c言語は速いのはいいのですが、いかんせん標準ライブラリ群が貧弱な面は否めません。
文字列周りの処理だとC＋＋のSTLあたりを使用すれば簡単ですが、純粋にCで簡単に作成してみました
- string_buffer.h
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | #ifndef _STRING_BUFFER_H #define _STRING_BUFFER_H #include <stdio.h> struct string_buffer { unsigned int item_size; char *item; unsigned int max_item_size; // 実際のメモリ確保量 }; extern struct string_buffer *create_string_buffer(); extern void delete_string_buffer(struct string_buffer *buf); extern int append_string_buffer(struct string_buffer *buf, char *val, unsigned int val_len); #endif |
- string_buffer.c
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 | #include "string_buffer.h" #define ITEM_SIZE 1024 struct string_buffer *create_string_buffer(){ struct string_buffer *buf; buf=(struct string_buffer *)malloc(sizeof(struct string_buffer)); if(buf==NULL)return NULL; buf->item=(char*)malloc(sizeof(char)*ITEM_SIZE); if(buf->item==NULL){ free(buf); return NULL; } buf->item[0]='\0'; buf->item_size=0; buf->max_item_size=ITEM_SIZE; return buf; } void delete_string_buffer(struct string_buffer *buf){ if(buf!=NULL){ if(buf->item!=NULL) free(buf->item); free(buf); } } int append_string_buffer(struct string_buffer *buf, char *val, unsigned int val_len){ int size; char *newbuf; int diff=buf->max_item_size-buf->item_size; if(diff>val_len){ strncat(buf->item,val,val_len); buf->item_size+=val_len; }else{ size=buf->max_item_size+ITEM_SIZE; newbuf=(char*)malloc(sizeof(char)*size); if(newbuf==NULL) return -1; newbuf[0]='\0'; strncpy(newbuf,buf->item,buf->item_size); free(buf->item); buf->item=newbuf; buf->max_item_size=size; return append_string_buffer(buf,val,val_len); } return 0; } |
実行してみます
- main.c
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | static void print_string_buffer(char *header,struct string_buffer *buf){ printf("%s:item_size=%d,char=%s,max_item_size=%d\n",header,buf->item_size,buf->item,buf->max_item_size); } int main(){ struct string_buffer *buf; buf=create_string_buffer(); if(buf==NULL)exit(0); append_string_buffer(buf,"test",sizeof("test")); print_string_buffer("1",buf); append_string_buffer(buf," 1111",sizeof(" 1111")); print_string_buffer("2",buf); append_string_buffer(buf,"",sizeof("")); print_string_buffer("3",buf); append_string_buffer(buf,"a",sizeof("a")); print_string_buffer("4",buf); append_string_buffer(buf,"12345678901234567890",12); print_string_buffer("5",buf); append_string_buffer(buf,"123",sizeof("123")); print_string_buffer("6",buf); delete_string_buffer(buf); } |
- 実行結果
1 2 3 4 5 6 7 | $ a.out 1:item_size=5,char=test,max_item_size=1024 2:item_size=11,char=test 1111,max_item_size=1024 3:item_size=12,char=test 1111,max_item_size=1024 4:item_size=14,char=test 1111a,max_item_size=1024 5:item_size=26,char=test 1111a123456789012,max_item_size=1024 6:item_size=30,char=test 1111a123456789012123,max_item_size=1024 |