c语言 - 使用 μC/OS-II 向前解析 json

Question

任何人都可以帮助编写C解析器(使用Codewarrior(来解析以下文件吗？我尝试了许多 C 语言 json 解析器，但不幸的是没有得到这个想法，或者它们使它变得困难。

[
[0,"Door1","Door1Drv","Calculator","Alarm"],
[1,"Door3","Door3Drv","Calculator","Alarm"],
[2,"Door2","Door2Drv","Calculator","Alarm"]]

Answer 1

对于提前申请，建议使用冷冻。如果您的应用程序具有如上所示的固定数据格式，请参阅下面的参考。

相当基本的版本如下所示：

#include <stdio.h>
#define MAX_PRAM    4
struct param_t {
int id;
// FIXME: use pointer & malloc to allocate if possible
char data[MAX_PRAM][30];
};
static int parse(const char *buff, int start, const int end,
struct param_t *out)
{
char *ptr = out->data[0];
int state = 0;
int index = 0;
int param_index = 0;
printf("t> parse next record<%d:%d>n", start, end);
while((start < end) && (param_index < MAX_PRAM)) {
char ch = buff[start];
// printf("t> state: %d, char '%c'n", state, ch);
switch (state) {
case 0: // searching for start point
if ((ch >= '0') && (ch <= '9')) {
out->id = ch - '0';
state++;
}
break;
case 1: // parse number
if ((ch < '0') || (ch > '9')) {
printf ("t> number %dn", out->id);
state++;
if (ch == '"')
state++;
} else
out->id = (out->id * 10) + (ch - '0');
break;
case 2: // search string
if (ch == '"') {
index = 0;
state++;
}
break;
case 3: // get string
if (ch == '"') { // finish one string, parse next one if need
ptr[index] = '';
printf ("t> string '%s', length %dn",
out->data[param_index], index);
param_index++;
ptr = out->data[param_index];
state--;
} else
ptr[index++] = ch;
break;
default: // EOS - exit
break;
}
start++;
}
return (param_index >= 4) ? start : 0;
}
//
// main entry
//
int main(int argc, char *argv[]) {
int file = open("test.txt", 0 /* 0 ~ O_RDONLY in fcntl.h */ );
if (file) {
char buff[1024] = { 0 };
struct param_t param = { 0 };
int len = read(file, buff, 1024);
int pos = 0;
while((pos = parse(buff, pos, len, &param)) > 0) {
printf ("t%dn", param.id);
printf("[%4d] %d - %-10s | %-10s | %-15s | %-10s n",
pos, param.id, param.data[0], param.data[1], param.data[2],
param.data[3]);
}
close(file);
}
}

带输入：

[[10,"Door0",
"Door0Drv","Calculator0","Alarm0"],
[15,"Door1","Door1Drv","Calculator1","Alarm1"],
[230,"Door2","Door2Drv","Calculator2",
"Alarm2"]]

输出如下所示：

> number 10
> string 'Door0', length 5
> string 'Door0Drv', length 8
> string 'Calculator0', length 11
> string 'Alarm0', length 6
10
[  49] 10 - Door0      | Door0Drv   | Calculator0     | Alarm0
> number 15
> string 'Door1', length 5
> string 'Door1Drv', length 8
> string 'Calculator1', length 11
> string 'Alarm1', length 6
15
[ 100] 15 - Door1      | Door1Drv   | Calculator1     | Alarm1
> number 230
> string 'Door2', length 5
> string 'Door2Drv', length 8
> string 'Calculator2', length 11
> string 'Alarm2', length 6
230
[ 158] 230 - Door2      | Door2Drv   | Calculator2     | Alarm2

随意定制。