Laboratoire de l'Informatique et du Parallélisme » Pobyso

/** @file read-lines-from-file.c */

/******************************************************************************/

/**

 * Read lines from a text file, filtering out empty, #-comment lines,

 * leading spaces and tab, trailing comments.

 *

 * @author: ST

 * @date: 2016-10-21

 *

 */

/* Includes according to the "general to particular" rule. */

/* includes of system headers */

#include <stdlib.h>

#include <stdio.h>

#include <libgen.h>

/* includes of project headers */

/* includes of local headers */

#include <read-lines-from-file.h>

/* Types, constants and macros definitions */

/* Global variables */

/* Functions */

/** Scout the file for lines count and maximum lines length.

 * The file is specified by its name.

 * The data are returned through pointer arguments.

 * @param fileName (in);

 * @param linesCountPtr (in/out);

 * @param maxLineLengthPtr (in/out);

 * @return 0 if OK and != 0 if something goes wrong. */

int

rlff_scout_file_from_name(char* fileName,

                          unsigned int* linesCountPtr,

                          unsigned int* maxLineLengthPtr);

/** Scout the file for lines count and maximum lines length.

 * The file is specified by a handle open on it in "read" mode (at least).

 * The data are returned through pointer arguments.

 * @param fileHandle (in);

 * @param linesCountPtr (in/out);

 * @param maxLineLengthPtr (in/out);

* @return 0 if OK and != 0 if something goes wrong. */

int

rlff_scout_file_from_handle(FILE* fileHandle,

                            unsigned int* linesCountPtr,

                            unsigned int* maxLineLengthPtr);

/** Dealloc a readLines struct that has been initialized (even partly)

 * @see read-lines-from-file.h#rlff_free_lines.*/

void

rlff_free_lines(rlff_readLines_t* linesRead)

{

  if (linesRead == NULL) { return; }

  if (linesRead->lines == NULL) { return; }

  free(linesRead->lines);

  free(linesRead);

} /* End free_lines. */

/** @see read-lines-from-file.h#rlff_get_line_at. */

char*

rlff_get_line_at(rlff_readLines_t* linesRead, unsigned int lineIndex)

{

  if (linesRead == NULL)

  {

    #ifndef NDEBUG

    fprintf(stderr,

            "\n%s: linesRead is a NULL pointer.\n",

            __func__);

    #endif

    return NULL;

  }

  if (lineIndex > (linesRead->linesNum -1))

  {

    #ifndef NDEBUG

    fprintf(stderr,

            "\n%s: requested line (%d) is beyond\n",

            __func__,

            lineIndex);

    fprintf(stderr,

            "maximum index (%d).\n",

            linesRead->linesNum -1);

    #endif

    return NULL;

  }

  return linesRead->lines + lineIndex * linesRead->linesLength;

} /* End rlff_get_line_at. */

/** @see read-lines-from-file.h#rlff_print_lines */

void

  rlff_print_lines(rlff_readLines_t* linesRead)

{

  unsigned int i = 0;

  if (linesRead == NULL) { return; }

  for (i = 0 ; i < linesRead->linesNum ; i++)

  {

    fprintf(stdout,

            "%s\n",

            rlff_get_line_at(linesRead, i));

  }

} /* End rlff_print_lines. */

/** @see read-lines-from-file.h#rlff_read_lines_from file_name */

rlff_readLines_t*

rlff_read_lines_from_file_name(char* fileName)

{

  FILE* linesFile               = NULL;

  /* Current character position in read file. Starts at 0. */

  rlff_readLines_t* linesRead   = NULL;

  /* Argument check. */

  if (fileName == NULL)

  {

    #ifndef NDEBUG

    fprintf(stderr,

            "\n%s: fileName is a NULL pointer.\n",

            __func__);

    #endif

    return NULL;

  }

  /* Try to open the file in read-only mode. */

  linesFile = fopen(fileName, "r");

  if (linesFile == NULL)

  {

    #ifndef NDEBUG

    fprintf(stderr,

            "\n%s: could not open file %s.\n",

            __func__,

            fileName);

    #endif

    return NULL;

  }

  linesRead = rlff_read_lines_from_file_handle(linesFile);

  fclose(linesFile);

  return linesRead;

} /* End rlff_read_lines_from_file_name. */

/** @see read-lines-from-file.h#rlff_read_lines_from file_handle */

rlff_readLines_t*

rlff_read_lines_from_file_handle(FILE* fileHandle)

{

  char c                        = '\0';

  char* bufferCurrentLinePtr    = NULL;

  char* bufferCurrentCharPtr    = NULL;

  /* Current character position in read file. Starts at 0. */

  rlff_readLines_t* linesRead   = NULL;

  unsigned int rlffLinesCount   = 0;

  unsigned int rlffLinesLength  = 0;

  /* Argument check. */

  if (fileHandle == NULL)

  {

    #ifndef NDEBUG

    fprintf(stderr,

            "\n%s: fileHandle is a NULL pointer.\n",

            __func__);

    #endif

    return NULL;

  }

  /* Get the file data. */

  if (rlff_scout_file_from_handle(fileHandle,

                                  &rlffLinesCount,

                                  &rlffLinesLength))

  {

    #ifndef NDEBUG

    fprintf(stderr,

            "\n%s: could not scout the file.\n",

            __func__);

    #endif

    return NULL;

  }

  /* Try to allocate the pointer returned structure. */

  linesRead = malloc(sizeof(rlff_readLines_t));

  if (linesRead == NULL)

  {

    #ifndef NDEBUG

    fprintf(stderr,

            "\n%s: could not alloc memory for the rlff_readLines_t.\n",

            __func__);

    #endif

    return NULL;

  }

  linesRead->linesNum     = rlffLinesCount;

  linesRead->linesLength  = rlffLinesLength;

  if ((rlffLinesCount == 0) || (rlffLinesLength == 0))

  {

    /* The file is somehow empty: not an actual error. */

    linesRead->linesNum     = 0;

    linesRead->linesLength  = 0;

    linesRead->lines        = NULL;

    return linesRead;

  }

  /* Try to allocate the lines buffer. */

  linesRead->lines =

      malloc(rlffLinesCount * rlffLinesLength * sizeof(char));

  if (linesRead->lines == NULL)

  {

    #ifndef NDEBUG

    fprintf(stderr,

            "\n%s: could not alloc memory for the lines buffer.\n",

            __func__);

    #endif

    free(linesRead);

    return NULL;

  }

  bufferCurrentLinePtr = linesRead->lines;

  bufferCurrentCharPtr = bufferCurrentLinePtr;

  /* Get the chars of the file. */

  while ((c = fgetc(fileHandle)) != EOF)

  {

    /* Skipping initial spaces. */

    while((c == ' ') || (c == '\t'))

    {

      c = fgetc(fileHandle);

      if (c == EOF)

      {

        return linesRead;

      }

    } /* End while */

    /* A line of spaces or an empty line. */

    if (c == '\n')

    {

      continue;

    }

    /* First character afer spaces is '#'.  Read the comment

     * to the end of the line or of the file. */

    if (c == '#')

    {

      while(((c = fgetc(fileHandle)) != EOF) && (c != '\n')) {}

      if (c == '\n')

      {

        continue;

      }

      else /* c == EOF */

      {

        return linesRead;

      }

    } /* End c == '#'. */

    *bufferCurrentCharPtr = c;

    bufferCurrentCharPtr++;

    /* A line with usefull content. */

    while(((c = fgetc(fileHandle)) != EOF) && (c != '\n') && (c != '#'))

    {

      *bufferCurrentCharPtr = c;

      bufferCurrentCharPtr++;

    }

    if (c == '#')

    {

      while(((c = fgetc(fileHandle)) != EOF) && (c != '\n')) {}

    }

    if (c == EOF)

    {

        return linesRead;

    } /* End c == EOF. */

    /* End of a line with useful content. */

    /* At the end of a useful lines. */

    if (c == '\n')

    {

      *bufferCurrentCharPtr = '\0';

      /* Delete trailing spaces. */

      while (bufferCurrentCharPtr > bufferCurrentLinePtr)

      {

        bufferCurrentCharPtr--;

        if ((*bufferCurrentCharPtr == ' ') ||

            (*bufferCurrentCharPtr == '\t'))

        {

          *bufferCurrentCharPtr = '\0';

        }

        else

        {

          break;

        }

      } /* End while. */

      bufferCurrentLinePtr += linesRead->linesLength;

      bufferCurrentCharPtr = bufferCurrentLinePtr;

    } /* End c == '\n'. */

  } /* End main while; ancillary*/

  /* Normal reading exit. */

  return linesRead;

} /* End rlff_read_lines_from_file_handle. */

int

rlff_scout_file_from_name(char* fileName,

                          unsigned int* linesCountPtr,

                          unsigned int* maxLineLengthPtr)

{

  FILE* linesFileHandle         = NULL;

  int returnValue               = 0;

  /* Arguments check. */

  if ((fileName         == NULL)    ||

      (linesCountPtr    == NULL)  ||

      (maxLineLengthPtr == NULL))

  {

    #ifndef NDEBUG

    if (fileName == NULL)

    {

      fprintf(stderr,

              "\n%s: \"fileName\" is a NULL pointer.\n",

              __func__);

    }

    if (linesCountPtr == NULL)

    {

      fprintf(stderr,

              "\n%s: \"linesCountPtr\" is a NULL pointer.\n",

              __func__);

    }

    if (maxLineLengthPtr == NULL)

    {

      fprintf(stderr,

              "\n%s: \"maxLineLengthPtr\" is a NULL pointer.\n",

              __func__);

    }

    #endif

    return 1;

  } /* End arguments check. */

  /* Open file and deal with errors. */

  linesFileHandle = fopen(fileName, "r");

  if (linesFileHandle == NULL)

  {

    fprintf(stderr,

            "\n%s: could not open file %s.\n",

            __func__,

            fileName);

    return 1;

  }

  *linesCountPtr      = 0;

  *maxLineLengthPtr   = 0;

  /* Scan the file. */

  returnValue = rlff_scout_file_from_handle(linesFileHandle,

                                            linesCountPtr,

                                            maxLineLengthPtr);

  fclose(linesFileHandle);

  return returnValue;

} /* End rlff_scout_file_from_name. */

int

rlff_scout_file_from_handle(FILE* fileHandle,

                            unsigned int* linesCountPtr,

                            unsigned int* maxLineLengthPtr)

{

  char c                        = '\0';

  unsigned int charsCount       = 0;

  /* Arguments check. */

  if ((fileHandle       == NULL)  ||

      (linesCountPtr    == NULL)  ||

      (maxLineLengthPtr == NULL))

  {

    #ifndef NDEBUG

    if (fileHandle == NULL)

    {

      fprintf(stderr,

              "\n%s: \"fileHandle\" is a NULL pointer.\n",

              __func__);

    }

    if (linesCountPtr == NULL)

    {

      fprintf(stderr,

              "\n%s: \"linesCountPtr\" is a NULL pointer.\n",

              __func__);

    }

    if (maxLineLengthPtr == NULL)

    {

      fprintf(stderr,

              "\n%s: \"maxLineLengthPtr\" is a NULL pointer.\n",

              __func__);

    }

    #endif

    return 1;

  } /* End arguments check. */

  *linesCountPtr      = 0;

  *maxLineLengthPtr   = 0;

  /* Scan the file. */

  while((c = fgetc(fileHandle)) != EOF)

  {

    (*linesCountPtr)++;

    charsCount++;

    while((c == ' ') || (c == '\t'))

    {

      c = fgetc(fileHandle);

      if (c == EOF)

      {

        (*linesCountPtr)--;

        return 0;

      }

    } /* End while */

    /* A line of spaces. */

    if (c == '\n')

    {

      (*linesCountPtr)--;

      charsCount = 0;

      continue;

    }

    /* First character after spaces is '#'.  Read the comment

     * to the end of the line or of the file. */

    if (c == '#')

    {

      (*linesCountPtr)--;

      charsCount = 0;

      while(((c = fgetc(fileHandle)) != EOF) && (c != '\n')) {}

      if (c == '\n')

      {

        continue;

      }

      else /* c == EOF */

      {

        break;

      }

    } /* End c == '#'. */

    while(((c = fgetc(fileHandle)) != EOF) && (c != '\n'))

    {

      charsCount++;

    }

    if (c == EOF)

    {

      /* Allow for space of the terminal '\0'. */

      if (charsCount + 1 > *maxLineLengthPtr)

      {

        (*maxLineLengthPtr) = charsCount + 1;

      }

      break;

    } /* End c == EOF. */

    if (c == '\n')

    {

      /* Allow for space of the terminal '\0'. */

      if (charsCount + 1 > *maxLineLengthPtr)

      {

        (*maxLineLengthPtr) = charsCount + 1;

      }

      charsCount = 0;

    } /* End c == '\n'. */

  } /* End while. */

  return 0;

} /* End rlff_scout_file_from_handle. */