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mirror of https://github.com/qpdf/qpdf.git synced 2024-07-01 01:23:34 +00:00
qpdf/libqpdf/QPDFTokenizer.cc
Jay Berkenbilt 5d4cad9c02 ABI change: fix use of off_t, size_t, and integer types
Significantly improve the code's use of off_t for file offsets, size_t
for memory sizes, and integer types in cases where there has to be
compatibility with external interfaces.  Rework sections of the code
that would have prevented qpdf from working on files larger than 2 (or
maybe 4) GB in size.
2012-06-20 15:20:26 -04:00

463 lines
8.8 KiB
C++

#include <qpdf/QPDFTokenizer.hh>
// DO NOT USE ctype -- it is locale dependent for some things, and
// it's not worth the risk of including it in case it may accidentally
// be used.
#include <qpdf/PCRE.hh>
#include <qpdf/QTC.hh>
#include <stdexcept>
#include <string.h>
// See note above about ctype.
static bool is_hex_digit(char ch)
{
return (strchr("0123456789abcdefABCDEF", ch) != 0);
}
QPDFTokenizer::QPDFTokenizer() :
pound_special_in_name(true)
{
reset();
}
void
QPDFTokenizer::allowPoundAnywhereInName()
{
QTC::TC("qpdf", "QPDFTokenizer allow pound anywhere in name");
this->pound_special_in_name = false;
}
void
QPDFTokenizer::reset()
{
state = st_top;
type = tt_bad;
val = "";
raw_val = "";
error_message = "";
unread_char = false;
char_to_unread = '\0';
string_depth = 0;
string_ignoring_newline = false;
last_char_was_bs = false;
}
void
QPDFTokenizer::presentCharacter(char ch)
{
PCRE num_re("^[\\+\\-]?(?:\\.\\d+|\\d+(?:\\.\\d+)?)$");
if (state == st_token_ready)
{
throw std::logic_error(
"INTERNAL ERROR: QPDF tokenizer presented character "
"while token is waiting");
}
char orig_ch = ch;
// State machine is implemented such that some characters may be
// handled more than once. This happens whenever you have to use
// the character that caused a state change in the new state.
bool handled = true;
if (state == st_top)
{
// Note: we specifically do not use ctype here. It is
// locale-dependent.
if (strchr(" \t\n\v\f\r", ch))
{
// ignore
}
else if (ch == '%')
{
// Discard comments
state = st_in_comment;
}
else if (ch == '(')
{
string_depth = 1;
string_ignoring_newline = false;
memset(bs_num_register, '\0', sizeof(bs_num_register));
last_char_was_bs = false;
state = st_in_string;
}
else if (ch == '<')
{
state = st_lt;
}
else if (ch == '>')
{
state = st_gt;
}
else
{
val += ch;
if (ch == ')')
{
type = tt_bad;
QTC::TC("qpdf", "QPDF_Tokenizer bad )");
error_message = "unexpected )";
state = st_token_ready;
}
else if (ch == '[')
{
type = tt_array_open;
state = st_token_ready;
}
else if (ch == ']')
{
type = tt_array_close;
state = st_token_ready;
}
else if (ch == '{')
{
type = tt_brace_open;
state = st_token_ready;
}
else if (ch == '}')
{
type = tt_brace_close;
state = st_token_ready;
}
else
{
state = st_literal;
}
}
}
else if (state == st_in_comment)
{
if ((ch == '\r') || (ch == '\n'))
{
state = st_top;
}
}
else if (state == st_lt)
{
if (ch == '<')
{
val = "<<";
type = tt_dict_open;
state = st_token_ready;
}
else
{
handled = false;
state = st_in_hexstring;
}
}
else if (state == st_gt)
{
if (ch == '>')
{
val = ">>";
type = tt_dict_close;
state = st_token_ready;
}
else
{
val = ">";
type = tt_bad;
QTC::TC("qpdf", "QPDF_Tokenizer bad >");
error_message = "unexpected >";
unread_char = true;
char_to_unread = ch;
state = st_token_ready;
}
}
else if (state == st_in_string)
{
if (string_ignoring_newline && (! ((ch == '\r') || (ch == '\n'))))
{
string_ignoring_newline = false;
}
size_t bs_num_count = strlen(bs_num_register);
bool ch_is_octal = ((ch >= '0') && (ch <= '7'));
if ((bs_num_count == 3) || ((bs_num_count > 0) && (! ch_is_octal)))
{
// We've accumulated \ddd. PDF Spec says to ignore
// high-order overflow.
val += (char) strtol(bs_num_register, 0, 8);
memset(bs_num_register, '\0', sizeof(bs_num_register));
bs_num_count = 0;
}
if (string_ignoring_newline && ((ch == '\r') || (ch == '\n')))
{
// ignore
}
else if (ch_is_octal && (last_char_was_bs || (bs_num_count > 0)))
{
bs_num_register[bs_num_count++] = ch;
}
else if (last_char_was_bs)
{
switch (ch)
{
case 'n':
val += '\n';
break;
case 'r':
val += '\r';
break;
case 't':
val += '\t';
break;
case 'b':
val += '\b';
break;
case 'f':
val += '\f';
break;
case '\r':
case '\n':
string_ignoring_newline = true;
break;
default:
// PDF spec says backslash is ignored before anything else
val += ch;
break;
}
}
else if (ch == '\\')
{
// last_char_was_bs is set/cleared below as appropriate
if (bs_num_count)
{
throw std::logic_error(
"INTERNAL ERROR: QPDFTokenizer: bs_num_count != 0 "
"when ch == '\\'");
}
}
else if (ch == '(')
{
val += ch;
++string_depth;
}
else if ((ch == ')') && (--string_depth == 0))
{
type = tt_string;
state = st_token_ready;
}
else
{
val += ch;
}
last_char_was_bs = ((! last_char_was_bs) && (ch == '\\'));
}
else if (state == st_literal)
{
if (strchr(" \t\n\v\f\r()<>[]{}/%", ch) != 0)
{
// A C-locale whitespace character or delimiter terminates
// token. It is important to unread the whitespace
// character even though it is ignored since it may be the
// newline after a stream keyword. Removing it here could
// make the stream-reading code break on some files,
// though not on any files in the test suite as of this
// writing.
type = tt_word;
unread_char = true;
char_to_unread = ch;
state = st_token_ready;
}
else
{
val += ch;
}
}
else
{
handled = false;
}
if (handled)
{
// okay
}
else if (state == st_in_hexstring)
{
if (ch == '>')
{
type = tt_string;
state = st_token_ready;
if (val.length() % 2)
{
// PDF spec says odd hexstrings have implicit
// trailing 0.
val += '0';
}
char num[3];
num[2] = '\0';
std::string nval;
for (unsigned int i = 0; i < val.length(); i += 2)
{
num[0] = val[i];
num[1] = val[i+1];
char nch = (char)(strtol(num, 0, 16));
nval += nch;
}
val = nval;
}
else if (is_hex_digit(ch))
{
val += ch;
}
else if (strchr(" \t\n\v\f\r", ch))
{
// ignore
}
else
{
type = tt_bad;
QTC::TC("qpdf", "QPDF_Tokenizer bad (");
error_message = std::string("invalid character (") +
ch + ") in hexstring";
state = st_token_ready;
}
}
else
{
throw std::logic_error(
"INTERNAL ERROR: invalid state while reading token");
}
if ((state == st_token_ready) && (type == tt_word))
{
if ((val.length() > 0) && (val[0] == '/'))
{
type = tt_name;
// Deal with # in name token. Note: '/' by itself is a
// valid name, so don't strip leading /. That way we
// don't have to deal with the empty string as a name.
std::string nval = "/";
char const* valstr = val.c_str() + 1;
for (char const* p = valstr; *p; ++p)
{
if ((*p == '#') && this->pound_special_in_name)
{
if (p[1] && p[2] &&
is_hex_digit(p[1]) && is_hex_digit(p[2]))
{
char num[3];
num[0] = p[1];
num[1] = p[2];
num[2] = '\0';
char ch = (char)(strtol(num, 0, 16));
if (ch == '\0')
{
type = tt_bad;
QTC::TC("qpdf", "QPDF_Tokenizer null in name");
error_message =
"null character not allowed in name token";
nval += "#00";
}
else
{
nval += ch;
}
p += 2;
}
else
{
QTC::TC("qpdf", "QPDF_Tokenizer bad name");
type = tt_bad;
error_message = "invalid name token";
nval += *p;
}
}
else
{
nval += *p;
}
}
val = nval;
}
else if (num_re.match(val.c_str()))
{
if (val.find('.') != std::string::npos)
{
type = tt_real;
}
else
{
type = tt_integer;
}
}
else if ((val == "true") || (val == "false"))
{
type = tt_bool;
}
else if (val == "null")
{
type = tt_null;
}
else
{
// I don't really know what it is, so leave it as tt_word.
// Lots of cases ($, #, etc.) other than actual words fall
// into this category, but that's okay at least for now.
type = tt_word;
}
}
if (! (betweenTokens() || ((state == st_token_ready) && unread_char)))
{
this->raw_val += orig_ch;
}
}
void
QPDFTokenizer::presentEOF()
{
switch (state)
{
case st_token_ready:
case st_top:
// okay
break;
case st_in_comment:
state = st_top;
break;
default:
type = tt_bad;
error_message = "EOF while reading token";
state = st_token_ready;
}
}
bool
QPDFTokenizer::getToken(Token& token, bool& unread_char, char& ch)
{
bool ready = (this->state == st_token_ready);
unread_char = this->unread_char;
ch = this->char_to_unread;
if (ready)
{
token = Token(type, val, raw_val, error_message);
reset();
}
return ready;
}
bool
QPDFTokenizer::betweenTokens()
{
return ((state == st_top) || (state == st_in_comment));
}