prosody
6dde2c9fa272
util-src/strbitop.c

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util-src/strbitop.c @ 11169:6dde2c9fa272 0.11

util.strbitop: Create buffer in the correct size (optimization) This avoids dynamically growing the buffer as Lua does when luaL_addchar is used, thus saving on realloc calls.
author Kim Alvefur <zash@zash.se>
date Thu, 15 Oct 2020 16:43:30 +0200
parent 11167:ba32b9a6d75b
child 11171:2c1583bb0e0f
comparison
equal deleted inserted replaced
11168:cde600e2fdf9 11169:6dde2c9fa272
1 /* 1 /*
2 * This project is MIT licensed. Please see the 2 * This project is MIT licensed. Please see the
3 * COPYING file in the source package for more information. 3 * COPYING file in the source package for more information.
4 * 4 *
5 * Copyright (C) 2016 Kim Alvefur 5 * Copyright (C) 2016-2020 Kim Alvefur
6 */ 6 */
7 7
8 #include <lua.h> 8 #include <lua.h>
9 #include <lauxlib.h> 9 #include <lauxlib.h>
10 10
25 if(a == 0 || b == 0) { 25 if(a == 0 || b == 0) {
26 lua_settop(L, 1); 26 lua_settop(L, 1);
27 return 1; 27 return 1;
28 } 28 }
29 29
30 char *cbuf = luaL_buffinitsize(L, &buf, a);
31
30 for(i = 0; i < a; i++) { 32 for(i = 0; i < a; i++) {
31 luaL_addchar(&buf, str_a[i] & str_b[i % b]); 33 cbuf[i] = str_a[i] & str_b[i % b];
32 } 34 }
33 35
36 luaL_addsize(&buf, a);
34 luaL_pushresult(&buf); 37 luaL_pushresult(&buf);
35 return 1; 38 return 1;
36 } 39 }
37 40
38 int strop_or(lua_State *L) { 41 int strop_or(lua_State *L) {
46 if(a == 0 || b == 0) { 49 if(a == 0 || b == 0) {
47 lua_settop(L, 1); 50 lua_settop(L, 1);
48 return 1; 51 return 1;
49 } 52 }
50 53
54 char *cbuf = luaL_buffinitsize(L, &buf, a);
55
51 for(i = 0; i < a; i++) { 56 for(i = 0; i < a; i++) {
52 luaL_addchar(&buf, str_a[i] | str_b[i % b]); 57 cbuf[i] = str_a[i] | str_b[i % b];
53 } 58 }
54 59
60 luaL_addsize(&buf, a);
55 luaL_pushresult(&buf); 61 luaL_pushresult(&buf);
56 return 1; 62 return 1;
57 } 63 }
58 64
59 int strop_xor(lua_State *L) { 65 int strop_xor(lua_State *L) {
60 luaL_Buffer buf; 66 luaL_Buffer buf;
61 size_t a, b, i; 67 size_t a, b, i;
62 const char *str_a = luaL_checklstring(L, 1, &a); 68 const char *str_a = luaL_checklstring(L, 1, &a);
63 const char *str_b = luaL_checklstring(L, 2, &b); 69 const char *str_b = luaL_checklstring(L, 2, &b);
64 70
65 luaL_buffinit(L, &buf);
66
67 if(a == 0 || b == 0) { 71 if(a == 0 || b == 0) {
68 lua_settop(L, 1); 72 lua_settop(L, 1);
69 return 1; 73 return 1;
70 } 74 }
71 75
76 char *cbuf = luaL_buffinitsize(L, &buf, a);
77
72 for(i = 0; i < a; i++) { 78 for(i = 0; i < a; i++) {
73 luaL_addchar(&buf, str_a[i] ^ str_b[i % b]); 79 cbuf[i] = str_a[i] ^ str_b[i % b];
74 } 80 }
75 81
82 luaL_addsize(&buf, a);
76 luaL_pushresult(&buf); 83 luaL_pushresult(&buf);
77 return 1; 84 return 1;
78 } 85 }
79 86
80 LUA_API int luaopen_util_strbitop(lua_State *L) { 87 LUA_API int luaopen_util_strbitop(lua_State *L) {