CTDP linux 程序员手册 C和C++编程(11)Viewmod程序

 

大家可以通过这个例子体会linux的c编程。
#include <termios.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <dirent.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <sys/signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#define _POSIX_SOURCE 1         //POSIX 兼容源码
#define FALSE 0
#define TRUE 1
#define MAX_DEVICES 64
#define MAX_IDS 64
#define LINE_LENGTH 1128
FILE *output;
char input_fname[80];                                                                           //打印机的文件名称
FILE *input_file;
mode_t mode;
char Char;                                                                             //用于单个char的处理
int display;               //"-D" 项: 0-ASC,1-ASC/HEX, 2-Hex 3-dec 4-dec/asc 5-DOS text 6-UNIX text 7- strip all non-asc
int out_length; //-L 选项
int display_col;         //显示列计数
int char_len;
int asc_char;            //0-non-asc, 1-asc, 2-CR, 3-LF
int nospace;
int last_char;            //最后一个 char的类型
int get_linestring(char *file_line, char *label_name, int qty_statements, int strno);
int freadln(FILE *handle,char *outputline); //从一个文件读一行
void Process_Bufchar();           //一次处理一个在缓存中的Char
main(int Parm_Count, char *Parms[])
{
   char message[90];
   int start_options, in_source, done;
   char *lastslash;                                                 //最后一个slash 的字符串地址
   char dirname[80];                               //目录名称
   DIR *current_directory;
   int i;
   char In1, Key;
   char buf[255];                       //数据缓存
   out_length = 80;
   display = 1; //缺省值 HEX/ASC 显示, 在CR, CR/LF, LF后断开
   start_options=0;
   in_source = 0;          //缺省值,便准输出
   if (Parm_Count>1) //在程序名后面如果有参数
   {
        start_options = 1;
        strcpy(message,Parms[1]);
                               if (message[0]!='-') //如果是一个输入文件的名称
                               {
                                              if ((input_file = fopen(Parms[1], "rb")) == NULL)
                                              {
                                                             fprintf(stderr,"%s: Unable to open the input file %s\n",Parms[0],Parms[1]);
                                                             exit(1);                     //发生错误退出
                                              }
                                              else
                                              {
                                                             in_source = 1; //file
                                              }
                               } //end 如果是一个输入文件
               } //end在程序名后面如果有参数
               //获得参数
               if (start_options<Parm_Count) //如果开始选项存在
               {
                               for (i=1; i<Parm_Count; i++)
                               {
                                              strcpy(message, Parms[i]);
                                              if (message[0]=='-')
                                              {
                                                             if ((message[1]=='D') || (message[1]=='d')) //if display option
                                                             {
                                                                            if (message[2]=='0') display=0;
                                                                            if (message[2]=='1') display=1;
                                                                            if (message[2]=='2') display=2;
                                                                            if (message[2]=='3') display=3;
                                                                            if (message[2]=='4') display=4;
                                                                            if (message[2]=='5') display=5;
                                                                            if (message[2]=='6') display=6;
                                                                            if (message[2]=='7') display=7;
                                                             }
                                                             if ((message[1]=='L') || (message[1]=='l')) //如果有 length选项
                                                             {
                                                                            out_length=atoi(&message[2]);
                                                             }
                                              }
                               }
               } //end如果开始选项存在
               done = 0;
               display_col=0;
               nospace = 1; //我们不需要space
               last_char=4;
               while (!done)
               {
                               if (in_source==1) //从文件读一个字符
                               {
                                              if ((Char=fgetc(input_file))==EOF)
                                              {
                                                             done = 1;
                                              }
                               }
                               else         //从标准输入读一个字符
                               {
                                              Char=getchar();
                                              if (Char==EOF)
                                              {
                                                             done = 1;
                                              }
                               }
                               if (done==0)             //输出这个字符到标准输出
                               {
                                              asc_char=0;             //假设不是 asc 字符
                                              if ((Char>31) && (Char < 127)) asc_char = 1;
                                              if (Char==13) asc_char = 2;
                                              if (Char==10) asc_char = 3;
                                  switch (display)
                                              {
                                              case 0:                    //ASC
                                                             if (asc_char < 2) char_len=1;
                                                             else char_len=0;
                                                             if (display_col+char_len>out_length)
                                                             {
                                                                            putchar(10); //如果此行太长滚动
                                                                            display_col=0;
                                                             }
                                                             putchar(Char);
                                                              display_col++;
                                                             if (asc_char==3) display_col=0;
                                                             break;
                                              case 1:                    //ASC/HEX
                                              default:
                                                             if (asc_char==1) char_len=1;
                                                             else char_len=2;
                                                             if ((display_col==0) || (last_char==4) || ((last_char==1) && (asc_char==1))) nospace=1; //dont need space
                                                             else nospace=0;
                                                             if (nospace==0) char_len++; //如果我们需要一个 space
                                                             if (display_col+char_len>out_length)
                                                             {
                                                                            putchar(10); //如果此行太长滚动
                                                                            display_col=0;
                                                                            if (nospace==0)
                                                                            {
                                                                                            nospace=1;
                                                                                            char_len--;
                                                                            }
                                                             }
                                                             if (nospace==0) //加一个 space
                                                             {
                                                                            putchar(' ');
                                                                            display_col++;
                                                             }
                                                             if (asc_char==1)
                                                             {
                                                                            putchar(Char);
                                                                            display_col++;
                                                             }
                                                             else
                                                             {
                                                                            sprintf(message,"%2x",Char);
                                                                            fputs(message,stdout);
                                                                            display_col +=2;
                                                                            if (asc_char==3)
                                                                            {
                                                                                            putchar(10);
                                                                                            display_col=0;
                                                                            }
                                                             }
                                                             if ((last_char==2) && (asc_char!=3)) //如果有 CR 没有 LF
                                                             {
                                                                            putchar(10);
                                                                            display_col=0;
                                                             }
 
                                                             last_char=asc_char;
                                                             break;
                                              case 2:                    //hex
                                                             char_len=2;
                                                             if (display_col==0) nospace = 1;
                                                             else nospace = 0;
                                                             if (nospace == 0) char_len++;                  //如果我们需要一个 space
                                                             if (display_col+char_len>out_length)
                                                             {
                                                                            putchar(10); //如果此行太长滚动
                                                                            display_col=0;
                                                                            if (nospace==0)
                                                                            {
                                                                                            nospace=1;
                                                                                            char_len--;
                                                                            }
                                                             }
                                                             if (nospace==0) //添加space
                                                             {
                                                                            putchar(' ');
                                                                            display_col++;
                                                             }
                                                             sprintf(message,"%2x",Char);
                                                             fputs(message,stdout);
                                                             display_col +=2;
                                                             break;
                                              case 5:     //unix 文本 – 调整dos文本,在所有LF加CR 
                                                             if (Char==10) putchar(13);
                                                             putchar(Char);
                                                             break;
                                              case 6:                    //dos 文本 – 到 unix, 跳过所有CR
                                                             if ((last_char==2) && (asc_char !=3)) putchar(10); //if this char is not a LF and the last one was CR, need a line feed for unix
                                                             if (Char!=13) putchar(Char);
                                                             last_char=asc_char;
                                                             break;
                                              case 3:                    //decimal
                                                             char_len=3;
                                                             if (display_col==0) nospace = 1;
                                                             else nospace = 0;
                                                             if (nospace == 0) char_len++;                  //如果我们需要一个 space
                                                             if (display_col+char_len>out_length)
                                                             {
                                                                            putchar(10); //如果此行太长滚动
                                                                            display_col=0;
                                                                            if (nospace==0)
                                                                            {
                                                                                            nospace=1;
                                                                                            char_len--;
                                                                            }
                                                             }
                                                             if (nospace==0) //添加一个 space
                                                             {
                                                                            putchar(' ');
                                                                            display_col++;
                                                             }
                                                             sprintf(message,"%3d",Char);
                                                             fputs(message,stdout);
                                                             display_col +=2;
                                                             break;
                                              case 4:                    //decimal asc
                                                             if (asc_char==1) char_len=1;
                                                             else char_len=3;
                                                             if ((display_col==0) || (last_char==4) || ((last_char==1) && (asc_char==1))) nospace=1; //dont need space
                                                             else nospace=0;
                                                             if (nospace==0) char_len++; //如果我们需要一个space
                                                             if (display_col+char_len>out_length)
                                                             {
                                                                            putchar(10); //如果此行太长滚动
                                                                            display_col=0;
                                                                            if (nospace==0)
                                                                            {
                                                                                            nospace=1;
                                                                                            char_len--;
                                                                            }
                                                             }
                                                             if (nospace==0) //add a space
                                                             {
                                                                            putchar(' ');
                                                                            display_col++;
                                                             }
                                                             if (asc_char==1)
                                                             {
                                                                            putchar(Char);
                                                                            display_col++;
                                                             }
                                                             else
                                                             {
                                                                            sprintf(message,"%3d",Char);
                                                                            fputs(message,stdout);
                                                                            display_col +=2;
                                                                            if (asc_char==3)
                                                                            {
                                                                                            putchar(10);
                                                                                            display_col=0;
                                                                            }
                                                             }
                                                             if ((last_char==2) && (asc_char!=3)) //如果有 CR 没有 LF
                                                             {
                                                                            putchar(10);
                                                                            display_col=0;
                                                             }
                                                             last_char=asc_char;
                                                             break;
                                              case 7:                                   //跳过所有得 non-asc 字符转到 Unix 文件 (除了ASC 和 LF)
                                                             if ((asc_char==1) || (asc_char==3)) putchar(Char);
                                                             break;
                                              } //end of switch display
                               } //end of if not done
               } //end of while not done
} //end of main

原文:

翻译 CTDP linux 程序员手册 C和C++编程(11)Viewmod程序

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