77 lines
1.2 KiB
C
77 lines
1.2 KiB
C
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#include "file.h"
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#define DEFAULT_BUFFER_SIZE 4096
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#define FILE_UNUSABLE(f) (((f)->f_flags & (FILE_EOF | FILE_ERR)) != 0)
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int __libc_file_refill(struct __opaque_file *f)
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{
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f->f_buf_datalen = 0;
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f->f_buf_readptr = 0;
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if (f->f_fd < 0) {
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return EBADF;
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}
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if (f->f_flags & FILE_ERR) {
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return EIO;
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}
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if (f->f_flags & FILE_EOF) {
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return SUCCESS;
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}
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if (!f->f_buf) {
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f->f_buf_max = DEFAULT_BUFFER_SIZE;
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f->f_buf = malloc(f->f_buf_max);
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if (!f->f_buf) {
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f->f_buf_max = 0;
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return ENOMEM;
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}
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}
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long r = read(f->f_fd, f->f_buf, f->f_buf_max);
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if (r < 0) {
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return -r;
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}
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f->f_buf_datalen = r;
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return SUCCESS;
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}
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int __libc_file_read(struct __opaque_file *f, void *out, size_t count)
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{
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if (f->f_fd < 0) {
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return EBADF;
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}
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if (f->f_flags & FILE_ERR) {
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return EIO;
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}
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if (f->f_flags & FILE_EOF) {
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return SUCCESS;
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}
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size_t available = f->f_buf_datalen - f->f_buf_readptr;
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if (count > available) {
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count = available;
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}
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memcpy(out, f->f_buf + f->f_buf_readptr, count);
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f->f_buf_readptr += count;
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return count;
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}
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size_t __libc_file_available(struct __opaque_file *f)
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{
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return f->f_buf_datalen - f->f_buf_readptr;
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}
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