80 lines
1.8 KiB
C
80 lines
1.8 KiB
C
#ifndef __SCANF_H__
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# define __SCANF_H__
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <stdio.h>
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#include <stdbool.h>
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/*
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** General utilities for scanf(); we expose them here as we use subfunctions of
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** strto*() from <stdlib.h> to implement numerical specifiers.
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*/
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/*
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** Input for scanf; exactly one of str and fp must be non-NULL. We include a
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** single-character buffer for convenience for scanning functions to test the
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** next character, which can be flushed back by ungetc().
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*/
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struct __scanf_input {
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char const * __restrict__ str;
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FILE *fp;
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// max char to read from the input stream as per user length modifier
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int readmaxlength;
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int currentlength;
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// total number of char read so far in the current call of a XYscanf() function (to return a %n when required)
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int readsofar;
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int buffer;
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};
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/* Generic formatted scaning. */
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extern int __scanf(
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struct __scanf_input * __restrict__ __in,
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char const * __restrict__ __format,
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va_list *__args);
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/* Initialize the input by feeding the buffer byte. */
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void __scanf_start(struct __scanf_input *__in);
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/* Fetch the next byte from the input and return it (don't call directly). */
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int __scanf_fetch(struct __scanf_input *__in);
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/* Read the next byte while maintaining the buffer. */
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static inline int __scanf_in(struct __scanf_input *__in)
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{
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int c = __in->buffer;
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__in->buffer = __scanf_fetch(__in);
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__in->readsofar++;
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__in->currentlength++;
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return c;
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}
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/* Peek the next byte without advancing. */
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static inline int __scanf_peek(struct __scanf_input *__in)
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{
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if (__in->readmaxlength==-1 || __in->currentlength<__in->readmaxlength )
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return __in->buffer;
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else return 0;
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}
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/* Close the input by unsending the buffer once finished. */
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void __scanf_end(struct __scanf_input *__in);
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#ifdef __cplusplus
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}
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#endif
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#endif /* __SCANF_H__ */
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