1 /*
2  * Copyright (c) Facebook, Inc.
3  * All rights reserved.
4  *
5  * This source code is licensed under both the BSD-style license (found in the
6  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7  * in the COPYING file in the root directory of this source tree).
8  * You may select, at your option, one of the above-listed licenses.
9  */
10 
11 #ifndef DATA_H
12 #define DATA_H
13 
14 #include <stddef.h>
15 #include <stdint.h>
16 
17 typedef enum {
18     data_type_file = 1,  /**< This data is a file. *.zst */
19     data_type_dir = 2,   /**< This data is a directory. *.tar.zst */
20 } data_type_t;
21 
22 typedef struct {
23     char const* url;   /**< Where to get this resource. */
24     uint64_t xxhash64; /**< Hash of the url contents. */
25     char const* path;  /**< The path of the unpacked resource (derived). */
26 } data_resource_t;
27 
28 typedef struct {
29     data_resource_t data;
30     data_resource_t dict;
31     data_type_t type;  /**< The type of the data. */
32     char const* name;  /**< The logical name of the data (no extension). */
33 } data_t;
34 
35 /**
36  * The NULL-terminated list of data objects.
37  */
38 extern data_t const* const* data;
39 
40 
41 int data_has_dict(data_t const* data);
42 
43 /**
44  * Initializes the data module and downloads the data necessary.
45  * Caches the downloads in dir. We add a stamp file in the directory after
46  * a successful download. If a stamp file already exists, and matches our
47  * current data stamp, we will use the cached data without downloading.
48  *
49  * @param dir The directory to cache the downloaded data into.
50  *
51  * @returns 0 on success.
52  */
53 int data_init(char const* dir);
54 
55 /**
56  * Must be called at exit to free resources allocated by data_init().
57  */
58 void data_finish(void);
59 
60 typedef struct {
61     uint8_t* data;
62     size_t size;
63     size_t capacity;
64 } data_buffer_t;
65 
66 /**
67  * Read the file that data points to into a buffer.
68  * NOTE: data must be a file, not a directory.
69  *
70  * @returns The buffer, which is NULL on failure.
71  */
72 data_buffer_t data_buffer_get_data(data_t const* data);
73 
74 /**
75  * Read the dictionary that the data points to into a buffer.
76  *
77  * @returns The buffer, which is NULL on failure.
78  */
79 data_buffer_t data_buffer_get_dict(data_t const* data);
80 
81 /**
82  * Read the contents of filename into a buffer.
83  *
84  * @returns The buffer, which is NULL on failure.
85  */
86 data_buffer_t data_buffer_read(char const* filename);
87 
88 /**
89  * Create a buffer with the specified capacity.
90  *
91  * @returns The buffer, which is NULL on failure.
92  */
93 data_buffer_t data_buffer_create(size_t capacity);
94 
95 /**
96  * Calls memcmp() on the contents [0, size) of both buffers.
97  */
98 int data_buffer_compare(data_buffer_t buffer1, data_buffer_t buffer2);
99 
100 /**
101  * Frees an allocated buffer.
102  */
103 void data_buffer_free(data_buffer_t buffer);
104 
105 
106 typedef struct {
107     data_buffer_t const* buffers;
108     size_t size;
109 } data_buffers_t;
110 
111 /**
112  * @returns a list of buffers for every file in data. It is zero sized on error.
113  */
114 data_buffers_t data_buffers_get(data_t const* data);
115 
116 /**
117  * Frees the data buffers.
118  */
119 void data_buffers_free(data_buffers_t buffers);
120 
121 #endif
122