50 lines
1.7 KiB
Plaintext
50 lines
1.7 KiB
Plaintext
BUFFER Library.
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[Note: I wrote this when I saw a Malloc version of strdup() in there which
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I'd written myself anyway. I was so annoyed at not noticing this I decided to
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document it :-) Steve.]
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The buffer library handles simple character arrays. Buffers are used for various
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purposes in the library, most notably memory BIOs.
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The library uses the BUF_MEM structure defined in buffer.h:
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typedef struct buf_mem_st
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{
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int length; /* current number of bytes */
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char *data;
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int max; /* size of buffer */
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} BUF_MEM;
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'length' is the current size of the buffer in bytes, 'max' is the amount of
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memory allocated to the buffer. There are three functions which handle these
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and one "miscelanous" function.
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BUF_MEM *BUF_MEM_new()
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This allocates a new buffer of zero size. Returns the buffer or NULL on error.
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void BUF_MEM_free(BUF_MEM *a)
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This frees up an already existing buffer. The data is zeroed before freeing
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up in case the buffer contains sensitive data.
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int BUF_MEM_grow(BUF_MEM *str, int len)
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This changes the size of an already existing buffer. It returns zero on error
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or the new size (i.e. 'len'). Any data already in the buffer is preserved if
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it increases in size.
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char * BUF_strdup(char *str)
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This is the previously mentioned strdup function: like the standard library
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strdup() it copies a null terminated string into a block of allocated memory
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and returns a pointer to the allocated block.
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Unlike the standard C library strdup() this function uses Malloc() and so
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should be used in preference to the standard library strdup() because it can
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be used for memory leak checking or replacing the malloc() function.
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The memory allocated from BUF_strdup() should be freed up using the Free()
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function.
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