feat: add public API header and format spec

include/fpk.h

@@ -0,0 +1,63 @@
+#ifndef FPK_H
+#define FPK_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#define FPK_MAGIC "FPK1"
+#define FPK_MAGIC_SIZE 4
+#define FPK_VERSION 1
+
+#define FPK_HEADER_SIZE 28
+/*
+ * magic          4
+ * entry_count    8
+ * dir_offset     8
+ * strtab_offset  8
+ *               --
+ *               28
+ */
+#define FPK_DIR_ENTRY_SIZE 25
+/*
+ * path_offset  8
+ * data_offset  8
+ * data_size    8
+ * method       1
+ *             --
+ *             25
+ */
+
+#define FPK_METHOD_STORE 0
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct {
+	const char *path;
+	uint64_t data_offset;
+	uint64_t data_size;
+	uint8_t method;
+} fpk_entry_t;
+
+struct fpk;
+struct fpk_writer;
+
+struct fpk *fpk_open(const char *path);
+void fpk_close(struct fpk *fpk);
+fpk_entry_t *fpk_find(struct fpk *fpk, const char *path);
+void *fpk_read(struct fpk *fpk, const fpk_entry_t *entry, size_t *out_size);
+uint64_t fpk_entry_count(const struct fpk *fpk);
+const fpk_entry_t *fpk_entry_at(const struct fpk *fpk, uint64_t index);
+
+struct fpk_writer *fpk_writer_open(const char *path);
+int fpk_writer_add(struct fpk_writer *w, const char *path, const void *data,
+		    size_t size);
+int fpk_writer_finalize(struct fpk_writer *w);
+void fpk_writer_close(struct fpk_writer *w);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* FPK_H */

include/fpk_version.h

@@ -0,0 +1,16 @@
+#ifndef FPK_VERSION_H
+#define FPK_VERSION_H
+
+#define FPK_VERSION_MAJOR 0
+#define FPK_VERSION_MINOR 1
+#define FPK_VERSION_PATCH 0
+
+#define FPK_STRINGIFY_HELPER(x) #x
+#define FPK_STRINGIFY(x) FPK_STRINGIFY_HELPER(x)
+
+#define FPK_VERSION_STRING                                                    \
+	FPK_STRINGIFY(FPK_VERSION_MAJOR)                                       \
+	"." FPK_STRINGIFY(FPK_VERSION_MINOR) "." FPK_STRINGIFY(                \
+	    FPK_VERSION_PATCH)
+
+#endif /* FPK_VERSION_H */