implement support for ctable2 format (read/write)

git-svn-id: http://svn.osgeo.org/metacrs/proj/trunk@2121 4e78687f-474d-0410-85f9-8d5e500ac6b2

1 files changed, 143 insertions, 6 deletions

diff --git a/src/nad_init.c b/src/nad_init.c
index da10dd2b..20f1adb6 100644
--- a/src/nad_init.c
+++ b/src/nad_init.c
@@ -45,6 +45,38 @@
 #endif /* _WIN32_WCE */
 
 /************************************************************************/
+/*                             swap_words()                             */
+/*                                                                      */
+/*      Convert the byte order of the given word(s) in place.           */
+/************************************************************************/
+
+static int  byte_order_test = 1;
+#define IS_LSB	(((unsigned char *) (&byte_order_test))[0] == 1)
+
+static void swap_words( void *data_in, int word_size, int word_count )
+
+{
+    int	word;
+    unsigned char *data = (unsigned char *) data_in;
+
+    for( word = 0; word < word_count; word++ )
+    {
+        int	i;
+        
+        for( i = 0; i < word_size/2; i++ )
+        {
+            int	t;
+            
+            t = data[i];
+            data[i] = data[word_size-i-1];
+            data[word_size-i-1] = t;
+        }
+        
+        data += word_size;
+    }
+}
+
+/************************************************************************/
 /*                          nad_ctable_load()                           */
 /*                                                                      */
 /*      Load the data portion of a ctable formatted grid.               */
@@ -66,6 +98,79 @@ int nad_ctable_load( projCtx ctx, struct CTABLE *ct, FILE *fid )
         pj_dalloc( ct->cvs );
         ct->cvs = NULL;
 
+        pj_log( ctx, PJ_LOG_ERROR, 
+                "ctable loading failed on fread() - binary incompatible?\n" );
+        pj_ctx_set_errno( ctx, -38 );
+        return 0;
+    }
+
+    return 1;
+} 
+
+/************************************************************************/
+/*                          nad_ctable_init()                           */
+/*                                                                      */
+/*      Read the header portion of a "ctable" format grid.              */
+/************************************************************************/
+
+struct CTABLE *nad_ctable_init( projCtx ctx, FILE * fid )
+{
+    struct CTABLE *ct;
+    int		id_end;
+
+    /* read the table header */
+    ct = (struct CTABLE *) pj_malloc(sizeof(struct CTABLE));
+    if( ct == NULL 
+        || fread( ct, sizeof(struct CTABLE), 1, fid ) != 1 )
+    {
+        pj_ctx_set_errno( ctx, -38 );
+        return NULL;
+    }
+
+    /* do some minimal validation to ensure the structure isn't corrupt */
+    if( ct->lim.lam < 1 || ct->lim.lam > 100000 
+        || ct->lim.phi < 1 || ct->lim.phi > 100000 )
+    {
+        pj_ctx_set_errno( ctx, -38 );
+        return NULL;
+    }
+    
+    /* trim white space and newlines off id */
+    for( id_end = strlen(ct->id)-1; id_end > 0; id_end-- )
+    {
+        if( ct->id[id_end] == '\n' || ct->id[id_end] == ' ' )
+            ct->id[id_end] = '\0';
+        else
+            break;
+    }
+
+    ct->cvs = NULL;
+
+    return ct;
+}
+
+/************************************************************************/
+/*                          nad_ctable2_load()                          */
+/*                                                                      */
+/*      Load the data portion of a ctable2 formatted grid.              */
+/************************************************************************/
+
+int nad_ctable2_load( projCtx ctx, struct CTABLE *ct, FILE *fid )
+
+{
+    int  a_size;
+
+    fseek( fid, 160, SEEK_SET );
+
+    /* read all the actual shift values */
+    a_size = ct->lim.lam * ct->lim.phi;
+    ct->cvs = (FLP *) pj_malloc(sizeof(FLP) * a_size);
+    if( ct->cvs == NULL 
+        || fread(ct->cvs, sizeof(FLP), a_size, fid) != a_size )
+    {
+        pj_dalloc( ct->cvs );
+        ct->cvs = NULL;
+
         if( getenv("PROJ_DEBUG") != NULL )
         {
             fprintf( stderr, 
@@ -76,29 +181,61 @@ int nad_ctable_load( projCtx ctx, struct CTABLE *ct, FILE *fid )
         return 0;
     }
 
+    if( !IS_LSB )
+    {
+        swap_words( ct->cvs, 4, a_size * 2 );
+    }
+
     return 1;
 } 
 
 /************************************************************************/
-/*                          nad_ctable_init()                           */
+/*                          nad_ctable2_init()                          */
 /*                                                                      */
-/*      Read the header portion of a "ctable" format grid.              */
+/*      Read the header portion of a "ctable2" format grid.             */
 /************************************************************************/
 
-struct CTABLE *nad_ctable_init( projCtx ctx, FILE * fid )
+struct CTABLE *nad_ctable2_init( projCtx ctx, FILE * fid )
 {
     struct CTABLE *ct;
     int		id_end;
+    char        header[160];
+
+    if( fread( header, sizeof(header), 1, fid ) != 1 )
+    {
+        pj_ctx_set_errno( ctx, -38 );
+        return NULL;
+    }
+
+    if( !IS_LSB )
+    {
+        swap_words( header +  96, 8, 4 );
+        swap_words( header + 128, 4, 2 );
+    }
+
+    if( strncmp(header,"CTABLE V2",9) != 0 )
+    {
+        pj_log( ctx, PJ_LOG_ERROR, "ctable2 - wrong header!" );
+        pj_ctx_set_errno( ctx, -38 );
+        return NULL;
+    }
 
     /* read the table header */
     ct = (struct CTABLE *) pj_malloc(sizeof(struct CTABLE));
-    if( ct == NULL 
-        || fread( ct, sizeof(struct CTABLE), 1, fid ) != 1 )
+    if( ct == NULL )
     {
         pj_ctx_set_errno( ctx, -38 );
         return NULL;
     }
 
+    memcpy( ct->id,       header +  16, 80 );
+    memcpy( &ct->ll.lam,  header +  96, 8 );
+    memcpy( &ct->ll.phi,  header + 104, 8 );
+    memcpy( &ct->del.lam, header + 112, 8 );
+    memcpy( &ct->del.phi, header + 120, 8 );
+    memcpy( &ct->lim.lam, header + 128, 4 );
+    memcpy( &ct->lim.phi, header + 132, 4 );
+
     /* do some minimal validation to ensure the structure isn't corrupt */
     if( ct->lim.lam < 1 || ct->lim.lam > 100000 
         || ct->lim.phi < 1 || ct->lim.phi > 100000 )
@@ -142,7 +279,7 @@ struct CTABLE *nad_init(projCtx ctx, char *name)
     if (!(fid = pj_open_lib(ctx, fname, "rb"))) {
         return 0;
     }
-    
+
     ct = nad_ctable_init( ctx, fid );
     if( ct != NULL )
     {