在C中读取unicode文件时出错 [英] Getting error while reading unicode file in C

问题描述

我想使用以下代码读取C（Cygwin / GCC）中的unicode文件：

  #include< stdio.h> 
 #include< stdlib.h> 
 #include< glib.h> 
 
 
 void split_parse（char * text）{
 char ** res = g_strsplit（text，=，2）; 
 printf（Key =％s：，res [0]）; 
 printf（Value =％s，res [1]）; 
 printf（\\\
）; 
} 
 
 int main（int argc，char ** argv）
 {
 setenv（CYGWIN，nodosfilewarning，1）; 
 
 GIOChannel * channel; 
 GError * err = NULL; 
 int reading = 0; 
 const gchar * enc; 
 guchar magic [2] = {0}; 
 gsize bytes_read = 0; 
 
 const char * filename =C：\\CONFIG; 
 
 
 channel = g_io_channel_new_file（filename，r，& err）; 
 
 if（！channel）{
 g_print（％s，err-> message）; 
 return 1; 
} 
 
 if（g_io_channel_set_encoding（channel，NULL，& err）！= G_IO_STATUS_NORMAL）{
 g_print（g_io_channel_set_encoding：％s\\\
，err->信息）; 
 return 1; 
} 
 
 if（g_io_channel_read_chars（channel，（gchar *）magic，2，& bytes_read，& err）！= G_IO_STATUS_NORMAL）{
 g_print（g_io_channel_read_chars：％ s\\\
，err-> message）; 
 return 1; 
} 
 
 if（magic [0] == 0xFF&& magic [1] == 0xFE）
 {
 enc =UTF-16LE ; 
} 
 else if（magic [0] == 0xFE&& magic [1] == 0xFF）
 {
 enc =UTF-16BE; 
} 
 else 
 {
 enc =UTF-8; 
 if（g_io_channel_seek_position（channel，0，G_SEEK_CUR，& err）== G_IO_STATUS_ERROR）
 {
 g_print（g_io_channel_seek：failed\\\
）; 
 return 1; 
} 
} 
 
 if（g_io_channel_set_encoding（channel，enc，& err）！= G_IO_STATUS_NORMAL）{
 g_print（％s，err->信息）; 
 return 1; 
} 
 
 reading = 1; 
 GIOStatus status; 
 char * str = NULL; 
 size_t len; 
 
 while（阅读）{
 
 status = g_io_channel_read_line（channel，& str，& len，NULL，& err）; 
 switch（status）{
 case G_IO_STATUS_EOF：
 reading = 0; 
 break; 
 case G_IO_STATUS_NORMAL：
 if（len == 0）continue; 
 split_parse（str）; 
 break; 
 case G_IO_STATUS_AGAIN：continue; 
 case G_IO_STATUS_ERROR：
默认值：
 // throw error; 
 reading = 0; 
 break; 
} 
} 
 
 g_free（str）; 
 g_io_channel_unref（channel）; 
 
 return（EXIT_SUCCESS）; 
} 
  

文件（C：\CONFIG）的内容如下： p>

  h-debug =1
 name = ME 
ÆÆЮ©=2¾1¼
  

在读取它时，我总是在while循环中的g_io_channel_read_line获取以下错误消息：

0x800474f8转换输入中的字节序列无效

我做错了？

$ b

编辑：Hexdump的文件 $ b

解决方案

您的文件包含（EF BB BF）的3字节UTF8 BOM。字节顺序标记。

您的代码默认为UTF8，但不消耗BOM。

  channel，0，G_SEEK_CUR和&err 
  

s / b

 频道，3，G_SEEK_CUR和& err 
  

此外，我建议将 magic 读取4个字节并肯定地辨别BOM。

如果没有找到BOM，您可以假设编码为NULL，我认为是二进制。

---

UTF32BE\x00\x00\xFE\xFF

UTF32LE\xFF\xFE\x00\x00

UTF8\xEF\\ \\ xBB \xBF

UTF16BE\xFE\xFF

UTF16LE\xFF\xFE

二进制NULL

I want to read a unicode file in C (Cygwin/GCC) using the following code:

#include <stdio.h>
#include <stdlib.h>
#include <glib.h>


void split_parse(char* text){
    char** res = g_strsplit(text, "=", 2);
    printf("Key = %s : ", res[0]);
    printf("Value = %s", res[1]);
    printf("\n");
}

int main(int argc, char **argv)
{
    setenv ("CYGWIN", "nodosfilewarning", 1);

    GIOChannel *channel;
    GError *err = NULL;
    int reading = 0;
    const gchar* enc;
    guchar magic[2] = { 0 };
    gsize bytes_read = 0;

    const char* filename = "C:\\CONFIG";


    channel = g_io_channel_new_file (filename, "r", &err);

    if (!channel) {
        g_print("%s", err->message);
        return 1;
    }

    if (g_io_channel_set_encoding(channel, NULL, &err) != G_IO_STATUS_NORMAL) {
        g_print("g_io_channel_set_encoding: %s\n", err->message);
        return 1;
    }

    if (g_io_channel_read_chars(channel, (gchar*) magic, 2, &bytes_read, &err) != G_IO_STATUS_NORMAL) {
        g_print("g_io_channel_read_chars: %s\n", err->message);
        return 1;
    }

    if (magic[0] == 0xFF && magic[1] == 0xFE)
    {
        enc = "UTF-16LE";
    }
    else if (magic[0] == 0xFE && magic[1] == 0xFF)
    {
        enc = "UTF-16BE";
    }
    else
    {
        enc = "UTF-8";
        if (g_io_channel_seek_position(channel, 0, G_SEEK_CUR, &err) == G_IO_STATUS_ERROR)
        {
            g_print("g_io_channel_seek: failed\n");
            return 1;
        }
    }

    if (g_io_channel_set_encoding (channel, enc, &err) != G_IO_STATUS_NORMAL) {
        g_print("%s", err->message);
        return 1;
    }

    reading = 1;
    GIOStatus status;
    char* str = NULL;
    size_t len;

    while(reading){

        status = g_io_channel_read_line(channel, &str, &len, NULL, &err);
        switch(status){
            case G_IO_STATUS_EOF:
                reading = 0;
                break;
            case G_IO_STATUS_NORMAL:
                if(len == 0) continue;
                split_parse(str);
                break;
            case G_IO_STATUS_AGAIN: continue;
            case G_IO_STATUS_ERROR:
            default:
                //throw error;
                reading = 0;
                break;
        }
    }

    g_free(str);
    g_io_channel_unref(channel);

    return(EXIT_SUCCESS);
}

The file (C:\CONFIG) content is as follows:

h-debug="1"
name=ME
ÃÆÿЮ©=2¾1¼

While reading it I am always getting the following error message at "g_io_channel_read_line" inside the while loop:

0x800474f8 "Invalid byte sequence in conversion input"

What am I doing wrong? How to read a file like this in C using glib?

EDIT: Hexdump of the file

解决方案

Your file contains the 3-byte UTF8 BOM of (EF BB BF). byte-order-mark.

Your code defaults to UTF8, but does not consume the BOM.

channel, 0, G_SEEK_CUR, &err

s/b

channel, 3, G_SEEK_CUR, &err

Further, I would recommend extending your magic code to read 4 bytes and affirmatively discern the BOM.

If you do not find a BOM, you could assume encoding NULL which I think is binary. Or throw an error Or fix the wayward text file Or, if your are pedantic, sequentially try all known encoding types.

---

UTF32BE "\x00\x00\xFE\xFF"
UTF32LE "\xFF\xFE\x00\x00"
UTF8 "\xEF\xBB\xBF"
UTF16BE "\xFE\xFF"
UTF16LE "\xFF\xFE"
NULL for binary

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