76 lines
2.4 KiB
C
76 lines
2.4 KiB
C
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/* File ggets.c - goodgets is a safe alternative to gets */
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/* By C.B. Falconer. Public domain 2002-06-22 */
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/* attribution appreciated. */
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/* Revised 2002-06-26 New prototype.
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2002-06-27 Incomplete final lines
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2006-06-14 Simplified, using getc, not fgets
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2006-06-15 Fixed memory leak at EOF
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*/
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/* fggets and ggets [which is fggets(ln, stdin)] set *ln to
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a buffer filled with the next complete line from the text
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stream f. The storage has been allocated within fggets,
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and is normally reduced to be an exact fit. The trailing
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\n has been removed, so the resultant line is ready for
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dumping with puts. The buffer will be as large as is
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required to hold the complete line.
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Note: this means a final file line without a \n terminator
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has an effective \n appended, as EOF occurs within the read.
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If no error occurs fggets returns 0. If an EOF occurs on
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the input file, EOF is returned. For memory allocation
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errors some positive value is returned. In this case *ln
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may point to a partial line. For other errors memory is
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freed and *ln is set to NULL.
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Freeing of assigned storage is the callers responsibility
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "ggets.h"
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#define INITSIZE 112 /* power of 2 minus 16, helps malloc */
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#define DELTASIZE (INITSIZE + 16)
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enum {OK = 0, NOMEM};
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int fggets(char* *ln, FILE *f)
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{
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int cursize, ch, ix;
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char *buffer, *temp;
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*ln = NULL; /* default */
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if (NULL == (buffer = malloc(INITSIZE))) return NOMEM;
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cursize = INITSIZE;
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ix = 0;
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while ((EOF != (ch = getc(f))) && ('\n' != ch)) {
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if (ix >= (cursize - 1)) { /* extend buffer */
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cursize += DELTASIZE;
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if (NULL == (temp = realloc(buffer, (size_t)cursize))) {
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/* ran out of memory, return partial line */
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buffer[ix] = '\0';
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*ln = buffer;
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return NOMEM;
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}
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buffer = temp;
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}
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buffer[ix++] = ch;
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}
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if ((EOF == ch) && (0 == ix)) {
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free(buffer);
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return EOF;
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}
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buffer[ix] = '\0';
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if (NULL == (temp = realloc(buffer, (size_t)ix + 1))) {
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*ln = buffer; /* without reducing it */
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}
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else *ln = temp;
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return OK;
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} /* fggets */
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/* End of ggets.c */
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