C Guide

The C implementation is the lowest-level ASUN runtime in the repository. It uses explicit schema descriptors and does not rely on reflection or code generation at runtime.

Minimum Version

• C11
• No external runtime dependency beyond the C standard library

Implementation Model

• You define an AsunSchema explicitly with field metadata.
• Text and binary encode/decode both use that schema descriptor.
• There is no native ASUN map type. Keyed collections should be modeled as arrays of entry structs.

Current Support

• Compact text encode/decode
• Pretty text encode/decode
• Binary encode/decode
• Scalars, arrays, nested structs, struct arrays, optional / empty-slot values

Binary decode is not self-describing. You must pass the schema descriptor.

Core API

#include "asun.h"

AsunBuffer *asun_encode(const AsunSchema *schema, const void *data, size_t count);
AsunBuffer *asun_encode_pretty(const AsunSchema *schema, const void *data, size_t count);
int asun_decode(const char *text, const AsunSchema *schema, void *out, size_t *count);

AsunBuffer *asun_encode_bin(const AsunSchema *schema, const void *data, size_t count);
int asun_decode_bin(const uint8_t *data, size_t len,
                    const AsunSchema *schema, void *out, size_t *count);

Example

typedef struct {
    int64_t id;
    char name[64];
    bool active;
} User;

static const AsunField user_fields[] = {
    { "id",     ASUN_INT,  offsetof(User, id)     },
    { "name",   ASUN_STR,  offsetof(User, name)   },
    { "active", ASUN_BOOL, offsetof(User, active) },
};

static const AsunSchema user_schema = {
    .fields = user_fields,
    .field_count = 3,
    .struct_size = sizeof(User),
};

Notes

• Schema names in text remain only int, float, str, and bool.
• C uses explicit descriptors because the language itself has no reflection layer.
• For keyed data, model [{key@str,value@T}] with an ordinary entry struct array.

Build and Test

cd asun-c
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build
ctest --test-dir build --output-on-failure