Files
cgit/src/objects.c
2024-05-29 15:29:00 +02:00

142 lines
3.5 KiB
C

#include <assert.h>
#include <math.h>
#include <openssl/sha.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <zlib.h>
#include "includes.h"
#include "utils.h"
#include "objects.h"
size_t header_size(struct object *obj)
{
return strlen(obj->object_type) + 2 + decimal_len(obj->size);
}
size_t object_size(struct object *obj)
{
return header_size(obj) + obj->size;
}
int full_object(struct object *obj, char *buffer, size_t buffer_size)
{
char* hr_size = malloc(decimal_len(obj->size) + 1);
sprintf(hr_size, "%li", obj->size);
size_t data_size = object_size(obj);
assert(data_size <= buffer_size);
char *writing = buffer;
memcpy(writing, obj->object_type, strlen(obj->object_type));
writing += strlen(obj->object_type);
memcpy(writing, " ", 1);
writing ++;
memcpy(writing, hr_size, strlen(hr_size));
writing += strlen(hr_size);
memcpy(writing, "\0", 1);
writing ++;
memcpy(writing, obj->content, obj->size);
free(hr_size);
return 0;
}
void hash_object(struct object *obj, char *result)
{
unsigned char md_buffer[DIGEST_LENGTH] = {0};
size_t data_size = object_size(obj);
char* data = malloc(data_size);
full_object(obj, data, data_size);
SHA1(data, data_size, md_buffer);
for (int i = 0; i < DIGEST_LENGTH; i++)
{
sprintf((result + (2 * i)), "%.2x", md_buffer[i]);
}
free(data);
}
int uncompress_object(struct object *obj, char* compressed, uLongf comp_size)
{
uLongf def_size = HEADER_MAX_SIZE;
uLongf content_size = 0;
char* deflated = malloc(def_size);
int res = uncompress((Bytef *) deflated, &def_size, (Bytef *)compressed, comp_size);
if (res != Z_OK && res != Z_BUF_ERROR)
{
return res;
}
int header_size = strlen(deflated) + 1;
def_size = header_size;
strtok(deflated, " ");
char *hr_size = strtok(NULL, " ");
content_size = strtol(hr_size, NULL, 10);
def_size += content_size;
deflated = realloc(deflated, def_size);
res = uncompress((Bytef *) deflated, &def_size, (Bytef *)compressed, comp_size);
if(res != Z_OK) {
return res;
}
char *content_type_tmp = strtok(deflated, " ");
obj->size = content_size;
obj->object_type = malloc(strlen(content_type_tmp) + 1);
strncpy(obj->object_type, content_type_tmp, strlen(content_type_tmp) + 1);
obj->content = malloc(obj->size);
memcpy(obj->content, deflated + header_size, obj->size);
free(deflated);
return 0;
}
int compress_object(struct object *obj, char* compressed, uLongf *comp_size)
{
size_t data_size = object_size(obj);
char* data = malloc(data_size);
full_object(obj, data, data_size);
int res = compress((Bytef *)compressed, comp_size, (Bytef *)data, data_size);
free(data);
return res;
}
int blob_from_file(char *filename, struct object *object)
{
FILE* file = fopen(filename, "r");
if (file == NULL)
return -1;
struct stat file_info;
if (stat(filename, &file_info) != 0)
return -1;
object->object_type = "blob";
object->size = file_info.st_size;
object->content = realloc(object->content, object->size);
fread(object->content, 1, object->size, file);
fclose(file);
return 0;
}
void free_object(struct object *obj)
{
if (obj->content != NULL)
free(obj->content);
}
// int main(void)
// {
// char result[SHA_DIGEST_LENGTH * 2] = {0};
// char* str = "Hello, world!\n";
// hash_object(str, strlen(str), "blob", result);
// printf("%s\n", result);
// }