File syn_cbor_write.h¶

FileList > src > syntropic > util > syn_cbor_write.h

Streaming CBOR encoder — zero-alloc, caller-provided buffer. More...

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

Classes¶

Type	Name
struct	SYN_CborWriter CBOR encoder state. Caller-allocated; zero heap.

Public Functions¶

Type	Name
void	syn_cbor_write_array_begin (SYN_CborWriter * w, size_t count) Open a CBOR array with `count` items.
void	syn_cbor_write_bool (SYN_CborWriter * w, bool v) Write a boolean (0xF4 = false, 0xF5 = true).
void	syn_cbor_write_bytes (SYN_CborWriter * w, const uint8_t * data, size_t len) Write a byte string (major type 2).
void	syn_cbor_write_float (SYN_CborWriter * w, float v) Write an IEEE 754 single-precision float (major type 7, info=26).
void	syn_cbor_write_int (SYN_CborWriter * w, int64_t v) Write a signed integer.
void	syn_cbor_write_map_begin (SYN_CborWriter * w, size_t count) Open a CBOR map with `count` key-value pairs.
void	syn_cbor_write_null (SYN_CborWriter * w) Write a null (0xF6).
void	syn_cbor_write_text (SYN_CborWriter * w, const char * str, size_t len) Write a UTF-8 text string (major type 3).
void	syn_cbor_write_text_cstr (SYN_CborWriter * w, const char * str) Write a null-terminated UTF-8 text string.
void	syn_cbor_write_uint (SYN_CborWriter * w, uint64_t v) Write an unsigned integer.
void	syn_cbor_writer_init (SYN_CborWriter * w, uint8_t * buf, size_t cap) Initialize a CBOR writer.

Public Static Functions¶

Type	Name
size_t	syn_cbor_writer_len (const SYN_CborWriter * w) Return bytes encoded so far.
bool	syn_cbor_writer_ok (const SYN_CborWriter * w) Return true if no overflow has occurred.

Detailed Description¶

Encodes CBOR (RFC 8949) items into a fixed buffer. No heap, no recursion, no indefinite-length items. Map and array sizes must be known before writing begins.

Supported types: unsigned int, signed int, float32, bool, null, text string, byte string, array, map.

** **

uint8_t buf[32];
SYN_CborWriter w;
syn_cbor_writer_init(&w, buf, sizeof(buf));
syn_cbor_write_map_begin(&w, 2);         // A2
  syn_cbor_write_uint(&w, 1);            // key 1 = temperature
  syn_cbor_write_float(&w, 23.5f);       // 23.5
  syn_cbor_write_uint(&w, 2);            // key 2 = humidity
  syn_cbor_write_uint(&w, 60);           // 60
// result: A2 01 FA41BC0000 02 183C  (10 bytes)

** **

syn_cbor_write_map_begin(&w, 1);
  syn_cbor_write_text_cstr(&w, "temp");
  syn_cbor_write_float(&w, 23.5f);

Public Functions Documentation¶

function syn_cbor_write_array_begin¶

Open a CBOR array with count items.

void syn_cbor_write_array_begin (
    SYN_CborWriter * w,
    size_t count
)

Caller must write exactly count items after this call.

Parameters:

w Writer.
count Number of items that follow.

function syn_cbor_write_bool¶

Write a boolean (0xF4 = false, 0xF5 = true).

void syn_cbor_write_bool (
    SYN_CborWriter * w,
    bool v
)

Parameters:

w Writer.
v Value.

function syn_cbor_write_bytes¶

Write a byte string (major type 2).

void syn_cbor_write_bytes (
    SYN_CborWriter * w,
    const uint8_t * data,
    size_t len
)

Parameters:

w Writer.
data Pointer to raw bytes.
len Byte count.

function syn_cbor_write_float¶

Write an IEEE 754 single-precision float (major type 7, info=26).

void syn_cbor_write_float (
    SYN_CborWriter * w,
    float v
)

Parameters:

w Writer.
v Float value.

function syn_cbor_write_int¶

Write a signed integer.

void syn_cbor_write_int (
    SYN_CborWriter * w,
    int64_t v
)

Positive values are encoded as major type 0 (uint). Negative values are encoded as major type 1.

Parameters:

w Writer.
v Signed value to encode.

function syn_cbor_write_map_begin¶

Open a CBOR map with count key-value pairs.

void syn_cbor_write_map_begin (
    SYN_CborWriter * w,
    size_t count
)

Caller must write exactly count pairs (key item + value item each) after this call.

Parameters:

w Writer.
count Number of key-value pairs that follow.

function syn_cbor_write_null¶

Write a null (0xF6).

void syn_cbor_write_null (
    SYN_CborWriter * w
)

Parameters:

w Writer.

function syn_cbor_write_text¶

Write a UTF-8 text string (major type 3).

void syn_cbor_write_text (
    SYN_CborWriter * w,
    const char * str,
    size_t len
)

Parameters:

w Writer.
str Pointer to string data.
len Byte length (not counting any null terminator).

function syn_cbor_write_text_cstr¶

Write a null-terminated UTF-8 text string.

void syn_cbor_write_text_cstr (
    SYN_CborWriter * w,
    const char * str
)

Parameters:

w Writer.
str Null-terminated string.

function syn_cbor_write_uint¶

Write an unsigned integer.

void syn_cbor_write_uint (
    SYN_CborWriter * w,
    uint64_t v
)

Parameters:

w Writer.
v Value to encode (CBOR major type 0).

function syn_cbor_writer_init¶

Initialize a CBOR writer.

void syn_cbor_writer_init (
    SYN_CborWriter * w,
    uint8_t * buf,
    size_t cap
)

Parameters:

w Writer to initialize. Must not be NULL.
buf Output buffer. Must not be NULL.
cap Buffer capacity in bytes.

Public Static Functions Documentation¶

function syn_cbor_writer_len¶

Return bytes encoded so far.

static inline size_t syn_cbor_writer_len (
    const SYN_CborWriter * w
)

Parameters:

w Writer.

Returns:

Byte count.

function syn_cbor_writer_ok¶

Return true if no overflow has occurred.

static inline bool syn_cbor_writer_ok (
    const SYN_CborWriter * w
)

Parameters:

w Writer.

Returns:

true if OK.

The documentation for this class was generated from the following file src/syntropic/util/syn_cbor_write.h