// vim: ts=4 sw=4 expandtab ft=c

// Copyright (C) 2000, 2002 The University of Melbourne.
// Copyright (C) 2016, 2018 The Mercury team.
// This file is distributed under the terms specified in COPYING.LIB.

// This module contains the implementation of Mercury streams using
// C `FILE *' streams.

#include "mercury_file.h"
#include "mercury_std.h"    // for MR_assert

#ifdef MR_NATIVE_GC
static int next_id = 0;
#endif

#ifndef MR_NEW_MERCURYFILE_STRUCT
void
MR_mercuryfile_init(FILE *file, int line_number, MercuryFile *mf)
{
    MR_file(*mf)        = file;
    MR_line_number(*mf) = line_number;
  #ifdef MR_NATIVE_GC
    mf->id = ++next_id;
  #endif
}

#else // MR_NEW_MERCURYFILE_STRUCT

void
MR_mercuryfile_init(FILE *file, int line_number, MercuryFile *mf)
{
    mf->stream_type = MR_FILE_STREAM;
    mf->stream_info.file = file;
    mf->line_number = line_number;

    mf->close       = MR_close;
    mf->read        = MR_read;
    mf->write       = MR_write;

    mf->flush       = MR_flush;
    mf->ungetc      = MR_ungetch;
    mf->getc        = MR_getch;
    mf->vprintf     = MR_vfprintf;
    mf->putc        = MR_putch;
    mf->ferror      = MR_ferror;
  #ifdef MR_NATIVE_GC
    mf->id = ++next_id;
  #endif
}

int
MR_getch(MR_StreamInfo *info)
{
    MR_assert(info != NULL);
    return getc(info->file);
}

int
MR_ungetch(MR_StreamInfo *info, int ch)
{
    MR_assert(info != NULL);
    return ungetc(ch, info->file);
}

int
MR_putch(MR_StreamInfo *info, int ch)
{
    MR_assert(info != NULL);
    return putc(ch, info->file);
}

int
MR_ferror(MR_StreamInfo *info)
{
    MR_assert(info != NULL);
    return ferror(info->file);
}

int
MR_close(MR_StreamInfo *info)
{
    MR_assert(info != NULL);
    return fclose(info->file);
}

int
MR_flush(MR_StreamInfo *info)
{
    MR_assert(info != NULL);
    return fflush(info->file);
}

int
MR_vfprintf(MR_StreamInfo *info, const char *format, va_list ap)
{
    MR_assert(info != NULL);
    MR_assert(format != NULL);

    return vfprintf(info->file, format, ap);
}

int
MR_read(MR_StreamInfo *info, void *buffer, size_t size)
{
    int rc;
    MR_assert(info != NULL);
    rc = fread(buffer, sizeof(unsigned char), size, info->file);

    // Handle error/eof special cases.
    if ((rc < size) && feof(info->file)) {
        // Nothing to do.
        ;
    } else if (ferror(info->file)) {
        rc = -1;
    }

    return rc;
}

int
MR_write(MR_StreamInfo *info, const void *buffer, size_t size)
{
    int rc;

    MR_assert(info != NULL);
    rc = fwrite(buffer, sizeof(unsigned char), size, info->file);

    return (rc < size ? -1 : rc);
}

#endif // MR_NEW_MERCURYFILE_STRUCT