read_file.c

/*
 * read_file.c
 * Jonathan D. Stott <jonathan.stott@gmail.com>
 *
 */
#include <zlib.h>
#include "helper.h"

#include "tip_trace_binary.h"

#define BUFSIZE 1048576

static int read_binary_float_sheet(int x, int y, float ** E, const char *filename);
static int read_binary_double_sheet(int x, int y, float ** E, const char *filename);
static int read_text_sheet(int x, int y, float ** E, const char *filename);

int read_file(file_type_t file_type, int x, int y, float **sheet, const char *filename) {
// reads in the given file, assigning the values to sheet.
//
// file_type:   Type of files in the list
// x:           x dimension of the sheet
// y:           y dimension of the sheet
// sheet[y][x]: 2D sheet of floats
// filename:    filename to open
//
// returns:
//  0:  success
//  <0: error
    switch(file_type) {
        case BINARY_FLOAT:
              return read_binary_float_sheet(x, y, sheet, filename);
        case BINARY_DOUBLE:
              return read_binary_double_sheet(x, y, sheet, filename);
        case TEXT:
              return read_text_sheet(x, y, sheet, filename);
        default:
              fprintf(stderr, "Unknown sheet type\n");
              return -1;
    }
}


static int read_binary_float_sheet(int x, int y, float ** E, const char * filename) {
    gzFile sheet_file;
    int rw;

    sheet_file = gzopen(filename, "r");

    if (!sheet_file) {
        perror(filename);
        return -1;
    }

    rw = gzread(sheet_file, E[0], sizeof(float)*x*y);
    if (rw != x*y*sizeof(float)) {
        fprintf(stderr, "Problem reading %s\n", filename);
        fprintf(stderr, "%d/%d floats read\n", rw, x*y);
        gzclose(sheet_file);
        return -1;
    }

    gzclose(sheet_file);
    return 0;
}

static int read_binary_double_sheet(int x, int y, float ** E, const char * filename) {
    gzFile sheet_file;
    int rw, j, i;

    double ** sheet;

    sheet_file = gzopen(filename, "r");

    if (!sheet_file) {
        perror(filename);
        return -1;
    }

    D_ARRAY_2D(sheet, y, x);


    rw = gzread(sheet_file, sheet[0], sizeof(double)*x*y);
    if (rw != x*y*sizeof(double)) {
        fprintf(stderr, "Problem reading %s\n", filename);
        fprintf(stderr, "%d/%d doubles read\n", rw, x*y);
        free(sheet[0]);
        free(sheet);
        gzclose(sheet_file);
        return -1;
    }

    for (j = 0; j < y; ++j) {
        for (i = 0; i < x; ++i) {
            E[j][i] = (float) sheet[j][i];
        }
    }

    free(sheet[0]);
    free(sheet);

    gzclose(sheet_file);
    return 0;
}

static int read_text_sheet(int x, int y, float ** E, const char * filename) {
    gzFile sheet_file;
    char *buffer, *c, *pos, *prev_pos;
    size_t i, j;

    sheet_file = gzopen(filename, "r");

    if (!sheet_file) {
        perror(filename);
        return -1;
    }

    // allocate a 1mb buffer
    buffer = calloc(BUFSIZE, sizeof(char));
    if (!buffer) {
        gzclose(sheet_file);
        return -1;
    }

    // zero our counters
    i = j = 0;

    while (j < y) {
        // read in a line
        c = gzgets(sheet_file, buffer, BUFSIZE);

        // check we were successful.
        if (Z_NULL == c) {
            fprintf(stderr, "Error reading from '%s' on line %lu\n", filename, j);
            free(buffer);
            gzclose(sheet_file);
            return -1;
        }

        pos = buffer;
        prev_pos = 0;
        i = 0;
        while ((i < x) && (prev_pos != pos)) {
            // assign the previous position to prev_pos
            // this will be used to tell when we have the last float in the
            // line.
            prev_pos = pos;

            // read the float from the buffer line
            E[j][i] = (float) strtod(pos, &pos);

            ++i;
        }

        // check we read in all we should.
        if (i != x) {
            fprintf(stderr, "Error reading from '%s' on line %lu.  %lu/%d floats read\n", filename, j, i, x);
            free(buffer);
            gzclose(sheet_file);
            return -1;
        }

        ++j;

        // if we've reached the end of the file, break.
        if (gzeof(sheet_file))
            break;
    }

    // check we read in all we should.
    if (j != y) {
        fprintf(stderr, "Error reading from '%s'. %lu/%d lines read\n", filename, j, y);
        free(buffer);
        gzclose(sheet_file);
        return -1;
    }

    // cleanup, and return.
    free(buffer);
    gzclose(sheet_file);

    return 0;
}