1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
#include "stream.h"
#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <lauxlib.h>
#include <lua.h>
/// Creates and pushes new Stream into the Lua stack.
/// \param L Lua state to push to
/// \param fd File descriptor used by the Stream
/// \return TODO
int stream_push_new(lua_State * L, const int fd)
{
struct stream * s = lua_newuserdata(L, sizeof(struct stream));
memset(s, 0, sizeof(struct stream));
s->fd = fd;
if (1 == luaL_newmetatable(L, "stream"))
{
lua_pushliteral(L, "__gc");
lua_pushcfunction(L, stream_gc);
lua_rawset(L, -3);
lua_pushliteral(L, "__index");
lua_createtable(L, 0, 1);
lua_pushliteral(L, "read");
lua_pushcfunction(L, stream_read);
lua_rawset(L, -3);
lua_rawset(L, -3);
}
lua_setmetatable(L, -2);
return LUA_OK;
}
/// Metamethod to handle garbage collection of Stream userdata.
/// \param L Lua state in which Stream resides
/// \return Number of the results pushed to the stack; always zero in this case
int stream_gc(lua_State * L)
{
int n = lua_gettop(L);
if (1 != n)
{
lua_pushliteral(L, "Invalid number of arguments received");
return lua_error(L);
}
struct stream * s = lua_touserdata(L, -1);
if (NULL == s)
{
lua_pushliteral(L, "Missing stream argument");
return lua_error(L);
}
if (NULL != s->in.data)
{
free(s->in.data);
}
lua_pop(L, 1);
return 0;
}
/// Starts reading operation from a stream.
/// \param L Lua state in which Stream resides
/// \return Number of the results pushed to the stack
int stream_read(lua_State * L)
{
int n = lua_gettop(L);
if (2 > n)
{
lua_pushliteral(L, "At least two arguments expected");
return lua_error(L);
}
struct stream * s = lua_touserdata(L, 1);
if (NULL == s)
{
// TODO: Improve error handling and raising in steam_* lua_CFunctions
lua_pushliteral(L, "Missing stream argument");
return lua_error(L);
}
if (NULL == s->in.data)
{
void * buffer = malloc(1024);
if (NULL == buffer)
{
lua_pushliteral(L, "Could not allocate buffer for stream");
return lua_error(L);
}
s->in.data = buffer;
s->in.allocated = 1024;
s->in.length = 0;
s->in.offset = 0;
}
return stream_readk(L, LUA_OK, (lua_KContext) s); // Intentionally do not remove arguments from the stack.
}
static int until(struct buffer * b, const char * pattern, const int pattern_length)
{
int offset = b->offset;
while (offset + pattern_length <= b->length)
{
if (0 == strncmp(&b->data[offset], pattern, pattern_length))
{
return offset;
}
else
{
offset++;
}
}
return -1;
}
/// Continuation function and core implementation of the reading operation from a stream.
/// \param L Lua state running reading operation
/// \param status TODO
/// \param ctx Address of the Stream that is being read
/// \param Number of the results pushed to the stack
int stream_readk(lua_State * L, int status, lua_KContext ctx)
{
struct stream * s = (struct stream *) ctx;
int remaining_bytes = s->in.length - s->in.offset;
int offset = -1;
size_t len;
const char * pattern = lua_tolstring(L, 2, &len);
const int pattern_length = (int) len;
// TODO: NULL check
if (pattern_length <= remaining_bytes)
{
offset = until(&s->in, pattern, pattern_length);
}
if (-1 == offset || 0 == remaining_bytes)
{
if (0 < s->in.length && 0 <= s->in.allocated - s->in.offset - 1)
{
// TODO: Allow buffer to grow some before raising an error.
lua_pushliteral(L, "Read buffer growing not implemented");
return lua_error(L);
}
// TODO: Allow user to control amount of bytes being read.
int length = read(s->fd, s->in.data + s->in.offset, s->in.allocated - s->in.offset - 1);
if (-1 == length)
{
if (EWOULDBLOCK == errno || EAGAIN == errno)
{
return lua_yieldk(L, 0, ctx, stream_readk);
}
else
{
lua_pop(L, 1);
lua_pushstring(L, strerror(errno));
return lua_error(L);
}
}
s->in.data[length] = 0;
s->in.length = s->in.offset + length;
offset = until(&s->in, pattern, pattern_length);
if (-1 == offset)
{
// TODO: Reiterate at this point, grow buffer until some error is reached or pattern is found.
lua_pushliteral(L, "Could not find pattern");
return lua_error(L);
}
}
lua_pushlstring(L, &s->in.data[s->in.offset], offset - s->in.offset);
s->in.offset = offset + 1;
for (int n = -lua_gettop(L); n < -1; ++n)
{
lua_remove(L, n);
}
return 1;
}
|
