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#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include "mallocvar.h"
#include "nstring.h"
#include "io.h"
void
pm_freadline(FILE * const fileP,
const char ** const lineP,
const char ** const errorP) {
/*----------------------------------------------------------------------------
Read a line (assuming the file is text with lines delimited by newlines)
from file *fileP. Return that line in newly malloced storage as *lineP.
The newline delimiter is not part of the line.
As a special case, if the file doesn't end in a newline, the characters
after the last newline are a line.
If there are no more lines in the file, return *lineP == NULL.
-----------------------------------------------------------------------------*/
char * buffer;
size_t bufferSize;
size_t cursor;
bool gotLine;
bool eof;
bufferSize = 1024; /* initial value */
*errorP = NULL; /* initial value */
MALLOCARRAY(buffer, bufferSize);
for (cursor = 0, gotLine = false, eof = false;
!gotLine && !eof && !*errorP; ) {
if (cursor + 1 >= bufferSize) {
if (bufferSize > INT_MAX/2) {
free(buffer);
buffer = NULL;
} else {
bufferSize *= 2;
REALLOCARRAY(buffer, bufferSize);
}
}
if (!buffer)
pm_asprintf(errorP,
"Couldn't get memory for a %u-byte file read buffer.",
(unsigned int)bufferSize);
else {
int const rc = getc(fileP);
if (rc < 0) {
if (feof(fileP))
eof = true;
else
pm_asprintf(errorP,
"Failed to read a character from file. "
"Errno = %d (%s)",
errno, strerror(errno));
} else {
char const c = (char)rc;
if (c == '\n')
gotLine = true;
else {
buffer[cursor++] = c;
}
}
}
}
if (*errorP) {
if (buffer)
free(buffer);
} else {
if (eof && cursor == 0) {
*lineP = NULL;
free(buffer);
} else {
assert(cursor < bufferSize);
buffer[cursor++] = '\0';
*lineP = buffer;
}
}
}
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