prosody
0e1d8f2f02bf
util-src/ringbuffer.c

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util-src/ringbuffer.c @ 8543:0e1d8f2f02bf

util.ringbuffer: Add various comments
author Kim Alvefur <zash@zash.se>
date Sat, 24 Feb 2018 14:44:46 +0100
parent 7969:1c6a07606309
child 8544:e7214441523b
comparison
equal deleted inserted replaced
8542:8c39ec8e6018 8543:0e1d8f2f02bf
37 37
38 if(b->rpos == b->wpos) { /* empty */ 38 if(b->rpos == b->wpos) { /* empty */
39 return 0; 39 return 0;
40 } 40 }
41 41
42 /* look for a matching first byte */
42 for(i = 0; i <= b->blen - l; i++) { 43 for(i = 0; i <= b->blen - l; i++) {
43 if(b->buffer[(b->rpos + i) % b->alen] == *s) { 44 if(b->buffer[(b->rpos + i) % b->alen] == *s) {
44 m = 1; 45 m = 1;
45 46
47 /* check if the following byte also match */
46 for(j = 1; j < l; j++) 48 for(j = 1; j < l; j++)
47 if(b->buffer[(b->rpos + i + j) % b->alen] != s[j]) { 49 if(b->buffer[(b->rpos + i + j) % b->alen] != s[j]) {
48 m = 0; 50 m = 0;
49 break; 51 break;
50 } 52 }
56 } 58 }
57 59
58 return 0; 60 return 0;
59 } 61 }
60 62
63 /*
64 * Find first position of a substring in buffer
65 * (buffer, string) -> number
66 */
61 int rb_find(lua_State *L) { 67 int rb_find(lua_State *L) {
62 size_t l, m; 68 size_t l, m;
63 ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt"); 69 ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt");
64 const char *s = luaL_checklstring(L, 2, &l); 70 const char *s = luaL_checklstring(L, 2, &l);
65 m = find(b, s, l); 71 m = find(b, s, l);
70 } 76 }
71 77
72 return 0; 78 return 0;
73 } 79 }
74 80
81 /*
82 * Read bytes from buffer
83 * (buffer, number, boolean?) -> string
84 */
75 int rb_read(lua_State *L) { 85 int rb_read(lua_State *L) {
76 ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt"); 86 ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt");
77 size_t r = luaL_checkinteger(L, 2); 87 size_t r = luaL_checkinteger(L, 2);
78 int peek = lua_toboolean(L, 3); 88 int peek = lua_toboolean(L, 3);
79 89
81 lua_pushnil(L); 91 lua_pushnil(L);
82 return 1; 92 return 1;
83 } 93 }
84 94
85 if((b->rpos + r) > b->alen) { 95 if((b->rpos + r) > b->alen) {
96 /* Substring wraps around to the beginning of the buffer */
86 lua_pushlstring(L, &b->buffer[b->rpos], b->alen - b->rpos); 97 lua_pushlstring(L, &b->buffer[b->rpos], b->alen - b->rpos);
87 lua_pushlstring(L, b->buffer, r - (b->alen - b->rpos)); 98 lua_pushlstring(L, b->buffer, r - (b->alen - b->rpos));
88 lua_concat(L, 2); 99 lua_concat(L, 2);
89 } else { 100 } else {
90 lua_pushlstring(L, &b->buffer[b->rpos], r); 101 lua_pushlstring(L, &b->buffer[b->rpos], r);
97 } 108 }
98 109
99 return 1; 110 return 1;
100 } 111 }
101 112
113 /*
114 * Read buffer until first occurence of a substring
115 * (buffer, string) -> string
116 */
102 int rb_readuntil(lua_State *L) { 117 int rb_readuntil(lua_State *L) {
103 size_t l, m; 118 size_t l, m;
104 ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt"); 119 ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt");
105 const char *s = luaL_checklstring(L, 2, &l); 120 const char *s = luaL_checklstring(L, 2, &l);
106 m = find(b, s, l); 121 m = find(b, s, l);
112 } 127 }
113 128
114 return 0; 129 return 0;
115 } 130 }
116 131
132 /*
133 * Write bytes into the buffer
134 * (buffer, string) -> integer
135 */
117 int rb_write(lua_State *L) { 136 int rb_write(lua_State *L) {
118 size_t l, w = 0; 137 size_t l, w = 0;
119 ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt"); 138 ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt");
120 const char *s = luaL_checklstring(L, 2, &l); 139 const char *s = luaL_checklstring(L, 2, &l);
121 140