blob: d8a4d49bd62b017ae39bed16e767941940b41102 [file] [log] [blame]
#ifndef CN_ENCODER_C
#define CN_ENCODER_C
#ifdef __cplusplus
extern "C" {
#endif
#ifdef EMACS_INDENTATION_HELPER
} /* Duh. */
#endif
#include <arpa/inet.h>
#include <string.h>
#include <strings.h>
#include <stdbool.h>
#include <assert.h>
#include "cn-cbor/cn-cbor.h"
#include "cbor.h"
#define hton8p(p) (*(uint8_t*)(p))
#define hton16p(p) (htons(*(uint16_t*)(p)))
#define hton32p(p) (htonl(*(uint32_t*)(p)))
static uint64_t hton64p(const uint8_t *p) {
/* TODO: does this work on both BE and LE systems? */
uint64_t ret = hton32p(p);
ret <<= 32;
ret |= hton32p(p+4);
return ret;
}
typedef struct _write_state
{
uint8_t *buf;
ssize_t offset;
ssize_t size;
} cn_write_state;
#define ensure_writable(sz) if ((ws->offset<0) || (ws->offset + (sz) >= ws->size)) { \
ws->offset = -1; \
return; \
}
#define write_byte_and_data(b, data, sz) \
ws->buf[ws->offset++] = (b); \
memcpy(ws->buf+ws->offset, (data), (sz)); \
ws->offset += sz;
#define write_byte(b) \
ws->buf[ws->offset++] = (b); \
#define write_byte_ensured(b) \
ensure_writable(1); \
write_byte(b); \
static uint8_t _xlate[] = {
IB_FALSE, /* CN_CBOR_FALSE */
IB_TRUE, /* CN_CBOR_TRUE */
IB_NIL, /* CN_CBOR_NULL */
IB_UNDEF, /* CN_CBOR_UNDEF */
IB_UNSIGNED, /* CN_CBOR_UINT */
IB_NEGATIVE, /* CN_CBOR_INT */
IB_BYTES, /* CN_CBOR_BYTES */
IB_TEXT, /* CN_CBOR_TEXT */
IB_BYTES, /* CN_CBOR_BYTES_CHUNKED */
IB_TEXT, /* CN_CBOR_TEXT_CHUNKED */
IB_ARRAY, /* CN_CBOR_ARRAY */
IB_MAP, /* CN_CBOR_MAP */
IB_TAG, /* CN_CBOR_TAG */
IB_PRIM, /* CN_CBOR_SIMPLE */
0xFF, /* CN_CBOR_DOUBLE */
0xFF /* CN_CBOR_INVALID */
};
static inline bool is_indefinite(const cn_cbor *cb)
{
return (cb->flags & CN_CBOR_FL_INDEF) != 0;
}
static void _write_positive(cn_write_state *ws, cn_cbor_type typ, uint64_t val) {
uint8_t ib;
assert((size_t)typ < sizeof(_xlate));
ib = _xlate[typ];
if (ib == 0xFF) {
ws->offset = -1;
return;
}
if (val < 24) {
ensure_writable(1);
write_byte(ib | val);
} else if (val < 256) {
ensure_writable(2);
write_byte(ib | 24);
write_byte((uint8_t)val);
} else if (val < 65536) {
uint16_t be16 = (uint16_t)val;
ensure_writable(3);
be16 = hton16p(&be16);
write_byte_and_data(ib | 25, (const void*)&be16, 2);
} else if (val < 0x100000000L) {
uint32_t be32 = (uint32_t)val;
ensure_writable(5);
be32 = hton32p(&be32);
write_byte_and_data(ib | 26, (const void*)&be32, 4);
} else {
uint64_t be64;
ensure_writable(9);
be64 = hton64p((const uint8_t*)&val);
write_byte_and_data(ib | 27, (const void*)&be64, 8);
}
}
#ifndef CBOR_NO_FLOAT
static void _write_double(cn_write_state *ws, double val)
{
float float_val = val;
if (float_val == val) { /* 32 bits is enough and we aren't NaN */
uint32_t be32;
uint16_t be16, u16;
union {
float f;
uint32_t u;
} u32;
u32.f = float_val;
if ((u32.u & 0x1FFF) == 0) { /* worth trying half */
int s16 = (u32.u >> 16) & 0x8000;
int exp = (u32.u >> 23) & 0xff;
int mant = u32.u & 0x7fffff;
if (exp == 0 && mant == 0)
; /* 0.0, -0.0 */
else if (exp >= 113 && exp <= 142) /* normalized */
s16 += ((exp - 112) << 10) + (mant >> 13);
else if (exp >= 103 && exp < 113) { /* denorm, exp16 = 0 */
if (mant & ((1 << (126 - exp)) - 1))
goto float32; /* loss of precision */
s16 += ((mant + 0x800000) >> (126 - exp));
} else if (exp == 255 && mant == 0) { /* Inf */
s16 += 0x7c00;
} else
goto float32; /* loss of range */
ensure_writable(3);
u16 = s16;
be16 = hton16p((const uint8_t*)&u16);
write_byte_and_data(IB_PRIM | 25, (const void*)&be16, 2);
return;
}
float32:
ensure_writable(5);
be32 = hton32p((const uint8_t*)&u32.u);
write_byte_and_data(IB_PRIM | 26, (const void*)&be32, 4);
} else if (val != val) { /* NaN -- we always write a half NaN*/
ensure_writable(3);
write_byte_and_data(IB_PRIM | 25, (const void*)"\x7e\x00", 2);
} else {
uint64_t be64;
/* Copy the same problematic implementation from the decoder. */
union {
double d;
uint64_t u;
} u64;
u64.d = val;
ensure_writable(9);
be64 = hton64p((const uint8_t*)&u64.u);
write_byte_and_data(IB_PRIM | 27, (const void*)&be64, 8);
}
}
#endif /* CBOR_NO_FLOAT */
// TODO: make public?
typedef void (*cn_visit_func)(const cn_cbor *cb, int depth, void *context);
static void _visit(const cn_cbor *cb,
cn_visit_func visitor,
cn_visit_func breaker,
void *context)
{
const cn_cbor *p = cb;
int depth = 0;
while (p)
{
visit:
visitor(p, depth, context);
if (p->first_child) {
p = p->first_child;
depth++;
} else{
// Empty indefinite
if (is_indefinite(p)) {
breaker(p->parent, depth, context);
}
if (p->next) {
p = p->next;
} else {
while (p->parent) {
depth--;
if (is_indefinite(p->parent)) {
breaker(p->parent, depth, context);
}
if (p->parent->next) {
p = p->parent->next;
goto visit;
}
p = p->parent;
}
return;
}
}
}
}
#define CHECK(st) (st); \
if (ws->offset < 0) { return; }
void _encoder_visitor(const cn_cbor *cb, int depth, void *context)
{
cn_write_state *ws = context;
UNUSED_PARAM(depth);
switch (cb->type) {
case CN_CBOR_ARRAY:
if (is_indefinite(cb)) {
write_byte_ensured(IB_ARRAY | AI_INDEF);
} else {
CHECK(_write_positive(ws, CN_CBOR_ARRAY, cb->length));
}
break;
case CN_CBOR_MAP:
if (is_indefinite(cb)) {
write_byte_ensured(IB_MAP | AI_INDEF);
} else {
CHECK(_write_positive(ws, CN_CBOR_MAP, cb->length/2));
}
break;
case CN_CBOR_BYTES_CHUNKED:
case CN_CBOR_TEXT_CHUNKED:
write_byte_ensured(_xlate[cb->type] | AI_INDEF);
break;
case CN_CBOR_TEXT:
case CN_CBOR_BYTES:
CHECK(_write_positive(ws, cb->type, cb->length));
ensure_writable(cb->length);
memcpy(ws->buf+ws->offset, cb->v.str, cb->length);
ws->offset += cb->length;
break;
case CN_CBOR_FALSE:
case CN_CBOR_TRUE:
case CN_CBOR_NULL:
case CN_CBOR_UNDEF:
write_byte_ensured(_xlate[cb->type]);
break;
case CN_CBOR_TAG:
case CN_CBOR_UINT:
case CN_CBOR_SIMPLE:
CHECK(_write_positive(ws, cb->type, cb->v.uint));
break;
case CN_CBOR_INT:
assert(cb->v.sint < 0);
CHECK(_write_positive(ws, CN_CBOR_INT, ~(cb->v.sint)));
break;
case CN_CBOR_DOUBLE:
#ifndef CBOR_NO_FLOAT
CHECK(_write_double(ws, cb->v.dbl));
#endif /* CBOR_NO_FLOAT */
break;
case CN_CBOR_FLOAT:
#ifndef CBOR_NO_FLOAT
CHECK(_write_double(ws, cb->v.f));
#endif /* CBOR_NO_FLOAT */
break;
case CN_CBOR_INVALID:
ws->offset = -1;
break;
}
}
void _encoder_breaker(const cn_cbor *cb, int depth, void *context)
{
cn_write_state *ws = context;
UNUSED_PARAM(cb);
UNUSED_PARAM(depth);
write_byte_ensured(IB_BREAK);
}
ssize_t cn_cbor_encoder_write(uint8_t *buf,
size_t buf_offset,
size_t buf_size,
const cn_cbor *cb)
{
cn_write_state ws = { buf, buf_offset, buf_size };
_visit(cb, _encoder_visitor, _encoder_breaker, &ws);
if (ws.offset < 0) { return -1; }
return ws.offset - buf_offset;
}
#ifdef __cplusplus
}
#endif
#endif /* CN_CBOR_C */