file.c

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#include <stdint.h>
#include <stdio.h>
#include <string.h>
 
#include <unistd.h>
#include <errno.h>
 
#include <syscall.h>
 
static FILE __stdin = { 1, STDIN_FILENO, 0 };
static FILE __stdout = { 1, STDOUT_FILENO, 0 };
static FILE __stderr = { 1, STDERR_FILENO, 0 };
 
FILE *stdin = &__stdin;
FILE *stdout = &__stdout;
FILE *stderr = &__stderr;
 
static FILE fds[FOPEN_MAX] = {
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
    { 0, 0, 0 },
};
 
FILE *
_alloc_file()
{
    int i;
 
    for (i = 0; i < FOPEN_MAX; i++) {
        if (fds[i].in_use == 0) {
            fds[i].in_use = 1;
            return &fds[i];
        }
    }
 
    // XXX: malloc
 
    return NULL;
}
 
void
_free_file(FILE *fh)
{
    fh->fd = 0;
    fh->offset = 0;
    fh->in_use = 0;
 
    // XXX: free
}
 
FILE *
fopen(const char *path, const char *mode)
{
    uint64_t fd;
    FILE *fh;
    // XXX: handle mode
 
    fd = OSOpen(path, 0);
    if (fd == 0)
        return NULL;
 
    fh = _alloc_file();
    fh->fd = fd;
    fh->offset = 0;
 
    // XXX: handle append
 
    return fh;
}
 
int
fclose(FILE *fh)
{
    int status = OSClose(fh->fd);
 
    _free_file(fh);
 
    return status;
}
 
int
feof(FILE *fh)
{
    errno = ENOSYS;
    return -1;
}
 
int
fflush(FILE *fh)
{
    errno = ENOSYS;
    return -1;
}
 
size_t
fread(void *buf, size_t size, size_t nmemb, FILE *fh)
{
    return OSRead(fh->fd, buf, 0, size * nmemb);
    // set errno
}
 
size_t
fwrite(const void *buf, size_t size, size_t nmemb, FILE *fh)
{
    return OSWrite(fh->fd, buf, 0, size * nmemb);
    // set errno
}
 
int
fputc(int ch, FILE *fh)
{
    if (fwrite(&ch, 1, 1, fh) == 1)
        return ch;
    return EOF;
}
 
int
fputs(const char *str, FILE *fh)
{
    int status = fwrite(str, strlen(str), 1, fh);
    if (status > 0)
        return status;
    // XXX: error handling
    return EOF;
}
 
int
puts(const char *str)
{
    int status, status2;
    status = fputs(str, stdout);
    if (status < 0)
        return EOF;
 
    status2 = fputc('\n', stdout);
    if (status2 < 0)
        return EOF;
 
    return status;
}
 
int
fgetc(FILE *fh)
{
    char ch;
    if (fread(&ch, 1, 1, fh) == 1)
        return ch;
    return EOF;
}
 
char *
fgets(char *str, int size, FILE *fh)
{
    int i;
 
    for (i = 0; i < (size - 1); i++) {
        int ch = fgetc(fh);
        if (ch == EOF)
            return NULL;
        if (ch == '\b') {
            if (i > 0)
                i -= 1;
            i -= 1;
            continue;
        }
        str[i] = (char)ch;
        if (ch == '\n') {
            str[i + 1] = '\0';
            return str;
        }
    }
 
    str[size - 1] = '\0';
    return str;
}