/* Implementation of pgm_image.h */
/* Last edited on 2004-11-07 02:04:40 by stolfi */

#include <stdlib.h>
#include <stdio.h>
#include <assert.h>

#include <pgm_image.h>
#include <pgm.h>

pgm_image *new_pgm_image(int cols, int rows)
  { pgm_image *img = (pgm_image *)malloc(sizeof(pgm_image));
    assert(img != NULL);
    img->cols = cols;
    img->rows = rows;
    if ((cols == 0) || (rows == 0))
      { img->pix = (pixval**)NULL; }
    else
      { img->pix = alloc_pgm_pixels(cols, rows); }
    return(img);
  }

void free_pgm_image(pgm_image *img)
  { if (img == NULL) return;
    free_pgm_pixels(img->pix, img->cols, img->rows);
    free(img);
  }
  
pixval** alloc_pgm_pixels(int cols, int rows)
  { int row;
    pixval **pix = (pixval**)malloc(rows*sizeof(pixval*));
    if (pix == (pixval**)NULL) pm_error("out of memory");
    for (row = 0; row < rows; row++)
      { if (cols == 0)
          { pix[row] = (pixval*)NULL; }
        else
          { pix[row] = (pixval*)malloc(cols*sizeof(pixval));
            if (pix[row] == (pixval*)NULL) pm_error("out of memory");
          }
      }
    return pix;
  }
  
void free_pgm_pixels(pixval **pix, int cols, int rows)
  { int row;
    if (pix == NULL) { return; }
    for (row = 0; row < rows; row++) 
      { if (pix[row] != NULL) { free(pix[row]); } }
    free(pix);
  }
   
pgm_image *read_pgm_image(char *name)
  { FILE *rd = NULL;
    if (name == NULL) pm_error("no file name given");
    else if (strlen(name) == 0) pm_error("empty file name");
    else if (strcmp(name, "-") == 0) 
      { rd = stdin; }
    else
      { rd = pm_openr(name); }
    pgm_image *img = fread_pgm_image(rd);
    if (rd != stdin) { pm_close(rd); }
    return img;
  }
  
pgm_image *fread_pgm_image(FILE *rd)
  { pgm_image *img = new_pgm_image(0,0);
    img->pix = pgm_readpgm(rd, &(img->cols), &(img->rows), &(img->maxval));
    return(img);
  }

void write_pgm_image(char *name, pgm_image *img, int forceplain)
  { FILE *wr = NULL;
    if (name == NULL) pm_error("no file name given");
    else if (strlen(name) == 0) pm_error("empty file name");
    else if (strcmp(name, "-") == 0) 
      { wr = stdout; }
    else
      { wr = pm_openw(name); }
    fwrite_pgm_image(wr, img, forceplain);
    if (wr != stdout) { pm_close(wr); }
  }
  
void fwrite_pgm_image(FILE *wr, pgm_image *img, int forceplain)
  { int row;
    pgm_writepgminit(wr, img->cols, img->rows, img->maxval, forceplain);
    for (row = 0; row < img->rows; row++)
      { pgm_writepgmrow(wr, img->pix[row], img->cols, img->maxval, forceplain); }
    fflush(wr);
  }