/* 终端特殊字符 ---- VMIN, VTIME
* 下面的内容出自 man tcgetattr 里面.
* VMIN: Minimum number of characters for noncanonical read (MIN).
* VTIME: Timeout in deciseconds for noncanonical read (TIME).
* 注意, 这两个值只在非经典模式下有效.
*
* In noncanonical mode input is available immediately (without the user
* having to type a line-delimiter character), and line editing is disabled.
* The settings of MIN (c_cc[VMIN] and TIME (c_cc[VTIME]) determine the
* circumstances in which a read() completes; there are four distinct cases:
* (1)MIN == 0; TIME == 0: If data is available, read() returns immediately,
* with the lesser of the number of bytes available, or the number of
* bytes requested. If no data is available, read() returns 0.
* (2)MIN > 0; TIME == 0: read() blocks until the lesser of MIN bytes or
* the number of bytes requested are available, and returns the lesser
* of these two values.
* (3)MIN == 0; TIME > 0: TIME specifies the limit for a timer in tenths of
* a second. The timer is started when read() is called. read() returns
* either when at least one byte of data is available, or when the timer
* expires. If the timer expires without any input becoming available,
* read() returns 0.
* (4)MIN > 0; TIME > 0: TIME specifies the limit for a timer in tenths of
* a second. Once an initial byte of input becomes available, the timer
* is restarted after each further byte is received. read() returns
* either when the lesser of the number of bytes requested or MIN byte
* have been read, or when the inter-byte timeout expires. Because the
* timer is only started after the initial byte becomes available, at
* least one byte will be read.
*/
int main(void)
{
struct termios term, oldterm;
if (tcgetattr(STDIN_FILENO, &term) < 0) {
perror("tcgetattr STDIN_FILENO error");
return 1;
}
oldterm = term;
/* 刚开始写代码时,忘记将终端设为非经典模式,然后下面一直不超时.
* VMIN, VTIME 这两个值是在非经典模式下才生效的.
*/
term.c_lflag &= ~ICANON;
printf("first: term.c_cc[VMIN]: %d, term.c_cc[VTIME]: %d\n",
term.c_cc[VMIN], term.c_cc[VTIME]);
/* MIN == 0, TIME == 0. 根据上面的描述,如果此时没有输入,read()会
* 立刻返回.从执行结果,也是会立刻就返回,且返回值是0,遇到了EOF.
*/
set_min_time(STDIN_FILENO, &term, 0, 0);
/* MIN == 3, TIME == 0. 根据上面的描述, read()函数将会一直阻塞,直到
* 读取了 3 个字符为止.从执行结果看,无法做到输入更多的字符,当输入第
* 三个字符时,read()立刻就会返回.结束本次read().由于read()函数返回
* 后,就无法再输入,我们甚至无法输入第四个字符,也就说,不存在剩余的字
* 符,以供下一次的read()函数读取.
*/
set_min_time(STDIN_FILENO, &term, 3, 0);
/* MIN == 0, TIME == 20, 2秒超时. 此时,定时器会在read()函数被调用时,
* 立刻启动.如果指定时间内都没有字符,read()会返回0. 如果在指定时间内
* 有字符输入,read()函数会读取到输入的字符并返回.按照上面的描述,它会
* 读取到至少一个字符,但是从执行结果来看,它每次都只能读取到一个字符,
* read()函数会在读取到一个字符后立刻返回,无法读取到多个字符.
*/
set_min_time(STDIN_FILENO, &term, 0, 20);
/* MIN == 3, TIME == 20, 2秒超时. 此时,定时器会在读取到第一个字符后才
* 启动,而不是在调用read()函数时就立刻启动,且每次读取到一个字符时,定
* 时器会重置,从新开始计时.所以如果第一个字符一直不输入的话,read()函数
* 将会一直阻塞.从执行结果看,read()函数也是在读取到第三个字符后,立刻
* 返回,无法输入多余的字符以供下一次的read()函数读取
*/
set_min_time(STDIN_FILENO, &term, 3, 20);
/* MIN == 0, TIME == 0. 如上所述,由于上面无法输入多余的字符,所以下面
* 下面还是会立刻读取到EOF,读取不到上次输入剩余的字符.因为不存在所谓
* 的剩余字符. man手册中描述的"the number of bytes available",目前
* 还不清楚这些"可用字符"是怎么来的.
*/
set_min_time(STDIN_FILENO, &term, 0, 0);
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &oldterm) < 0) {
perror("tcsetattr STDIN_FILENO, error");
return 1;
}
return 0;
}
void set_option(char *line)
{
char name[64];
char value[64];
char *find_value;
strip(line);
if( strlen(line) > 64 ) return;
strcpy(name, line+15);
find_value = strstr(line, " value ");
if(find_value)
{
strcpy(value, find_value+7);
name[strlen(line+15)-strlen(value)-7] = '\0';
}
else
{
value[0] = '\0';
}
if(strcmp(name, "Personality") == 0)
{
set_personality_name( value );
}
else if(strcmp(name, "Min Time") == 0)
{
set_min_time( value );
}
else if(strcmp(name, "Max Time") == 0)
{
set_max_time( value );
}
else if(strcmp(name, "Hash") == 0)
{
set_hash( value );
}
/* setoption name <id> [value <x>]
this is sent to the engine when the user wants to change the internal parameters
of the engine. For the "button" type no value is needed.
One string will be sent for each parameter and this will only be sent when the engine is waiting.
The name and value of the option in <id> should not be case sensitive and can inlude spaces.
The substrings "value" and "name" should be avoided in <id> and <x> to allow unambiguous parsing,
for example do not use <name> = "draw value".
Here are some strings for the example below:
"setoption name Nullmove value true\n"
"setoption name Selectivity value 3\n"
"setoption name Style value Risky\n"
"setoption name Clear Hash\n"
"setoption name NalimovPath value c:\chess\tb\4;c:\chess\tb\5\n"
*/
}
