diff --git a/app/core/gimpbrushgenerated-load.c b/app/core/gimpbrushgenerated-load.c
index 2d03a028b0..2e122f49bb 100644
--- a/app/core/gimpbrushgenerated-load.c
+++ b/app/core/gimpbrushgenerated-load.c
@@ -28,6 +28,7 @@
 
 #include "core-types.h"
 
+#include "gimp-utils.h"
 #include "gimpbrushgenerated.h"
 #include "gimpbrushgenerated-load.h"
 
@@ -64,8 +65,8 @@ gimp_brush_generated_load (GimpContext   *context,
   /* make sure the file we are reading is the right type */
   linenum = 1;
   string_len = 256;
-  string = g_data_input_stream_read_line (data_input, &string_len,
-                                          NULL, error);
+  string = gimp_data_input_stream_read_line_always (data_input, &string_len,
+                                                    NULL, error);
   if (! string)
     goto failed;
 
@@ -82,8 +83,8 @@ gimp_brush_generated_load (GimpContext   *context,
   /* make sure we are reading a compatible version */
   linenum++;
   string_len = 256;
-  string = g_data_input_stream_read_line (data_input, &string_len,
-                                          NULL, error);
+  string = gimp_data_input_stream_read_line_always (data_input, &string_len,
+                                                    NULL, error);
   if (! string)
     goto failed;
 
@@ -107,8 +108,8 @@ gimp_brush_generated_load (GimpContext   *context,
   /* read name */
   linenum++;
   string_len = 256;
-  string = g_data_input_stream_read_line (data_input, &string_len,
-                                          NULL, error);
+  string = gimp_data_input_stream_read_line_always (data_input, &string_len,
+                                                    NULL, error);
   if (! string)
     goto failed;
 
@@ -138,8 +139,8 @@ gimp_brush_generated_load (GimpContext   *context,
       /* read shape */
       linenum++;
       string_len = 256;
-      string = g_data_input_stream_read_line (data_input, &string_len,
-                                              NULL, error);
+      string = gimp_data_input_stream_read_line_always (data_input, &string_len,
+                                                        NULL, error);
       if (! string)
         goto failed;
 
@@ -162,21 +163,34 @@ gimp_brush_generated_load (GimpContext   *context,
   /* read brush spacing */
   linenum++;
   string_len = 256;
-  string = g_data_input_stream_read_line (data_input, &string_len,
-                                          NULL, error);
+  string = gimp_data_input_stream_read_line_always (data_input, &string_len,
+                                                    NULL, error);
   if (! string)
     goto failed;
-  spacing = g_ascii_strtod (string, NULL);
+  if (! gimp_ascii_strtod (string, NULL, &spacing))
+    {
+      g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
+                   _("Invalid brush spacing."));
+      g_free (string);
+      goto failed;
+    }
   g_free (string);
 
+
   /* read brush radius */
   linenum++;
   string_len = 256;
-  string = g_data_input_stream_read_line (data_input, &string_len,
-                                          NULL, error);
+  string = gimp_data_input_stream_read_line_always (data_input, &string_len,
+                                                    NULL, error);
   if (! string)
     goto failed;
-  radius = g_ascii_strtod (string, NULL);
+  if (! gimp_ascii_strtod (string, NULL, &radius))
+    {
+      g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
+                   _("Invalid brush radius."));
+      g_free (string);
+      goto failed;
+    }
   g_free (string);
 
   if (have_shape)
@@ -184,42 +198,67 @@ gimp_brush_generated_load (GimpContext   *context,
       /* read number of spikes */
       linenum++;
       string_len = 256;
-      string = g_data_input_stream_read_line (data_input, &string_len,
-                                              NULL, error);
+      string = gimp_data_input_stream_read_line_always (data_input, &string_len,
+                                                        NULL, error);
       if (! string)
         goto failed;
-      spikes = CLAMP (atoi (string), 2, 20);
+      if (! gimp_ascii_strtoi (string, NULL, 10, &spikes) ||
+          spikes < 2 || spikes > 20)
+        {
+          g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
+                       _("Invalid brush spike count."));
+          g_free (string);
+          goto failed;
+        }
       g_free (string);
     }
 
   /* read brush hardness */
   linenum++;
   string_len = 256;
-  string = g_data_input_stream_read_line (data_input, &string_len,
-                                          NULL, error);
+  string = gimp_data_input_stream_read_line_always (data_input, &string_len,
+                                                    NULL, error);
   if (! string)
     goto failed;
-  hardness = g_ascii_strtod (string, NULL);
+  if (! gimp_ascii_strtod (string, NULL, &hardness))
+    {
+      g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
+                   _("Invalid brush hardness."));
+      g_free (string);
+      goto failed;
+    }
   g_free (string);
 
   /* read brush aspect_ratio */
   linenum++;
   string_len = 256;
-  string = g_data_input_stream_read_line (data_input, &string_len,
-                                          NULL, error);
+  string = gimp_data_input_stream_read_line_always (data_input, &string_len,
+                                                    NULL, error);
   if (! string)
     goto failed;
-  aspect_ratio = g_ascii_strtod (string, NULL);
+  if (! gimp_ascii_strtod (string, NULL, &aspect_ratio))
+    {
+      g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
+                   _("Invalid brush aspect ratio."));
+      g_free (string);
+      goto failed;
+    }
   g_free (string);
 
   /* read brush angle */
   linenum++;
   string_len = 256;
-  string = g_data_input_stream_read_line (data_input, &string_len,
-                                          NULL, error);
+  string = gimp_data_input_stream_read_line_always (data_input, &string_len,
+                                                    NULL, error);
   if (! string)
     goto failed;
-  angle = g_ascii_strtod (string, NULL);
+  if (! gimp_ascii_strtod (string, NULL, &angle))
+    {
+      g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
+                   _("Invalid brush angle."));
+      g_free (string);
+      goto failed;
+    }
   g_free (string);
 
   g_object_unref (data_input);
diff --git a/app/core/gimpgradient-load.c b/app/core/gimpgradient-load.c
index cc23086ba0..f4129578ac 100644
--- a/app/core/gimpgradient-load.c
+++ b/app/core/gimpgradient-load.c
@@ -32,6 +32,7 @@
 
 #include "config/gimpxmlparser.h"
 
+#include "gimp-utils.h"
 #include "gimpgradient.h"
 #include "gimpgradient-load.h"
 
@@ -61,8 +62,8 @@ gimp_gradient_load (GimpContext   *context,
 
   linenum = 1;
   line_len = 1024;
-  line = g_data_input_stream_read_line (data_input, &line_len,
-                                        NULL, error);
+  line = gimp_data_input_stream_read_line_always (data_input, &line_len,
+                                                  NULL, error);
   if (! line)
     goto failed;
 
@@ -82,8 +83,8 @@ gimp_gradient_load (GimpContext   *context,
 
   linenum++;
   line_len = 1024;
-  line = g_data_input_stream_read_line (data_input, &line_len,
-                                        NULL, error);
+  line = gimp_data_input_stream_read_line_always (data_input, &line_len,
+                                                  NULL, error);
   if (! line)
     goto failed;
 
@@ -100,8 +101,8 @@ gimp_gradient_load (GimpContext   *context,
 
       linenum++;
       line_len = 1024;
-      line = g_data_input_stream_read_line (data_input, &line_len,
-                                            NULL, error);
+      line = gimp_data_input_stream_read_line_always (data_input, &line_len,
+                                                      NULL, error);
       if (! line)
         goto failed;
     }
@@ -128,6 +129,10 @@ gimp_gradient_load (GimpContext   *context,
     {
       GimpGradientSegment *seg;
       gchar               *end;
+      gint                 color;
+      gint                 type;
+      gint                 left_color_type;
+      gint                 right_color_type;
 
       seg = gimp_gradient_segment_new ();
 
@@ -140,99 +145,80 @@ gimp_gradient_load (GimpContext   *context,
 
       linenum++;
       line_len = 1024;
-      line = g_data_input_stream_read_line (data_input, &line_len,
-                                            NULL, error);
+      line = gimp_data_input_stream_read_line_always (data_input, &line_len,
+                                                      NULL, error);
       if (! line)
         goto failed;
 
-      seg->left = g_ascii_strtod (line, &end);
-      if (end && errno != ERANGE)
-        seg->middle = g_ascii_strtod (end, &end);
-      if (end && errno != ERANGE)
-        seg->right = g_ascii_strtod (end, &end);
+      if (! gimp_ascii_strtod (line, &end, &seg->left)          ||
+          ! gimp_ascii_strtod (end,  &end, &seg->middle)        ||
+          ! gimp_ascii_strtod (end,  &end, &seg->right)         ||
 
-      if (end && errno != ERANGE)
-        seg->left_color.r = g_ascii_strtod (end, &end);
-      if (end && errno != ERANGE)
-        seg->left_color.g = g_ascii_strtod (end, &end);
-      if (end && errno != ERANGE)
-        seg->left_color.b = g_ascii_strtod (end, &end);
-      if (end && errno != ERANGE)
-        seg->left_color.a = g_ascii_strtod (end, &end);
+          ! gimp_ascii_strtod (end,  &end, &seg->left_color.r)  ||
+          ! gimp_ascii_strtod (end,  &end, &seg->left_color.g)  ||
+          ! gimp_ascii_strtod (end,  &end, &seg->left_color.b)  ||
+          ! gimp_ascii_strtod (end,  &end, &seg->left_color.a)  ||
 
-      if (end && errno != ERANGE)
-        seg->right_color.r = g_ascii_strtod (end, &end);
-      if (end && errno != ERANGE)
-        seg->right_color.g = g_ascii_strtod (end, &end);
-      if (end && errno != ERANGE)
-        seg->right_color.b = g_ascii_strtod (end, &end);
-      if (end && errno != ERANGE)
-        seg->right_color.a = g_ascii_strtod (end, &end);
-
-      if (errno != ERANGE)
+          ! gimp_ascii_strtod (end,  &end, &seg->right_color.r) ||
+          ! gimp_ascii_strtod (end,  &end, &seg->right_color.g) ||
+          ! gimp_ascii_strtod (end,  &end, &seg->right_color.b) ||
+          ! gimp_ascii_strtod (end,  &end, &seg->right_color.a))
         {
-          gint color;
-          gint type;
-          gint left_color_type;
-          gint right_color_type;
+          g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
+                       _("Corrupt segment %d."), i);
+          g_free (line);
+          goto failed;
+        }
 
-          switch (sscanf (end, "%d %d %d %d",
-                          &type, &color,
-                          &left_color_type, &right_color_type))
+      switch (sscanf (end, "%d %d %d %d",
+                      &type, &color,
+                      &left_color_type, &right_color_type))
+        {
+        case 4:
+          seg->left_color_type  = (GimpGradientColor) left_color_type;
+          if (seg->left_color_type < GIMP_GRADIENT_COLOR_FIXED ||
+              seg->left_color_type > GIMP_GRADIENT_COLOR_BACKGROUND_TRANSPARENT)
             {
-            case 4:
-              seg->left_color_type  = (GimpGradientColor) left_color_type;
-              if (seg->left_color_type < GIMP_GRADIENT_COLOR_FIXED ||
-                  seg->left_color_type > GIMP_GRADIENT_COLOR_BACKGROUND_TRANSPARENT)
-                {
-                  g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
-                               _("Corrupt segment %d."), i);
-                  g_free (line);
-                  goto failed;
-                }
-
-              seg->right_color_type = (GimpGradientColor) right_color_type;
-              if (seg->right_color_type < GIMP_GRADIENT_COLOR_FIXED ||
-                  seg->right_color_type > GIMP_GRADIENT_COLOR_BACKGROUND_TRANSPARENT)
-                {
-                  g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
-                               _("Corrupt segment %d."), i);
-                  g_free (line);
-                  goto failed;
-                }
-              /* fall thru */
-
-            case 2:
-              seg->type  = (GimpGradientSegmentType) type;
-              if (seg->type < GIMP_GRADIENT_SEGMENT_LINEAR ||
-                  seg->type > GIMP_GRADIENT_SEGMENT_SPHERE_DECREASING)
-                {
-                  g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
-                               _("Corrupt segment %d."), i);
-                  g_free (line);
-                  goto failed;
-                }
-
-              seg->color = (GimpGradientSegmentColor) color;
-              if (seg->color < GIMP_GRADIENT_SEGMENT_RGB ||
-                  seg->color > GIMP_GRADIENT_SEGMENT_HSV_CW)
-                {
-                  g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
-                               _("Corrupt segment %d."), i);
-                  g_free (line);
-                  goto failed;
-                }
-              break;
-
-            default:
               g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
                            _("Corrupt segment %d."), i);
               g_free (line);
               goto failed;
             }
-        }
-      else
-        {
+
+          seg->right_color_type = (GimpGradientColor) right_color_type;
+          if (seg->right_color_type < GIMP_GRADIENT_COLOR_FIXED ||
+              seg->right_color_type > GIMP_GRADIENT_COLOR_BACKGROUND_TRANSPARENT)
+            {
+              g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
+                           _("Corrupt segment %d."), i);
+              g_free (line);
+              goto failed;
+            }
+          /* fall thru */
+
+        case 2:
+          seg->type  = (GimpGradientSegmentType) type;
+          if (seg->type < GIMP_GRADIENT_SEGMENT_LINEAR ||
+              seg->type > GIMP_GRADIENT_SEGMENT_SPHERE_DECREASING)
+            {
+              g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
+                           _("Corrupt segment %d."), i);
+              g_free (line);
+              goto failed;
+            }
+
+          seg->color = (GimpGradientSegmentColor) color;
+          if (seg->color < GIMP_GRADIENT_SEGMENT_RGB ||
+              seg->color > GIMP_GRADIENT_SEGMENT_HSV_CW)
+            {
+              g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
+                           _("Corrupt segment %d."), i);
+              g_free (line);
+              goto failed;
+            }
+          break;
+
+        default:
           g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
                        _("Corrupt segment %d."), i);
           g_free (line);
@@ -241,8 +227,10 @@ gimp_gradient_load (GimpContext   *context,
 
       g_free (line);
 
-      if ((  prev && (prev->right < seg->left)) ||
-          (! prev && (0.0         < seg->left)))
+      if (seg->left   > seg->middle              ||
+          seg->middle > seg->right               ||
+          (  prev && (prev->right != seg->left)) ||
+          (! prev && (0.0         != seg->left)))
         {
           g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
                        _("Segments do not span the range 0-1."));
@@ -252,7 +240,7 @@ gimp_gradient_load (GimpContext   *context,
       prev = seg;
     }
 
-  if (prev->right < 1.0)
+  if (prev->right != 1.0)
     {
       g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
                    _("Segments do not span the range 0-1."));
diff --git a/app/core/gimppalette-load.c b/app/core/gimppalette-load.c
index c2af11fc62..83de26cd6b 100644
--- a/app/core/gimppalette-load.c
+++ b/app/core/gimppalette-load.c
@@ -28,6 +28,7 @@
 
 #include "core-types.h"
 
+#include "gimp-utils.h"
 #include "gimppalette.h"
 #include "gimppalette-load.h"
 
@@ -59,8 +60,8 @@ gimp_palette_load (GimpContext   *context,
 
   linenum = 1;
   str_len = 1024;
-  str = g_data_input_stream_read_line (data_input, &str_len,
-                                       NULL, error);
+  str = gimp_data_input_stream_read_line_always (data_input, &str_len,
+                                                 NULL, error);
   if (! str)
     goto failed;
 
@@ -80,8 +81,8 @@ gimp_palette_load (GimpContext   *context,
 
   linenum++;
   str_len = 1024;
-  str = g_data_input_stream_read_line (data_input, &str_len,
-                                       NULL, error);
+  str = gimp_data_input_stream_read_line_always (data_input, &str_len,
+                                                 NULL, error);
   if (! str)
     goto failed;
 
@@ -97,8 +98,8 @@ gimp_palette_load (GimpContext   *context,
 
       linenum++;
       str_len = 1024;
-      str = g_data_input_stream_read_line (data_input, &str_len,
-                                           NULL, error);
+      str = gimp_data_input_stream_read_line_always (data_input, &str_len,
+                                                     NULL, error);
       if (! str)
         goto failed;
 
@@ -106,7 +107,14 @@ gimp_palette_load (GimpContext   *context,
         {
           gint columns;
 
-          columns = atoi (g_strstrip (str + strlen ("Columns: ")));
+          if (! gimp_ascii_strtoi (g_strstrip (str + strlen ("Columns: ")),
+                                   NULL, 10, &columns))
+            {
+              g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
+                           _("Invalid column count."));
+              g_free (str);
+              goto failed;
+            }
 
           if (columns < 0 || columns > 256)
             {
@@ -122,8 +130,8 @@ gimp_palette_load (GimpContext   *context,
 
           linenum++;
           str_len = 1024;
-          str = g_data_input_stream_read_line (data_input, &str_len,
-                                               NULL, error);
+          str = gimp_data_input_stream_read_line_always (data_input, &str_len,
+                                                         NULL, error);
           if (! str)
             goto failed;
         }
@@ -138,7 +146,7 @@ gimp_palette_load (GimpContext   *context,
     {
       GError *my_error = NULL;
 
-      if (str[0] != '#' && str[0] != '\n')
+      if (str[0] != '#' && str[0] != '\0')
         {
           tok = strtok (str, " \t");
           if (tok)
@@ -196,24 +204,14 @@ gimp_palette_load (GimpContext   *context,
       str_len = 1024;
       str = g_data_input_stream_read_line (data_input, &str_len,
                                            NULL, &my_error);
-      if (! str)
+      if (! str && my_error)
         {
-          if (! palette->colors)
-            {
-              g_propagate_error (error, my_error);
-              goto failed;
-            }
-
-          if (my_error)
-            {
-              g_message (_("Reading palette file '%s': "
-                           "Read %d colors from truncated file: %s"),
-                         gimp_file_get_utf8_name (file),
-                         g_list_length (palette->colors),
-                         my_error->message);
-              g_clear_error (&my_error);
-              break;
-            }
+          g_message (_("Reading palette file '%s': "
+                       "Read %d colors from truncated file: %s"),
+                     gimp_file_get_utf8_name (file),
+                     g_list_length (palette->colors),
+                     my_error->message);
+          g_clear_error (&my_error);
         }
     }
 
diff --git a/app/operations/gimpcurvesconfig.c b/app/operations/gimpcurvesconfig.c
index 013bc5b584..349b6982cc 100644
--- a/app/operations/gimpcurvesconfig.c
+++ b/app/operations/gimpcurvesconfig.c
@@ -31,6 +31,7 @@
 
 #include "operations-types.h"
 
+#include "core/gimp-utils.h"
 #include "core/gimpcurve.h"
 #include "core/gimphistogram.h"
 
@@ -537,8 +538,8 @@ gimp_curves_config_load_cruft (GimpCurvesConfig  *config,
   data_input = g_data_input_stream_new (input);
 
   line_len = 64;
-  line = g_data_input_stream_read_line (data_input, &line_len,
-                                        NULL, error);
+  line = gimp_data_input_stream_read_line_always (data_input, &line_len,
+                                                  NULL, error);
   if (! line)
     return FALSE;
 
diff --git a/app/operations/gimplevelsconfig.c b/app/operations/gimplevelsconfig.c
index 7f05aa2d39..e8d8561237 100644
--- a/app/operations/gimplevelsconfig.c
+++ b/app/operations/gimplevelsconfig.c
@@ -33,6 +33,7 @@
 
 #include "operations-types.h"
 
+#include "core/gimp-utils.h"
 #include "core/gimpcurve.h"
 #include "core/gimphistogram.h"
 
@@ -831,8 +832,8 @@ gimp_levels_config_load_cruft (GimpLevelsConfig  *config,
   data_input = g_data_input_stream_new (input);
 
   line_len = 64;
-  line = g_data_input_stream_read_line (data_input, &line_len,
-                                        NULL, error);
+  line = gimp_data_input_stream_read_line_always (data_input, &line_len,
+                                                  NULL, error);
   if (! line)
     return FALSE;
 
@@ -854,8 +855,8 @@ gimp_levels_config_load_cruft (GimpLevelsConfig  *config,
       gint   fields;
 
       line_len = 64;
-      line = g_data_input_stream_read_line (data_input, &line_len,
-                                            NULL, error);
+      line = gimp_data_input_stream_read_line_always (data_input, &line_len,
+                                                      NULL, error);
       if (! line)
         {
           g_object_unref (data_input);