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New version from Eric; Now thread safe for 1 reader, 1 writer

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This commit is contained in:
Marty Kraimer
2000-10-12 13:58:57 +00:00
parent 566ca6aacf
commit 36b24f350e
1 changed files with 37 additions and 32 deletions
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src/libCom/osi/os/default/osdRing.c
+37 -32
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@@ -22,8 +22,8 @@ of this distribution.
typedef struct ringPvt {
int nextPut;
int nextGet;
int size;
char *buffer;
int size;
char *buffer;
}ringPvt;
@@ -46,75 +46,80 @@ epicsShareFunc void epicsShareAPI ringDelete(ringId id)
epicsShareFunc int epicsShareAPI ringGet(ringId id, char *value,int nbytes)
{
ringPvt *pring = (ringPvt *)id;
int nextGet = pring->nextGet;
int nextPut = pring->nextPut;
int size = pring->size;
int count;
if (pring->nextGet <= pring->nextPut) {
count = pring->nextPut - pring->nextGet;
if (nextGet <= nextPut) {
count = nextPut - nextGet;
if (count < nbytes)
nbytes = count;
memcpy (value, &pring->buffer[pring->nextGet], nbytes);
pring->nextGet += nbytes;
memcpy (value, &pring->buffer[nextGet], nbytes);
nextGet += nbytes;
}
else {
int nextGet;
count = pring->size - pring->nextGet;
count = size - nextGet;
if (count > nbytes)
count = nbytes;
memcpy (value, &pring->buffer[pring->nextGet], count);
if ((nextGet = pring->nextGet + count) == pring->size) {
memcpy (value, &pring->buffer[nextGet], count);
if ((nextGet = nextGet + count) == size) {
int nLeft = nbytes - count;
if (nLeft > pring->nextPut)
nLeft = pring->nextPut;
if (nLeft > nextPut)
nLeft = nextPut;
memcpy (value+count, &pring->buffer[0], nLeft);
pring->nextGet = nLeft;
nextGet = nLeft;
nbytes = count + nLeft;
}
else {
nbytes = count;
pring->nextGet = nextGet;
}
}
pring->nextGet = nextGet;
return nbytes;
}
epicsShareFunc int epicsShareAPI ringPut(ringId id, char *value,int nbytes)
{
ringPvt *pring = (ringPvt *)id;
int nextGet = pring->nextGet;
int nextPut = pring->nextPut;
int size = pring->size;
int count;
if (pring->nextPut < pring->nextGet) {
count = pring->nextGet - pring->nextPut - 1;
if (nextPut < nextGet) {
count = nextGet - nextPut - 1;
if (nbytes > count)
nbytes = count;
memcpy (&pring->buffer[pring->nextPut], value, nbytes);
pring->nextPut += nbytes;
memcpy (&pring->buffer[nextPut], value, nbytes);
nextPut += nbytes;
}
else if (pring->nextGet == 0) {
count = pring->size - pring->nextPut - 1;
else if (nextGet == 0) {
count = size - nextPut - 1;
if (nbytes > count)
nbytes = count;
memcpy (&pring->buffer[pring->nextPut], value, nbytes);
pring->nextPut += nbytes;
memcpy (&pring->buffer[nextPut], value, nbytes);
nextPut += nbytes;
}
else {
int nextPut;
count = pring->size - pring->nextPut;
count = size - nextPut;
if (count > nbytes)
count = nbytes;
memcpy (&pring->buffer[pring->nextPut], value, count);
if ((nextPut = pring->nextPut + count) == pring->size) {
memcpy (&pring->buffer[nextPut], value, count);
if ((nextPut = nextPut + count) == size) {
int nLeft = nbytes - count;
if (nLeft > (pring->nextGet - 1))
nLeft = pring->nextGet - 1;
if (nLeft > (nextGet - 1))
nLeft = nextGet - 1;
memcpy (&pring->buffer[0], value+count, nLeft);
pring->nextPut = nLeft;
nextPut = nLeft;
nbytes = count + nLeft;
}
else {
nbytes = count;
pring->nextPut = nextPut;
nextPut = nextPut;
}
}
pring->nextPut = nextPut;
return nbytes;
}
@@ -132,7 +137,7 @@ epicsShareFunc int epicsShareAPI ringFreeBytes(ringId id)
n = pring->nextGet - pring->nextPut - 1;
if (n < 0)
n += pring->size;
n += pring->size;
return n;
}
@@ -143,7 +148,7 @@ epicsShareFunc int epicsShareAPI ringUsedBytes(ringId id)
n = pring->nextPut - pring->nextGet;
if (n < 0)
n += pring->size;
n += pring->size;
return n;
}