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https://github.com/fluencelabs/musl
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835f9f950e
this header evolved to facilitate the extremely lazy practice of omitting explicit includes of the necessary headers in individual stdio source files; not only was this sloppy, but it also increased build time. now, stdio_impl.h is only including the headers it needs for its own use; any further headers needed by source files are included directly where needed.
43 lines
936 B
C
43 lines
936 B
C
#include "stdio_impl.h"
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#include <limits.h>
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#include <string.h>
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#include <errno.h>
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#include <stdint.h>
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static size_t sn_write(FILE *f, const unsigned char *s, size_t l)
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{
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size_t k = f->wend - f->wpos;
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if (k > l) k = l;
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memcpy(f->wpos, s, k);
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f->wpos += k;
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/* pretend to succeed, but discard extra data */
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return l;
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}
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int vsnprintf(char *restrict s, size_t n, const char *restrict fmt, va_list ap)
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{
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int r;
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char b;
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FILE f = { .lbf = EOF, .write = sn_write, .lock = -1 };
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if (n-1 > INT_MAX-1) {
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if (n) {
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errno = EOVERFLOW;
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return -1;
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}
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s = &b;
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n = 1;
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}
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/* Ensure pointers don't wrap if "infinite" n is passed in */
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if (n > (char *)0+SIZE_MAX-s-1) n = (char *)0+SIZE_MAX-s-1;
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f.buf_size = n;
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f.buf = f.wpos = (void *)s;
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f.wbase = f.wend = (void *)(s+n);
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r = vfprintf(&f, fmt, ap);
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/* Null-terminate, overwriting last char if dest buffer is full */
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if (n) f.wpos[-(f.wpos == f.wend)] = 0;
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return r;
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}
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