capnp_c.h

/* vim: set sw=8 ts=8 sts=8 noet: */
/* capnp_c.h
 *
 * Copyright (C) 2013 James McKaskill
 * Copyright (C) 2014 Steve Dee
 *
 * This software may be modified and distributed under the terms
 * of the MIT license.  See the LICENSE file for details.
 */

#ifndef CAPNP_C_H
#define CAPNP_C_H

#include <stdint.h>
#include <stdio.h>
#include <unistd.h>

#if defined(unix) && !defined(__APPLE__) && !defined(__FreeBSD__)
#include <endian.h>
#elif defined(__FreeBSD__)
#include <sys/endian.h>
#endif

/* ssize_t is a POSIX type, not an ISO C one...
 * Windows seems to only have SSIZE_T in BaseTsd.h
 */
#ifdef _MSC_VER
typedef intmax_t ssize_t;
#else
#include <stddef.h>
#endif

// Cross-platform macro ALIGNED_(x) aligns a struct by `x` bytes.
#ifdef _MSC_VER
#define ALIGNED_(x) __declspec(align(x))
#endif
#ifdef __GNUC__
#define ALIGNED_(x) __attribute__ ((aligned(x)))
#endif

#ifdef __cplusplus
extern "C" {
#endif

#if defined(__cplusplus) || (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L)
#define CAPN_INLINE static inline
#else
#define CAPN_INLINE static
#endif

#define CAPN_VERSION 1

/* struct capn is a common structure shared between segments in the same
 * session/context so that far pointers between segments will be created.
 *
 * lookup is used to lookup segments by id when derefencing a far pointer
 *
 * create is used to create or lookup an alternate segment that has at least
 * sz available (ie returned seg->len + sz <= seg->cap)
 *
 * create_local is used to create a segment for the copy tree and should be
 * allocated in the local memory space.
 *
 * Allocated segments must be zero initialized.
 *
 * create and lookup can be NULL if you don't need multiple segments and don't
 * want to support copying
 *
 * seglist and copylist are linked lists which can be used to free up segments
 * on cleanup, but should not be modified by the user.
 *
 * lookup, create, create_local, and user can be set by the user. Other values
 * should be zero initialized.
 */
struct capn {
	/* user settable */
	struct capn_segment *(*lookup)(void* /*user*/, uint32_t /*id */);
	struct capn_segment *(*create)(void* /*user*/, uint32_t /*id */, int /*sz*/);
	struct capn_segment *(*create_local)(void* /*user*/, int /*sz*/);
	void *user;
	/* zero initialized, user should not modify */
	uint32_t segnum;
	struct capn_tree *copy;
	struct capn_tree *segtree;
	struct capn_segment *seglist, *lastseg;
	struct capn_segment *copylist;
};

/* struct capn_tree is a rb tree header used internally for the segment id
 * lookup and copy tree */
struct capn_tree {
	struct capn_tree *parent, *link[2];
	unsigned int red : 1;
};

struct capn_tree *capn_tree_insert(struct capn_tree *root, struct capn_tree *n);

/* struct capn_segment contains the information about a single segment.
 *
 * capn points to a struct capn that is shared between segments in the
 * same session
 *
 * id specifies the segment id, used for far pointers
 *
 * data specifies the segment data. This should not move after creation.
 *
 * len specifies the current segment length. This is 0 for a blank
 * segment.
 *
 * cap specifies the segment capacity.
 *
 * When creating new structures len will be incremented until it reaches cap,
 * at which point a new segment will be requested via capn->create. The
 * create callback can either create a new segment or expand an existing
 * one by incrementing cap and returning the expanded segment.
 *
 * data, len, and cap must all be 8 byte aligned, hence the ALIGNED_(8) macro
 * on the struct definition.
 *
 * data, len, cap, and user should all be set by the user. Other values
 * should be zero initialized.
 */

struct ALIGNED_(8) capn_segment {
	struct capn_tree hdr;
	struct capn_segment *next;
	struct capn *capn;
	uint32_t id;
	/* user settable */
	char *data;
	size_t len, cap;
	void *user;
};

enum CAPN_TYPE {
	CAPN_NULL = 0,
	CAPN_STRUCT = 1,
	CAPN_LIST = 2,
	CAPN_PTR_LIST = 3,
	CAPN_BIT_LIST = 4,
	CAPN_FAR_POINTER = 5,
};

struct capn_ptr {
	unsigned int type : 4;
	unsigned int has_ptr_tag : 1;
	unsigned int is_list_member : 1;
	unsigned int is_composite_list : 1;
	unsigned int datasz : 19;
	unsigned int ptrs : 16;
	int len;
	char *data;
	struct capn_segment *seg;
};

struct capn_text {
	int len;
	const char *str;
	struct capn_segment *seg;
};

typedef struct capn_ptr capn_ptr;
typedef struct capn_text capn_text;
typedef struct {capn_ptr p;} capn_data;
typedef struct {capn_ptr p;} capn_list1;
typedef struct {capn_ptr p;} capn_list8;
typedef struct {capn_ptr p;} capn_list16;
typedef struct {capn_ptr p;} capn_list32;
typedef struct {capn_ptr p;} capn_list64;

struct capn_msg {
	struct capn_segment *seg;
	uint64_t iface;
	uint16_t method;
	capn_ptr args;
};

/* capn_append_segment appends a segment to a session */
void capn_append_segment(struct capn*, struct capn_segment*);

capn_ptr capn_root(struct capn *c);
void capn_resolve(capn_ptr *p);

#define capn_len(list) ((list).p.type == CAPN_FAR_POINTER ? (capn_resolve(&(list).p), (list).p.len) : (list).p.len)

/* capn_getp|setp functions get/set ptrs in list/structs
 * off is the list index or pointer index in a struct
 * capn_setp will copy the data, create far pointers, etc if the target
 * is in a different segment/context.
 * Both of these will use/return inner pointers for composite lists.
 */
capn_ptr capn_getp(capn_ptr p, int off, int resolve);
int capn_setp(capn_ptr p, int off, capn_ptr tgt);

capn_text capn_get_text(capn_ptr p, int off, capn_text def);
capn_data capn_get_data(capn_ptr p, int off);
int capn_set_text(capn_ptr p, int off, capn_text tgt);
/* there is no set_data -- use capn_new_list8 + capn_setv8 instead
 * and set data.p = list.p */

/* capn_get* functions get data from a list
 * The length of the list is given by p->size
 * off specifies how far into the list to start
 * sz indicates the number of elements to get
 * The function returns the number of elements read or -1 on an error.
 * off must be byte aligned for capn_getv1
 */
int capn_get1(capn_list1 p, int off);
uint8_t capn_get8(capn_list8 p, int off);
uint16_t capn_get16(capn_list16 p, int off);
uint32_t capn_get32(capn_list32 p, int off);
uint64_t capn_get64(capn_list64 p, int off);
int capn_getv1(capn_list1 p, int off, uint8_t *data, int sz);
int capn_getv8(capn_list8 p, int off, uint8_t *data, int sz);
int capn_getv16(capn_list16 p, int off, uint16_t *data, int sz);
int capn_getv32(capn_list32 p, int off, uint32_t *data, int sz);
int capn_getv64(capn_list64 p, int off, uint64_t *data, int sz);

/* capn_set* functions set data in a list
 * off specifies how far into the list to start
 * sz indicates the number of elements to write
 * The function returns the number of elemnts written or -1 on an error.
 * off must be byte aligned for capn_setv1
 */
int capn_set1(capn_list1 p, int off, int v);
int capn_set8(capn_list8 p, int off, uint8_t v);
int capn_set16(capn_list16 p, int off, uint16_t v);
int capn_set32(capn_list32 p, int off, uint32_t v);
int capn_set64(capn_list64 p, int off, uint64_t v);
int capn_setv1(capn_list1 p, int off, const uint8_t *data, int sz);
int capn_setv8(capn_list8 p, int off, const uint8_t *data, int sz);
int capn_setv16(capn_list16 p, int off, const uint16_t *data, int sz);
int capn_setv32(capn_list32 p, int off, const uint32_t *data, int sz);
int capn_setv64(capn_list64 p, int off, const uint64_t *data, int sz);

/* capn_new_* functions create a new object
 * datasz is in bytes, ptrs is # of pointers, sz is # of elements in the list
 * On an error a CAPN_NULL pointer is returned
 */
capn_ptr capn_new_string(struct capn_segment *seg, const char *str, ssize_t sz);
capn_ptr capn_new_struct(struct capn_segment *seg, int datasz, int ptrs);
capn_ptr capn_new_interface(struct capn_segment *seg, int datasz, int ptrs);
capn_ptr capn_new_ptr_list(struct capn_segment *seg, int sz);
capn_ptr capn_new_list(struct capn_segment *seg, int sz, int datasz, int ptrs);
capn_list1 capn_new_list1(struct capn_segment *seg, int sz);
capn_list8 capn_new_list8(struct capn_segment *seg, int sz);
capn_list16 capn_new_list16(struct capn_segment *seg, int sz);
capn_list32 capn_new_list32(struct capn_segment *seg, int sz);
capn_list64 capn_new_list64(struct capn_segment *seg, int sz);

/* capn_read|write* functions read/write struct values
 * off is the offset into the structure in bytes
 * Rarely should these be called directly, instead use the generated code.
 * Data must be xored with the default value
 * These are inlined
 */
CAPN_INLINE uint8_t capn_read8(capn_ptr p, int off);
CAPN_INLINE uint16_t capn_read16(capn_ptr p, int off);
CAPN_INLINE uint32_t capn_read32(capn_ptr p, int off);
CAPN_INLINE uint64_t capn_read64(capn_ptr p, int off);
CAPN_INLINE int capn_write1(capn_ptr p, int off, int val);
CAPN_INLINE int capn_write8(capn_ptr p, int off, uint8_t val);
CAPN_INLINE int capn_write16(capn_ptr p, int off, uint16_t val);
CAPN_INLINE int capn_write32(capn_ptr p, int off, uint32_t val);
CAPN_INLINE int capn_write64(capn_ptr p, int off, uint64_t val);

/* capn_init_malloc inits the capn struct with a create function which
 * allocates segments on the heap using malloc
 *
 * capn_init_(fp|mem) inits by reading segments in from the file/memory buffer
 * in serialized form (optionally packed). It will then setup the create
 * function ala capn_init_malloc so that further segments can be created.
 *
 * capn_free frees all the segment headers and data created by the create
 * function setup by capn_init_*
 */
void capn_init_malloc(struct capn *c);
int capn_init_fp(struct capn *c, FILE *f, int packed);
int capn_init_mem(struct capn *c, const uint8_t *p, size_t sz, int packed);

/* capn_size() calculates the amount of memory required to serialise the given
 * Cap'n Proto structure in the unpacked format. It does NOT apply to packed
 * serialisation, as that may (in rare cases) actually become bigger than the
 * input. A buffer of this size can then be passed to capn_write_mem() without
 * fear of truncation (again, only in the unpacked case).
 */
int64_t capn_size(struct capn *c);

/* capn_write_(fp|mem) writes segments to the file/memory buffer in
 * serialized form and returns the number of bytes written.
 */
/* TODO */
/*int capn_write_fp(struct capn *c, FILE *f, int packed);*/
int capn_write_fd(struct capn *c, ssize_t (*write_fd)(int fd, const void *p, size_t count), int fd, int packed);
int64_t capn_write_mem(struct capn *c, uint8_t *p, size_t sz, int packed);

void capn_free(struct capn *c);
void capn_reset_copy(struct capn *c);

/* Inline functions */


CAPN_INLINE uint8_t capn_flip8(uint8_t v) {
	return v;
}
CAPN_INLINE uint16_t capn_flip16(uint16_t v) {
#if defined(__BYTE_ORDER) && (__BYTE_ORDER == __LITTLE_ENDIAN)
	return v;
#elif defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN) && \
      defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 8
	return __builtin_bswap16(v);
#else
	union { uint16_t u; uint8_t v[2]; } s;
	s.v[0] = (uint8_t)v;
	s.v[1] = (uint8_t)(v>>8);
	return s.u;
#endif
}
CAPN_INLINE uint32_t capn_flip32(uint32_t v) {
#if defined(__BYTE_ORDER) && (__BYTE_ORDER == __LITTLE_ENDIAN)
	return v;
#elif defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN) && \
      defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 8
	return __builtin_bswap32(v);
#else
	union { uint32_t u; uint8_t v[4]; } s;
	s.v[0] = (uint8_t)v;
	s.v[1] = (uint8_t)(v>>8);
	s.v[2] = (uint8_t)(v>>16);
	s.v[3] = (uint8_t)(v>>24);
	return s.u;
#endif
}
CAPN_INLINE uint64_t capn_flip64(uint64_t v) {
#if defined(__BYTE_ORDER) && (__BYTE_ORDER == __LITTLE_ENDIAN)
	return v;
#elif defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN) && \
      defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 8
	return __builtin_bswap64(v);
#else
	union { uint64_t u; uint8_t v[8]; } s;
	s.v[0] = (uint8_t)v;
	s.v[1] = (uint8_t)(v>>8);
	s.v[2] = (uint8_t)(v>>16);
	s.v[3] = (uint8_t)(v>>24);
	s.v[4] = (uint8_t)(v>>32);
	s.v[5] = (uint8_t)(v>>40);
	s.v[6] = (uint8_t)(v>>48);
	s.v[7] = (uint8_t)(v>>56);
	return s.u;
#endif
}

CAPN_INLINE int capn_write1(capn_ptr p, int off, int val) {
	if (off >= p.datasz*8) {
		return -1;
	} else if (val) {
		uint8_t tmp = (uint8_t)(1 << (off & 7));
		((uint8_t*) p.data)[off >> 3] |= tmp;
		return 0;
	} else {
		uint8_t tmp = (uint8_t)(~(1 << (off & 7)));
		((uint8_t*) p.data)[off >> 3] &= tmp;
		return 0;
	}
}

CAPN_INLINE uint8_t capn_read8(capn_ptr p, int off) {
	return off+1 <= p.datasz ? capn_flip8(*(uint8_t*) (p.data+off)) : 0;
}
CAPN_INLINE int capn_write8(capn_ptr p, int off, uint8_t val) {
	if (off+1 <= p.datasz) {
		*(uint8_t*) (p.data+off) = capn_flip8(val);
		return 0;
	} else {
		return -1;
	}
}

CAPN_INLINE uint16_t capn_read16(capn_ptr p, int off) {
	return off+2 <= p.datasz ? capn_flip16(*(uint16_t*) (p.data+off)) : 0;
}
CAPN_INLINE int capn_write16(capn_ptr p, int off, uint16_t val) {
	if (off+2 <= p.datasz) {
		*(uint16_t*) (p.data+off) = capn_flip16(val);
		return 0;
	} else {
		return -1;
	}
}

CAPN_INLINE uint32_t capn_read32(capn_ptr p, int off) {
	return off+4 <= p.datasz ? capn_flip32(*(uint32_t*) (p.data+off)) : 0;
}
CAPN_INLINE int capn_write32(capn_ptr p, int off, uint32_t val) {
	if (off+4 <= p.datasz) {
		*(uint32_t*) (p.data+off) = capn_flip32(val);
		return 0;
	} else {
		return -1;
	}
}

CAPN_INLINE uint64_t capn_read64(capn_ptr p, int off) {
	return off+8 <= p.datasz ? capn_flip64(*(uint64_t*) (p.data+off)) : 0;
}
CAPN_INLINE int capn_write64(capn_ptr p, int off, uint64_t val) {
	if (off+8 <= p.datasz) {
		*(uint64_t*) (p.data+off) = capn_flip64(val);
		return 0;
	} else {
		return -1;
	}
}

union capn_conv_f32 {
	uint32_t u;
	float f;
};

union capn_conv_f64 {
	uint64_t u;
	double f;
};

CAPN_INLINE float capn_to_f32(uint32_t v) {
	union capn_conv_f32 u;
	u.u = v;
	return u.f;
}
CAPN_INLINE double capn_to_f64(uint64_t v) {
	union capn_conv_f64 u;
	u.u = v;
	return u.f;
}
CAPN_INLINE uint32_t capn_from_f32(float v) {
	union capn_conv_f32 u;
	u.f = v;
	return u.u;
}
CAPN_INLINE uint64_t capn_from_f64(double v) {
	union capn_conv_f64 u;
	u.f = v;
	return u.u;
}

#ifdef __cplusplus
}
#endif

#endif