c9abac9fad
Added some optional debug. Turned debug off. Fixed handling of LValues to work with stack frames better. Fixed the handling of stack frames in function calls. Fixed a bug in popping variable stack frames. git-svn-id: http://picoc.googlecode.com/svn/trunk@65 21eae674-98b7-11dd-bd71-f92a316d2d60
113 lines
3.4 KiB
C
113 lines
3.4 KiB
C
#include <string.h>
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#include "picoc.h"
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/* hash function for strings */
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static unsigned int TableHash(const char *Key, int Len)
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{
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unsigned int Hash = Len;
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int Offset;
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int Count;
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for (Count = 0, Offset = 8; Count < Len; Count++, Offset+=7)
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{
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if (Offset > sizeof(unsigned int) * 8 - 7)
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Offset -= sizeof(unsigned int) * 8 - 6;
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Hash ^= *Key++ << Offset;
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}
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return Hash;
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}
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/* initialise a table */
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void TableInit(struct Table *Tbl, struct TableEntry **HashTable, int Size, int OnHeap)
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{
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Tbl->Size = Size;
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Tbl->OnHeap = OnHeap;
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Tbl->HashTable = HashTable;
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memset(HashTable, '\0', sizeof(struct TableEntry *) * Size);
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}
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/* check a hash table entry for a key */
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static int TableSearch(struct Table *Tbl, const char *Key, int *AddAt)
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{
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struct TableEntry *Entry;
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int HashValue = ((unsigned long)Key) % Tbl->Size; /* shared strings have unique addresses so we don't need to hash them */
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for (Entry = Tbl->HashTable[HashValue]; Entry != NULL; Entry = Entry->Next)
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{
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if (Entry->p.v.Key == Key)
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return HashValue; /* found */
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}
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*AddAt = HashValue; /* didn't find it in the chain */
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return -1;
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}
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/* set an identifier to a value. returns FALSE if it already exists.
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* Key must be a shared string from StrRegister() */
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int TableSet(struct Table *Tbl, const char *Key, struct Value *Val)
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{
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int AddAt;
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int HashPos = TableSearch(Tbl, Key, &AddAt);
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if (HashPos == -1)
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{ /* add it to the table */
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struct TableEntry *NewEntry = VariableAlloc(NULL, sizeof(struct TableEntry), Tbl->OnHeap);
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NewEntry->p.v.Key = Key;
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NewEntry->p.v.Val = Val;
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NewEntry->Next = Tbl->HashTable[AddAt];
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Tbl->HashTable[AddAt] = NewEntry;
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return TRUE;
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}
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return FALSE;
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}
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/* find a value in a table. returns FALSE if not found.
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* Key must be a shared string from StrRegister() */
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int TableGet(struct Table *Tbl, const char *Key, struct Value **Val)
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{
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int AddAt;
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int HashPos = TableSearch(Tbl, Key, &AddAt);
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if (HashPos == -1)
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return FALSE;
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*Val = Tbl->HashTable[HashPos]->p.v.Val;
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return TRUE;
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}
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/* check a hash table entry for an identifier */
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static int TableSearchIdentifier(struct Table *Tbl, const char *Key, int Len, int *AddAt)
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{
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struct TableEntry *Entry;
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int HashValue = TableHash(Key, Len) % Tbl->Size;
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for (Entry = Tbl->HashTable[HashValue]; Entry != NULL; Entry = Entry->Next)
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{
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if (strncmp(&Entry->p.Key[0], Key, Len) == 0 && Entry->p.Key[Len] == '\0')
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return HashValue; /* found */
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}
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*AddAt = HashValue; /* didn't find it in the chain */
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return -1;
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}
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/* set an identifier and return the identifier. share if possible */
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const char *TableSetIdentifier(struct Table *Tbl, const char *Ident, int IdentLen)
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{
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int AddAt;
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int HashPos = TableSearchIdentifier(Tbl, Ident, IdentLen, &AddAt);
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if (HashPos != -1)
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return &Tbl->HashTable[HashPos]->p.Key[0];
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else
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{ /* add it to the table - we economise by not allocating the whole structure here */
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struct TableEntry *NewEntry = HeapAlloc(sizeof(struct TableEntry *) + IdentLen + 1);
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strncpy((char *)&NewEntry->p.Key[0], Ident, IdentLen);
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NewEntry->Next = Tbl->HashTable[AddAt];
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Tbl->HashTable[AddAt] = NewEntry;
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return &NewEntry->p.Key[0];
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}
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}
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