Feature/add grib

Makefile

@@ -115,6 +115,39 @@ USHOW_LIBS += $(ZARR_LIBS)
 UTERM_LIBS += $(ZARR_LIBS)
 endif
 
+# GRIB support (optional) - build with: make WITH_GRIB=1
+# Requires: eccodes (brew install eccodes on macOS)
+ifdef WITH_GRIB
+GRIB_PKG_CFLAGS := $(shell pkg-config --cflags eccodes 2>/dev/null)
+GRIB_PKG_LIBS := $(shell pkg-config --libs eccodes 2>/dev/null)
+
+ifneq ($(strip $(GRIB_PKG_CFLAGS)$(GRIB_PKG_LIBS)),)
+  GRIB_CFLAGS := -DHAVE_GRIB $(GRIB_PKG_CFLAGS)
+  GRIB_LIBS := $(GRIB_PKG_LIBS)
+else
+  # DKRZ Levante spack path (eccodes uses lib64)
+  DKRZ_ECCODES := /sw/spack-levante/eccodes-2.44.0-hsksp4
+
+  ifneq ($(wildcard $(DKRZ_ECCODES)/include/eccodes.h),)
+    GRIB_PREFIX ?= $(DKRZ_ECCODES)
+    GRIB_LIBDIR := $(GRIB_PREFIX)/lib64
+    GRIB_RPATH := -Wl,-rpath,$(GRIB_LIBDIR)
+  else
+    GRIB_PREFIX ?= $(shell brew --prefix eccodes 2>/dev/null || echo "/usr/local")
+    GRIB_LIBDIR := $(GRIB_PREFIX)/lib
+    GRIB_RPATH :=
+  endif
+
+  GRIB_CFLAGS := -DHAVE_GRIB -I$(GRIB_PREFIX)/include
+  GRIB_LIBS := -L$(GRIB_LIBDIR) -leccodes $(GRIB_RPATH)
+endif
+
+BASE_CFLAGS += $(GRIB_CFLAGS)
+X11_FULL_CFLAGS += $(GRIB_CFLAGS)
+USHOW_LIBS += $(GRIB_LIBS)
+UTERM_LIBS += $(GRIB_LIBS)
+endif
+
 # Directories
 SRCDIR = src
 OBJDIR = obj
@@ -146,6 +179,11 @@ USHOW_SRCS += $(SRCDIR)/cJSON/cJSON.c
 UTERM_SRCS += $(SRCDIR)/cJSON/cJSON.c
 endif
 
+# Add grib sources if enabled
+ifdef WITH_GRIB
+COMMON_SRCS += $(SRCDIR)/file_grib.c
+endif
+
 USHOW_OBJS = $(USHOW_SRCS:$(SRCDIR)/%.c=$(OBJDIR)/%.o)
 UTERM_OBJS = $(UTERM_SRCS:$(SRCDIR)/%.c=$(OBJDIR)/%.o)
 
@@ -231,6 +269,11 @@ $(OBJDIR)/file_zarr.o: $(SRCDIR)/file_zarr.c $(SRCDIR)/file_zarr.h $(SRCDIR)/ush
 $(OBJDIR)/cJSON/cJSON.o: $(SRCDIR)/cJSON/cJSON.c $(SRCDIR)/cJSON/cJSON.h
 endif
 
+# GRIB dependencies (when WITH_GRIB is set)
+ifdef WITH_GRIB
+$(OBJDIR)/file_grib.o: $(SRCDIR)/file_grib.c $(SRCDIR)/file_grib.h $(SRCDIR)/ushow.defines.h
+endif
+
 # Print configuration
 info:
 	@echo "CC: $(CC)"

README.md

@@ -31,12 +31,18 @@ For optional Zarr support:
 brew install c-blosc lz4
 ```
 
+For optional GRIB support:
+```bash
+brew install eccodes
+```
+
 Install [XQuartz](https://www.xquartz.org/) for X11 support. After installation, the X11 libraries will be in `/opt/X11`.
 
 Build:
 ```bash
-make                  # Without zarr support
+make                  # Without zarr/grib support
 make WITH_ZARR=1      # With zarr support
+make WITH_GRIB=1      # With grib support
 make uterm            # Build terminal viewer only
 ```
 
@@ -54,10 +60,16 @@ For optional Zarr support:
 sudo apt-get install libblosc-dev liblz4-dev
 ```
 
+For optional GRIB support:
+```bash
+sudo apt-get install libeccodes-dev
+```
+
 Build:
 ```bash
-make                  # Without zarr support
+make                  # Without zarr/grib support
 make WITH_ZARR=1      # With zarr support
+make WITH_GRIB=1      # With grib support
 make uterm            # Build terminal viewer only
 ```
 
@@ -69,8 +81,9 @@ On Levante, the Makefile automatically uses the DKRZ spack-installed libraries:
 
 No modules need to be loaded. Simply run:
 ```bash
-make                  # Without zarr support
+make                  # Without zarr/grib support
 make WITH_ZARR=1      # With zarr support (uses system blosc/lz4)
+make WITH_GRIB=1      # With grib support (uses system eccodes)
 ```
 
 The binary will have the library paths embedded (via rpath), so it runs without setting `LD_LIBRARY_PATH`.
@@ -103,7 +116,7 @@ No libraries should show as "not found".
 ## Usage
 
 ```bash
-./ushow [options] <data_file.nc|data.zarr> [file2 ...]
+./ushow [options] <data_file.nc|data.zarr|data.grib> [file2 ...]
 
 Options:
   -m, --mesh <file>      Mesh file with coordinates (for unstructured data)
@@ -115,7 +128,7 @@ Options:
 
 Terminal quick-look mode:
 ```bash
-./uterm [options] <data_file.nc|data.zarr> [file2 ...]
+./uterm [options] <data_file.nc|data.zarr|data.grib> [file2 ...]
 
 Options (uterm):
   -m, --mesh <file>      Mesh file with coordinates
@@ -159,6 +172,12 @@ Zarr store (requires `make WITH_ZARR=1`):
 ./ushow data.zarr -r 0.25              # Higher resolution display
 ```
 
+GRIB file (requires `make WITH_GRIB=1`):
+```bash
+./ushow data.grib                      # Single GRIB file
+./uterm data.grib --color
+```
+
 Zarr store with consolidated metadata (faster loading):
 ```bash
 # Zarr stores with .zmetadata file are loaded more efficiently