diff options
Diffstat (limited to 'util/alevt/cache.c')
| -rw-r--r-- | util/alevt/cache.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/util/alevt/cache.c b/util/alevt/cache.c new file mode 100644 index 0000000..c747448 --- /dev/null +++ b/util/alevt/cache.c @@ -0,0 +1,229 @@ +#include <stdlib.h> +#include <string.h> +#include "misc.h" +#include "dllist.h" +#include "cache.h" +#include "help.h" + + +static inline int hash(int pgno) +{ + // very simple... + return pgno % HASH_SIZE; +} + + +static void do_erc(struct vt_page *ovtp, struct vt_page *nvtp) +{ + int l, c; + + if (nvtp->errors == 0 && ovtp->lines == nvtp->lines) + return; + + for (l = 0; l < H; ++l) + { + if (~nvtp->lines & (1 << l)) + memcpy(nvtp->data[l], ovtp->data[l], W); + else if (ovtp->lines & (1 << l)) + for (c = 0; c < W; ++c) + if (nvtp->data[l][c] == BAD_CHAR) + nvtp->data[l][c] = ovtp->data[l][c]; + } + nvtp->lines |= ovtp->lines; +} + + +static void cache_close(struct cache *ca) +{ + struct cache_page *cp; + int i; + + for (i = 0; i < HASH_SIZE; ++i) + while (not dl_empty(ca->hash + i)) + { + cp = PTR ca->hash[i].first; + dl_remove(cp->node); + free(cp); + } + free(ca); +} + + +static void cache_reset(struct cache *ca) +{ + struct cache_page *cp, *cpn; + int i; + + for (i = 0; i < HASH_SIZE; ++i) + for (cp = PTR ca->hash[i].first; cpn = PTR cp->node->next; cp = cpn) + if (cp->page->pgno / 256 != 9) // don't remove help pages + { + dl_remove(cp->node); + free(cp); + ca->npages--; + } + memset(ca->hi_subno, 0, sizeof(ca->hi_subno[0]) * 0x900); +} + +/* Get a page from the cache. + If subno is SUB_ANY, the newest subpage of that page is returned */ + + +static struct vt_page * cache_get(struct cache *ca, int pgno, int subno) +{ + struct cache_page *cp; + int h = hash(pgno); + + for (cp = PTR ca->hash[h].first; cp->node->next; cp = PTR cp->node->next) + if (cp->page->pgno == pgno) + if (subno == ANY_SUB || cp->page->subno == subno) + { + // found, move to front (make it 'new') + dl_insert_first(ca->hash + h, dl_remove(cp->node)); + return cp->page; + } + return 0; +} + +/* Put a page in the cache. + If it's already there, it is updated. */ + + +static struct vt_page * cache_put(struct cache *ca, struct vt_page *vtp) +{ + struct cache_page *cp; + int h = hash(vtp->pgno); + + for (cp = PTR ca->hash[h].first; cp->node->next; cp = PTR cp->node->next) + if (cp->page->pgno == vtp->pgno && cp->page->subno == vtp->subno) + break; + + if (cp->node->next) + { + // move to front. + dl_insert_first(ca->hash + h, dl_remove(cp->node)); + if (ca->erc) + do_erc(cp->page, vtp); + } + else + { + cp = malloc(sizeof(*cp)); + if (cp == 0) + return 0; + if (vtp->subno >= ca->hi_subno[vtp->pgno]) + ca->hi_subno[vtp->pgno] = vtp->subno + 1; + ca->npages++; + dl_insert_first(ca->hash + h, cp->node); + } + + *cp->page = *vtp; + return cp->page; +} + +/* Same as cache_get but doesn't make the found entry new */ + + +static struct vt_page * cache_lookup(struct cache *ca, int pgno, int subno) +{ + struct cache_page *cp; + int h = hash(pgno); + + for (cp = PTR ca->hash[h].first; cp->node->next; cp = PTR cp->node->next) + if (cp->page->pgno == pgno) + if (subno == ANY_SUB || cp->page->subno == subno) + return cp->page; + return 0; +} + + +static struct vt_page * cache_foreach_pg(struct cache *ca, int pgno, int subno, + int dir, int (*func)(), void *data) +{ + struct vt_page *vtp, *s_vtp = 0; + + if (ca->npages == 0) + return 0; + + if (vtp = cache_lookup(ca, pgno, subno)) + subno = vtp->subno; + else if (subno == ANY_SUB) + subno = dir < 0 ? 0 : 0xffff; + + for (;;) + { + subno += dir; + while (subno < 0 || subno >= ca->hi_subno[pgno]) + { + pgno += dir; + if (pgno < 0x100) + pgno = 0x9ff; + if (pgno > 0x9ff) + pgno = 0x100; + subno = dir < 0 ? ca->hi_subno[pgno] - 1 : 0; + } + if (vtp = cache_lookup(ca, pgno, subno)) + { + if (s_vtp == vtp) + return 0; + if (s_vtp == 0) + s_vtp = vtp; + if (func(data, vtp)) + return vtp; + } + } +} + + +static int cache_mode(struct cache *ca, int mode, int arg) +{ + int res = -1; + + switch (mode) + { + case CACHE_MODE_ERC: + res = ca->erc; + ca->erc = arg ? 1 : 0; + break; + } + return res; +} + + +static struct cache_ops cops = +{ + cache_close, + cache_get, + cache_put, + cache_reset, + cache_foreach_pg, + cache_mode, +}; + + +struct cache * cache_open(void) +{ + struct cache *ca; + struct vt_page *vtp; + int i; + + if (not(ca = malloc(sizeof(*ca)))) + goto fail1; + + for (i = 0; i < HASH_SIZE; ++i) + dl_init(ca->hash + i); + + memset(ca->hi_subno, 0, sizeof(ca->hi_subno)); + ca->erc = 1; + ca->npages = 0; + ca->op = &cops; + + for (vtp = help_pages; vtp < help_pages + nr_help_pages; vtp++) + cache_put(ca, vtp); + + return ca; + +fail2: + free(ca); +fail1: + return 0; +} |