elk/src/cstring.c

81 lines
2.7 KiB
C

/* cstring.c: Convert Scheme strings to C strings. The contents of strings
* has to be copied, because strings in Elk do not have a terminating null-
* byte (strings may _contain_ null-bytes).
*
* Get_String() and Get_Strsym() allocate memory in NUMSTRBUFS cyclically
* reused buffers in the C heap.
* The macros Get_String_Stack() and Get_Strsym_Stack() in include/cstring.h
* allocate memory on the stack. They have to be used whenever more than
* NUMSTRBUFS strings are active in a function at the same time.
*
* $Id$
*
* Copyright 1990, 1991, 1992, 1993, 1994, 1995, Oliver Laumann, Berlin
* Copyright 2002, 2003 Sam Hocevar <sam@hocevar.net>, Paris
*
* This software was derived from Elk 1.2, which was Copyright 1987, 1988,
* 1989, Nixdorf Computer AG and TELES GmbH, Berlin (Elk 1.2 has been written
* by Oliver Laumann for TELES Telematic Services, Berlin, in a joint project
* between TELES and Nixdorf Microprocessor Engineering, Berlin).
*
* Oliver Laumann, TELES GmbH, Nixdorf Computer AG and Sam Hocevar, as co-
* owners or individual owners of copyright in this software, grant to any
* person or company a worldwide, royalty free, license to
*
* i) copy this software,
* ii) prepare derivative works based on this software,
* iii) distribute copies of this software or derivative works,
* iv) perform this software, or
* v) display this software,
*
* provided that this notice is not removed and that neither Oliver Laumann
* nor Teles nor Nixdorf are deemed to have made any representations as to
* the suitability of this software for any purpose nor are held responsible
* for any defects of this software.
*
* THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
*/
#include "config.h"
#include <string.h>
#include "kernel.h"
static char *heapstr[NUMSTRBUFS];
static unsigned int heaplen[NUMSTRBUFS];
static int nextstr;
void Init_Cstring() { /* Preallocate memory to avoid fragmentation */
int i;
for (i = 0; i < NUMSTRBUFS; i++)
heapstr[i] = Safe_Malloc (heaplen[i] = 512);
}
char *Get_String (Object str) {
char **pp = &heapstr[nextstr];
unsigned int len;
Check_Type (str, T_String);
len = STRING(str)->size + 1;
if (len > heaplen[nextstr]) {
Disable_Interrupts;
*pp = Safe_Realloc (*pp, len);
heaplen[nextstr] = len;
Enable_Interrupts;
}
memcpy (*pp, STRING(str)->data, --len);
(*pp)[len] = '\0';
if (++nextstr == NUMSTRBUFS) nextstr = 0;
return *pp;
}
char *Get_Strsym (Object str) {
if (TYPE(str) == T_Symbol)
str = SYMBOL(str)->name;
else if (TYPE(str) != T_String)
Wrong_Type_Combination (str, "string or symbol");
return Get_String (str);
}