prosody
37a6a535343e
util-src/strbitop.c

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util-src/strbitop.c @ 11163:37a6a535343e 0.11

util.strbitop: Library for bitwise operations on strings
author Kim Alvefur <zash@zash.se>
date Sat, 07 Sep 2019 13:37:47 +0200
child 11167:ba32b9a6d75b
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11162:ee399a0522cc 11163:37a6a535343e
1 /*
2 * This project is MIT licensed. Please see the
3 * COPYING file in the source package for more information.
4 *
5 * Copyright (C) 2016 Kim Alvefur
6 */
7
8 #include <lua.h>
9 #include <lauxlib.h>
10
11 #if (LUA_VERSION_NUM == 501)
12 #define luaL_setfuncs(L, R, N) luaL_register(L, NULL, R)
13 #endif
14
15 /* TODO Deduplicate code somehow */
16
17 int strop_and(lua_State* L) {
18 luaL_Buffer buf;
19 size_t a, b, i;
20 const char* str_a = luaL_checklstring(L, 1, &a);
21 const char* str_b = luaL_checklstring(L, 2, &b);
22
23 luaL_buffinit(L, &buf);
24
25 if(a == 0 || b == 0) {
26 lua_settop(L, 1);
27 return 1;
28 }
29
30 for(i = 0; i < a; i++) {
31 luaL_addchar(&buf, str_a[i] & str_b[i % b]);
32 }
33
34 luaL_pushresult(&buf);
35 return 1;
36 }
37
38 int strop_or(lua_State* L) {
39 luaL_Buffer buf;
40 size_t a, b, i;
41 const char* str_a = luaL_checklstring(L, 1, &a);
42 const char* str_b = luaL_checklstring(L, 2, &b);
43
44 luaL_buffinit(L, &buf);
45
46 if(a == 0 || b == 0) {
47 lua_settop(L, 1);
48 return 1;
49 }
50
51 for(i = 0; i < a; i++) {
52 luaL_addchar(&buf, str_a[i] | str_b[i % b]);
53 }
54
55 luaL_pushresult(&buf);
56 return 1;
57 }
58
59 int strop_xor(lua_State* L) {
60 luaL_Buffer buf;
61 size_t a, b, i;
62 const char* str_a = luaL_checklstring(L, 1, &a);
63 const char* str_b = luaL_checklstring(L, 2, &b);
64
65 luaL_buffinit(L, &buf);
66
67 if(a == 0 || b == 0) {
68 lua_settop(L, 1);
69 return 1;
70 }
71
72 for(i = 0; i < a; i++) {
73 luaL_addchar(&buf, str_a[i] ^ str_b[i % b]);
74 }
75
76 luaL_pushresult(&buf);
77 return 1;
78 }
79
80 LUA_API int luaopen_util_strbitop(lua_State *L) {
81 luaL_Reg exports[] = {
82 { "sand", strop_and },
83 { "sor", strop_or },
84 { "sxor", strop_xor },
85 { NULL, NULL }
86 };
87
88 lua_newtable(L);
89 luaL_setfuncs(L, exports, 0);
90 return 1;
91 }