78 lines
3.2 KiB
C
78 lines
3.2 KiB
C
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/****************************************************************
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* *
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* Copyright 2001, 2003 Sanchez Computer Associates, Inc. *
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* *
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* This source code contains the intellectual property *
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* of its copyright holder(s), and is made available *
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* under a license. If you do not know the terms of *
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* the license, please stop and do not read further. *
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* *
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****************************************************************/
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#include "mdef.h"
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#include "gtm_string.h"
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#include "error.h"
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#include "gtm_maxstr.h"
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/* GT.M string buffer stack where each entry is allocated geometrically on the need basis */
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GBLDEF mstr maxstr_buff[MAXSTR_STACK_SIZE];
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GBLDEF int maxstr_stack_level = -1;
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/* This handler is to release the heap storage allocated within a function in case of errors.
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* The suggested protocol is that after a function is done with using the string buffer, the macro
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* MAXSTR_BUFF_FINI used in the function epilog releases the malloc'd storage. But if an error
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* occurs within the function body, the function epilog is not executed so this condition handler
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* should do the same so that the storage is not kept dangling. */
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CONDITION_HANDLER(gtm_maxstr_ch)
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{
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START_CH;
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if (maxstr_buff[maxstr_stack_level].addr)
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{
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free(maxstr_buff[maxstr_stack_level].addr);
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maxstr_buff[maxstr_stack_level].addr = NULL;
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}
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maxstr_buff[maxstr_stack_level].len = 0;
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maxstr_stack_level--;
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NEXTCH;
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}
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/* The routine checks if the currently available buffer (either 32K automatic or >32K malloc'd)
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* is sufficient for the new space requirement. If not sufficient, it keeps doubling the buffer size
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* and checks until a new buffer size is large enough to accommodate the incoming string. It then
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* allocates the new buffer and releases the previously malloc'd buffer.
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* Note that if strings fit within 32K, the automating buffer is used and no heap storage is used.
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* Parameters:
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*
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* space_needed - buffer space needed to accommodate the string that is about to be written
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* buff - address of the pointer to the beginning of the buffer. If reallocation occurs, buff will be
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* modified to point to the reallocated buffer.
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* space_occupied - how full is the buffer?
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*
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* Returns the new allocated buffer size.
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*/
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int gtm_maxstr_alloc(int space_needed, char** buff, int space_occupied)
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{
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int new_buff_size;
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if (space_needed > (maxstr_buff[maxstr_stack_level].len - space_occupied))
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{ /* Existing buffer is not sufficient. reallocate the buffer with the double the size */
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new_buff_size = maxstr_buff[maxstr_stack_level].len;
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while (space_needed > new_buff_size - space_occupied)
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new_buff_size += new_buff_size;
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if (NULL != maxstr_buff[maxstr_stack_level].addr)
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{
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assert(maxstr_buff[maxstr_stack_level].addr == *buff);
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maxstr_buff[maxstr_stack_level].addr = (char *)malloc(new_buff_size);
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memcpy(maxstr_buff[maxstr_stack_level].addr, *buff, space_occupied);
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free(*buff);
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} else
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{
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maxstr_buff[maxstr_stack_level].addr = (char *)malloc(new_buff_size);
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memcpy(maxstr_buff[maxstr_stack_level].addr, *buff, space_occupied);
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}
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*buff = maxstr_buff[maxstr_stack_level].addr;
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maxstr_buff[maxstr_stack_level].len = new_buff_size;
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}
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return maxstr_buff[maxstr_stack_level].len;
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}
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