Crate cobhan

cobhan-rust - FFI Data Interface

Cobhan FFI is a system for enabling shared code to be written in Rust and consumed from all major languages/platforms in a safe and effective way, using easy helper functions to manage any unsafe data marshaling.

Types

• Supported types
  • i32 - 32bit signed integer
  • i64 - 64bit signed integer
  • fl64 - double precision 64bit IEEE 754 floating point
  • Cobhan buffer - length delimited 8bit buffer (no null delimiters)
    • utf-8 encoded string
    • JSON
    • binary data
• Cobhan buffer details
  • Callers provide the output buffer allocation and capacity
  • Called functions can transparently return larger values via temporary files
  • Modern tmpfs is entirely memory backed
• Return values
  • Functions that return scalar values can return the value directly
    • Functions can use special case and return maximum positive or maximum negative or zero values to represent error or overflow conditions
    • Functions can allow scalar values to wrap
    • Functions should document their overflow / underflow behavior

Constants

BUFFER_HEADER_SIZE

64 bit buffer header provides 8 byte alignment for data pointers

ERR_BUFFER_TOO_LARGE

One of the provided buffer lengths is too large

ERR_BUFFER_TOO_SMALL

One of the provided buffers was too small

ERR_COPY_FAILED

Failed to copy a buffer (copy length != expected length)

ERR_INVALID_UTF8

UTF8 in a String or JSON is invalid.

ERR_JSON_DECODE_FAILED

Failed to decode a JSON buffer

ERR_JSON_ENCODE_FAILED

Failed to encode to JSON buffer

ERR_NONE

No Error

ERR_NULL_PTR

One of the provided pointers is NULL / nil / 0

ERR_READ_TEMP_FILE_FAILED

TempFile for large partial data failed to read.

ERR_WRITE_TEMP_FILE_FAILED

TempFile for large partial data failed to write.

Functions

bytes_to_cbuffer^⚠

Takes a Vec<u8> and fallibly encodes it into a provided external Cobhan Buffer.

cbuffer_to_hashmap_json^⚠

Takes a pointer to an external Cobhan Buffer and fallibly attempts to interpret it as a Hashmap<String, serde_json::Value>.

cbuffer_to_string^⚠

Takes a pointer to an external Cobhan Buffer and fallibly attempts to interpret it as a String.

cbuffer_to_vector^⚠

Takes a pointer to an external Cobhan Buffer and fallibly attempts to interpret it as a Vec<u8>.

hashmap_json_to_cbuffer^⚠

Takes a Hashmap<String, serde_json::Value> and fallibly encodes it in JSON into a provided external Cobhan Buffer.

string_to_cbuffer^⚠

Takes a String and fallibly encodes it into a provided external Cobhan Buffer.