postgresql/contrib/string/string_io.c

/*
 * string_io.c --
 *
 * This file defines new input/output conversion routines for strings.
 *
 * Copyright (c) 1996, Massimo Dal Zotto <dz@cs.unitn.it>
 */

#include <ctype.h>
#include <string.h>

#include "postgres.h"
#include "utils/elog.h"
#include "utils/palloc.h"
#include "utils/builtins.h"

#include "string_io.h"

/* define this if you want to see iso-8859 characters */
#define ISO8859

#define MIN(x, y)	((x) < (y) ? (x) : (y))
#define	VALUE(char) 	((char) - '0')
#define	DIGIT(val)	((val) + '0')
#define ISOCTAL(c) 	(((c) >= '0') && ((c) <= '7'))
#ifndef ISO8859
#define NOTPRINTABLE(c)	(!isprint(c))
#else
#define NOTPRINTABLE(c)	(!isprint(c) && ((c) < 0xa0))
#endif

/*
 * string_output() --
 *
 * This function takes a pointer to a string data and an optional
 * data size and returns a printable representation of the data
 * translating all escape sequences to C-like \nnn or \c escapes.
 * The function is used by output methods of various string types.
 *
 * Arguments:
 *	data -		input data (can be NULL)
 *	size -		optional size of data. A negative value indicates
 *			that data is a null terminated string.
 *
 * Returns:
 *	a pointer to a new string containing the printable
 *	representation of data.
 */

char *
string_output(char *data, int size)
{
    register unsigned char c, *p, *r, *result;
    register int l, len;

    if (data == NULL) {
	result = (char *) palloc(2);
	result[0] = '-';
	result[1] = '\0';
	return (result);
    }

    if (size < 0) {
	size = strlen(data);
    }

    /* adjust string length for escapes */
    len = size;
    for (p=data,l=size; l>0; p++,l--) {
	switch (*p) {
	  case '\\':
	  case '"' :
	  case '{':
	  case '}':
	  case '\b':
	  case '\f':
	  case '\n':
	  case '\r':
	  case '\t':
	  case '\v':
	    len++;
	    break;
	  default:
	    if (NOTPRINTABLE(*p)) {
		len += 3;
	    }
	}
    }
    len++;

    result = (char *) palloc(len);

    for (p=data,r=result,l=size; (l > 0) && (c = *p); p++,l--) {
	switch (c) {
	  case '\\':
	  case '"' :
	  case '{':
	  case '}':
	    *r++ = '\\';
	    *r++ = c;
	    break;
	  case '\b':
	    *r++ = '\\';
	    *r++ = 'b';
	    break;
	  case '\f':
	    *r++ = '\\';
	    *r++ = 'f';
	    break;
	  case '\n':
	    *r++ = '\\';
	    *r++ = 'n';
	    break;
	  case '\r':
	    *r++ = '\\';
	    *r++ = 'r';
	    break;
	  case '\t':
	    *r++ = '\\';
	    *r++ = 't';
	    break;
	  case '\v':
	    *r++ = '\\';
	    *r++ = 'v';
	    break;
	  default:
	    if (NOTPRINTABLE(c)) {
		*r = '\\';
		r += 3;
		*r-- = DIGIT(c & 07);
		c >>= 3;
		*r-- = DIGIT(c & 07);
		c >>= 3;
		*r   = DIGIT(c & 03);
		r += 3;
	    } else {
		*r++ = c;
	    }
	}
    }
    *r = '\0';

    return((char *) result);
}

/*
 * string_input() --
 *
 * This function accepts a C string in input and copies it into a new 
 * object allocated with palloc() translating all escape sequences.
 * An optional header can be allocatd before the string, for example
 * to hold the length of a varlena object.
 * This function is not necessary for input from sql commands because
 * the parser already does escape translation, all data input routines
 * receive strings in internal form.
 *
 * Arguments:
 *	str -		input string possibly with escapes
 *	size -		the required size of new data. A value of 0
 *			indicates a variable size string, while a
 *			negative value indicates a variable size string
 *			of size not greater than this absolute value.
 *	hdrsize -	size of an optional header to be allocated before
 *			the data. It must then be filled by the caller.
 *	rtn_size -	an optional pointer to an int variable where the
 *			size of the new string is stored back.
 *
 * Returns:
 *	a pointer to the new string or the header.
 */

char *
string_input(char *str, int size, int hdrsize, int *rtn_size)
{
    register unsigned char *p, *r;
    unsigned char *result;
    int len;

    if ((str == NULL) || (hdrsize < 0)) {
	return (char *) NULL;
    }

    /* Compute result size */
    len = strlen(str);
    for (p=str; *p; ) {
	if (*p++ == '\\') {
	    if (ISOCTAL(*p)) {
		if (ISOCTAL(*(p+1))) {
		    p++;
		    len--;
		}
		if (ISOCTAL(*(p+1))) {
		    p++;
		    len--;
		}
	    }
	    if (*p) p++;
	    len--;
	}
    }

    /* result has variable length */
    if (size == 0) {
	size = len+1;
    } else

    /* result has variable length with maximum size */
    if (size < 0) {
	size = MIN(len, - size)+1;
    }

    result = (char *) palloc(hdrsize+size);
    memset(result, 0, hdrsize+size);
    if (rtn_size) {
	*rtn_size = size;
    }

    r = result + hdrsize;
    for (p=str; *p; ) {
	register unsigned char c;
	if ((c = *p++) == '\\') {
	    switch (c = *p++) {
	      case '\0':
		p--;
		break;
	      case '0':
	      case '1':
	      case '2':
	      case '3':
	      case '4':
	      case '5':
	      case '6':
	      case '7':
		c = VALUE(c);
		if (isdigit(*p)) {
		    c = (c<<3) + VALUE(*p++);
		}
		if (isdigit(*p)) {
		    c = (c<<3) + VALUE(*p++);
		}
		*r++ = c;
		break;
	      case 'b':
		*r++ = '\b';
		break;
	      case 'f':
		*r++ = '\f';
		break;
	      case 'n':
		*r++ = '\n';
		break;
	      case 'r':
		*r++ = '\r';
		break;
	      case 't':
		*r++ = '\t';
		break;
	      case 'v':
		*r++ = '\v';
		break;
	      default:
		*r++ = c;
	    }
	} else {
	    *r++ = c;
	}
    }

    return((char *) result);
}

char *
c_charout(int32 c)
{
    char str[2];

    str[0] = (char) c;
    str[1] = '\0';

    return (string_output(str, 1));
}

char *
c_char2out(uint16 s)
{
    return (string_output((char *) &s, 2));
}

char *
c_char4out(uint32 s)
{
    return (string_output((char *) &s, 4));
}

char *
c_char8out(char *s)
{
    return (string_output(s, 8));
}

char *
c_char16out(char *s)
{
    return (string_output(s, 16));
}

/*
 * This can be used for text, bytea, SET and unknown data types
 */

char *
c_textout(struct varlena *vlena)
{
    int len = 0;
    char *s = NULL;

    if (vlena) {
	len = VARSIZE(vlena) - VARHDRSZ;
	s = VARDATA(vlena);
    }
    return (string_output(s, len));
}

/*
 * This can be used for varchar and bpchar strings
 */

char *
c_varcharout(char *s)
{
    int len = 0;

    if (s) {
	len = *(int32*)s - 4;
	s += 4;
    }
    return (string_output(s, len));
}

#if 0
struct varlena *
c_textin(char *str)
{
    struct varlena *result;
    int len;

    if (str == NULL) {
	return ((struct varlena *) NULL);
    }

    result = (struct varlena *) string_input(str, 0, VARHDRSZ, &len);
    VARSIZE(result) = len;

    return (result);
}

char *
c_char16in(char *str)
{
    return (string_input(str, 16, 0, NULL));
}
#endif


/* end of file */