78 lines
2.0 KiB
C
78 lines
2.0 KiB
C
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#include <defs.h>
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#include <string.h>
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#include <iobuf.h>
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#include <error.h>
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#include <assert.h>
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/*
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* iobuf_init - init io buffer struct.
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* set up io_base to point to the buffer you want to transfer to, and set io_len to the length of buffer;
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* initialize io_offset as desired;
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* initialize io_resid to the total amount of data that can be transferred through this io.
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*/
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struct iobuf *
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iobuf_init(struct iobuf *iob, void *base, size_t len, off_t offset) {
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iob->io_base = base;
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iob->io_offset = offset;
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iob->io_len = iob->io_resid = len;
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return iob;
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}
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/* iobuf_move - move data (iob->io_base ---> data OR data --> iob->io.base) in memory
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* @copiedp: the size of data memcopied
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*
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* iobuf_move may be called repeatedly on the same io to transfer
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* additional data until the available buffer space the io refers to
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* is exhausted.
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*/
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int
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iobuf_move(struct iobuf *iob, void *data, size_t len, bool m2b, size_t *copiedp) {
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size_t alen;
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if ((alen = iob->io_resid) > len) {
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alen = len;
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}
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if (alen > 0) {
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void *src = iob->io_base, *dst = data;
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if (m2b) {
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void *tmp = src;
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src = dst, dst = tmp;
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}
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memmove(dst, src, alen);
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iobuf_skip(iob, alen), len -= alen;
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}
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if (copiedp != NULL) {
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*copiedp = alen;
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}
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return (len == 0) ? 0 : -E_NO_MEM;
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}
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/*
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* iobuf_move_zeros - set io buffer zero
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* @copiedp: the size of data memcopied
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*/
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int
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iobuf_move_zeros(struct iobuf *iob, size_t len, size_t *copiedp) {
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size_t alen;
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if ((alen = iob->io_resid) > len) {
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alen = len;
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}
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if (alen > 0) {
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memset(iob->io_base, 0, alen);
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iobuf_skip(iob, alen), len -= alen;
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}
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if (copiedp != NULL) {
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*copiedp = alen;
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}
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return (len == 0) ? 0 : -E_NO_MEM;
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}
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/*
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* iobuf_skip - change the current position of io buffer
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*/
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void
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iobuf_skip(struct iobuf *iob, size_t n) {
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assert(iob->io_resid >= n);
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iob->io_base += n, iob->io_offset += n, iob->io_resid -= n;
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}
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