45 lines
1.3 KiB
C++
45 lines
1.3 KiB
C++
#if !defined(FCODER_LEX_GEN_HAND_WRITTEN)
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#define FCODER_LEX_GEN_HAND_WRITTEN
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internal u64
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lexeme_hash(u64 seed, u8 *ptr, umem size){
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u64 result = 0;
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for (umem i = 0; i < size; i += 1, ptr += 1){
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result ^= ((*ptr) ^ result*59) + seed;
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}
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return(result);
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}
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internal Lexeme_Table_Lookup
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lexeme_table_lookup(u64 *hash_array, String_Const_u8 *key_array,
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Lexeme_Table_Value *value_array, i32 slot_count, u64 seed,
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u8 *ptr, umem size){
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Lexeme_Table_Lookup result = {};
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u64 hash = lexeme_hash(seed, ptr, size);
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u64 comparison_hash = hash | 1;
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i32 first_index = (hash % slot_count);
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i32 index = first_index;
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for (;;){
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if (hash_array[index] == comparison_hash){
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if (string_match(SCu8(ptr, size), key_array[index])){
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result.found_match = true;
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result.base_kind = value_array[index].base_kind;
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result.sub_kind = value_array[index].sub_kind;
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break;
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}
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}
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else if (hash_array[index] == 0){
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break;
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}
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index += 1;
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if (index == slot_count){
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index = 0;
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}
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if (index == first_index){
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break;
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}
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}
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return(result);
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}
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#endif |