pack.c

/*
   +----------------------------------------------------------------------+
   | PHP Version 4                                                        |
   +----------------------------------------------------------------------+
   | Copyright (c) 1997-2002 The PHP Group                                |
   +----------------------------------------------------------------------+
   | This source file is subject to version 2.02 of the PHP license,      |
   | that is bundled with this package in the file LICENSE, and is        |
   | available at through the world-wide-web at                           |
   | http://www.php.net/license/2_02.txt.                                 |
   | If you did not receive a copy of the PHP license and are unable to   |
   | obtain it through the world-wide-web, please send a note to          |
   | license@php.net so we can mail you a copy immediately.               |
   +----------------------------------------------------------------------+
   | Author: Chris Schneider <cschneid@relog.ch>                          |
   +----------------------------------------------------------------------+
 */
/* $Id$ */

#include "php.h"

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#ifdef PHP_WIN32
#include <windows.h>
#include <winsock.h>
#define O_RDONLY _O_RDONLY
#include "win32/param.h"
#else
#include <sys/param.h>
#endif
#include "ext/standard/head.h"
#include "safe_mode.h"
#include "php_string.h"
#include "pack.h"
#if HAVE_PWD_H
#ifdef PHP_WIN32
#include "win32/pwd.h"
#else
#include <pwd.h>
#endif
#endif
#include "fsock.h"
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif

/* Whether machine is little endian */
char machine_little_endian;

/* Mapping of byte from char (8bit) to long for machine endian */
static int byte_map[1];

/* Mappings of bytes from int (machine dependant) to int for machine endian */
static int int_map[sizeof(int)];

/* Mappings of bytes from shorts (16bit) for all endian environments */
static int machine_endian_short_map[2];
static int big_endian_short_map[2];
static int little_endian_short_map[2];

/* Mappings of bytes from longs (32bit) for all endian environments */
static int machine_endian_long_map[4];
static int big_endian_long_map[4];
static int little_endian_long_map[4];

/* {{{ php_pack
 */
static void php_pack(zval **val, int size, int *map, char *output)
{
	int i;
	char *v;

	convert_to_long_ex(val);
	v = (char *) &Z_LVAL_PP(val);

	for (i = 0; i < size; i++) {
		*output++ = v[map[i]];
	}
}
/* }}} */

/* pack() idea stolen from Perl (implemented formats behave the same as there)
 * Implemented formats are A, a, h, H, c, C, s, S, i, I, l, L, n, N, f, d, x, X, @.
 */
/* {{{ proto string pack(string format, mixed arg1 [, mixed arg2 [, mixed ...]])
   Takes one or more arguments and packs them into a binary string according to the format argument */
PHP_FUNCTION(pack)
{
	zval ***argv;
	int argc, i;
	int currentarg;
	char *format;
	int formatlen;
	char *formatcodes;
	int *formatargs;
	int formatcount = 0;
	int outputpos = 0, outputsize = 0;
	char *output;

	argc = ZEND_NUM_ARGS();

	if (argc < 1) {
		WRONG_PARAM_COUNT;
	}

	argv = emalloc(argc * sizeof(zval **));

	if (zend_get_parameters_array_ex(argc, argv) == FAILURE) {
		efree(argv);
		WRONG_PARAM_COUNT;
	}

	convert_to_string_ex(argv[0]);
	format = Z_STRVAL_PP(argv[0]);
	formatlen = Z_STRLEN_PP(argv[0]);

	/* We have a maximum of <formatlen> format codes to deal with */
	formatcodes = emalloc(formatlen * sizeof(*formatcodes));
	formatargs = emalloc(formatlen * sizeof(*formatargs));
	currentarg = 1;

	/* Preprocess format into formatcodes and formatargs */
	for (i = 0; i < formatlen; formatcount++) {
		char code = format[i++];
		int arg = 1;

		/* Handle format arguments if any */
		if (i < formatlen) {
			char c = format[i];

			if (c == '*') {
				arg = -1;
				i++;
			}
			else if (c >= '0' && c <= '9') {
				arg = atoi(&format[i]);
		  
				while (format[i] >= '0' && format[i] <= '9' && i < formatlen) {
					i++;
				}
			}
		}

		/* Handle special arg '*' for all codes and check argv overflows */
		switch ((int) code) {
			/* Never uses any args */
			case 'x': 
			case 'X':	
			case '@':
				if (arg < 0) {
					php_error(E_WARNING, "pack type %c: '*' ignored", code);
					arg = 1;
				}
				break;

			/* Always uses one arg */
			case 'a': 
			case 'A': 
			case 'h': 
			case 'H':
				if (currentarg >= argc) {
					efree(argv);
					efree(formatcodes);
					efree(formatargs);
					php_error(E_WARNING, "pack type %c: not enough arguments", code);
					RETURN_FALSE;
				}

				if (arg < 0) {
					arg = Z_STRLEN_PP(argv[currentarg]);
				}

				currentarg++;
				break;

			/* Use as many args as specified */
			case 'c': 
			case 'C': 
			case 's': 
			case 'S': 
			case 'i': 
			case 'I':
			case 'l': 
			case 'L': 
			case 'n': 
			case 'N': 
			case 'v': 
			case 'V':
			case 'f': 
			case 'd': 
				if (arg < 0) {
					arg = argc - currentarg;
				}

				currentarg += arg;

				if (currentarg > argc) {
					efree(argv);
					efree(formatcodes);
					efree(formatargs);
					php_error(E_WARNING, "pack type %c: too few arguments", code);
					RETURN_FALSE;
				}
				break;

			default:
				php_error(E_WARNING, "pack type %c: unknown format code", code);
				RETURN_FALSE;
		}

		formatcodes[formatcount] = code;
		formatargs[formatcount] = arg;
	}

	if (currentarg < argc) {
		php_error(E_WARNING, "pack %d arguments unused", (argc - currentarg));
	}

	/* Calculate output length and upper bound while processing*/
	for (i = 0; i < formatcount; i++) {
	    int code = (int) formatcodes[i];
		int arg = formatargs[i];

		switch ((int) code) {
			case 'h': 
			case 'H': 
				outputpos += (arg + 1) / 2;		/* 4 bit per arg */
				break;

			case 'a': 
			case 'A':
			case 'c': 
			case 'C':
			case 'x':
				outputpos += arg;		/* 8 bit per arg */
				break;

			case 's': 
			case 'S': 
			case 'n': 
			case 'v':
				outputpos += arg * 2;	/* 16 bit per arg */
				break;

			case 'i': 
			case 'I':
				outputpos += arg * sizeof(int);
				break;

			case 'l': 
			case 'L': 
			case 'N': 
			case 'V':
				outputpos += arg * 4;	/* 32 bit per arg */
				break;

			case 'f':
				outputpos += arg * sizeof(float);
				break;

			case 'd':
				outputpos += arg * sizeof(double);
				break;

			case 'X':
				outputpos -= arg;

				if (outputpos < 0) {
					php_error(E_WARNING, "pack type %c: outside of string", code);
					outputpos = 0;
				}
				break;

			case '@':
				outputpos = arg;
				break;
		}

		if (outputsize < outputpos) {
			outputsize = outputpos;
		}
	}

	output = emalloc(outputsize + 1);
	outputpos = 0;
	currentarg = 1;

	/* Do actual packing */
	for (i = 0; i < formatcount; i++) {
	    int code = (int) formatcodes[i];
		int arg = formatargs[i];
		zval **val;

		switch ((int) code) {
			case 'a': 
			case 'A': 
				memset(&output[outputpos], (code == 'a') ? '\0' : ' ', arg);
				val = argv[currentarg++];
				convert_to_string_ex(val);
				memcpy(&output[outputpos], Z_STRVAL_PP(val),
					   (Z_STRLEN_PP(val) < arg) ? Z_STRLEN_PP(val) : arg);
				outputpos += arg;
				break;

			case 'h': 
			case 'H': {
				int nibbleshift = (code == 'h') ? 0 : 4;
				int first = 1;
				char *v;

				val = argv[currentarg++];
				convert_to_string_ex(val);
				v = Z_STRVAL_PP(val);
				outputpos--;
				if(arg > Z_STRLEN_PP(val)) {
					php_error(E_WARNING, "pack type %c: not enough characters in string", code);
					arg = Z_STRLEN_PP(val);
				}

				while (arg-- > 0) {
					char n = *v++;

					if (n >= '0' && n <= '9') {
						n -= '0';
					} else if (n >= 'A' && n <= 'F') {
						n -= ('A' - 10);
					} else if (n >= 'a' && n <= 'f') {
						n -= ('a' - 10);
					} else {
						php_error(E_WARNING, "pack type %c: illegal hex digit %c", code, n);
						n = 0;
					}

					if (first--) {
						output[++outputpos] = 0;
					} else {
					  first = 1;
					}

					output[outputpos] |= (n << nibbleshift);
					nibbleshift = (nibbleshift + 4) & 7;
				}

				outputpos++;
				break;
			}

			case 'c': 
			case 'C':
				while (arg-- > 0) {
					php_pack(argv[currentarg++], 1, byte_map, &output[outputpos]);
					outputpos++;
				}
				break;

			case 's': 
			case 'S': 
			case 'n': 
			case 'v': {
				int *map = machine_endian_short_map;

				if (code == 'n') {
					map = big_endian_short_map;
				} else if (code == 'v') {
					map = little_endian_short_map;
				}

				while (arg-- > 0) {
					php_pack(argv[currentarg++], 2, map, &output[outputpos]);
					outputpos += 2;
				}
				break;
			}

			case 'i': 
			case 'I': 
				while (arg-- > 0) {
					php_pack(argv[currentarg++], sizeof(int), int_map, &output[outputpos]);
					outputpos += sizeof(int);
				}
				break;

			case 'l': 
			case 'L': 
			case 'N': 
			case 'V': {
				int *map = machine_endian_long_map;

				if (code == 'N') {
					map = big_endian_long_map;
				} else if (code == 'V') {
					map = little_endian_long_map;
				}

				while (arg-- > 0) {
					php_pack(argv[currentarg++], 4, map, &output[outputpos]);
					outputpos += 4;
				}
				break;
			}

			case 'f': {
				float v;

				while (arg-- > 0) {
					val = argv[currentarg++];
					convert_to_double_ex(val);
					v = (float) Z_DVAL_PP(val);
					memcpy(&output[outputpos], &v, sizeof(v));
					outputpos += sizeof(v);
				}
				break;
			}

			case 'd': {
				double v;

				while (arg-- > 0) {
					val = argv[currentarg++];
					convert_to_double_ex(val);
					v = (double) Z_DVAL_PP(val);
					memcpy(&output[outputpos], &v, sizeof(v));
					outputpos += sizeof(v);
				}
				break;
			}

			case 'x':
				memset(&output[outputpos], '\0', arg);
				outputpos += arg;
				break;

			case 'X':
				outputpos -= arg;

				if (outputpos < 0) {
					outputpos = 0;
				}
				break;

			case '@':
				if (arg > outputpos) {
					memset(&output[outputpos], '\0', arg - outputpos);
				}
				outputpos = arg;
				break;
		}
	}

	efree(argv);
	efree(formatcodes);
	efree(formatargs);
	output[outputpos] = '\0';
	RETVAL_STRINGL(output, outputpos, 1);
	efree(output);
}
/* }}} */

/* {{{ php_unpack
 */
static long php_unpack(char *data, int size, int issigned, int *map)
{
	long result;
	char *cresult = (char *) &result;
	int i;

	result = issigned ? -1 : 0;

	for (i = 0; i < size; i++) {
		cresult[map[i]] = *data++;
	}

	return result;
}
/* }}} */

/* unpack() is based on Perl's unpack(), but is modified a bit from there.
 * Rather than depending on error-prone ordered lists or syntactically
 * unpleasant pass-by-reference, we return an object with named paramters 
 * (like *_fetch_object()). Syntax is "f[repeat]name/...", where "f" is the
 * formatter char (like pack()), "[repeat]" is the optional repeater argument,
 * and "name" is the name of the variable to use.
 * Example: "c2chars/nints" will return an object with fields
 * chars1, chars2, and ints.
 * Numeric pack types will return numbers, a and A will return strings,
 * f and d will return doubles.
 * Implemented formats are A, a, h, H, c, C, s, S, i, I, l, L, n, N, f, d, x, X, @.
 */
/* {{{ proto array unpack(string format, string input)
   Unpack binary string into named array elements according to format argument */
PHP_FUNCTION(unpack)
{
	zval **formatarg;
	zval **inputarg;
	char *format;
	char *input;
	int formatlen;
	int inputpos, inputlen;
	int i;

	if (ZEND_NUM_ARGS() != 2 || 
        zend_get_parameters_ex(2, &formatarg, &inputarg) == FAILURE) {
		WRONG_PARAM_COUNT;
	}

	convert_to_string_ex(formatarg);
	convert_to_string_ex(inputarg);

	format = Z_STRVAL_PP(formatarg);
	formatlen = Z_STRLEN_PP(formatarg);
	input = Z_STRVAL_PP(inputarg);
	inputlen = Z_STRLEN_PP(inputarg);
	inputpos = 0;

	if (array_init(return_value) == FAILURE)
		return;

	while (formatlen-- > 0) {
		char type = *(format++);
		char c;
		int arg = 1;
		char *name;
		int namelen;
		int size=0;

		/* Handle format arguments if any */
		if (formatlen > 0) {
			c = *format;

			if (c >= '0' && c <= '9') {
				arg = atoi(format);

				while (formatlen > 0 && *format >= '0' && *format <= '9') {
					format++;
					formatlen--;
				}
			} else if (c == '*') {
				arg = -1;
				format++;
				formatlen--;
			}
		}

		/* Get of new value in array */
		name = format;

		while (formatlen > 0 && *format != '/') {
			formatlen--;
			format++;
		}

		namelen = format - name;

		if (namelen > 200)
			namelen = 200;

		switch ((int) type) {
			/* Never use any input */
			case 'X': 
				size = -1;
				break;

			case '@':
				size = 0;
				break;

			case 'a': 
			case 'A':
				size = arg;
				arg = 1;
				break;

			case 'h': 
			case 'H': 
				size = (arg > 0) ? arg / 2 : arg;
				arg = 1;
				break;

			/* Use 1 byte of input */
			case 'c': 
			case 'C':
			case 'x':
				size = 1;
				break;

			/* Use 2 bytes of input */
			case 's': 
			case 'S': 
			case 'n': 
			case 'v':
				size = 2;
				break;

			/* Use sizeof(int) bytes of input */
			case 'i': 
			case 'I':
				size = sizeof(int);
				break;

			/* Use 4 bytes of input */
			case 'l': 
			case 'L': 
			case 'N': 
			case 'V':
				size = 4;
				break;

			/* Use sizeof(float) bytes of input */
			case 'f':
				size = sizeof(float);
				break;

			/* Use sizeof(double) bytes of input */
			case 'd':
				size = sizeof(double);
				break;
		}

		/* Do actual unpacking */
		for (i = 0; i != arg; i++ ) {
			/* Space for name + number, safe as namelen is ensured <= 200 */
			char n[256];

			if (arg != 1) {
				/* Need to add element number to name */
				sprintf(n, "%.*s%d", namelen, name, i + 1);
			} else {
				/* Truncate name to next format code or end of string */
				sprintf(n, "%.*s", namelen, name);
			}

			if ((inputpos + size) <= inputlen) {
				switch ((int) type) {
					case 'a': 
					case 'A': {
						char pad = (type == 'a') ? '\0' : ' ';
						int len = inputlen - inputpos;	/* Remaining string */

						/* If size was given take minimum of len and size */
						if ((size >= 0) && (len > size)) {
							len = size;
						}

						size = len;

						/* Remove padding chars from unpacked data */
						while (--len >= 0) {
							if (input[inputpos + len] != pad)
								break;
						}

						add_assoc_stringl(return_value, n, &input[inputpos], len + 1, 1);
						break;
					}
					
					case 'h': 
					case 'H': {
						int len = (inputlen - inputpos) * 2;	/* Remaining */
						int nibbleshift = (type == 'h') ? 0 : 4;
						int first = 1;
						char *buf;
						int ipos, opos;

						/* If size was given take minimum of len and size */
						if (size >= 0 && len > (size * 2)) {
							len = size * 2;
						} 

						buf = emalloc(len + 1);

						for (ipos = opos = 0; opos < len; opos++) {
							char c = (input[inputpos + ipos] >> nibbleshift) & 0xf;

							if (c < 10) {
								c += '0';
							} else {
								c += 'a' - 10;
							}

							buf[opos] = c;
							nibbleshift = (nibbleshift + 4) & 7;

							if (first-- == 0) {
								ipos++;
								first = 1;
							}
						}

						buf[len] = '\0';
						add_assoc_stringl(return_value, n, buf, len, 1);
						efree(buf);
						break;
					}

					case 'c': 
					case 'C': {
						int issigned = (type == 'c') ? (input[inputpos] & 0x80) : 0;
						long v = php_unpack(&input[inputpos], 1, issigned, byte_map);
						add_assoc_long(return_value, n, v);
						break;
					}

					case 's': 
					case 'S': 
					case 'n': 
					case 'v': {
						long v;
						int issigned = 0;
						int *map = machine_endian_short_map;

						if (type == 's') {
							issigned = input[inputpos + (machine_little_endian ? 1 : 0)] & 0x80;
						} else if (type == 'n') {
							map = big_endian_short_map;
						} else if (type == 'v') {
							map = little_endian_short_map;
						}

						v = php_unpack(&input[inputpos], 2, issigned, map);
						add_assoc_long(return_value, n, v);
						break;
					}

					case 'i': 
					case 'I': {
						long v;
						int issigned = 0;

						if (type == 'i') {
							issigned = input[inputpos + (machine_little_endian ? (sizeof(int) - 1) : 0)] & 0x80;
						}

						v = php_unpack(&input[inputpos], sizeof(int), issigned, int_map);
						add_assoc_long(return_value, n, v);
						break;
					}

					case 'l': 
					case 'L': 
					case 'N': 
					case 'V': {
						int issigned = 0;
						int *map = machine_endian_long_map;
						long v;

						if (type == 'l') {
							issigned = input[inputpos + (machine_little_endian ? 3 : 0)] & 0x80;
						} else if (type == 'N') {
							map = big_endian_long_map;
						} else if (type == 'V') {
							map = little_endian_long_map;
						}

						v = php_unpack(&input[inputpos], 4, issigned, map);
						add_assoc_long(return_value, n, v);
						break;
					}

					case 'f': {
						float v;

						memcpy(&v, &input[inputpos], sizeof(float));
						add_assoc_double(return_value, n, (double)v);
						break;
					}

					case 'd': {
						double v;

						memcpy(&v, &input[inputpos], sizeof(double));
						add_assoc_double(return_value, n, v);
						break;
					}

					case 'x':
						/* Do nothing with input, just skip it */
						break;

					case 'X':
						if (inputpos < size) {
							inputpos = -size;
							i = arg - 1;		/* Break out of for loop */

							if (arg >= 0) {
								php_error(E_WARNING, "pack type %c: outside of string", type);
							}
						}
						break;

					case '@':
						if (arg <= inputlen) {
							inputpos = arg;
						} else {
							php_error(E_WARNING, "pack type %c: outside of string", type);
						}

						i = arg - 1;	/* Done, break out of for loop */
						break;
				}

				inputpos += size;
			} else if (arg < 0) {
				/* Reached end of input for '*' repeater */
				break;
			} else {
				php_error(E_WARNING, "pack type %c: not enough input, need %d, have %d", type, size, inputlen - inputpos);
				RETURN_FALSE;
			}
		}

		formatlen--;	/* Skip '/' separator, does no harm if inputlen == 0 */
		format++;
	}
}
/* }}} */

/* {{{ PHP_MINIT_FUNCTION
 */
PHP_MINIT_FUNCTION(pack)
{
	int machine_endian_check = 1;
	int i;

	machine_little_endian = ((char *)&machine_endian_check)[0];

	if (machine_little_endian) {
		/* Where to get lo to hi bytes from */
		byte_map[0] = 0;

		for (i = 0; i < sizeof(int); i++) {
			int_map[i] = i;
		}

		machine_endian_short_map[0] = 0;
		machine_endian_short_map[1] = 1;
		big_endian_short_map[0] = 1;
		big_endian_short_map[1] = 0;
		little_endian_short_map[0] = 0;
		little_endian_short_map[1] = 1;

		machine_endian_long_map[0] = 0;
		machine_endian_long_map[1] = 1;
		machine_endian_long_map[2] = 2;
		machine_endian_long_map[3] = 3;
		big_endian_long_map[0] = 3;
		big_endian_long_map[1] = 2;
		big_endian_long_map[2] = 1;
		big_endian_long_map[3] = 0;
		little_endian_long_map[0] = 0;
		little_endian_long_map[1] = 1;
		little_endian_long_map[2] = 2;
		little_endian_long_map[3] = 3;
	}
	else {
		zval val;
		int size = sizeof(Z_LVAL(val));
		Z_LVAL(val)=0; /*silence a warning*/

		/* Where to get hi to lo bytes from */
		byte_map[0] = size - 1;

		for (i = 0; i < sizeof(int); i++) {
			int_map[i] = size - (sizeof(int) - i);
		}

		machine_endian_short_map[0] = size - 2;
		machine_endian_short_map[1] = size - 1;
		big_endian_short_map[0] = size - 2;
		big_endian_short_map[1] = size - 1;
		little_endian_short_map[0] = size - 1;
		little_endian_short_map[1] = size - 2;

		machine_endian_long_map[0] = size - 4;
		machine_endian_long_map[1] = size - 3;
		machine_endian_long_map[2] = size - 2;
		machine_endian_long_map[3] = size - 1;
		big_endian_long_map[0] = size - 4;
		big_endian_long_map[1] = size - 3;
		big_endian_long_map[2] = size - 2;
		big_endian_long_map[3] = size - 1;
		little_endian_long_map[0] = size - 1;
		little_endian_long_map[1] = size - 2;
		little_endian_long_map[2] = size - 3;
		little_endian_long_map[3] = size - 4;
	}

	return SUCCESS;
}
/* }}} */

/*
 * Local variables:
 * tab-width: 4
 * c-basic-offset: 4
 * End:
 * vim600: noet sw=4 ts=4 fdm=marker
 * vim<600: noet sw=4 ts=4
 */