[svn-r23230] Purpose: Implement H5Dscatter and H5Dgather

Description:
Adds 2 new API functions, H5Dscatter and H5Dgather.  H5Dscatter retrieves data
from a specified callback function and scatters it into a selection, defined by
a supplied dataspace, within a supplied memory buffer.  H5Dgather gathers data
from a selection within a supplied memory buffer and passes it in a contiguous
form to a supplied callback function.  Added tests for these functions

Tested: jam, ostrich, koala (h5committest); ummon

5 files changed, 1229 insertions, 1 deletions

diff --git a/bin/trace b/bin/trace
index 67aeb17..657ac92 100755
--- a/bin/trace
+++ b/bin/trace
@@ -99,7 +99,9 @@ $Source = "";
 	       "H5A_operator2_t"            => "x",
 	       "H5A_info_t"                 => "x",
                "H5AC_cache_config_t"        => "x",
+               "H5D_gather_func_t"          => "x",
                "H5D_operator_t"             => "x",
+               "H5D_scatter_func_t"         => "x",
                "H5E_auto_t"                 => "x",
                "H5E_auto1_t"                => "x",
                "H5E_auto2_t"                => "x",
diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index 6d329bb..a67c613 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -106,6 +106,9 @@ New Features
 
     Library:
     --------
+    - Added new API functions H5Dscatter and H5Dgather to scatter data to and
+      and gather data from a selection within a memory buffer.
+      (NAF - 2013/02/05)
     - The library now supports the data conversion from enumeration to numeric
       (integer and floating-point number) datatypes. See Issue 8221.
       (SLU - 2012/10/23)  
diff --git a/src/H5Dpublic.h b/src/H5Dpublic.h
index 523f2b2..484b176 100644
--- a/src/H5Dpublic.h
+++ b/src/H5Dpublic.h
@@ -107,6 +107,15 @@ extern "C" {
 typedef herr_t (*H5D_operator_t)(void *elem, hid_t type_id, unsigned ndim,
 				 const hsize_t *point, void *operator_data);
 
+/* Define the operator function pointer for H5Dscatter() */
+typedef herr_t (*H5D_scatter_func_t)(void **src_buf/*out*/,
+                                     size_t *src_buf_bytes_used/*out*/,
+                                     void *op_data);
+
+/* Define the operator function pointer for H5Dgather() */
+typedef herr_t (*H5D_gather_func_t)(const void *dst_buf,
+                                    size_t dst_buf_bytes_used, void *op_data);
+
 H5_DLL hid_t H5Dcreate2(hid_t loc_id, const char *name, hid_t type_id,
     hid_t space_id, hid_t lcpl_id, hid_t dcpl_id, hid_t dapl_id);
 H5_DLL hid_t H5Dcreate_anon(hid_t file_id, hid_t type_id, hid_t space_id,
@@ -131,6 +140,10 @@ H5_DLL herr_t H5Dvlen_get_buf_size(hid_t dataset_id, hid_t type_id, hid_t space_
 H5_DLL herr_t H5Dfill(const void *fill, hid_t fill_type, void *buf,
         hid_t buf_type, hid_t space);
 H5_DLL herr_t H5Dset_extent(hid_t dset_id, const hsize_t size[]);
+H5_DLL herr_t H5Dscatter(H5D_scatter_func_t op, void *op_data, hid_t type_id,
+    hid_t dst_space_id, void *dst_buf);
+H5_DLL herr_t H5Dgather(hid_t src_space_id, void *src_buf, hid_t type_id,
+    size_t dst_buf_size, void *dst_buf, H5D_gather_func_t op, void *op_data);
 H5_DLL herr_t H5Ddebug(hid_t dset_id);
 
 /* Symbols defined for compatibility with previous versions of the HDF5 API.
diff --git a/src/H5Dscatgath.c b/src/H5Dscatgath.c
index 49b6132..74d6749 100644
--- a/src/H5Dscatgath.c
+++ b/src/H5Dscatgath.c
@@ -27,6 +27,7 @@
 #include "H5Dpkg.h"		/* Dataset functions			*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5FLprivate.h"	/* Free Lists                           */
+#include "H5Iprivate.h"		/* IDs                                  */
 
 
 /****************/
@@ -361,7 +362,7 @@ done:
  *		copies them into the gather buffer TGATH_BUF.
  *		Each element is ELMT_SIZE bytes and arranged in application
  *		memory according to SPACE.
- *		The caller is requesting that at most NELMTS be gathered.
+ *		The caller is requesting that exactly NELMTS be gathered.
  *
  * Return:	Success:	Number of elements copied.
  *		Failure:	0
@@ -899,3 +900,200 @@ H5D__compound_opt_write(size_t nelmts, const H5D_type_info_t *type_info)
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* end H5D__compound_opt_write() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Dscatter
+ *
+ * Purpose:     Scatters data provided by the callback op to the
+ *              destination buffer dst_buf, where the dimensions of
+ *              dst_buf and the selection to be scattered to are specified
+ *              by the dataspace dst_space_id.  The type of the data to be
+ *              scattered is specified by type_id.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Neil Fortner
+ *              14 Jan 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Dscatter(H5D_scatter_func_t op, void *op_data, hid_t type_id,
+    hid_t dst_space_id, void *dst_buf)
+{
+    H5T_t *type;                /* Datatype */
+    H5S_t *dst_space;           /* Dataspace */
+    H5S_sel_iter_t iter;        /* Selection iteration info*/
+    hbool_t iter_init = FALSE;  /* Selection iteration info has been initialized */
+    void *src_buf = NULL;       /* Source (contiguous) data buffer */
+    size_t src_buf_nbytes = 0;  /* Size of src_buf */
+    size_t type_size;           /* Datatype element size */
+    hssize_t nelmts;            /* Number of remaining elements in selection */
+    size_t nelmts_scatter = 0;  /* Number of elements to scatter to dst_buf */
+    H5D_dxpl_cache_t _dxpl_cache; /* Data transfer property cache buffer */
+    H5D_dxpl_cache_t *dxpl_cache = &_dxpl_cache; /* Data transfer property cache */
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE5("e", "x*xii*x", op, op_data, type_id, dst_space_id, dst_buf);
+
+    /* Check args */
+    if(op == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid callback function pointer")
+    if(NULL == (type = (H5T_t *)H5I_object_verify(type_id, H5I_DATATYPE)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a datatype")
+    if(NULL == (dst_space= (H5S_t *)H5I_object_verify(dst_space_id, H5I_DATASPACE)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a dataspace")
+    if(dst_buf == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no destination buffer provided")
+
+    /* Fill the DXPL cache values for later use */
+    if(H5D__get_dxpl_cache(H5P_DATASET_XFER_DEFAULT, &dxpl_cache) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't fill dxpl cache")
+
+    /* Get datatype element size */
+    if(0 == (type_size = H5T_GET_SIZE(type)))
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get datatype size")
+
+    /* Get number of elements in dataspace */
+    if((nelmts = (hssize_t)H5S_GET_SELECT_NPOINTS(dst_space)) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOUNT, FAIL, "unable to get number of elements in selection")
+
+    /* Initialize selection iterator */
+    if(H5S_select_iter_init(&iter, dst_space, type_size) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to initialize selection iterator information")
+    iter_init = TRUE;
+
+    /* Loop until all data has been scattered */
+    while(nelmts > 0) {
+        /* Make callback to retrieve data */
+        if(op(&src_buf, &src_buf_nbytes, op_data) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CALLBACK, FAIL, "callback operator returned failure")
+
+        /* Calculate number of elements */
+        nelmts_scatter = src_buf_nbytes / type_size;
+
+        /* Check callback results */
+        if(!src_buf)
+            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "callback did not return a buffer")
+        if(src_buf_nbytes == 0)
+            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "callback returned a buffer size of 0")
+        if(src_buf_nbytes % type_size)
+            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "buffer size is not a multiple of datatype size")
+        if(nelmts_scatter > (size_t)nelmts)
+            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "callback returned more elements than in selection")
+
+        /* Scatter data */
+        if(H5D__scatter_mem(src_buf, dst_space, &iter, nelmts_scatter, dxpl_cache, dst_buf) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "scatter failed")
+
+        nelmts -= (hssize_t)nelmts_scatter;
+    } /* end while */
+
+done:
+    /* Release selection iterator */
+    if(iter_init) {
+        if(H5S_SELECT_ITER_RELEASE(&iter) < 0)
+            HDONE_ERROR(H5E_DATASET, H5E_CANTFREE, FAIL, "Can't release selection iterator")
+    } /* end if */
+
+    FUNC_LEAVE_API(ret_value)
+}   /* H5Dscatter() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Dgather
+ *
+ * Purpose:     Gathers data provided from the source buffer src_buf to
+ *              contiguous buffer dst_buf, then calls the callback op.
+ *              The dimensions of src_buf and the selection to be gathered
+ *              are specified by the dataspace src_space_id.  The type of
+ *              the data to be gathered is specified by type_id.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Neil Fortner
+ *              16 Jan 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Dgather(hid_t src_space_id, void *src_buf, hid_t type_id, size_t dst_buf_size,
+    void *dst_buf, H5D_gather_func_t op, void *op_data)
+{
+    H5T_t *type;                /* Datatype */
+    H5S_t *src_space;           /* Dataspace */
+    H5S_sel_iter_t iter;        /* Selection iteration info*/
+    hbool_t iter_init = FALSE;  /* Selection iteration info has been initialized */
+    size_t type_size;           /* Datatype element size */
+    hssize_t nelmts;            /* Number of remaining elements in selection */
+    size_t dst_buf_nelmts;      /* Number of elements that can fit in dst_buf */
+    size_t nelmts_gathered;     /* Number of elements gathered from src_buf */
+    H5D_dxpl_cache_t _dxpl_cache; /* Data transfer property cache buffer */
+    H5D_dxpl_cache_t *dxpl_cache = &_dxpl_cache; /* Data transfer property cache */
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE7("e", "i*xiz*xx*x", src_space_id, src_buf, type_id, dst_buf_size,
+             dst_buf, op, op_data);
+
+    /* Check args */
+    if(NULL == (src_space= (H5S_t *)H5I_object_verify(src_space_id, H5I_DATASPACE)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a dataspace")
+    if(src_buf == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no source buffer provided")
+    if(NULL == (type = (H5T_t *)H5I_object_verify(type_id, H5I_DATATYPE)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a datatype")
+    if(dst_buf_size == 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "destination buffer size is 0")
+    if(dst_buf == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no destination buffer provided")
+    if(op == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid callback function pointer")
+
+    /* Fill the DXPL cache values for later use */
+    if(H5D__get_dxpl_cache(H5P_DATASET_XFER_DEFAULT, &dxpl_cache) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't fill dxpl cache")
+
+    /* Get datatype element size */
+    if(0 == (type_size = H5T_GET_SIZE(type)))
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get datatype size")
+
+    /* Get number of elements in dst_buf_size */
+    dst_buf_nelmts = dst_buf_size / type_size;
+    if(dst_buf_nelmts == 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "destination buffer is not large enough to hold one element")
+
+    /* Get number of elements in dataspace */
+    if((nelmts = (hssize_t)H5S_GET_SELECT_NPOINTS(src_space)) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOUNT, FAIL, "unable to get number of elements in selection")
+
+    /* Initialize selection iterator */
+    if(H5S_select_iter_init(&iter, src_space, type_size) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to initialize selection iterator information")
+    iter_init = TRUE;
+
+    /* Loop until all data has been scattered */
+    while(nelmts > 0) {
+        /* Gather data */
+        if(0 == (nelmts_gathered = H5D__gather_mem(src_buf, src_space, &iter, MIN(dst_buf_nelmts, (size_t)nelmts), dxpl_cache, dst_buf)))
+            HGOTO_ERROR(H5E_IO, H5E_CANTCOPY, FAIL, "gather failed")
+        HDassert(nelmts_gathered == MIN(dst_buf_nelmts, (size_t)nelmts));
+
+        /* Make callback to process dst_buf */
+        if(op(dst_buf, nelmts_gathered * type_size, op_data) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CALLBACK, FAIL, "callback operator returned failure")
+
+        nelmts -= (hssize_t)nelmts_gathered;
+    } /* end while */
+
+done:
+    /* Release selection iterator */
+    if(iter_init) {
+        if(H5S_SELECT_ITER_RELEASE(&iter) < 0)
+            HDONE_ERROR(H5E_DATASET, H5E_CANTFREE, FAIL, "Can't release selection iterator")
+    } /* end if */
+
+    FUNC_LEAVE_API(ret_value)
+}   /* H5Dgather() */
+
diff --git a/test/dsets.c b/test/dsets.c
index 838ef48..96611d9 100644
--- a/test/dsets.c
+++ b/test/dsets.c
@@ -8181,6 +8181,1012 @@ error:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    test_scatter
+ *
+ * Purpose:     Tests H5Dscatter with a variety of different selections
+ *              and source buffer sizes.
+ *
+ * Return:      Success: 0
+ *              Failure: -1
+ *
+ * Programmer:  Neil Fortner
+ *              Wednesday, January 16, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+typedef struct scatter_info_t {
+    int *src_buf;   /* Source data buffer */
+    size_t block;   /* Maximum number of elements to return to H5Dscatter() */
+    size_t size;    /* Remaining number of elements to return */
+} scatter_info_t;
+
+#define TEST_SCATTER_CHECK_ARR(ARR, EXP) \
+    for(i=0; i<(int)(sizeof(ARR)/sizeof(ARR[0])); i++) \
+        for(j=0; j<(int)(sizeof(ARR[0])/sizeof(ARR[0][0])); j++) \
+            for(k=0; k<(int)(sizeof(ARR[0][0])/sizeof(ARR[0][0][0])); k++) \
+                if(ARR[i][j][k] != EXP[i][j][k]) { \
+                    H5_FAILED(); AT(); \
+                    printf("  " #ARR "[%d][%d][%d] == %d, " #EXP "[%d][%d][%d] == %d\n", i, j, k, ARR[i][j][k], i, j, k, EXP[i][j][k]); \
+                    goto error; \
+                }
+
+static herr_t
+scatter_cb(void **src_buf/*out*/, size_t *src_buf_bytes_used/*out*/,
+    void *_scatter_info)
+{
+    scatter_info_t *scatter_info = (scatter_info_t *)_scatter_info;
+    size_t nelmts;      /* Number of elements to return in src_buf */
+
+    /* Calculate number of elements */
+    nelmts = MIN(scatter_info->block, scatter_info->size);
+    HDassert(nelmts > 0);
+
+    /* Set output variables */
+    *src_buf = (void *)scatter_info->src_buf;
+    *src_buf_bytes_used = nelmts * sizeof(scatter_info->src_buf[0]);
+
+    /* Update scatter_info */
+    scatter_info->src_buf += nelmts;
+    scatter_info->size -= nelmts;
+
+    return SUCCEED;
+}
+
+static herr_t
+test_scatter(void)
+{
+    hid_t       sid = -1;       /* Dataspace ID */
+    hsize_t     dim[3] = {8, 4, 8}; /* Dataspace dimensions */
+    hsize_t     start[3] = {0, 0, 0};
+    hsize_t     stride[3] = {0, 0, 0};
+    hsize_t     count[3] = {0, 0, 0};
+    hsize_t     block[3] = {0, 0, 0};
+    hsize_t     start2[3] = {0, 0, 0};
+    hsize_t     count2[3] = {0, 0, 0};
+    hsize_t     point[4][3] = {{2, 3, 2}, {3, 0, 2}, {7, 2, 0}, {0, 1, 5}};
+    size_t      src_buf_size;
+    int         src_buf[36];    /* Source data buffer */
+    int         dst_buf[8][4][8]; /* Destination data buffer */
+    int         expect_dst_buf[8][4][8]; /* Expected destination data buffer */
+    scatter_info_t scatter_info; /* Operator data for callback */
+    int         i, j, k, src_i; /* Local index variables */
+
+    TESTING("H5Dscatter()");
+
+    /* Create dataspace */
+    if((sid = H5Screate_simple(3, dim, NULL)) < 0) TEST_ERROR
+
+    /* Initialize src_buf */
+    for(i=0; i<(int)(sizeof(src_buf)/sizeof(src_buf[0])); i++)
+        src_buf[i] = i + 1;
+
+
+    /*
+     * Test 1: Simple case
+     */
+    /* Select hyperslab */
+    count[0] = 1;
+    count[1] = 1;
+    count[2] = 8;
+    if(H5Sselect_hyperslab(sid, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
+        TEST_ERROR
+
+    /* Initialize dst_buf and expect_dst_buf */
+    (void)HDmemset(expect_dst_buf, 0, sizeof(expect_dst_buf));
+    for(i=0; i<8; i++)
+        expect_dst_buf[0][0][i] = src_buf[i];
+
+    /* Loop over buffer sizes */
+    for(src_buf_size=1; src_buf_size<=9; src_buf_size++) {
+        /* Reset dst_buf */
+        (void)HDmemset(dst_buf, 0, sizeof(dst_buf));
+
+        /* Set up scatter info */
+        scatter_info.src_buf = src_buf;
+        scatter_info.block = src_buf_size;
+        scatter_info.size = 8;
+
+        /* Scatter data */
+        if(H5Dscatter(scatter_cb, &scatter_info, H5T_NATIVE_INT, sid, dst_buf) < 0)
+            TEST_ERROR
+
+        /* Verify data */
+        TEST_SCATTER_CHECK_ARR(dst_buf, expect_dst_buf)
+    } /* end for */
+
+
+    /*
+     * Test 2: Single block in dataset
+     */
+    /* Select hyperslab */
+    start[0] = 3;
+    start[1] = 2;
+    start[2] = 4;
+    count[0] = 2;
+    count[1] = 3;
+    count[2] = 2;
+    if(H5Sselect_hyperslab(sid, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
+        TEST_ERROR
+
+    /* Initialize expect_dst_buf */
+    (void)HDmemset(expect_dst_buf, 0, sizeof(expect_dst_buf));
+    src_i = 0;
+    for(i=3; i<5; i++)
+        for(j=2; j<5; j++)
+            for(k=4; k<6; k++)
+                expect_dst_buf[i][j][k] = src_buf[src_i++];
+
+    /* Loop over buffer sizes */
+    for(src_buf_size=1; src_buf_size<=13; src_buf_size++) {
+        /* Reset dst_buf */
+        (void)HDmemset(dst_buf, 0, sizeof(dst_buf));
+
+        /* Set up scatter info */
+        scatter_info.src_buf = src_buf;
+        scatter_info.block = src_buf_size;
+        scatter_info.size = 12;
+
+        /* Scatter data */
+        if(H5Dscatter(scatter_cb, &scatter_info, H5T_NATIVE_INT, sid, dst_buf) < 0)
+            TEST_ERROR
+
+        /* Verify data */
+        TEST_SCATTER_CHECK_ARR(dst_buf, expect_dst_buf)
+    } /* end for */
+
+
+    /*
+     * Test 3: Multiple blocks
+     */
+    /* Select hyperslab */
+    start[0] = 1;
+    start[1] = 1;
+    start[2] = 1;
+    stride[0] = 3;
+    stride[1] = 4;
+    stride[2] = 5;
+    count[0] = 3;
+    count[1] = 1;
+    count[2] = 2;
+    block[0] = 1;
+    block[1] = 3;
+    block[2] = 2;
+    if(H5Sselect_hyperslab(sid, H5S_SELECT_SET, start, stride ,count, block) < 0)
+        TEST_ERROR
+
+    /* Initialize expect_dst_buf */
+    /* Iterate over block containing selection, checking if each element is in
+     * selection.  Note that the algorithm used here (if statement) would not
+     * work for overlapping hyperslabs. */
+    (void)HDmemset(expect_dst_buf, 0, sizeof(expect_dst_buf));
+    src_i = 0;
+    for(i=1; i<8; i++)
+        for(j=1; j<4; j++)
+            for(k=1; k<8; k++)
+                if((hsize_t)i >= start[0]
+                        && ((hsize_t)i - start[0]) % stride[0] < block[0]
+                        && ((hsize_t)i - start[0]) / stride[0] < count[0]
+                        && (hsize_t)j >= start[1]
+                        && ((hsize_t)j - start[1]) % stride[1] < block[1]
+                        && ((hsize_t)j - start[1]) / stride[1] < count[1]
+                        && (hsize_t)k >= start[2]
+                        && ((hsize_t)k - start[2]) % stride[2] < block[2]
+                        && ((hsize_t)k - start[2]) / stride[2] < count[2])
+                    expect_dst_buf[i][j][k] = src_buf[src_i++];
+
+    /* Loop over buffer sizes */
+    for(src_buf_size=1; src_buf_size<=37; src_buf_size++) {
+        /* Reset dst_buf */
+        (void)HDmemset(dst_buf, 0, sizeof(dst_buf));
+
+        /* Set up scatter info */
+        scatter_info.src_buf = src_buf;
+        scatter_info.block = src_buf_size;
+        scatter_info.size = 36;
+
+        /* Scatter data */
+        if(H5Dscatter(scatter_cb, &scatter_info, H5T_NATIVE_INT, sid, dst_buf) < 0)
+            TEST_ERROR
+
+        /* Verify data */
+        TEST_SCATTER_CHECK_ARR(dst_buf, expect_dst_buf)
+    } /* end for */
+
+
+    /*
+     * Test 4: Compound selection
+     */
+    /* Select hyperslabs */
+    start[0] = 2;
+    start[1] = 1;
+    start[2] = 1;
+    count[0] = 2;
+    count[1] = 3;
+    count[2] = 2;
+    if(H5Sselect_hyperslab(sid, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
+        TEST_ERROR
+    start2[0] = 1;
+    start2[1] = 2;
+    start2[2] = 2;
+    count2[0] = 3;
+    count2[1] = 2;
+    count2[2] = 2;
+    if(H5Sselect_hyperslab(sid, H5S_SELECT_XOR, start2, NULL ,count2, NULL) < 0)
+        TEST_ERROR
+
+    /* Initialize expect_dst_buf */
+    /* Iterate over block containing selection, checking if each element is in
+     * selection. */
+    (void)HDmemset(expect_dst_buf, 0, sizeof(expect_dst_buf));
+    src_i = 0;
+    for(i=1; i<4; i++)
+        for(j=1; j<4; j++)
+            for(k=1; k<4; k++)
+                if(!(((hsize_t)i >= start[0] && (hsize_t)i < start[0] + count[0])
+                        && ((hsize_t)j >= start[1] && (hsize_t)j < start[1] + count[1])
+                        && ((hsize_t)k >= start[2] && (hsize_t)k < start[2] + count[2]))
+                        != !(((hsize_t)i >= start2[0] && (hsize_t)i < start2[0] + count2[0])
+                        && ((hsize_t)j >= start2[1] && (hsize_t)j < start2[1] + count2[1])
+                        && ((hsize_t)k >= start2[2] && (hsize_t)k < start2[2] + count2[2])))
+                    expect_dst_buf[i][j][k] = src_buf[src_i++];
+
+    /* Loop over buffer sizes */
+    for(src_buf_size=1; src_buf_size<=17; src_buf_size++) {
+        /* Reset dst_buf */
+        (void)HDmemset(dst_buf, 0, sizeof(dst_buf));
+
+        /* Set up scatter info */
+        scatter_info.src_buf = src_buf;
+        scatter_info.block = src_buf_size;
+        scatter_info.size = 16;
+
+        /* Scatter data */
+        if(H5Dscatter(scatter_cb, &scatter_info, H5T_NATIVE_INT, sid, dst_buf) < 0)
+            TEST_ERROR
+
+        /* Verify data */
+        TEST_SCATTER_CHECK_ARR(dst_buf, expect_dst_buf)
+    } /* end for */
+
+
+    /*
+     * Test 5: Point selection
+     */
+    /* Select hyperslabs */
+    if(H5Sselect_elements(sid, H5S_SELECT_SET, sizeof(point) / sizeof(point[0]), (hsize_t *)point) < 0)
+        TEST_ERROR
+
+    /* Initialize expect_dst_buf */
+    /* Iterate over block containing selection, checking if each element is in
+     * selection. */
+    (void)HDmemset(expect_dst_buf, 0, sizeof(expect_dst_buf));
+    for(i=0; i<(int)(sizeof(point) / sizeof(point[0])); i++)
+        expect_dst_buf[point[i][0]][point[i][1]][point[i][2]]
+                = src_buf[i];
+
+    /* Loop over buffer sizes */
+    for(src_buf_size=1; src_buf_size<=5; src_buf_size++) {
+        /* Reset dst_buf */
+        (void)HDmemset(dst_buf, 0, sizeof(dst_buf));
+
+        /* Set up scatter info */
+        scatter_info.src_buf = src_buf;
+        scatter_info.block = src_buf_size;
+        scatter_info.size = 4;
+
+        /* Scatter data */
+        if(H5Dscatter(scatter_cb, &scatter_info, H5T_NATIVE_INT, sid, dst_buf) < 0)
+            TEST_ERROR
+
+        /* Verify data */
+        TEST_SCATTER_CHECK_ARR(dst_buf, expect_dst_buf)
+    } /* end for */
+
+
+    /* Close everything */
+    if(H5Sclose(sid) < 0) TEST_ERROR
+
+    PASSED();
+
+    return 0;
+
+error:
+    H5E_BEGIN_TRY {
+        H5Sclose(sid);
+    } H5E_END_TRY;
+    return -1;
+} /* end test_scatter() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    test_gather
+ *
+ * Purpose:     Tests H5Dgather with a variety of different selections and
+ *              destination buffer sizes.
+ *
+ * Return:      Success: 0
+ *              Failure: -1
+ *
+ * Programmer:  Neil Fortner
+ *              Wednesday, January 16, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+typedef struct gather_info_t {
+    int *expect_dst_buf; /* Expected destination data buffer */
+    size_t max_nelmts;  /* Maximum number of elements passed to callback */
+    hbool_t last_call;  /* Whether this should be the last time the callback is called */
+} gather_info_t;
+
+static herr_t
+gather_cb(const void *dst_buf, size_t dst_buf_bytes_used,
+    void *_gather_info)
+{
+    gather_info_t *gather_info = (gather_info_t *)_gather_info;
+    size_t nelmts;      /* Number of elements in src_buf */
+    int i;              /* Local index variable */
+
+    HDassert(dst_buf_bytes_used > 0);
+
+    /* Calculate number of elements */
+    nelmts = dst_buf_bytes_used / sizeof(gather_info->expect_dst_buf[0]);
+
+    /* Make sure the number of bytes is a multiple of the number of elements */
+    if(nelmts * sizeof(gather_info->expect_dst_buf[0]) != dst_buf_bytes_used)
+        TEST_ERROR
+
+    /* Make sure we weren't passed more data than we requested to be passed at
+     * once */
+    if(nelmts > gather_info->max_nelmts)
+        TEST_ERROR
+
+    /* If we were passed less data than requested, make sure this is the last
+     * time the callback was called */
+    if(gather_info->last_call)
+        TEST_ERROR
+    if(nelmts < gather_info->max_nelmts)
+        gather_info->last_call = TRUE;
+
+    /* Compare data and expected data */
+    for(i=0; i<(int)nelmts; i++)
+        if(((const int *)dst_buf)[i] != *((gather_info->expect_dst_buf)++))
+            TEST_ERROR
+
+    return SUCCEED;
+
+error:
+    return FAIL;
+}
+
+static herr_t
+test_gather(void)
+{
+    hid_t       sid = -1;       /* Dataspace ID */
+    hsize_t     dim[3] = {8, 4, 8}; /* Dataspace dimensions */
+    hsize_t     start[3] = {0, 0, 0};
+    hsize_t     stride[3] = {0, 0, 0};
+    hsize_t     count[3] = {0, 0, 0};
+    hsize_t     block[3] = {0, 0, 0};
+    hsize_t     start2[3] = {0, 0, 0};
+    hsize_t     count2[3] = {0, 0, 0};
+    hsize_t     point[4][3] = {{2, 3, 2}, {3, 0, 2}, {7, 2, 0}, {0, 1, 5}};
+    size_t      dst_buf_size;
+    int         src_buf[8][4][8]; /* Source data buffer */
+    int         dst_buf[36];    /* Destination data buffer */
+    int         expect_dst_buf[36]; /* Expected destination data buffer */
+    gather_info_t gather_info;  /* Operator data for callback */
+    int         i, j, k, dst_i; /* Local index variables */
+
+    TESTING("H5Dgather()");
+
+    /* Create dataspace */
+    if((sid = H5Screate_simple(3, dim, NULL)) < 0) TEST_ERROR
+
+    /* Initialize src_buf */
+    for(i=0; i<(int)(sizeof(src_buf)/sizeof(src_buf[0])); i++)
+        for(j=0; j<(int)(sizeof(src_buf[0])/sizeof(src_buf[0][0])); j++)
+            for(k=0; k<(int)(sizeof(src_buf[0][0])/sizeof(src_buf[0][0][0])); k++)
+                src_buf[i][j][k] = 1 + k
+                        + (int)(sizeof(src_buf[0][0]) / sizeof(src_buf[0][0][0])) * j
+                        + (int)(sizeof(src_buf[0]) / sizeof(src_buf[0][0][0])) * i;
+
+
+    /*
+     * Test 1: Simple case
+     */
+    /* Select hyperslab */
+    count[0] = 1;
+    count[1] = 1;
+    count[2] = 10;
+    if(H5Sselect_hyperslab(sid, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
+        TEST_ERROR
+
+    /* Initialize expect_dst_buf */
+    (void)HDmemset(expect_dst_buf, 0, sizeof(expect_dst_buf));
+    for(i=0; i<10; i++)
+        expect_dst_buf[i] = src_buf[0][0][i];
+
+    /* Loop over buffer sizes */
+    for(dst_buf_size=1; dst_buf_size<=11; dst_buf_size++) {
+        /* Reset dst_buf */
+        (void)HDmemset(dst_buf, 0, sizeof(dst_buf));
+
+        /* Initialize gather_info */
+        gather_info.expect_dst_buf = expect_dst_buf;
+        gather_info.max_nelmts = dst_buf_size;
+        gather_info.last_call = FALSE;
+
+        /* Gather data */
+        if(H5Dgather(sid, src_buf, H5T_NATIVE_INT, dst_buf_size * sizeof(dst_buf[0]), dst_buf, gather_cb, &gather_info) < 0)
+            TEST_ERROR
+
+        /* Verify that all data has been gathered (and verified) */
+        if(gather_info.expect_dst_buf - expect_dst_buf != 10) TEST_ERROR
+    } /* end for */
+
+    /* Test with a dst_buf_size that is not a multiple of the datatype size */
+    /* Reset dst_buf */
+    dst_buf_size = 7;
+    (void)HDmemset(dst_buf, 0, sizeof(dst_buf));
+
+    /* Initialize gather_info */
+    gather_info.expect_dst_buf = expect_dst_buf;
+    gather_info.max_nelmts = dst_buf_size - 1;
+    gather_info.last_call = FALSE;
+
+    /* Gather data */
+    if(H5Dgather(sid, src_buf, H5T_NATIVE_INT, dst_buf_size * sizeof(dst_buf[0]) - 1, dst_buf, gather_cb, &gather_info) < 0)
+        TEST_ERROR
+
+    /* Verify that all data has been gathered (and verified) */
+    if(gather_info.expect_dst_buf - expect_dst_buf != 10) TEST_ERROR
+
+
+    /*
+     * Test 2: Single block in dataset
+     */
+    /* Select hyperslab */
+    start[0] = 3;
+    start[1] = 2;
+    start[2] = 4;
+    count[0] = 2;
+    count[1] = 3;
+    count[2] = 2;
+    if(H5Sselect_hyperslab(sid, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
+        TEST_ERROR
+
+    /* Initialize expect_dst_buf */
+    (void)HDmemset(expect_dst_buf, 0, sizeof(expect_dst_buf));
+    dst_i = 0;
+    for(i=3; i<5; i++)
+        for(j=2; j<5; j++)
+            for(k=4; k<6; k++)
+                expect_dst_buf[dst_i++] = src_buf[i][j][k];
+
+    /* Loop over buffer sizes */
+    for(dst_buf_size=1; dst_buf_size<=13; dst_buf_size++) {
+        /* Reset dst_buf */
+        (void)HDmemset(dst_buf, 0, sizeof(dst_buf));
+
+        /* Initialize gather_info */
+        gather_info.expect_dst_buf = expect_dst_buf;
+        gather_info.max_nelmts = dst_buf_size;
+        gather_info.last_call = FALSE;
+
+        /* Gather data */
+        if(H5Dgather(sid, src_buf, H5T_NATIVE_INT, dst_buf_size * sizeof(dst_buf[0]), dst_buf, gather_cb, &gather_info) < 0)
+            TEST_ERROR
+
+        /* Verify that all data has been gathered (and verified) */
+        if(gather_info.expect_dst_buf - expect_dst_buf != 12) TEST_ERROR
+    } /* end for */
+
+
+    /*
+     * Test 3: Multiple blocks
+     */
+    /* Select hyperslab */
+    start[0] = 1;
+    start[1] = 1;
+    start[2] = 1;
+    stride[0] = 3;
+    stride[1] = 4;
+    stride[2] = 5;
+    count[0] = 3;
+    count[1] = 1;
+    count[2] = 2;
+    block[0] = 1;
+    block[1] = 3;
+    block[2] = 2;
+    if(H5Sselect_hyperslab(sid, H5S_SELECT_SET, start, stride ,count, block) < 0)
+        TEST_ERROR
+
+    /* Initialize expect_dst_buf */
+    /* Iterate over block containing selection, checking if each element is in
+     * selection.  Note that the algorithm used here (if statement) would not
+     * work for overlapping hyperslabs. */
+    (void)HDmemset(expect_dst_buf, 0, sizeof(expect_dst_buf));
+    dst_i = 0;
+    for(i=1; i<8; i++)
+        for(j=1; j<4; j++)
+            for(k=1; k<8; k++)
+                if((hsize_t)i >= start[0]
+                        && ((hsize_t)i - start[0]) % stride[0] < block[0]
+                        && ((hsize_t)i - start[0]) / stride[0] < count[0]
+                        && (hsize_t)j >= start[1]
+                        && ((hsize_t)j - start[1]) % stride[1] < block[1]
+                        && ((hsize_t)j - start[1]) / stride[1] < count[1]
+                        && (hsize_t)k >= start[2]
+                        && ((hsize_t)k - start[2]) % stride[2] < block[2]
+                        && ((hsize_t)k - start[2]) / stride[2] < count[2])
+                    expect_dst_buf[dst_i++] = src_buf[i][j][k];
+
+    /* Loop over buffer sizes */
+    for(dst_buf_size=1; dst_buf_size<=37; dst_buf_size++) {
+        /* Reset dst_buf */
+        (void)HDmemset(dst_buf, 0, sizeof(dst_buf));
+
+        /* Initialize gather_info */
+        gather_info.expect_dst_buf = expect_dst_buf;
+        gather_info.max_nelmts = dst_buf_size;
+        gather_info.last_call = FALSE;
+
+        /* Gather data */
+        if(H5Dgather(sid, src_buf, H5T_NATIVE_INT, dst_buf_size * sizeof(dst_buf[0]), dst_buf, gather_cb, &gather_info) < 0)
+            TEST_ERROR
+
+        /* Verify that all data has been gathered (and verified) */
+        if(gather_info.expect_dst_buf - expect_dst_buf != 36) TEST_ERROR
+    } /* end for */
+
+
+    /*
+     * Test 4: Compound selection
+     */
+    /* Select hyperslabs */
+    start[0] = 2;
+    start[1] = 1;
+    start[2] = 1;
+    count[0] = 2;
+    count[1] = 3;
+    count[2] = 2;
+    if(H5Sselect_hyperslab(sid, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
+        TEST_ERROR
+    start2[0] = 1;
+    start2[1] = 2;
+    start2[2] = 2;
+    count2[0] = 3;
+    count2[1] = 2;
+    count2[2] = 2;
+    if(H5Sselect_hyperslab(sid, H5S_SELECT_XOR, start2, NULL ,count2, NULL) < 0)
+        TEST_ERROR
+
+    /* Initialize expect_dst_buf */
+    /* Iterate over block containing selection, checking if each element is in
+     * selection. */
+    (void)HDmemset(expect_dst_buf, 0, sizeof(expect_dst_buf));
+    dst_i = 0;
+    for(i=1; i<4; i++)
+        for(j=1; j<4; j++)
+            for(k=1; k<4; k++)
+                if(!(((hsize_t)i >= start[0] && (hsize_t)i < start[0] + count[0])
+                        && ((hsize_t)j >= start[1] && (hsize_t)j < start[1] + count[1])
+                        && ((hsize_t)k >= start[2] && (hsize_t)k < start[2] + count[2]))
+                        != !(((hsize_t)i >= start2[0] && (hsize_t)i < start2[0] + count2[0])
+                        && ((hsize_t)j >= start2[1] && (hsize_t)j < start2[1] + count2[1])
+                        && ((hsize_t)k >= start2[2] && (hsize_t)k < start2[2] + count2[2])))
+                    expect_dst_buf[dst_i++] = src_buf[i][j][k];
+
+    /* Loop over buffer sizes */
+    for(dst_buf_size=1; dst_buf_size<=17; dst_buf_size++) {
+        /* Reset dst_buf */
+        (void)HDmemset(dst_buf, 0, sizeof(dst_buf));
+
+        /* Initialize gather_info */
+        gather_info.expect_dst_buf = expect_dst_buf;
+        gather_info.max_nelmts = dst_buf_size;
+        gather_info.last_call = FALSE;
+
+        /* Gather data */
+        if(H5Dgather(sid, src_buf, H5T_NATIVE_INT, dst_buf_size * sizeof(dst_buf[0]), dst_buf, gather_cb, &gather_info) < 0)
+            TEST_ERROR
+
+        /* Verify that all data has been gathered (and verified) */
+        if(gather_info.expect_dst_buf - expect_dst_buf != 16) TEST_ERROR
+    } /* end for */
+
+
+    /*
+     * Test 5: Point selection
+     */
+    /* Select hyperslabs */
+    if(H5Sselect_elements(sid, H5S_SELECT_SET, sizeof(point) / sizeof(point[0]), (hsize_t *)point) < 0)
+        TEST_ERROR
+
+    /* Initialize expect_dst_buf */
+    /* Iterate over block containing selection, checking if each element is in
+     * selection. */
+    (void)HDmemset(expect_dst_buf, 0, sizeof(expect_dst_buf));
+    for(i=0; i<(int)(sizeof(point) / sizeof(point[0])); i++)
+        expect_dst_buf[i] = src_buf[point[i][0]][point[i][1]][point[i][2]];
+
+    /* Loop over buffer sizes */
+    for(dst_buf_size=1; dst_buf_size<=5; dst_buf_size++) {
+        /* Reset dst_buf */
+        (void)HDmemset(dst_buf, 0, sizeof(dst_buf));
+
+        /* Initialize gather_info */
+        gather_info.expect_dst_buf = expect_dst_buf;
+        gather_info.max_nelmts = dst_buf_size;
+        gather_info.last_call = FALSE;
+
+        /* Gather data */
+        if(H5Dgather(sid, src_buf, H5T_NATIVE_INT, dst_buf_size * sizeof(dst_buf[0]), dst_buf, gather_cb, &gather_info) < 0)
+            TEST_ERROR
+
+        /* Verify that all data has been gathered (and verified) */
+        if(gather_info.expect_dst_buf - expect_dst_buf != 4) TEST_ERROR
+    } /* end for */
+
+
+    /* Close everything */
+    if(H5Sclose(sid) < 0) TEST_ERROR
+
+    PASSED();
+
+    return 0;
+
+error:
+    H5E_BEGIN_TRY {
+        H5Sclose(sid);
+    } H5E_END_TRY;
+    return -1;
+} /* end test_gather() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    test_scatter_error
+ *
+ * Purpose:     Tests H5Dscatter with a variety of different conditions
+ *              that should cause errors.
+ *
+ * Return:      Success: 0
+ *              Failure: -1
+ *
+ * Programmer:  Neil Fortner
+ *              Monday, February 4, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+scatter_error_cb_fail(void **src_buf/*out*/, size_t *src_buf_bytes_used/*out*/,
+    void *_scatter_info)
+{
+    scatter_info_t *scatter_info = (scatter_info_t *)_scatter_info;
+    size_t nelmts;      /* Number of elements to return in src_buf */
+
+    /* Calculate number of elements */
+    nelmts = MIN(scatter_info->block, scatter_info->size);
+    HDassert(nelmts > 0);
+
+    /* Set output variables */
+    *src_buf = (void *)scatter_info->src_buf;
+    *src_buf_bytes_used = nelmts * sizeof(scatter_info->src_buf[0]);
+
+    return FAIL;
+}
+
+static herr_t
+scatter_error_cb_null(void **src_buf/*out*/, size_t *src_buf_bytes_used/*out*/,
+    void *_scatter_info)
+{
+    scatter_info_t *scatter_info = (scatter_info_t *)_scatter_info;
+    size_t nelmts;      /* Number of elements to return in src_buf */
+
+    /* Calculate number of elements */
+    nelmts = MIN(scatter_info->block, scatter_info->size);
+    HDassert(nelmts > 0);
+
+    /* Set output variables */
+    *src_buf = NULL;
+    *src_buf_bytes_used = nelmts * sizeof(scatter_info->src_buf[0]);
+
+    return SUCCEED;
+}
+
+static herr_t
+scatter_error_cb_unalign(void **src_buf/*out*/, size_t *src_buf_bytes_used/*out*/,
+    void *_src_buf_bytes_used)
+{
+    /* Set output variables */
+    *src_buf = _src_buf_bytes_used;
+    *src_buf_bytes_used = *(size_t *)_src_buf_bytes_used;
+
+    return SUCCEED;
+}
+
+static herr_t
+test_scatter_error(void)
+{
+    hid_t       sid = -1;       /* Dataspace ID */
+    hsize_t     dim[1] = {10};  /* Dataspace dimensions */
+    hsize_t     start[3] = {2};
+    hsize_t     count[3] = {6};
+    int         src_buf[7];     /* Source data buffer */
+    int         dst_buf[10];    /* Destination data buffer */
+    scatter_info_t scatter_info; /* Operator data for callback */
+    size_t      cb_unalign_nbytes; /* Number of bytes to return for unaligned test */
+    herr_t      ret;            /* Return value */
+    int         i;              /* Local index variable */
+
+    TESTING("H5Dscatter() error conditions");
+
+    /* Create dataspace */
+    if((sid = H5Screate_simple(1, dim, NULL)) < 0) TEST_ERROR
+
+    /* Initialize src_buf */
+    for(i=0; i<(int)(sizeof(src_buf)/sizeof(src_buf[0])); i++)
+        src_buf[i] = i + 1;
+
+    /* Select hyperslab */
+    if(H5Sselect_hyperslab(sid, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
+        TEST_ERROR
+
+    /* Verify that base configuration passes */
+    scatter_info.src_buf = src_buf;
+    scatter_info.block = sizeof(src_buf)/sizeof(src_buf[0]);
+    scatter_info.size = 6;
+    if(H5Dscatter(scatter_cb, &scatter_info, H5T_NATIVE_INT, sid, dst_buf) < 0)
+        TEST_ERROR
+
+
+    /*
+     * Test invalid parameters
+     */
+    scatter_info.src_buf = src_buf;
+    scatter_info.size = 6;
+    H5E_BEGIN_TRY {
+        ret = H5Dscatter(NULL, NULL, H5T_NATIVE_INT, sid, dst_buf);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+    scatter_info.src_buf = src_buf;
+    scatter_info.size = 6;
+    H5E_BEGIN_TRY {
+        ret = H5Dscatter(scatter_cb, &scatter_info, sid, sid, dst_buf);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+    scatter_info.src_buf = src_buf;
+    scatter_info.size = 6;
+    H5E_BEGIN_TRY {
+        ret = H5Dscatter(scatter_cb, &scatter_info, H5T_NATIVE_INT, H5T_NATIVE_INT, dst_buf);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+    scatter_info.src_buf = src_buf;
+    scatter_info.size = 6;
+    H5E_BEGIN_TRY {
+        ret = H5Dscatter(scatter_cb, &scatter_info, H5T_NATIVE_INT, sid, NULL);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+
+    /*
+     * Test returning too many elements in callback
+     */
+    scatter_info.src_buf = src_buf;
+    scatter_info.size = 7;
+    H5E_BEGIN_TRY {
+        ret = H5Dscatter(scatter_cb, &scatter_info, H5T_NATIVE_INT, sid, dst_buf);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+
+    /*
+     * Test callback returns failure
+     */
+    scatter_info.src_buf = src_buf;
+    scatter_info.size = 6;
+    H5E_BEGIN_TRY {
+        ret = H5Dscatter(scatter_error_cb_fail, &scatter_info, H5T_NATIVE_INT, sid, dst_buf);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+
+    /*
+     * Test callback returns NULL buffer
+     */
+    scatter_info.src_buf = src_buf;
+    scatter_info.size = 6;
+    H5E_BEGIN_TRY {
+        ret = H5Dscatter(scatter_error_cb_null, &scatter_info, H5T_NATIVE_INT, sid, dst_buf);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+
+    /*
+     * Test callback returns 0 for src_buf_bytes_used
+     */
+    cb_unalign_nbytes = 0;
+    H5E_BEGIN_TRY {
+        ret = H5Dscatter(scatter_error_cb_unalign, &cb_unalign_nbytes, H5T_NATIVE_INT, sid, dst_buf);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+
+    /*
+     * Test callback returns src_buf_bytes_used that is not a multiple of
+     * datatype size
+     */
+    cb_unalign_nbytes = sizeof(src_buf[0]) - 1;
+    H5E_BEGIN_TRY {
+        ret = H5Dscatter(scatter_error_cb_unalign, &cb_unalign_nbytes, H5T_NATIVE_INT, sid, dst_buf);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+    cb_unalign_nbytes = sizeof(src_buf[0]) + 1;
+    H5E_BEGIN_TRY {
+        ret = H5Dscatter(scatter_error_cb_unalign, &cb_unalign_nbytes, H5T_NATIVE_INT, sid, dst_buf);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+
+    /* Close everything */
+    if(H5Sclose(sid) < 0) TEST_ERROR
+
+    PASSED();
+
+    return 0;
+
+error:
+    H5E_BEGIN_TRY {
+        H5Sclose(sid);
+    } H5E_END_TRY;
+    return -1;
+} /* end test_scatter_error() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    test_gather_error
+ *
+ * Purpose:     Tests H5Dgather with a variety of different conditions
+ *              that should cause errors.
+ *
+ * Return:      Success: 0
+ *              Failure: -1
+ *
+ * Programmer:  Neil Fortner
+ *              Monday, February 4, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+gather_error_cb_fail(const void UNUSED *dst_buf,
+    size_t UNUSED dst_buf_bytes_used, void UNUSED *op_data)
+{
+    return FAIL;
+}
+
+static herr_t
+test_gather_error(void)
+{
+    hid_t       sid = -1;       /* Dataspace ID */
+    hsize_t     dim[1] = {10};  /* Dataspace dimensions */
+    hsize_t     start[1] = {2};
+    hsize_t     count[1] = {6};
+    int         src_buf[10];    /* Source data buffer */
+    int         dst_buf[6];     /* Destination data buffer */
+    int         expect_dst_buf[6]; /* Expected destination data buffer */
+    gather_info_t gather_info;  /* Operator data for callback */
+    herr_t      ret;            /* Return value */
+    int         i;              /* Local index variable */
+
+    TESTING("H5Dgather() error conditions");
+
+    /* Create dataspace */
+    if((sid = H5Screate_simple(1, dim, NULL)) < 0) TEST_ERROR
+
+    /* Initialize src_buf */
+    for(i=0; i<(int)(sizeof(src_buf)/sizeof(src_buf[0])); i++)
+        src_buf[i] = 1 + i;
+
+    /* Select hyperslab */
+    if(H5Sselect_hyperslab(sid, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
+        TEST_ERROR
+
+    /* Initialize expect_dst_buf */
+    (void)HDmemset(expect_dst_buf, 0, sizeof(expect_dst_buf));
+    for(i=0; i<6; i++)
+        expect_dst_buf[i] = src_buf[i + 2];
+
+    /* Verify that base configuration passes */
+    gather_info.expect_dst_buf = expect_dst_buf;
+    gather_info.max_nelmts = 6;
+    gather_info.last_call = FALSE;
+    if(H5Dgather(sid, src_buf, H5T_NATIVE_INT, 6 * sizeof(dst_buf[0]), dst_buf, gather_cb, &gather_info) < 0)
+        TEST_ERROR
+
+    /*
+     * Test invalid parameters
+     */
+    gather_info.expect_dst_buf = expect_dst_buf;
+    gather_info.last_call = FALSE;
+    H5E_BEGIN_TRY {
+        ret = H5Dgather(H5T_NATIVE_INT, src_buf, H5T_NATIVE_INT, 6 * sizeof(dst_buf[0]), dst_buf, gather_cb, &gather_info);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+    gather_info.expect_dst_buf = expect_dst_buf;
+    gather_info.last_call = FALSE;
+    H5E_BEGIN_TRY {
+        ret = H5Dgather(sid, NULL, H5T_NATIVE_INT, 6 * sizeof(dst_buf[0]), dst_buf, gather_cb, &gather_info);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+    gather_info.expect_dst_buf = expect_dst_buf;
+    gather_info.last_call = FALSE;
+    H5E_BEGIN_TRY {
+        ret = H5Dgather(sid, src_buf, sid, 6 * sizeof(dst_buf[0]), dst_buf, gather_cb, &gather_info);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+    gather_info.expect_dst_buf = expect_dst_buf;
+    gather_info.last_call = FALSE;
+    H5E_BEGIN_TRY {
+        ret = H5Dgather(sid, src_buf, H5T_NATIVE_INT, 0, dst_buf, gather_cb, &gather_info);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+    gather_info.expect_dst_buf = expect_dst_buf;
+    gather_info.last_call = FALSE;
+    H5E_BEGIN_TRY {
+        ret = H5Dgather(sid, src_buf, H5T_NATIVE_INT, 1, dst_buf, gather_cb, &gather_info);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+    gather_info.expect_dst_buf = expect_dst_buf;
+    gather_info.last_call = FALSE;
+    H5E_BEGIN_TRY {
+        ret = H5Dgather(sid, src_buf, H5T_NATIVE_INT, 6 * sizeof(dst_buf[0]), NULL, gather_cb, &gather_info);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+    gather_info.expect_dst_buf = expect_dst_buf;
+    gather_info.last_call = FALSE;
+    H5E_BEGIN_TRY {
+        ret = H5Dgather(sid, src_buf, H5T_NATIVE_INT, 6 * sizeof(dst_buf[0]), dst_buf, NULL, &gather_info);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+
+    /*
+     * Test callback returns failure
+     */
+    gather_info.expect_dst_buf = expect_dst_buf;
+    gather_info.last_call = FALSE;
+    H5E_BEGIN_TRY {
+        ret = H5Dgather(sid, src_buf, H5T_NATIVE_INT, 6 * sizeof(dst_buf[0]), dst_buf, gather_error_cb_fail, NULL);
+    } H5E_END_TRY
+    if(ret >= 0) TEST_ERROR
+
+
+    /* Close everything */
+    if(H5Sclose(sid) < 0) TEST_ERROR
+
+    PASSED();
+
+    return 0;
+
+error:
+    H5E_BEGIN_TRY {
+        H5Sclose(sid);
+    } H5E_END_TRY;
+    return -1;
+} /* end test_gather_error() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	main
  *
  * Purpose:	Tests the dataset interface (H5D)
@@ -8315,6 +9321,12 @@ main(void)
     /* Close 2nd FAPL */
     if(H5Pclose(fapl2) < 0) TEST_ERROR
 
+    /* Tests that do not use files */
+    nerrors += (test_scatter() < 0                          ? 1 : 0);
+    nerrors += (test_gather() < 0                           ? 1 : 0);
+    nerrors += (test_scatter_error() < 0                    ? 1 : 0);
+    nerrors += (test_gather_error() < 0                     ? 1 : 0);
+
     /* Verify symbol table messages are cached */
     nerrors += (h5_verify_cached_stabs(FILENAME, fapl) < 0 ? 1 : 0);