master 370a386633b 1/4: Pacify -Wanalyzer-null-dereference in sfnt.c

[Paul Eggert]

branch: master
commit 370a386633b081107d30a00463dd0fe8d81b7e0f
Author: Paul Eggert <eggert@cs.ucla.edu>
Commit: Paul Eggert <eggert@cs.ucla.edu>

    Pacify -Wanalyzer-null-dereference in sfnt.c
    
    * src/sfnt.c (sfnt_map_table, sfnt_read_table)
    (sfnt_read_cvar_table): Pacify GCC -Wanalyzer-null-dereference.
    The change to sfnt_read_cvar_table fixes what appears to be
    an actual null-dereference bug.
---
 src/sfnt.c | 34 +++++++++++++---------------------
 1 file changed, 13 insertions(+), 21 deletions(-)

diff --git a/src/sfnt.c b/src/sfnt.c
index 1832082e4f9..8b7392b3af2 100644
--- a/src/sfnt.c
+++ b/src/sfnt.c
@@ -14085,22 +14085,18 @@ sfnt_map_table (int fd, struct sfnt_offset_subtable 
*subtable,
   struct sfnt_table_directory *directory;
   size_t offset, page, map_offset;
   void *data;
-  int i;
 
   /* Find the table in the directory.  */
 
-  for (i = 0; i < subtable->num_tables; ++i)
+  for (int i = 0; ; i++)
     {
-      if (subtable->subtables[i].tag == tag)
-       {
-         directory = &subtable->subtables[i];
-         break;
-       }
+      if (! (i < subtable->num_tables))
+       return 1;
+      directory = &subtable->subtables[i];
+      if (directory->tag == tag)
+       break;
     }
 
-  if (i == subtable->num_tables)
-    return 1;
-
   /* Now try to map the glyph data.  Make sure offset is a multiple of
      the page size.  */
 
@@ -14152,22 +14148,18 @@ sfnt_read_table (int fd, struct sfnt_offset_subtable 
*subtable,
 {
   struct sfnt_table_directory *directory;
   void *data;
-  int i;
 
   /* Find the table in the directory.  */
 
-  for (i = 0; i < subtable->num_tables; ++i)
+  for (int i = 0; ; i++)
     {
-      if (subtable->subtables[i].tag == tag)
-       {
-         directory = &subtable->subtables[i];
-         break;
-       }
+      if (! (i < subtable->num_tables))
+       return NULL;
+      directory = &subtable->subtables[i];
+      if (directory->tag == tag)
+       break;
     }
 
-  if (i == subtable->num_tables)
-    return NULL;
-
   /* Seek to the table.  */
 
   if (lseek (fd, directory->offset, SEEK_SET) != directory->offset)
@@ -15160,7 +15152,7 @@ sfnt_read_cvar_table (int fd, struct 
sfnt_offset_subtable *subtable,
          /* Copy in the shared point numbers instead.  */
          cvar->variation[i].num_points = npoints;
 
-         if (npoints != UINT16_MAX)
+         if (points && npoints != UINT16_MAX)
            {
              if (cvar->variation[i].num_points > cvt->num_elements)
                cvar->variation[i].num_points = cvt->num_elements;