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389 lines
8.2 KiB
389 lines
8.2 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Copyright (c) 2015 Google, Inc |
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* Written by Simon Glass <[email protected]> |
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* |
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* Copyright (c) 1992 Simon Glass |
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*/ |
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#include <common.h> |
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#include <errno.h> |
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#include <malloc.h> |
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#include "membuff.h" |
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void membuff_purge(struct membuff *mb) |
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{ |
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/* set mb->head and mb->tail so the buffers look empty */ |
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mb->head = mb->start; |
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mb->tail = mb->start; |
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} |
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static int membuff_putrawflex(struct membuff *mb, int maxlen, bool update, |
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char ***data, int *offsetp) |
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{ |
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int len; |
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/* always write to 'mb->head' */ |
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assert(data && offsetp); |
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*data = &mb->start; |
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*offsetp = mb->head - mb->start; |
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/* if there is no buffer, we can do nothing */ |
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if (!mb->start) |
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return 0; |
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/* |
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* if head is ahead of tail, we can write from head until the end of |
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* the buffer |
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*/ |
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if (mb->head >= mb->tail) { |
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/* work out how many bytes can fit here */ |
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len = mb->end - mb->head - 1; |
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if (maxlen >= 0 && len > maxlen) |
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len = maxlen; |
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/* update the head pointer to mark these bytes as written */ |
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if (update) |
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mb->head += len; |
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/* |
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* if the tail isn't at start of the buffer, then we can |
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* write one more byte right at the end |
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*/ |
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if ((maxlen < 0 || len < maxlen) && mb->tail != mb->start) { |
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len++; |
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if (update) |
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mb->head = mb->start; |
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} |
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/* otherwise now we can write until head almost reaches tail */ |
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} else { |
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/* work out how many bytes can fit here */ |
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len = mb->tail - mb->head - 1; |
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if (maxlen >= 0 && len > maxlen) |
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len = maxlen; |
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/* update the head pointer to mark these bytes as written */ |
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if (update) |
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mb->head += len; |
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} |
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/* return the number of bytes which can be/must be written */ |
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return len; |
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} |
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int membuff_putraw(struct membuff *mb, int maxlen, bool update, char **data) |
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{ |
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char **datap; |
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int offset; |
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int size; |
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size = membuff_putrawflex(mb, maxlen, update, &datap, &offset); |
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*data = *datap + offset; |
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return size; |
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} |
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bool membuff_putbyte(struct membuff *mb, int ch) |
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{ |
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char *data; |
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if (membuff_putraw(mb, 1, true, &data) != 1) |
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return false; |
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*data = ch; |
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return true; |
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} |
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int membuff_getraw(struct membuff *mb, int maxlen, bool update, char **data) |
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{ |
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int len; |
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/* assume for now there is no data to get */ |
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len = 0; |
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/* |
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* in this case head is ahead of tail, so we must return data between |
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*'tail' and 'head' |
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*/ |
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if (mb->head > mb->tail) { |
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/* work out the amount of data */ |
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*data = mb->tail; |
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len = mb->head - mb->tail; |
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/* check it isn't too much */ |
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if (maxlen >= 0 && len > maxlen) |
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len = maxlen; |
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/* & mark it as read from the buffer */ |
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if (update) |
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mb->tail += len; |
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} |
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/* |
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* if head is before tail, then we have data between 'tail' and 'end' |
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* and some more data between 'start' and 'head'(which we can't |
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* return this time |
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*/ |
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else if (mb->head < mb->tail) { |
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/* work out the amount of data */ |
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*data = mb->tail; |
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len = mb->end - mb->tail; |
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if (maxlen >= 0 && len > maxlen) |
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len = maxlen; |
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if (update) { |
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mb->tail += len; |
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if (mb->tail == mb->end) |
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mb->tail = mb->start; |
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} |
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} |
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debug("getraw: maxlen=%d, update=%d, head=%d, tail=%d, data=%d, len=%d", |
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maxlen, update, (int)(mb->head - mb->start), |
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(int)(mb->tail - mb->start), (int)(*data - mb->start), len); |
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/* return the number of bytes we found */ |
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return len; |
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} |
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int membuff_getbyte(struct membuff *mb) |
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{ |
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char *data = 0; |
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return membuff_getraw(mb, 1, true, &data) != 1 ? -1 : *(uint8_t *)data; |
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} |
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int membuff_peekbyte(struct membuff *mb) |
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{ |
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char *data = 0; |
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return membuff_getraw(mb, 1, false, &data) != 1 ? -1 : *(uint8_t *)data; |
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} |
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int membuff_get(struct membuff *mb, char *buff, int maxlen) |
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{ |
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char *data = 0, *buffptr = buff; |
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int len = 1, i; |
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/* |
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* do this in up to two lots(see GetRaw for why) stopping when there |
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* is no more data |
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*/ |
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for (i = 0; len && i < 2; i++) { |
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/* get a pointer to the data available */ |
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len = membuff_getraw(mb, maxlen, true, &data); |
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/* copy it into the buffer */ |
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memcpy(buffptr, data, len); |
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buffptr += len; |
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maxlen -= len; |
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} |
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/* return the number of bytes read */ |
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return buffptr - buff; |
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} |
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int membuff_put(struct membuff *mb, const char *buff, int length) |
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{ |
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char *data; |
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int towrite, i, written; |
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for (i = written = 0; i < 2; i++) { |
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/* ask where some data can be written */ |
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towrite = membuff_putraw(mb, length, true, &data); |
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/* and write it, updating the bytes length */ |
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memcpy(data, buff, towrite); |
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written += towrite; |
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buff += towrite; |
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length -= towrite; |
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} |
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/* return the number of bytes written */ |
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return written; |
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} |
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bool membuff_isempty(struct membuff *mb) |
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{ |
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return mb->head == mb->tail; |
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} |
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int membuff_avail(struct membuff *mb) |
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{ |
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struct membuff copy; |
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int i, avail; |
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char *data = 0; |
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/* make a copy of this buffer's control data */ |
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copy = *mb; |
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/* now read everything out of the copied buffer */ |
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for (i = avail = 0; i < 2; i++) |
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avail += membuff_getraw(©, -1, true, &data); |
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/* and return how much we read */ |
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return avail; |
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} |
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int membuff_size(struct membuff *mb) |
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{ |
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return mb->end - mb->start; |
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} |
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bool membuff_makecontig(struct membuff *mb) |
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{ |
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int topsize, botsize; |
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debug("makecontig: head=%d, tail=%d, size=%d", |
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(int)(mb->head - mb->start), (int)(mb->tail - mb->start), |
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(int)(mb->end - mb->start)); |
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/* |
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* first we move anything at the start of the buffer into the correct |
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* place some way along |
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*/ |
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if (mb->tail > mb->head) { |
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/* |
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* the data is split into two parts, from 0 to ->head and |
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* from ->tail to ->end. We move the stuff from 0 to ->head |
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* up to make space for the other data before it |
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*/ |
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topsize = mb->end - mb->tail; |
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botsize = mb->head - mb->start; |
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/* |
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* must move data at bottom up by 'topsize' bytes - check if |
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* there's room |
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*/ |
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if (mb->head + topsize >= mb->tail) |
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return false; |
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memmove(mb->start + topsize, mb->start, botsize); |
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debug(" - memmove(%d, %d, %d)", topsize, 0, botsize); |
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/* nothing at the start, so skip that step */ |
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} else { |
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topsize = mb->head - mb->tail; |
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botsize = 0; |
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} |
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/* now move data at top down to the bottom */ |
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memcpy(mb->start, mb->tail, topsize); |
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debug(" - memcpy(%d, %d, %d)", 0, (int)(mb->tail - mb->start), topsize); |
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/* adjust pointers */ |
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mb->tail = mb->start; |
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mb->head = mb->start + topsize + botsize; |
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debug(" - head=%d, tail=%d", (int)(mb->head - mb->start), |
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(int)(mb->tail - mb->start)); |
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/* all ok */ |
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return true; |
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} |
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int membuff_free(struct membuff *mb) |
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{ |
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return mb->end == mb->start ? 0 : |
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(mb->end - mb->start) - 1 - membuff_avail(mb); |
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} |
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int membuff_readline(struct membuff *mb, char *str, int maxlen, int minch) |
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{ |
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int len; /* number of bytes read (!= string length) */ |
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char *s, *end; |
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bool ok = false; |
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char *orig = str; |
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end = mb->head >= mb->tail ? mb->head : mb->end; |
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for (len = 0, s = mb->tail; s < end && len < maxlen - 1; str++) { |
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*str = *s++; |
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len++; |
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if (*str == '\n' || *str < minch) { |
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ok = true; |
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break; |
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} |
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if (s == end && mb->tail > mb->head) { |
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s = mb->start; |
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end = mb->head; |
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} |
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} |
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/* couldn't get the whole string */ |
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if (!ok) { |
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if (maxlen) |
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*orig = '\0'; |
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return 0; |
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} |
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/* terminate the string, update the membuff and return success */ |
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*str = '\0'; |
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mb->tail = s == mb->end ? mb->start : s; |
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return len; |
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} |
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int membuff_extend_by(struct membuff *mb, int by, int max) |
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{ |
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int oldhead, oldtail; |
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int size, orig; |
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char *ptr; |
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/* double the buffer size until it is big enough */ |
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assert(by >= 0); |
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for (orig = mb->end - mb->start, size = orig; size < orig + by;) |
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size *= 2; |
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if (max != -1) |
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size = min(size, max); |
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by = size - orig; |
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/* if we're already at maximum, give up */ |
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if (by <= 0) |
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return -E2BIG; |
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oldhead = mb->head - mb->start; |
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oldtail = mb->tail - mb->start; |
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ptr = realloc(mb->start, size); |
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if (!ptr) |
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return -ENOMEM; |
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mb->start = ptr; |
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mb->head = mb->start + oldhead; |
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mb->tail = mb->start + oldtail; |
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if (mb->head < mb->tail) { |
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memmove(mb->tail + by, mb->tail, orig - oldtail); |
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mb->tail += by; |
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} |
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mb->end = mb->start + size; |
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return 0; |
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} |
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void membuff_init(struct membuff *mb, char *buff, int size) |
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{ |
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mb->start = buff; |
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mb->end = mb->start + size; |
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membuff_purge(mb); |
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} |
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int membuff_new(struct membuff *mb, int size) |
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{ |
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mb->start = malloc(size); |
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if (!mb->start) |
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return -ENOMEM; |
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membuff_init(mb, mb->start, size); |
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return 0; |
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} |
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void membuff_uninit(struct membuff *mb) |
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{ |
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mb->end = NULL; |
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mb->start = NULL; |
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membuff_purge(mb); |
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} |
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void membuff_dispose(struct membuff *mb) |
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{ |
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free(&mb->start); |
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membuff_uninit(mb); |
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}
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