ami_stream.cpp

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/****************************************************************************
 *
 *  MODULE:     iostream
 *
 
 *  COPYRIGHT (C) 2007 Laura Toma
 *
 *
 
 *  Iostream is a library that implements streams, external memory
 *  sorting on streams, and an external memory priority queue on
 *  streams. These are the fundamental components used in external
 *  memory algorithms.
 
 * Credits: The library was developed by Laura Toma.  The kernel of
 * class STREAM is based on the similar class existent in the GPL TPIE
 * project developed at Duke University. The sorting and priority
 * queue have been developed by Laura Toma based on communications
 * with Rajiv Wickremesinghe. The library was developed as part of
 * porting Terraflow to GRASS in 2001.  PEARL upgrades in 2003 by
 * Rajiv Wickremesinghe as part of the Terracost project.
 
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.  *
 *  **************************************************************************/
 
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
 
extern "C" {
#include <grass/gis.h>
}
 
// #include <ami_stream.h>
#include <grass/iostream/ami_stream.h>
 
const char *ami_str_error[] = {
    "AMI_ERROR_NO_ERROR",
    "AMI_ERROR_IO_ERROR",
    "AMI_ERROR_END_OF_STREAM",
    "AMI_ERROR_OUT_OF_RANGE",
    "AMI_ERROR_READ_ONLY",
    "AMI_ERROR_OS_ERROR",
    "AMI_ERROR_MM_ERROR",
    "AMI_ERROR_OBJECT_INITIALIZATION",
    "AMI_ERROR_PERMISSION_DENIED",
    "AMI_ERROR_INSUFFICIENT_MAIN_MEMORY",
    "AMI_ERROR_INSUFFICIENT_AVAILABLE_STREAMS",
    "AMI_ERROR_ENV_UNDEFINED",
    "AMI_ERROR_NO_MAIN_MEMORY_OPERATION",
};
 
/**********************************************************************/
/* creates a random file name, opens the file for reading and writing
   and and returns a file descriptor */
int ami_single_temp_name(const std::string &base, char *tmp_path)
{
 
    char *base_dir;
    int fd;
 
    // get the dir
    base_dir = getenv(STREAM_TMPDIR);
    if (!base_dir) {
        fprintf(stderr, "ami_stream: %s not set\n", STREAM_TMPDIR);
        assert(base_dir);
        exit(1);
    }
    snprintf(tmp_path, GPATH_MAX, "%s/%s_XXXXXX", base_dir, base.c_str());
 
    fd = G_mkstemp(tmp_path, O_RDWR, 0600);
 
    if (fd == -1) {
        cerr << "ami_single_temp_name: ";
        perror("G_mkstemp() failed: ");
        assert(0);
        exit(1);
    }
    return fd;
}
 
/**********************************************************************/
/* given fd=fide descriptor, associates with it a stream aopened in
   access_mode and returns it */
FILE *open_stream(int fd, AMI_stream_type st)
{
    FILE *fp = NULL;
 
    assert(fd > -1);
    switch (st) {
    case AMI_READ_STREAM:
        fp = fdopen(fd, "rb");
        break;
    case AMI_WRITE_STREAM:
        fp = fdopen(fd, "wb");
        break;
    case AMI_APPEND_WRITE_STREAM:
        fp = fdopen(fd, "ab");
        break;
    case AMI_APPEND_STREAM:
        fp = fdopen(fd, "ab+");
        break;
    case AMI_READ_WRITE_STREAM:
        fp = fdopen(fd, "rb+");
        if (!fp) {
            // if file does not exist, create it
            fp = fdopen(fd, "wb+");
        }
        break;
    }
    if (!fp) {
        perror("fdopen");
    }
    assert(fp);
 
    return fp;
}
 
/**********************************************************************/
/* open the file whose name is pathname in access mode */
FILE *open_stream(char *pathname, AMI_stream_type st)
{
 
    FILE *fp = NULL;
    assert(pathname);
 
    switch (st) {
    case AMI_READ_STREAM:
        fp = fopen(pathname, "rb");
        break;
    case AMI_WRITE_STREAM:
        fp = fopen(pathname, "wb");
        break;
    case AMI_APPEND_WRITE_STREAM:
        fp = fopen(pathname, "ab");
        break;
    case AMI_APPEND_STREAM:
        fp = fopen(pathname, "ab+");
        assert(fp);
        G_fseek(fp, 0, SEEK_END);
        break;
    case AMI_READ_WRITE_STREAM:
        fp = fopen(pathname, "rb+");
        if (!fp) {
            // if file does not exist, create it
            fp = fopen(pathname, "wb+");
        }
        break;
    }
    if (!fp) {
        perror(pathname);
        assert(0);
        exit(1);
    }
    assert(fp);
    return fp;
}