navstr：一个简单的字符串数据解析实现

实现navstr的时候，我记得当时是为了帮下位机程序处理GPS文本信息。navstr的主要功能就是根据一些分割标记，从字符串中提取出一些数据来。

navstr.h

#pragma once/*
**  解析状态
*/
#define NS_NOPOS    -1  /* 未找到界定符 */
#define NS_OUTOFMEM -2  /* 输入缓冲区不足以存储目标 */
#define NS_FATAL    -3  /* 发生不可恢复错误 */
#define NS_OK        1  /* 解析正确 *//*
**  库特有的界定符
*/
#define NS_DELIMIT   0  /* 标示取到字符串结尾的界定符 *//*
**  结构体navstr
*/
typedef struct _navparser
{const char *text;const char *pos;const char *tail;
} navstr;/*
**  解析为用户指定枚举量的回调函数原型
*/
typedef int (*ns_pfn_enum)(const char *str);/*
**  初始化
*/
void ns_init(navstr *ns, const char *text);/*
**  重置以从头解析
*/
void ns_reset(navstr *ns);/*
**  字符串是否以特定文本开头
**  匹配时返回NS_OK，否则返回NS_NPOS
*/
int ns_start_with(navstr *ns, const char *head, int move);/*
**  跳转到下一个指定的界定符之后
**  成功跳转后返回NS_OK，否则返回NS_NPOS
*/
int ns_goto_next(navstr *ns, const char *delimit);/*
**  由界定符之前的文本，解析出一个整数
*/
int ns_int(navstr *ns, const char *delimit);/*
**  由界定符之前的文本，解析出一个浮点数
*/
double ns_double(navstr *ns, const char *delimit);/*
**  由界定符之前的文本，解析出一个字符串
*/
int ns_str(navstr *ns, const char *delimit, char *result, int rlen, int filter);/*
**  由界定符之前的文本，解析出一个枚举量
*/
int ns_enum(navstr *ns, const char *delimit, ns_pfn_enum pfn);/*
**  是否到达尾部
*/
int ns_end(const navstr *ns);

navstr.c

#include <string.h>
#include <assert.h>
#include <stdlib.h>
#include "navstr.h"void ns_init(navstr *ns, const char *text)
{ns->text = text;ns->pos = text;ns->tail = text + strlen(text);
}void ns_reset(navstr *ns)
{ns->pos = ns->text;
}int ns_start_with(navstr *ns, const char *head, int move)
{const char *p = strstr(ns->text, head);int ret = (p && p == ns->text) ? NS_OK : NS_NOPOS;if (ret == NS_OK && move)ns->pos += strlen(head);return ret;
}int ns_goto_next(navstr *ns, const char *delimit)
{if (ns->pos && ns->pos != ns->tail){const char *p = strstr(ns->pos, delimit);if (p){p += strlen(delimit);ns->pos = p;return NS_OK;}}return NS_NOPOS;
}static int ns_data(navstr *ns, const char *delimit, char *result, int rlen)
{if (ns->pos && ns->pos != ns->tail){const char *p = NULL;if (delimit != NS_DELIMIT)p = strstr(ns->pos, delimit);elsep = ns->tail;if (p){int len = (int)(p - ns->pos);if (len >= rlen)return NS_OUTOFMEM;for (int i = 0; i < len; i++)*result++ = *ns->pos++;*result = 0;if (delimit != NS_DELIMIT)ns->pos = p + strlen(delimit);elsens->pos = ns->tail;return NS_OK;}}return NS_NOPOS;
}int ns_int(navstr *ns, const char *delimit)
{char buf[32];int res = ns_data(ns, delimit, buf, 32);if (res == NS_OK)return atoi(buf);assert(0);return NS_FATAL;
}double ns_double(navstr *ns, const char *delimit)
{char buf[32];int res = ns_data(ns, delimit, buf, 32);if (res == NS_OK)return atof(buf);assert(0);return NS_FATAL;
}int ns_str(navstr *ns, const char *delimit, char *str, int slen, int filter)
{int res = ns_data(ns, delimit, str, slen);if (res == NS_OK && filter){char *end = str + strlen(str) - 1;while (str < end)*str++ = *(str + 1);*(str - 1) = 0;}return res;
}int ns_enum(navstr *ns, const char *delimit, ns_pfn_enum pfn)
{assert(pfn != 0x0);char buf[128];int res = ns_data(ns, delimit, buf, 128);if (res == NS_OK)return pfn(buf);assert(0);return NS_FATAL;
}int ns_end(const navstr * ns)
{return (ns->pos >= ns->tail) ? NS_OK : NS_NOPOS;
}

测试程序 main.c

#include <stdio.h>
#include <string.h>
#include <assert.h>
#include "navstr.h"enum COMPUTE
{SOL_ERROR,SOL_PROCESSING,SOL_COMPUTED,
};enum NARROW
{NARROW_INT,NARROW_FLOAT
};int get_compute_val(const char *str)
{if (strcmp(str, "SOL_COMPUTED") == 0) return SOL_COMPUTED;else if (strcmp(str, "SOL_PROCESSING") == 0) return SOL_PROCESSING;else if (strcmp(str, "SOL_ERROR") == 0) return SOL_ERROR;assert(0);
}int get_narrow(const char *str)
{if (strcmp(str, "NARROW_INT") == 0) return NARROW_INT;else if (strcmp(str, "NARROW_FLOAT") == 0) return NARROW_FLOAT;assert(0);
}int main()
{const char *instr = "#HEADINGA,COM3,0,60.0,FINESTEERING,2201,369102.000,00000000,0000,1114;""SOL_COMPUTED,,,NARROW_INT,,,1.622372866,90.625221252,-0.488150597,0.000000000,0.262617588,0.466465503,\"0004\",27,24,27,27,0,0,4,91*94714bcd";navstr ns;ns_init(&ns, instr);{int r;r = ns_start_with(&ns, "#HEADINGA", 0);r = ns_start_with(&ns, "#HEADINGB", 0);ns_goto_next(&ns, ";");int v;v = ns_enum(&ns, ",,,", get_compute_val);v = ns_enum(&ns, ",,,", get_narrow);double f;f = ns_double(&ns, ",");f = ns_double(&ns, ",");f = ns_double(&ns, ",");for (int i = 0; i < 3; i++)ns_goto_next(&ns, ",");char str[32];ns_str(&ns, ",", str, 32, 1);v = ns_int(&ns, ",");v = ns_int(&ns, ",");}{int r = NS_OK;char str[32];ns_reset(&ns);while (r != NS_NOPOS){r = ns_str(&ns, ",", str, 32, 0);if (r != NS_NOPOS)printf("%s\n", str);}if (ns_end(&ns) != NS_OK){ns_str(&ns, NS_DELIMIT, str, 32, 0);printf("%s\n", str);}}{const char *instr = "$GPGGA,080632.00,0000.0000000,N,00000,0000000,E,0,00,0.0,-6378154.1620,M,17.162,M,,*73";navstr ns;ns_init(&ns, instr);char str[32];ns_start_with(&ns, "$GPGGA", 1);ns_goto_next(&ns, ",");for (int i = 0; i < 2; i++){printf("%.2f\n", ns_double(&ns, ","));printf("%.7f\n", ns_double(&ns, ","));ns_str(&ns, ",", str, 32, 0);printf("%s\n", str);}}
}