51 lines
1.4 KiB
C
51 lines
1.4 KiB
C
/* Convert Scheme strings to C strings. The contents of strings has to
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* be copied, because strings in Elk do not have a terminating null-byte
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* (strings may _contain_ null-bytes).
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*
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* Get_String() and Get_Strsym() allocate memory in NUMSTRBUFS cyclically
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* reused buffers in the C heap.
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* The macros Get_String_Stack() and Get_Strsym_Stack() in include/cstring.h
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* allocate memory on the stack. They have to be used whenever more than
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* NUMSTRBUFS strings are active in a function at the same time.
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*/
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#include "kernel.h"
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#include <string.h>
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static char *heapstr[NUMSTRBUFS];
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static int heaplen[NUMSTRBUFS];
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static int nextstr;
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void Init_Cstring() { /* Preallocate memory to avoid fragmentation */
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int i;
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for (i = 0; i < NUMSTRBUFS; i++)
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heapstr[i] = Safe_Malloc (heaplen[i] = 512);
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}
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char *Get_String (Object str) {
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char **pp = &heapstr[nextstr];
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int len;
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Check_Type (str, T_String);
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if ((len = STRING(str)->size+1) > heaplen[nextstr]) {
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Disable_Interrupts;
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*pp = Safe_Realloc (*pp, len);
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heaplen[nextstr] = len;
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Enable_Interrupts;
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}
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memcpy (*pp, STRING(str)->data, --len);
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(*pp)[len] = '\0';
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if (++nextstr == NUMSTRBUFS) nextstr = 0;
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return *pp;
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}
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char *Get_Strsym (Object str) {
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if (TYPE(str) == T_Symbol)
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str = SYMBOL(str)->name;
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else if (TYPE(str) != T_String)
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Wrong_Type_Combination (str, "string or symbol");
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return Get_String (str);
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}
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