
    return rval;
}

static int mhdf_readwrite( hid_t data_id,
                           int read,
                           long offset,
                           long count,
                           hid_t type,
                           void* array,
                           hid_t io_prop,
                           mhdf_Status* status )
{
    hid_t slab_id, mem_id;
    hsize_t offsets[2], counts[2] = { 1, 1 };
    herr_t rval;
    int dims;
    /*#if (1000 * H5_VERS_MAJOR + H5_VERS_MINOR) < 1008*/
    const hsize_t one = 1;
    /*#endif*/

    if( offset < 0 || count < 0 )
    {
        mhdf_setFail( status,
                      "Invalid input for %s: "
                      "offset = %ld, count = %ld\n",
                      read ? "read" : "write", offset, count );
        return 0;
    }

    slab_id = H5Dget_space( data_id );
    if( slab_id < 0 )
    {
        mhdf_setFail( status, "Internal error calling H5Dget_space." );
        return 0;
    }

    dims = H5Sget_simple_extent_ndims( slab_id );
    if( dims < 1 || dims > 2 )
    {
        H5Sclose( slab_id );
        mhdf_setFail( status, "Internal error: unexpected dataset rank: %d.", dims );
        return 0;
    }

    dims = H5Sget_simple_extent_dims( slab_id, counts, NULL );
    if( dims < 0 )
    {
        H5Sclose( slab_id );
        mhdf_setFail( status, "Internal error calling H5Sget_simple_extend_dims." );
        return 0;
    }

    if( (unsigned long)( offset + count ) > counts[0] )
    {
        H5Sclose( slab_id );
        mhdf_setFail( status, "Requested %s of rows %ld to %ld of a %ld row table.\n", read ? "read" : "write", offset,
                      offset + count - 1, (long)counts[dims - 1] );
        return 0;
    }

    counts[0]  = (hsize_t)count;
    offsets[0] = (hsize_t)offset;
    offsets[1] = 0;
    if( count )
        rval = H5Sselect_hyperslab( slab_id, H5S_SELECT_SET, offsets, NULL, counts, NULL );
    else
        rval = H5Sselect_none( slab_id );
    if( rval < 0 )
    {
        H5Sclose( slab_id );
        mhdf_setFail( status, "Internal error calling H5Sselect_hyperslab." );
        return 0;
    }

    if( count )
        mem_id = H5Screate_simple( dims, counts, NULL );
    else
    {
        /*#if H5_VERS_MAJOR > 1 || H5_VERS_MINOR >= 8
            mem_id = H5Screate(H5S_NULL);
        #else*/
        mem_id = H5Screate_simple( 1, &one, NULL );
        if( mem_id && 0 > H5Sselect_none( mem_id ) )
        {
            H5Sclose( mem_id );
            mem_id = -1;
        }
        /*#endif*/
    }

    if( mem_id < 0 )
    {
        H5Sclose( slab_id );
        mhdf_setFail( status, "Internal error calling H5Screate_simple." );
        return 0;
    }

    if( read )
        rval = H5Dread( data_id, type, mem_id, slab_id, io_prop, array );
    else
    {
        VALGRIND_CHECK_MEM_IS_DEFINED( array, counts[0] * counts[1] * H5Tget_size( type ) );
        rval = H5Dwrite( data_id, type, mem_id, slab_id, io_prop, array );
    }
    H5Sclose( slab_id );
    H5Sclose( mem_id );
    if( rval < 0 )
    {
        mhdf_setFail( status, "Internal error calling H5D%s.", read ? "read" : "write" );
        return 0;
    }

    mhdf_setOkay( status );
    return 1;
}

static int mhdf_readwrite_column( hid_t data_id,
                                  int read,
                                  int column,
                                  long offset,
                                  long count,
                                  hid_t type,
                                  void* array,
                                  hid_t io_prop,
                                  mhdf_Status* status )
{
    hid_t slab_id, mem_id;
    hsize_t offsets[2], counts[2];
    herr_t rval;
    int dims;
    /*#if (1000 * H5_VERS_MAJOR + H5_VERS_MINOR) < 1008*/
    const hsize_t one = 1;
    /*#endif*/

    if( column < 0 || offset < 0 || count < 0 )
    {
        mhdf_setFail( status,
                      "Invalid input for %s: "
                      "column = %d, offset = %ld, count = %ld\n",
                      read ? "read" : "write", column, offset, count );
        return 0;
    }

    slab_id = H5Dget_space( data_id );
    if( slab_id < 0 )
    {
        mhdf_setFail( status, "Internal error calling H5Dget_space." );
        return 0;
    }

    dims = H5Sget_simple_extent_ndims( slab_id );
    if( dims < 1 || dims > 2 )
    {
        H5Sclose( slab_id );
        mhdf_setFail( status, "Internal error: unexpected dataset rank: %d.", dims );
        return 0;
    }

    dims = H5Sget_simple_extent_dims( slab_id, counts, NULL );
    if( dims < 0 )
    {
        H5Sclose( slab_id );
        mhdf_setFail( status, "Internal error calling H5Sget_simple_extend_dims." );
        return 0;
    }

    if( (unsigned long)( offset + count ) > counts[0] || (unsigned long)column > counts[1] )
    {
        H5Sclose( slab_id );
        mhdf_setFail( status, "Requested %s of (%ld,%d)->(%ld,%ld) of (%ld, %ld) table.\n", read ? "read" : "write",
                      offset, column, offset + count - 1, column, (long)counts[0], (long)counts[1] );
        return 0;
    }

    counts[0]  = (hsize_t)count;
    offsets[0] = (hsize_t)offset;
    counts[1]  = 1;
    offsets[1] = column;
    if( count )
        rval = H5Sselect_hyperslab( slab_id, H5S_SELECT_SET, offsets, NULL, counts, NULL );
    else
        rval = H5Sselect_none( slab_id );
    if( rval < 0 )
    {
        H5Sclose( slab_id );
        mhdf_setFail( status, "Internal error calling H5Sselect_hyperslab." );
        return 0;
    }

    if( count )
        mem_id = H5Screate_simple( dims, counts, NULL );
    else
    {
        /*#if H5_VERS_MAJOR > 1 || H5_VERS_MINOR >= 8
            mem_id = H5Screate(H5S_NULL);
        #else*/
        mem_id = H5Screate_simple( 1, &one, NULL );
        if( mem_id && 0 > H5Sselect_none( mem_id ) )
        {
            H5Sclose( mem_id );
            mem_id = -1;
        }
        /*#endif*/
    }

    if( mem_id < 0 )
    {
        H5Sclose( slab_id );
        mhdf_setFail( status, "Internal error calling H5Screate_simple." );
        return 0;
    }

    if( read )
        rval = H5Dread( data_id, type, mem_id, slab_id, io_prop, array );
    else
    {
        VALGRIND_CHECK_MEM_IS_DEFINED( array, count * H5Tget_size( type ) );
        rval = H5Dwrite( data_id, type, mem_id, slab_id, io_prop, array );
        VALGRIND_MAKE_MEM_UNDEFINED( array, count * H5Tget_size( type ) );
    }
    H5Sclose( slab_id );
    H5Sclose( mem_id );
    if( rval < 0 )
    {
        mhdf_setFail( status, "Internal error calling H5D%s.", read ? "read" : "write" );
        return 0;
    }

    mhdf_setOkay( status );
    return 1;
}

int mhdf_write_data( hid_t data_id,
                     long offset,
                     long count,
                     hid_t type_id,
                     const void* array,
                     hid_t prop,
                     mhdf_Status* status )
{
    return mhdf_readwrite( data_id, 0, offset, count, type_id, (void*)array, prop, status );
}

int mhdf_read_data( hid_t data_id,
                    long offset,
                    long count,
                    hid_t type_id,
                    void* array,
                    hid_t prop,
                    mhdf_Status* status )
{
    return mhdf_readwrite( data_id, 1, offset, count, type_id, array, prop, status );
}

int mhdf_read_column( hid_t data_id,
                      int column,
                      long offset,
                      long count,
                      hid_t type,
                      void* array,
                      hid_t prop,
                      mhdf_Status* status )
{
    return mhdf_readwrite_column( data_id, 1, column, offset, count, type, array, prop, status );
}

int mhdf_write_column( hid_t data_id,
                       int column,
                       long offset,
                       long count,
                       hid_t type,
                       const void* array,
                       hid_t prop,
                       mhdf_Status* status )
{
    return mhdf_readwrite_column( data_id, 0, column, offset, count, type, (void*)array, prop, status );
}

hid_t mhdf_create_table( hid_t group_id, const char* path, hid_t type, int rank, hsize_t* dims, mhdf_Status* status )
{
    return mhdf_create_table_with_prop( group_id, path, type, rank, dims, H5P_DEFAULT, status );
}

hid_t mhdf_create_table_with_prop( hid_t group_id,
                                   const char* path,
                                   hid_t type,
                                   int rank,
                                   hsize_t* dims,
                                   hid_t create_prop,
                                   mhdf_Status* status )
{
    hid_t space_id, table_id;

    space_id = H5Screate_simple( rank, dims, NULL );
    if( space_id < 0 )
    {
        mhdf_setFail( status, "Internal error calling H5Screate_simple." );
        return -1;
    }

#if defined( H5Dcreate_vers ) && H5Dcreate_vers > 1
    table_id = H5Dcreate2( group_id, path, type, space_id, H5P_DEFAULT, create_prop, H5P_DEFAULT );
#else
    table_id = H5Dcreate( group_id, path, type, space_id, create_prop );
#endif
    H5Sclose( space_id );
    if( table_id < 0 )
    {
        mhdf_setFail( status, "HDF5 DataSet creation failed." );
        return -1;
    }

    mhdf_setOkay( status );
    return table_id;
}

hid_t mhdf_open_table( hid_t group_id, const char* path, int columns, hsize_t* rows_out, mhdf_Status* status )
{
    hid_t table_id, space_id;
    hsize_t dims[2];
    int rank;

#if defined( H5Dopen_vers ) && H5Dopen_vers > 1
    table_id = H5Dopen2( group_id, path, H5P_DEFAULT );
#else
    table_id = H5Dopen( group_id, path );
#endif
    if( table_id < 0 )
    {
        mhdf_setFail( status, "HDF5 DataSet creation failed." );
        return -1;
    }

    space_id = H5Dget_space( table_id );
    if( space_id < 0 )
    {
        mhdf_setFail( status, "Internal error in H5Dget_space." );
        H5Dclose( table_id );
        return -1;
    }

    rank = H5Sget_simple_extent_ndims( space_id );
    if( rank != ( columns ? 1 : 2 ) )
    {
        mhdf_setFail( status, "Incorrect DataSpace for DataSet." );
        H5Sclose( space_id );
        H5Dclose( table_id );
        return -1;
    }

    rank = H5Sget_simple_extent_dims( space_id, dims, NULL );
    H5Sclose( space_id );
    if( rank < 0 )
    {
        mhdf_setFail( status, "Internal error calling H5Sget_simple_extent_dims." );
        H5Dclose( table_id );
        return -1;
    }

    *rows_out = dims[0];
    mhdf_setOkay( status );
    return table_id;
}

hid_t mhdf_open_table2( hid_t group_id,
                        const char* path,
                        int rank,
                        hsize_t* dims_out,
                        long* start_id_out,
                        mhdf_Status* status )
{
    hid_t table_id, space_id;

#if defined( H5Dopen_vers ) && H5Dopen_vers > 1
    table_id = H5Dopen2( group_id, path, H5P_DEFAULT );
#else
    table_id = H5Dopen( group_id, path );
#endif
    if( table_id < 0 )
    {
        mhdf_setFail( status, "HDF5 DataSet creation failed." );
        return -1;
    }

    space_id = H5Dget_space( table_id );
    if( space_id < 0 )
    {
        mhdf_setFail( status, "Internal error in H5Dget_space." );
        H5Dclose( table_id );
        return -1;
    }

    if( H5Sget_simple_extent_ndims( space_id ) != rank )
    {
        mhdf_setFail( status, "Incorrect DataSpace for DataSet." );
        H5Sclose( space_id );
        H5Dclose( table_id );
        return -1;
    }

    rank = H5Sget_simple_extent_dims( space_id, dims_out, NULL );
    H5Sclose( space_id );
    if( rank < 0 )
    {
        mhdf_setFail( status, "Internal error calling H5Sget_simple_extent_dims." );
        H5Dclose( table_id );
        return -1;
    }

    if( !mhdf_read_scalar_attrib( table_id, START_ID_ATTRIB, H5T_NATIVE_LONG, start_id_out, status ) )
    {
        mhdf_setFail( status, "File format error.  Failed to retreive ID offset." );
        H5Dclose( table_id );
        return -1;
    }

    mhdf_setOkay( status );
    return table_id;
}

hid_t mhdf_open_table_simple( hid_t group_id, const char* path, mhdf_Status* status )
{
    hid_t table_id;

#if defined( H5Dopen_vers ) && H5Dopen_vers > 1
    table_id = H5Dopen2( group_id, path, H5P_DEFAULT );
#else
    table_id = H5Dopen( group_id, path );
#endif
    if( table_id < 0 )
    {
        mhdf_setFail( status, "HDF5 DataSet creation failed." );
    }
    else
    {
        mhdf_setOkay( status );
    }

    return table_id;
}

static int qs_comp_int( const void* ptr1, const void* ptr2 )
{
    const int* left  = (const int*)ptr1;
    const int* right = (const int*)ptr2;
    return *left < *right ? -1 : *left > *right ? 1 : 0;
}

int mhdf_compact_to_ranges( int* length, int* ids, int ordered )<--- The function 'mhdf_compact_to_ranges' is never used.
{
    int new_length = 0;
    int *iter, *end;
    int prev, count;
<--- The scope of the variable 'count' can be reduced. [+]
The scope of the variable 'count' can be reduced. Warning: Be careful when fixing this message, especially when there are inner loops. Here is an example where cppcheck will write that the scope for 'i' can be reduced:
void f(int x)
{
    int i = 0;
    if (x) {
        // it's safe to move 'int i = 0;' here
        for (int n = 0; n < 10; ++n) {
            // it is possible but not safe to move 'int i = 0;' here
            do_something(&i);
        }
    }
}
When you see this message it is always safe to reduce the variable scope 1 level.
    int need_copy = 0;
    int *copy_ptr = 0, *w_iter;
    size_t blen;
<--- The scope of the variable 'blen' can be reduced. [+]
The scope of the variable 'blen' can be reduced. Warning: Be careful when fixing this message, especially when there are inner loops. Here is an example where cppcheck will write that the scope for 'i' can be reduced:
void f(int x)
{
    int i = 0;
    if (x) {
        // it's safe to move 'int i = 0;' here
        for (int n = 0; n < 10; ++n) {
            // it is possible but not safe to move 'int i = 0;' here
            do_something(&i);
        }
    }
}
When you see this message it is always safe to reduce the variable scope 1 level.

    if( !ordered ) qsort( ids, *length, sizeof( int ), &qs_comp_int );

    iter = ids;
    end  = ids + *length;
    while( iter != end )
    {
        prev = *( iter++ );
        while( iter < end && *( iter++ ) == ++prev )
            ;
        new_length += 2;
        if( new_length > ( iter - ids ) ) need_copy = 1;
    }

    if( new_length > *length ) return 0;

    if( need_copy )
    {
        blen     = sizeof( int ) * *length;
        copy_ptr = (int*)malloc( blen );
        memcpy( copy_ptr, ids, blen );
        iter = copy_ptr;
    }
    else
    {
        iter = ids;
    }

    end    = iter + *length;
    w_iter = ids;
    while( iter != end )
    {
        prev  = *( iter++ );
        count = 1;
        while( iter < end && *( iter++ ) == ++prev )
            ;
        *( w_iter++ ) = prev - count;
        *( w_iter++ ) = count;
    }

    *length = new_length;
    if( need_copy ) free( copy_ptr );
    return 1;
}

hid_t get_elem_type_enum( FileHandle* file_ptr, mhdf_Status* status )
{
    hid_t result;
#if defined( H5Topen_vers ) && H5Topen_vers > 1
    result = H5Topen2( file_ptr->hdf_handle, TYPE_ENUM_PATH, H5P_DEFAULT );
#else
    result = H5Topen( file_ptr->hdf_handle, TYPE_ENUM_PATH );
#endif
    if( result < 0 ) mhdf_setFail( status, "Element type enum does not exist in file.  Invalid file." );
    return result;
}

int mhdf_write_max_id( FileHandle* file_ptr, mhdf_Status* status )
{
    hid_t group_id, attr_id, space_id;
<--- The scope of the variable 'space_id' can be reduced. [+]
The scope of the variable 'space_id' can be reduced. Warning: Be careful when fixing this message, especially when there are inner loops. Here is an example where cppcheck will write that the scope for 'i' can be reduced:
void f(int x)
{
    int i = 0;
    if (x) {
        // it's safe to move 'int i = 0;' here
        for (int n = 0; n < 10; ++n) {
            // it is possible but not safe to move 'int i = 0;' here
            do_something(&i);
        }
    }
}
When you see this message it is always safe to reduce the variable scope 1 level.
    herr_t rval;

#if defined( H5Gopen_vers ) && H5Gopen_vers > 1
    group_id = H5Gopen2( file_ptr->hdf_handle, ROOT_GROUP, H5P_DEFAULT );
#else
    group_id = H5Gopen( file_ptr->hdf_handle, ROOT_GROUP );
#endif
    if( group_id < 0 )
    {
        mhdf_setFail( status, "Internal error -- file invalid." );
        return 0;
    }

    attr_id = H5Aopen_name( group_id, MAX_ID_ATTRIB );
    if( attr_id < 0 )
    {
        space_id = H5Screate( H5S_SCALAR );
#if defined( H5Acreate_vers ) && H5Acreate_vers > 1
        attr_id = H5Acreate2( group_id, MAX_ID_ATTRIB, H5T_NATIVE_ULONG, space_id, H5P_DEFAULT, H5P_DEFAULT );
#else
        attr_id = H5Acreate( group_id, MAX_ID_ATTRIB, H5T_NATIVE_ULONG, space_id, H5P_DEFAULT );
#endif
        H5Sclose( space_id );
    }
    H5Gclose( group_id );
    if( attr_id < 0 )
    {
        mhdf_setFail( status, "Failed to create attribute \"%s\" on \"%s\"", MAX_ID_ATTRIB, ROOT_GROUP );
        return 0;
    }

    rval = H5Awrite( attr_id, H5T_NATIVE_ULONG, &file_ptr->max_id );
    H5Aclose( attr_id );
    if( rval < 0 )
    {
        mhdf_setFail( status, "Failed to write \"%s\" attrib.", MAX_ID_ATTRIB );
        return 0;
    }

    return 1;
}

static int mhdf_api_handle_count = 0;

static int num_open()
{
    hid_t list[64];
    int nf, rval, i, count = 0;
<--- The scope of the variable 'rval' can be reduced. [+]
The scope of the variable 'rval' can be reduced. Warning: Be careful when fixing this message, especially when there are inner loops. Here is an example where cppcheck will write that the scope for 'i' can be reduced:
void f(int x)
{
    int i = 0;
    if (x) {
        // it's safe to move 'int i = 0;' here
        for (int n = 0; n < 10; ++n) {
            // it is possible but not safe to move 'int i = 0;' here
            do_something(&i);
        }
    }
}
When you see this message it is always safe to reduce the variable scope 1 level.

    nf = H5Fget_obj_ids( H5F_OBJ_ALL, H5F_OBJ_FILE, sizeof( list ) / sizeof( hid_t ), list );
    if( nf <= 0 || nf > 64 ) return 0;

    for( i = 0; i < nf; i++ )
    {
        rval = H5Fget_obj_count( list[i], H5F_OBJ_ALL );
        if( rval > 0 ) count += rval;
    }

    return count;
}

void mhdf_api_begin_internal()
{
    /* HDF5 docs are incorrect.  Passing H5F_OBJ_ALL as the first
       arg to H5Fget_obj_count returns the total number of open
       handles, not just those in files (i.e. temporary types and such.)
    mhdf_api_handle_count = H5Fget_obj_count( H5F_OBJ_ALL, H5F_OBJ_ALL );
       Need to loop to get actual file handles:
    */
    mhdf_api_handle_count = num_open();
}

void mhdf_api_end_internal( int expected_diff, const char* filename, int linenumber )
{
    if( mhdf_api_handle_count + expected_diff != num_open() )
    {
        fprintf( stderr, "Unclosed handles at end of mhdf API call.\n" );
        fprintf( stderr, "Entered with %d, expected %d change, got %d.\n", mhdf_api_handle_count, expected_diff,
                 num_open() );
        fprintf( stderr, "%s:%d\n", filename, linenumber );
        abort();
    }

    mhdf_api_handle_count = 0;
}