679 lines
14 KiB
C
679 lines
14 KiB
C
//
|
||
// PDF token parsing functions for PDFio.
|
||
//
|
||
// Copyright © 2021-2023 by Michael R Sweet.
|
||
//
|
||
// Licensed under Apache License v2.0. See the file "LICENSE" for more
|
||
// information.
|
||
//
|
||
|
||
#include "pdfio-private.h"
|
||
|
||
|
||
//
|
||
// This file parses PDF language syntax:
|
||
//
|
||
// << dict >> "<<" and ">>" delimit a dictionary
|
||
// (string) "(" and ")" delimit a string
|
||
// [array] "[" and "]" delimit an array
|
||
// <hex-string> "<" and ">" delimit a hex string
|
||
// {...} "{" and "}" are reserved as future delimiters
|
||
// /name "/" starts a name with any special characters
|
||
// quoted as "#HH" where HH is the byte value in hex.
|
||
// %comment "%" starts a comment to the end of a line
|
||
// keyword A keyword consists of other unreserved characters
|
||
// [-+]?[0-9]*(.[0-9]*)? A number optionally starts with "+" or "-".
|
||
//
|
||
// Newlines are CR, LF, or CR LF.
|
||
//
|
||
// Strings and names are returned with the leading delimiter ("(string",
|
||
// "<hex-string", "/name") and all escaping/whitespace removal resolved.
|
||
// Other delimiters, keywords, and numbers are returned as-is.
|
||
//
|
||
|
||
|
||
//
|
||
// Constants...
|
||
//
|
||
|
||
#define PDFIO_NUMBER_CHARS "0123456789-+."
|
||
#define PDFIO_DELIM_CHARS "<>(){}[]/%"
|
||
|
||
|
||
//
|
||
// Local functions...
|
||
//
|
||
|
||
static int get_char(_pdfio_token_t *tb);
|
||
|
||
|
||
//
|
||
// '_pdfioTokenClear()' - Clear the token stack.
|
||
//
|
||
|
||
void
|
||
_pdfioTokenClear(_pdfio_token_t *tb) // I - Token buffer/stack
|
||
{
|
||
PDFIO_DEBUG("_pdfioTokenClear(tb=%p)\n", tb);
|
||
|
||
while (tb->num_tokens > 0)
|
||
{
|
||
tb->num_tokens --;
|
||
free(tb->tokens[tb->num_tokens]);
|
||
tb->tokens[tb->num_tokens] = NULL;
|
||
}
|
||
}
|
||
|
||
|
||
//
|
||
// '_pdfioTokenFlush()' - Flush (consume) any bytes that have been used.
|
||
//
|
||
|
||
void
|
||
_pdfioTokenFlush(_pdfio_token_t *tb) // I - Token buffer/stack
|
||
{
|
||
if (tb->bufptr > tb->buffer)
|
||
{
|
||
size_t remaining = (size_t)(tb->bufend - tb->bufptr);
|
||
// Remaining bytes in buffer
|
||
|
||
// Consume what we've used...
|
||
PDFIO_DEBUG("_pdfioTokenFlush: Consuming %d bytes.\n", (int)(tb->bufptr - tb->buffer));
|
||
(tb->consume_cb)(tb->cb_data, (size_t)(tb->bufptr - tb->buffer));
|
||
|
||
if (remaining > 0)
|
||
{
|
||
// Shuffle remaining bytes for next call...
|
||
memmove(tb->buffer, tb->bufptr, remaining);
|
||
tb->bufptr = tb->buffer;
|
||
tb->bufend = tb->buffer + remaining;
|
||
|
||
#ifdef DEBUG
|
||
unsigned char *ptr; // Pointer into buffer
|
||
|
||
PDFIO_DEBUG("_pdfioTokenFlush: Remainder '");
|
||
for (ptr = tb->buffer; ptr < tb->bufend; ptr ++)
|
||
{
|
||
if (*ptr < ' ' || *ptr == 0x7f)
|
||
PDFIO_DEBUG("\\%03o", *ptr);
|
||
else
|
||
PDFIO_DEBUG("%c", *ptr);
|
||
}
|
||
PDFIO_DEBUG("'\n");
|
||
#endif // DEBUG
|
||
}
|
||
else
|
||
{
|
||
// Nothing left, reset pointers...
|
||
PDFIO_DEBUG("_pdfioTokenFlush: Resetting pointers.\n");
|
||
tb->bufptr = tb->bufend = tb->buffer;
|
||
}
|
||
}
|
||
}
|
||
|
||
|
||
//
|
||
// '_pdfioTokenGet()' - Get a token.
|
||
//
|
||
|
||
bool // O - `true` on success, `false` on failure
|
||
_pdfioTokenGet(_pdfio_token_t *tb, // I - Token buffer/stack
|
||
char *buffer, // I - String buffer
|
||
size_t bufsize) // I - Size of string buffer
|
||
{
|
||
// See if we have a token waiting on the stack...
|
||
if (tb->num_tokens > 0)
|
||
{
|
||
// Yes, return it...
|
||
size_t len; // Length of token
|
||
|
||
tb->num_tokens --;
|
||
|
||
if ((len = strlen(tb->tokens[tb->num_tokens])) > (bufsize - 1))
|
||
{
|
||
// Value too large...
|
||
PDFIO_DEBUG("_pdfioTokenGet(tb=%p, buffer=%p, bufsize=%u): Token '%s' from stack too large.\n", tb, buffer, (unsigned)bufsize, tb->tokens[tb->num_tokens]);
|
||
*buffer = '\0';
|
||
return (false);
|
||
}
|
||
|
||
memcpy(buffer, tb->tokens[tb->num_tokens], len);
|
||
buffer[len] = '\0';
|
||
|
||
PDFIO_DEBUG("_pdfioTokenGet(tb=%p, buffer=%p, bufsize=%u): Popping '%s' from stack.\n", tb, buffer, (unsigned)bufsize, buffer);
|
||
|
||
free(tb->tokens[tb->num_tokens]);
|
||
tb->tokens[tb->num_tokens] = NULL;
|
||
|
||
return (true);
|
||
}
|
||
|
||
// No, read a new one...
|
||
return (_pdfioTokenRead(tb, buffer, bufsize));
|
||
}
|
||
|
||
|
||
//
|
||
// '_pdfioTokenInit()' - Initialize a token buffer/stack.
|
||
//
|
||
|
||
void
|
||
_pdfioTokenInit(
|
||
_pdfio_token_t *ts, // I - Token buffer/stack
|
||
pdfio_file_t *pdf, // I - PDF file
|
||
_pdfio_tconsume_cb_t consume_cb, // I - Consume callback
|
||
_pdfio_tpeek_cb_t peek_cb, // I - Peek callback
|
||
void *cb_data) // I - Callback data
|
||
{
|
||
// Zero everything out and then initialize key pointers...
|
||
memset(ts, 0, sizeof(_pdfio_token_t));
|
||
|
||
ts->pdf = pdf;
|
||
ts->consume_cb = consume_cb;
|
||
ts->peek_cb = peek_cb;
|
||
ts->cb_data = cb_data;
|
||
ts->bufptr = ts->buffer;
|
||
ts->bufend = ts->buffer;
|
||
}
|
||
|
||
|
||
//
|
||
// '_pdfioTokenPush()' - Push a token on the token stack.
|
||
//
|
||
|
||
void
|
||
_pdfioTokenPush(_pdfio_token_t *tb, // I - Token buffer/stack
|
||
const char *token) // I - Token to push
|
||
{
|
||
if (tb->num_tokens < (sizeof(tb->tokens) / sizeof(tb->tokens[0])))
|
||
{
|
||
if ((tb->tokens[tb->num_tokens ++] = strdup(token)) == NULL)
|
||
tb->num_tokens --;
|
||
}
|
||
}
|
||
|
||
|
||
//
|
||
// '_pdfioTokenRead()' - Read a token from a file/stream.
|
||
//
|
||
|
||
bool // O - `true` on success, `false` on failure
|
||
_pdfioTokenRead(_pdfio_token_t *tb, // I - Token buffer/stack
|
||
char *buffer, // I - String buffer
|
||
size_t bufsize) // I - Size of string buffer
|
||
{
|
||
int ch, // Character
|
||
parens = 0; // Parenthesis level
|
||
char *bufptr, // Pointer into buffer
|
||
*bufend, // End of buffer
|
||
state = '\0'; // Current state
|
||
bool saw_nul = false; // Did we see a nul character?
|
||
size_t count = 0; // Number of whitespace/comment bytes
|
||
|
||
|
||
|
||
// "state" is:
|
||
//
|
||
// - '\0' for idle
|
||
// - '(' for literal string
|
||
// - '/' for name
|
||
// - '<' for possible hex string or dict
|
||
// - '>' for possible dict
|
||
// - '%' for comment
|
||
// - 'K' for keyword
|
||
// - 'N' for number
|
||
|
||
// Read the next token, skipping any leading whitespace...
|
||
bufptr = buffer;
|
||
bufend = buffer + bufsize - 1;
|
||
|
||
// Skip leading whitespace...
|
||
while ((ch = get_char(tb)) != EOF)
|
||
{
|
||
count ++;
|
||
|
||
if (ch == '%')
|
||
{
|
||
// Skip comment
|
||
PDFIO_DEBUG("_pdfioTokenRead: Skipping comment...\n");
|
||
while ((ch = get_char(tb)) != EOF)
|
||
{
|
||
count ++;
|
||
|
||
if (ch == '\n' || ch == '\r')
|
||
{
|
||
break;
|
||
}
|
||
else if (count > 2048)
|
||
{
|
||
_pdfioFileError(tb->pdf, "Comment too long.");
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
}
|
||
}
|
||
else if (!isspace(ch))
|
||
{
|
||
break;
|
||
}
|
||
else if (count > 2048)
|
||
{
|
||
_pdfioFileError(tb->pdf, "Too much whitespace.");
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
}
|
||
|
||
if (ch == EOF)
|
||
{
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
|
||
// Check for delimiters...
|
||
if (strchr(PDFIO_DELIM_CHARS, ch) != NULL)
|
||
{
|
||
*bufptr++ = state = (char)ch;
|
||
}
|
||
else if (strchr(PDFIO_NUMBER_CHARS, ch) != NULL)
|
||
{
|
||
// Number
|
||
state = 'N';
|
||
*bufptr++ = (char)ch;
|
||
}
|
||
else
|
||
{
|
||
// Keyword
|
||
state = 'K';
|
||
*bufptr++ = (char)ch;
|
||
}
|
||
|
||
PDFIO_DEBUG("_pdfioTokenRead: state='%c'\n", state);
|
||
|
||
switch (state)
|
||
{
|
||
case '(' : // Literal string
|
||
while ((ch = get_char(tb)) != EOF)
|
||
{
|
||
if (ch == 0)
|
||
saw_nul = true;
|
||
|
||
if (ch == '\\')
|
||
{
|
||
// Quoted character...
|
||
int i; // Looping var
|
||
|
||
switch (ch = get_char(tb))
|
||
{
|
||
case '0' : // Octal character escape
|
||
case '1' :
|
||
case '2' :
|
||
case '3' :
|
||
case '4' :
|
||
case '5' :
|
||
case '6' :
|
||
case '7' :
|
||
for (ch -= '0', i = 0; i < 2; i ++)
|
||
{
|
||
int tch = get_char(tb); // Next char
|
||
|
||
if (tch >= '0' && tch <= '7')
|
||
{
|
||
ch = (char)((ch << 3) | (tch - '0'));
|
||
}
|
||
else
|
||
{
|
||
tb->bufptr --;
|
||
break;
|
||
}
|
||
}
|
||
break;
|
||
|
||
case '\\' :
|
||
case '(' :
|
||
case ')' :
|
||
break;
|
||
|
||
case 'n' :
|
||
ch = '\n';
|
||
break;
|
||
|
||
case 'r' :
|
||
ch = '\r';
|
||
break;
|
||
|
||
case 't' :
|
||
ch = '\t';
|
||
break;
|
||
|
||
case 'b' :
|
||
ch = '\b';
|
||
break;
|
||
|
||
case 'f' :
|
||
ch = '\f';
|
||
break;
|
||
|
||
default :
|
||
// Ignore blackslash per PDF spec...
|
||
break;
|
||
}
|
||
}
|
||
else if (ch == '(')
|
||
{
|
||
// Keep track of parenthesis
|
||
parens ++;
|
||
}
|
||
else if (ch == ')')
|
||
{
|
||
if (parens == 0)
|
||
break;
|
||
|
||
parens --;
|
||
}
|
||
|
||
if (bufptr < bufend)
|
||
{
|
||
// Normal character...
|
||
*bufptr++ = (char)ch;
|
||
}
|
||
else
|
||
{
|
||
// Out of space
|
||
_pdfioFileError(tb->pdf, "Token too large.");
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
}
|
||
|
||
if (ch != ')')
|
||
{
|
||
_pdfioFileError(tb->pdf, "Unterminated string literal.");
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
|
||
if (saw_nul)
|
||
{
|
||
// Convert to a hex (binary) string...
|
||
char *litptr, // Pointer to literal character
|
||
*hexptr; // Pointer to hex character
|
||
size_t bytes = (size_t)(bufptr - buffer - 1);
|
||
// Bytes of data...
|
||
static const char *hexchars = "0123456789ABCDEF";
|
||
// Hex digits
|
||
|
||
PDFIO_DEBUG("_pdfioTokenRead: Converting nul-containing string to binary.\n");
|
||
|
||
if ((2 * (bytes + 1)) > bufsize)
|
||
{
|
||
// Out of space...
|
||
_pdfioFileError(tb->pdf, "Token too large.");
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
|
||
*buffer = '<';
|
||
for (litptr = bufptr - 1, hexptr = buffer + 2 * bytes - 1; litptr > buffer; litptr --, hexptr -= 2)
|
||
{
|
||
int litch = *litptr; // Grab the character
|
||
|
||
hexptr[0] = hexchars[(litch >> 4) & 15];
|
||
hexptr[1] = hexchars[litch & 15];
|
||
}
|
||
bufptr = buffer + 2 * bytes + 1;
|
||
}
|
||
break;
|
||
|
||
case 'K' : // keyword
|
||
while ((ch = get_char(tb)) != EOF && !isspace(ch))
|
||
{
|
||
if (strchr(PDFIO_DELIM_CHARS, ch) != NULL)
|
||
{
|
||
// End of keyword...
|
||
tb->bufptr --;
|
||
break;
|
||
}
|
||
else if (bufptr < bufend)
|
||
{
|
||
// Normal character...
|
||
*bufptr++ = (char)ch;
|
||
}
|
||
else
|
||
{
|
||
// Out of space...
|
||
_pdfioFileError(tb->pdf, "Token too large.");
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
}
|
||
|
||
if (ch == '\r')
|
||
{
|
||
// Look for a trailing LF
|
||
if ((ch = get_char(tb)) != EOF && ch != '\n')
|
||
tb->bufptr --;
|
||
}
|
||
break;
|
||
|
||
case 'N' : // number
|
||
while ((ch = get_char(tb)) != EOF && !isspace(ch))
|
||
{
|
||
if (!isdigit(ch) && ch != '.')
|
||
{
|
||
// End of number...
|
||
PDFIO_DEBUG("_pdfioTokenRead: End of number with ch=0x%02x\n", ch);
|
||
tb->bufptr --;
|
||
break;
|
||
}
|
||
else if (bufptr < bufend)
|
||
{
|
||
// Normal character...
|
||
*bufptr++ = (char)ch;
|
||
}
|
||
else
|
||
{
|
||
// Out of space...
|
||
_pdfioFileError(tb->pdf, "Token too large.");
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
}
|
||
break;
|
||
|
||
case '/' : // "/name"
|
||
while ((ch = get_char(tb)) != EOF && !isspace(ch))
|
||
{
|
||
if (strchr(PDFIO_DELIM_CHARS, ch) != NULL)
|
||
{
|
||
// End of keyword...
|
||
tb->bufptr --;
|
||
break;
|
||
}
|
||
else if (ch == '#')
|
||
{
|
||
// Quoted character (#xx) in name...
|
||
int i; // Looping var
|
||
|
||
for (i = 0, ch = 0; i < 2; i ++)
|
||
{
|
||
int tch = get_char(tb);
|
||
|
||
if (!isxdigit(tch & 255))
|
||
{
|
||
_pdfioFileError(tb->pdf, "Bad # escape in name.");
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
else if (isdigit(tch))
|
||
{
|
||
ch = ((ch & 255) << 4) | (tch - '0');
|
||
}
|
||
else
|
||
{
|
||
ch = ((ch & 255) << 4) | (tolower(tch) - 'a' + 10);
|
||
}
|
||
}
|
||
}
|
||
|
||
if (bufptr < bufend)
|
||
{
|
||
*bufptr++ = (char)ch;
|
||
}
|
||
else
|
||
{
|
||
// Out of space
|
||
_pdfioFileError(tb->pdf, "Token too large.");
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
}
|
||
|
||
if (bufptr == (buffer + 1))
|
||
{
|
||
_pdfioFileError(tb->pdf, "Empty name.");
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
break;
|
||
|
||
case '<' : // Potential hex string
|
||
if ((ch = get_char(tb)) == '<')
|
||
{
|
||
// Dictionary delimiter
|
||
*bufptr++ = (char)ch;
|
||
break;
|
||
}
|
||
else if (ch == '>')
|
||
{
|
||
// Issue #46: Empty hex string from Microsoft PDF generator; treat as
|
||
// empty literal string...
|
||
*buffer = '(';
|
||
break;
|
||
}
|
||
else if (!isspace(ch & 255) && !isxdigit(ch & 255))
|
||
{
|
||
_pdfioFileError(tb->pdf, "Syntax error: '<%c'", ch);
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
|
||
count = 0;
|
||
|
||
do
|
||
{
|
||
if (isxdigit(ch))
|
||
{
|
||
if (bufptr < bufend)
|
||
{
|
||
// Hex digit
|
||
*bufptr++ = (char)ch;
|
||
count = 0;
|
||
}
|
||
else
|
||
{
|
||
// Too large
|
||
_pdfioFileError(tb->pdf, "Token too large.");
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
}
|
||
else if (!isspace(ch))
|
||
{
|
||
_pdfioFileError(tb->pdf, "Invalid hex string character '%c'.", ch);
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
else
|
||
{
|
||
count ++;
|
||
if (count > 2048)
|
||
{
|
||
_pdfioFileError(tb->pdf, "Too much whitespace.");
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
}
|
||
}
|
||
while ((ch = get_char(tb)) != EOF && ch != '>');
|
||
|
||
if (ch == EOF)
|
||
{
|
||
_pdfioFileError(tb->pdf, "Unterminated hex string.");
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
break;
|
||
|
||
case '>' : // Dictionary
|
||
if ((ch = get_char(tb)) == '>')
|
||
{
|
||
*bufptr++ = '>';
|
||
}
|
||
else
|
||
{
|
||
_pdfioFileError(tb->pdf, "Syntax error: '>%c'.", ch);
|
||
*bufptr = '\0';
|
||
return (false);
|
||
}
|
||
break;
|
||
}
|
||
|
||
*bufptr = '\0';
|
||
|
||
PDFIO_DEBUG("_pdfioTokenRead: Read '%s'.\n", buffer);
|
||
|
||
return (bufptr > buffer);
|
||
}
|
||
|
||
|
||
//
|
||
// 'get_char()' - Get a character from the token buffer.
|
||
//
|
||
|
||
static int // O - Character or `EOF` on end-of-file
|
||
get_char(_pdfio_token_t *tb) // I - Token buffer
|
||
{
|
||
ssize_t bytes; // Bytes peeked
|
||
|
||
|
||
// Refill the buffer as needed...
|
||
if (tb->bufptr >= tb->bufend)
|
||
{
|
||
// Consume previous bytes...
|
||
if (tb->bufend > tb->buffer)
|
||
{
|
||
PDFIO_DEBUG("get_char: Consuming %d bytes.\n", (int)(tb->bufend - tb->buffer));
|
||
(tb->consume_cb)(tb->cb_data, (size_t)(tb->bufend - tb->buffer));
|
||
}
|
||
|
||
// Peek new bytes...
|
||
if ((bytes = (tb->peek_cb)(tb->cb_data, tb->buffer, sizeof(tb->buffer))) <= 0)
|
||
{
|
||
tb->bufptr = tb->bufend = tb->buffer;
|
||
return (EOF);
|
||
}
|
||
|
||
// Update pointers...
|
||
tb->bufptr = tb->buffer;
|
||
tb->bufend = tb->buffer + bytes;
|
||
|
||
#ifdef DEBUG
|
||
unsigned char *ptr; // Pointer into buffer
|
||
|
||
PDFIO_DEBUG("get_char: Read '");
|
||
for (ptr = tb->buffer; ptr < tb->bufend; ptr ++)
|
||
{
|
||
if (*ptr < ' ' || *ptr == 0x7f)
|
||
PDFIO_DEBUG("\\%03o", *ptr);
|
||
else
|
||
PDFIO_DEBUG("%c", *ptr);
|
||
}
|
||
PDFIO_DEBUG("'\n");
|
||
#endif // DEBUG
|
||
}
|
||
|
||
// Return the next character...
|
||
return (*(tb->bufptr)++);
|
||
}
|