ECC-2167 improved check on computed offset

Author: danovaro

src/eccodes/grib_api.h

@@ -1346,11 +1346,13 @@ void grib_get_reduced_row(long pl, double lon_first, double lon_last, long* npoi
 void grib_get_reduced_row_p(long pl, double lon_first, double lon_last, long* npoints, double* olon_first, double* olon_last);
 
 /* read products */
-int wmo_read_any_from_file_with_offset(FILE* f, void* buffer, size_t* len, off_t* offset);
 int wmo_read_any_from_file(FILE* f, void* buffer, size_t* len);
 int wmo_read_grib_from_file(FILE* f, void* buffer, size_t* len);
 int wmo_read_bufr_from_file(FILE* f, void* buffer, size_t* len);
 int wmo_read_gts_from_file(FILE* f, void* buffer, size_t* len);
+/* if f support ftell, offset is updated with the absolute position within the file, */
+/* otherwise, it accumulates the position across a series of calls */
+int wmo_read_any_from_file_with_offset(FILE* f, void* buffer, size_t* len, off_t* offset);
 int wmo_read_any_from_stream(void* stream_data, long (*stream_proc)(void*, void* buffer, long len), void* buffer, size_t* len);
 
 /* These functions allocate memory for the result so the user is responsible for freeing it */

src/eccodes/grib_io.cc

@@ -879,7 +879,7 @@ static int ecc_read_any(reader* r, int no_alloc, int grib_ok, int bufr_ok, int h
             case GRIB:
                 if (grib_ok) {
                     err = read_GRIB(r, no_alloc);
-                    if (r->offset == -5) {
+                    if (r->offset < 0) {
                         r->offset = offset - 4;
                     }
                     return err == GRIB_END_OF_FILE ? GRIB_PREMATURE_END_OF_FILE : err; /* Premature EOF */
@@ -889,7 +889,7 @@ static int ecc_read_any(reader* r, int no_alloc, int grib_ok, int bufr_ok, int h
             case BUFR:
                 if (bufr_ok) {
                     err = read_BUFR(r, no_alloc);
-                    if (r->offset == -5) {
+                    if (r->offset < 0) {
                         r->offset = offset - 4;
                     }
                     return err == GRIB_END_OF_FILE ? GRIB_PREMATURE_END_OF_FILE : err; /* Premature EOF */
@@ -913,7 +913,7 @@ static int ecc_read_any(reader* r, int no_alloc, int grib_ok, int bufr_ok, int h
             case BUDG:
                 if (grib_ok) {
                     err = read_PSEUDO(r, "BUDG", no_alloc);
-                    if (r->offset == -5) {
+                    if (r->offset < 0) {
                         r->offset = offset - 4;
                     }
                     return err == GRIB_END_OF_FILE ? GRIB_PREMATURE_END_OF_FILE : err; /* Premature EOF */
@@ -922,7 +922,7 @@ static int ecc_read_any(reader* r, int no_alloc, int grib_ok, int bufr_ok, int h
             case DIAG:
                 if (grib_ok) {
                     err = read_PSEUDO(r, "DIAG", no_alloc);
-                    if (r->offset == -5) {
+                    if (r->offset < 0) {
                         r->offset = offset - 4;
                     }
                     return err == GRIB_END_OF_FILE ? GRIB_PREMATURE_END_OF_FILE : err; /* Premature EOF */
@@ -931,7 +931,7 @@ static int ecc_read_any(reader* r, int no_alloc, int grib_ok, int bufr_ok, int h
             case TIDE:
                 if (grib_ok) {
                     err = read_PSEUDO(r, "TIDE", no_alloc);
-                    if (r->offset == -5) {
+                    if (r->offset < 0) {
                         r->offset = offset - 4;
                     }
                     return err == GRIB_END_OF_FILE ? GRIB_PREMATURE_END_OF_FILE : err; /* Premature EOF */