The fossil_media_yaml library provides a simple, linked-list-based parser for YAML key-value pairs. Each node stores a key, a value, and its indentation level. The library allows parsing YAML strings, retrieving values by key, printing the node list for debugging, and freeing memory. The C++ wrapper provides RAII management, move semantics, and convenient methods for value lookup and debug printing.
Code reference for C and C++ APIs for the respective Fossil Logic library.
HEADER REFERENCE #
#ifndef FOSSIL_MEDIA_YAML_H
#define FOSSIL_MEDIA_YAML_H
#include <stddef.h>
#include <stdint.h>
#ifdef __cplusplus
extern "C"
{
#endif
/**
* @brief YAML key-value pair node.
*/
typedef struct fossil_media_yaml_node_t {
char *key; /**< YAML key string */
char *value; /**< YAML value string */
size_t indent; /**< Indentation level */
struct fossil_media_yaml_node_t *next; /**< Next node in linked list */
} fossil_media_yaml_node_t;
/**
* @brief Parse YAML string into a linked list of nodes.
* @param input YAML text (null-terminated)
* @return Head of linked list, or NULL on failure.
*/
fossil_media_yaml_node_t *fossil_media_yaml_parse(const char *input);
/**
* @brief Free a linked list of YAML nodes.
* @param head Head of the linked list
*/
void fossil_media_yaml_free(fossil_media_yaml_node_t *head);
/**
* @brief Get the value for a given key (first match).
* @param head YAML node list
* @param key Key string to search
* @return Value string, or NULL if not found.
*/
const char *fossil_media_yaml_get(const fossil_media_yaml_node_t *head, const char *key);
/**
* @brief Print the YAML node list to stdout (debug).
* @param head YAML node list
*/
void fossil_media_yaml_print(const fossil_media_yaml_node_t *head);
#ifdef __cplusplus
}
#include <string>
#include <stdexcept>
#include <utility>
namespace fossil {
namespace media {
/**
* @brief C++ wrapper for YAML parsing and manipulation.
*/
class Yaml {
public:
/**
* @brief Construct a Yaml object by parsing a YAML string.
* @param input YAML text (null-terminated)
* @throw std::runtime_error on parse failure
*/
explicit Yaml(const char* input)
: head_(::fossil_media_yaml_parse(input)) {
if (!head_) {
throw std::runtime_error("Failed to parse YAML input");
}
}
/**
* @brief Destructor. Frees the linked list of YAML nodes.
*/
~Yaml() {
::fossil_media_yaml_free(head_);
}
// Non-copyable
Yaml(const Yaml&) = delete;
Yaml& operator=(const Yaml&) = delete;
// Movable
Yaml(Yaml&& other) noexcept : head_(other.head_) {
other.head_ = nullptr;
}
Yaml& operator=(Yaml&& other) noexcept {
if (this != &other) {
::fossil_media_yaml_free(head_);
head_ = other.head_;
other.head_ = nullptr;
}
return *this;
}
/**
* @brief Get the value for a given key (first match).
* @param key Key string to search
* @return Value string, or nullptr if not found.
*/
const char* get(const char* key) const {
return ::fossil_media_yaml_get(head_, key);
}
/**
* @brief Print the YAML node list to stdout (debug).
*/
void print() const {
::fossil_media_yaml_print(head_);
}
private:
fossil_media_yaml_node_t* head_;
};
} // namespace media
} // namespace fossil
#endif
#endif /* FOSSIL_MEDIA_YAML_H */SAMPLE CODE C #
#include "fossil/media/yaml.h"
#include <stdio.h>
int main() {
const char *yaml_text =
"name: John Doe\n"
"age: 30\n"
"city: New York\n";
fossil_media_yaml_node_t *root = fossil_media_yaml_parse(yaml_text);
if (!root) {
printf("Failed to parse YAML\n");
return 1;
}
const char *name = fossil_media_yaml_get(root, "name");
const char *age = fossil_media_yaml_get(root, "age");
const char *city = fossil_media_yaml_get(root, "city");
printf("Name: %s\nAge: %s\nCity: %s\n",
name ? name : "(none)",
age ? age : "(none)",
city ? city : "(none)");
fossil_media_yaml_free(root);
return 0;
}
SAMPLE CODE C++ #
#include "fossil/media/yaml.h"
#include <iostream>
int main() {
const char* yaml_text =
"name: John Doe\n"
"age: 30\n"
"city: New York\n";
try {
fossil::media::Yaml doc(yaml_text);
std::cout << "Name: " << (doc.get("name") ? doc.get("name") : "(none)") << "\n";
std::cout << "Age: " << (doc.get("age") ? doc.get("age") : "(none)") << "\n";
std::cout << "City: " << (doc.get("city") ? doc.get("city") : "(none)") << "\n";
std::cout << "\nYAML Debug Print:\n";
doc.print();
} catch (const std::runtime_error& e) {
std::cerr << "YAML error: " << e.what() << "\n";
}
}
