/*.......................................................................
* Private function used to allocate a hash-table node.
* The caller is responsible for checking that the specified symbol
* is unique and for installing the returned entry in the table.
*
* Input:
* hash HashTable * The table to allocate the node for.
* name const char * The name of the new entry.
* code int A user-supplied context code.
* fn void (*)(void) A user-supplied function pointer.
* data void * A user-supplied data pointer.
* del_fn SYM_DEL_FN(*) An optional 'data' destructor function.
* Output:
* return HashNode * The new node, or NULL on error.
*/
static HashNode *_new_HashNode(HashTable *hash, const char *name, int code,
void (*fn)(void), void *data, SYM_DEL_FN(*del_fn))
{
HashNode *node; /* The new node */
size_t len;
/*
* Allocate the new node from the free list.
*/
node = (HashNode *) _new_FreeListNode(hash->mem->node_memory);
if(!node)
return NULL;
/*
* Before attempting any operation that might fail, initialize the
* contents of 'node' at least up to the point at which it can be
* safely passed to _del_HashNode().
*/
node->symbol.name = NULL;
node->symbol.code = code;
node->symbol.fn = fn;
node->symbol.data = data;
node->symbol.del_fn = del_fn;
node->next = NULL;
/*
* Allocate a copy of 'name'.
*/
len = strlen(name) + 1;
node->symbol.name = _new_StringMemString(hash->mem->string_memory, len);
if(!node->symbol.name)
return _del_HashNode(hash, node);
/*
* If character-case is insignificant in the current table, convert the
* name to lower case while copying it.
*/
if(hash->case_sensitive) {
strlcpy(node->symbol.name, name, len);
} else {
const char *src = name;
char *dst = node->symbol.name;
for( ; *src; src++,dst++)
*dst = tolower(*src);
*dst = '\0';
};
return node;
}
/*.......................................................................
* Allocate an array of 'length' chars.
*
* Input:
* sm StringMem * The string free-list to allocate from.
* length size_t The length of the new string (including '\0').
* Output:
* return char * The new string or NULL on error.
*/
char *_new_StringMemString(StringMem *sm, size_t length)
{
char *string; /* The string to be returned */
int was_malloc; /* True if malloc was used to allocate the string */
/*
* Check arguments.
*/
if(!sm)
return NULL;
if(length < 1)
length = 1;
/*
* Allocate the new node from the free list if possible.
*/
if(length < SM_STRLEN) {
string = (char *)_new_FreeListNode(sm->fl);
if(!string)
return NULL;
was_malloc = 0;
} else {
string = (char *) malloc(length+1); /* Leave room for the flag byte */
if(!string)
return NULL;
/*
* Count malloc allocations.
*/
was_malloc = 1;
sm->nmalloc++;
};
/*
* Use the first byte of the string to record whether the string was
* allocated with malloc or from the free-list. Then return the rest
* of the string for use by the user.
*/
string[0] = (char) was_malloc;
return string + 1;
}
/*.......................................................................
* Create a new hash table.
*
* Input:
* mem HashMemory * An optional free-list for use in allocating
* HashTable containers and nodes. See explanation
* in hash.h. If you are going to allocate more
* than one hash table, then it will be more
* efficient to allocate a single free-list for
* all of them than to force each hash table
* to allocate its own private free-list.
* size int The size of the hash table. Best performance
* will be acheived if this is a prime number.
* hcase HashCase Specify how symbol case is considered when
* looking up symbols, from:
* IGNORE_CASE - Upper and lower case versions
* of a letter are treated as
* being identical.
* HONOUR_CASE - Upper and lower case versions
* of a letter are treated as
* being distinct.
* characters in a lookup name is significant.
* app_data void * Optional application data to be registered
* to the table. This is presented to user
* provided SYM_DEL_FN() symbol destructors along
* with the symbol data.
* del_fn() HASH_DEL_FN(*) If you want app_data to be free'd when the
* hash-table is destroyed, register a suitable
* destructor function here.
* Output:
* return HashTable * The new hash table, or NULL on error.
*/
HashTable *_new_HashTable(HashMemory *mem, int size, HashCase hcase,
void *app_data, HASH_DEL_FN(*del_fn))
{
HashTable *hash; /* The table to be returned */
int allocate_mem = !mem; /* True if mem should be internally allocated */
int i;
/*
* Check arguments.
*/
if(size <= 0) {
errno = EINVAL;
return NULL;
};
/*
* Allocate an internal free-list?
*/
if(allocate_mem) {
mem = _new_HashMemory(1, 100);
if(!mem)
return NULL;
};
/*
* Allocate the container.
*/
hash = (HashTable *) _new_FreeListNode(mem->hash_memory);
if(!hash) {
errno = ENOMEM;
if(allocate_mem)
mem = _del_HashMemory(mem, 1);
return NULL;
};
/*
* Before attempting any operation that might fail, initialize
* the container at least up to the point at which it can safely
* be passed to _del_HashTable().
*/
hash->mem = mem;
hash->internal_mem = allocate_mem;
hash->case_sensitive = hcase==HONOUR_CASE;
hash->size = size;
hash->bucket = NULL;
hash->keycmp = hash->case_sensitive ? _ht_strcmp : _ht_lower_strcmp;
hash->app_data = app_data;
hash->del_fn = del_fn;
/*
* Allocate the array of 'size' hash buckets.
*/
hash->bucket = (HashBucket *) malloc(sizeof(HashBucket) * size);
if(!hash->bucket) {
errno = ENOMEM;
return _del_HashTable(hash);
};
/*
* Initialize the bucket array.
*/
for(i=0; i<size; i++) {
HashBucket *b = hash->bucket + i;
b->head = NULL;
b->count = 0;
};
/*
* The table is ready for use - albeit currently empty.
*/
return hash;
}
/*.......................................................................
* Get a new directory reader object from the cache.
*
* Input:
* ef ExpandFile * The pathname expansion resource object.
* pathname const char * The pathname of the directory.
* Output:
* return DirNode * The cache entry of the new directory reader,
* or NULL on error. On error, ef->errmsg will
* contain a description of the error.
*/
static DirNode *ef_open_dir(ExpandFile *ef, const char *pathname)
{
char *errmsg = NULL; /* An error message from a called function */
DirNode *node; /* The cache node used */
/*
* Get the directory reader cache.
*/
DirCache *cache = &ef->cache;
/*
* Extend the cache if there are no free cache nodes.
*/
if(!cache->next) {
node = (DirNode *) _new_FreeListNode(cache->mem);
if(!node) {
snprintf(ef->errmsg, sizeof(ef->errmsg),
"Insufficient memory to open a new directory");
return NULL;
};
/*
* Initialize the cache node.
*/
node->next = NULL;
node->prev = NULL;
node->dr = NULL;
/*
* Allocate a directory reader object.
*/
node->dr = _new_DirReader();
if(!node->dr) {
snprintf(ef->errmsg, sizeof(ef->errmsg),
"Insufficient memory to open a new directory");
node = (DirNode *) _del_FreeListNode(cache->mem, node);
return NULL;
};
/*
* Append the node to the cache list.
*/
node->prev = cache->tail;
if(cache->tail)
cache->tail->next = node;
else
cache->head = node;
cache->next = cache->tail = node;
};
/*
* Get the first unused node, but don't remove it from the list yet.
*/
node = cache->next;
/*
* Attempt to open the specified directory.
*/
if(_dr_open_dir(node->dr, pathname, &errmsg)) {
strncpy(ef->errmsg, errmsg, ERRLEN);
ef->errmsg[ERRLEN] = '\0';
return NULL;
};
/*
* Now that we have successfully opened the specified directory,
* remove the cache node from the list, and relink the list around it.
*/
cache->next = node->next;
if(node->prev)
node->prev->next = node->next;
else
cache->head = node->next;
if(node->next)
node->next->prev = node->prev;
else
cache->tail = node->prev;
node->next = node->prev = NULL;
/*
* Return the successfully initialized cache node to the caller.
*/
return node;
}
/*.......................................................................
* Append an array of n characters to a character queue.
*
* Input:
* cq GlCharQueue * The queue to append to.
* chars const char * The array of n characters to be appended.
* n int The number of characters in chars[].
* write_fn GL_WRITE_FN * The function to call to output characters,
* or 0 to simply discard the contents of the
* queue. This will be called whenever the
* buffer becomes full. If it fails to release
* any space, the buffer will be extended.
* data void * Anonymous data to pass to write_fn().
* Output:
* return int The number of characters successfully
* appended. This will only be < n on error.
*/
int _glq_append_chars(GlCharQueue *cq, const char *chars, int n,
GlWriteFn *write_fn, void *data)
{
int ndone = 0; /* The number of characters appended so far */
/*
* Check the arguments.
*/
if(!cq || !chars) {
errno = EINVAL;
return 0;
};
/*
* The appended characters may have to be split between multiple
* buffers, so loop for each buffer.
*/
while(ndone < n) {
int ntodo; /* The number of characters remaining to be appended */
int nleft; /* The amount of space remaining in cq->buffers.tail */
int nnew; /* The number of characters to append to cq->buffers.tail */
/*
* Compute the offset at which the next character should be written
* into the tail buffer segment.
*/
int boff = cq->ntotal % GL_CQ_SIZE;
/*
* Since we don't allocate a new buffer until we have at least one
* character to write into it, if boff is 0 at this point, it means
* that we hit the end of the tail buffer segment on the last append,
* so we need to allocate a new one.
*
* If allocating this new node will require a call to malloc(), as
* opposed to using a currently unused node in the freelist, first try
* flushing the current contents of the buffer to the terminal. When
* write_fn() uses blocking I/O, this stops the buffer size ever getting
* bigger than a single buffer node. When it is non-blocking, it helps
* to keep the amount of memory, but it isn't gauranteed to do so.
*/
if(boff == 0 && _idle_FreeListNodes(cq->bufmem) == 0) {
switch(_glq_flush_queue(cq, write_fn, data)) {
case GLQ_FLUSH_DONE:
break;
case GLQ_FLUSH_AGAIN:
errno = 0; /* Don't confuse the caller */
break;
default:
return ndone; /* Error */
};
boff = cq->ntotal % GL_CQ_SIZE;
};
/*
* Since we don't allocate a new buffer until we have at least one
* character to write into it, if boff is 0 at this point, it means
* that we hit the end of the tail buffer segment on the last append,
* so we need to allocate a new one.
*/
if(boff == 0) {
/*
* Allocate the new node.
*/
CqCharBuff *node = (CqCharBuff *) _new_FreeListNode(cq->bufmem);
if(!node) {
_err_record_msg(cq->err, "Insufficient memory to buffer output.",
END_ERR_MSG);
return ndone;
};
/*
* Initialize the node.
*/
node->next = NULL;
/*
* Append the new node to the tail of the list.
*/
if(cq->buffers.tail)
cq->buffers.tail->next = node;
else
cq->buffers.head = node;
cq->buffers.tail = node;
};
/*
* How much room is there for new characters in the current tail node?
*/
nleft = GL_CQ_SIZE - boff;
/*
* How many characters remain to be appended?
*/
ntodo = n - ndone;
/*
* How many characters should we append to the current tail node?
*/
nnew = nleft < ntodo ? nleft : ntodo;
/*
* Append the latest prefix of nnew characters.
*/
memcpy(cq->buffers.tail->bytes + boff, chars + ndone, nnew);
cq->ntotal += nnew;
ndone += nnew;
};
/*
* Return the count of the number of characters successfully appended.
*/
return ndone;
}
