tree.c

#include "mvcs.h"

/* Write tree object */
int write_tree(tree_entry_t *entries, int count, unsigned char *hash) {
    /* Serialize tree entries */
    size_t total_size = 0;
    for (int i = 0; i < count; i++) {
        /* Format: "mode name\0hash" */
        total_size += snprintf(NULL, 0, "%o %s", entries[i].mode, entries[i].name) + 1 + HASH_SIZE;
    }
    
    unsigned char *data = malloc(total_size);
    if (!data) return -1;
    
    size_t offset = 0;
    for (int i = 0; i < count; i++) {
        int len = sprintf((char *)(data + offset), "%o %s", entries[i].mode, entries[i].name);
        offset += len + 1; /* Include null terminator */
        memcpy(data + offset, entries[i].hash, HASH_SIZE);
        offset += HASH_SIZE;
    }
    
    int ret = write_object(OBJ_TREE, data, total_size, hash);
    free(data);
    return ret;
}

/* Read tree object */
int read_tree(const unsigned char *hash, tree_entry_t **entries, int *count) {
    int type;
    void *data;
    size_t len;
    
    if (read_object(hash, &type, &data, &len) != 0 || type != OBJ_TREE) {
        return -1;
    }
    
    /* Parse tree entries */
    tree_entry_t *ent = malloc(sizeof(tree_entry_t) * MAX_TREE_ENTRIES);
    if (!ent) {
        free(data);
        return -1;
    }
    
    *count = 0;
    size_t offset = 0;
    unsigned char *bytes = (unsigned char *)data;
    
    while (offset < len && *count < MAX_TREE_ENTRIES) {
        /* Parse mode and name */
        int mode;
        char name[256];
        int parsed = sscanf((char *)(bytes + offset), "%o %255s", &mode, name);
        if (parsed != 2) break;
        
        ent[*count].mode = mode;
        strncpy(ent[*count].name, name, sizeof(ent[*count].name) - 1);
        ent[*count].name[sizeof(ent[*count].name) - 1] = '\0';
        
        /* Skip to hash */
        offset += strlen((char *)(bytes + offset)) + 1;
        
        /* Copy hash */
        if (offset + HASH_SIZE > len) break;
        memcpy(ent[*count].hash, bytes + offset, HASH_SIZE);
        offset += HASH_SIZE;
        
        (*count)++;
    }
    
    free(data);
    *entries = ent;
    return 0;
}