57 lines
1.2 KiB
C
57 lines
1.2 KiB
C
/*
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* pANS stdio -- freopen
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*/
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#include "iolib.h"
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/*
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* Open the named file with the given mode, using the given FILE
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* Legal modes are given below, `additional characters may follow these sequences':
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* r rb open to read
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* w wb open to write, truncating
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* a ab open to write positioned at eof, creating if non-existant
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* r+ r+b rb+ open to read and write, creating if non-existant
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* w+ w+b wb+ open to read and write, truncating
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* a+ a+b ab+ open to read and write, positioned at eof, creating if non-existant.
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*/
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FILE *freopen(const char *name, const char *mode, FILE *f){
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int m;
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if(f->state!=CLOSED){
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fclose(f);
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/* premature; fall through and see what happens */
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/* f->state=OPEN; */
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}
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m = *mode++;
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if(m == 0)
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return NULL;
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if(*mode == 'b')
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mode++;
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switch(m){
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default:
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return NULL;
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case 'r':
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f->fd=open(name, (*mode == '+'? ORDWR: OREAD));
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break;
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case 'w':
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f->fd=create(name, (*mode == '+'? ORDWR: OWRITE), 0666);
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break;
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case 'a':
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m = (*mode == '+'? ORDWR: OWRITE);
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f->fd=open(name, m);
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if(f->fd<0)
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f->fd=create(name, m, 0666);
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seek(f->fd, 0LL, 2);
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break;
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}
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if(f->fd==-1)
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return NULL;
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f->flags=(mode[0]=='a')? APPEND : 0;
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f->state=OPEN;
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f->buf=0;
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f->rp=0;
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f->wp=0;
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f->lp=0;
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return f;
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}
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