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117 lines
2.3 KiB
117 lines
2.3 KiB
#define _POSIX_C_SOURCE 200809l
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#define _GNU_SOURCE
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#include <stdlib.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <string.h>
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#include "cache.h"
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#include "hash.h"
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#include "font.h"
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#include "util.h"
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static struct hm_ref *hash_table;
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static struct font_glyph cache_array[CACHE_SIZE] = {0};
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// bitmap size is aligned to word
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// 2^6 == 64 bits, number of bits in a uint64_t
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#define _BSIZE (((CACHE_SIZE+0x3f)&(~0x3f))>>6)
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static uint64_t bitmap[_BSIZE] = {0};
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// bitmap operations
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#define B_RESET() for (int i = 0; i < _BSIZE; bitmap[i++] = 0);
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#define B_SET(x) bitmap[(x)>>6] |= (uint64_t)1<<((x)%64)
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#define B_TEST(x) (bitmap[(x)>>6]&((uint64_t)1<<((x)%64)))
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// reset the bitmap every n cycles
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#define NCYCLES (CACHE_SIZE/2)
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static int cycles = 0;
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static inline void set_bit(unsigned int x)
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{
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// printf("cycles: %d, set: %d\n", cycles, x);
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cycles = (cycles+1)%NCYCLES;
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if (!cycles) B_RESET();
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B_SET(x);
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}
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void cache_init(void)
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{
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hash_table = hm_create(CACHE_SIZE);
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}
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void cache_destroy(void)
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{
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hm_destroy(hash_table);
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}
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const struct font_glyph * cache_search(unsigned int code)
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{
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struct hm_entry *r = hm_search(hash_table, code);
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// miss
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if (!r)
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return NULL;
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// hit
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set_bit((struct font_glyph *)(r->data)-cache_array);
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return (struct font_glyph *)(r->data);
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}
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// return the first free spot into the cache
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unsigned int cache_get(void)
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{
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uint32_t x = 0;
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// find an open spot in the cache
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for (int b = 0; b < _BSIZE; b++) {
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if (bitmap[b] == 0) x = 64;
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else x = __builtin_clzll(bitmap[b]);
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x = 64-x;
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if (!B_TEST(x+64*b))
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return x+64*b;
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}
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return 0;
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}
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// inserts the font glyph into the cache
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const struct font_glyph * cache_insert(const struct font_glyph *g, unsigned int x)
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{
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struct font_glyph *spot = NULL;
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// allocation in cache failed
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if (B_TEST(x))
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return NULL;
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set_bit(x);
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spot = &cache_array[x];
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*spot = *g;
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/*
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for (int i = 0; i < _BSIZE; i++) {
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//print_byte(bitmap[i]);
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//print_byte(bitmap[i]>>8);
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//print_byte(bitmap[i]>>16);
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//print_byte(bitmap[i]>>24);
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//print_byte(bitmap[i]>>32);
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//print_byte(bitmap[i]>>40);
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//print_byte(bitmap[i]>>48);
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//print_byte(bitmap[i]>>56);
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printf("%lx", bitmap[i]);
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}
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printf("\n");
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*/
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struct hm_entry e = { .code = g->codepoint, .data = spot};
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if (!hm_insert(hash_table, &e))
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return NULL;
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return spot;
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}
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