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Speed up safe_fprintf by copying to a temp buffer, then writing

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blocks at a time, rather than using putc().
This commit is contained in:
kientzle 2004-05-17 07:35:52 +00:00
parent c2f5be1df1
commit cf027fa3ed
1 changed files with 32 additions and 13 deletions
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45
usr.bin/tar/util.c
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@ -54,7 +54,9 @@ safe_fprintf(FILE *f, const char *fmt, ...)
int length;
va_list ap;
char *p;
unsigned i;
char buff_stack[256];
char copy_buff[256];
/* Use a stack-allocated buffer if we can, for speed and safety. */
buff_heap = NULL;
@ -77,27 +79,44 @@ safe_fprintf(FILE *f, const char *fmt, ...)
}
}
for (p=buff; *p != '\0'; p++) {
unsigned char c = *p;
/* Write data, expanding unprintable characters. */
p = buff;
i = 0;
while (*p != '\0') {
unsigned char c = *p++;
if (isprint(c) && c != '\\')
putc(c, f);
else
copy_buff[i++] = c;
else {
copy_buff[i++] = '\\';
switch (c) {
case '\a': putc('\\', f); putc('a', f); break;
case '\b': putc('\\', f); putc('b', f); break;
case '\f': putc('\\', f); putc('f', f); break;
case '\n': putc('\\', f); putc('n', f); break;
case '\a': copy_buff[i++] = 'a'; break;
case '\b': copy_buff[i++] = 'b'; break;
case '\f': copy_buff[i++] = 'f'; break;
case '\n': copy_buff[i++] = 'n'; break;
#if '\r' != '\n'
/* On some platforms, \n and \r are the same. */
case '\r': putc('\\', f); putc('r', f); break;
case '\r': copy_buff[i++] = 'r'; break;
#endif
case '\t': putc('\\', f); putc('t', f); break;
case '\v': putc('\\', f); putc('v', f); break;
case '\\': putc('\\', f); putc('\\', f); break;
case '\t': copy_buff[i++] = 't'; break;
case '\v': copy_buff[i++] = 'v'; break;
case '\\': copy_buff[i++] = '\\'; break;
default:
fprintf(f, "\\%03o", c);
sprintf(copy_buff + i, "%03o", c);
i += 3;
}
}
/* If our temp buffer is full, dump it and keep going. */
if (i > (sizeof(copy_buff) - 8)) {
copy_buff[i++] = '\0';
fprintf(f, "%s", copy_buff);
i = 0;
}
}
copy_buff[i++] = '\0';
fprintf(f, "%s", copy_buff);
/* If we allocated a heap-based buffer, free it now. */
if (buff_heap != NULL)
free(buff_heap);