Software /
code /
prosody
File
util-src/ringbuffer.c @ 10688:83668e16b9a3
MUC: Switch to new storage format by default
Changing the default setting of `new_muc_storage_format` from false to true.
The code supports reading both formats since 0.11, but servers with MUCs stored
using the new format will not be able to downgrade to 0.10 or earlier.
The new format is clearer (less nesting for the most commonly-accessed data),
and combined with the new map-store methods, allows for some operations to become
more efficient (such as finding out which MUCs on a service a given user is affiliated
with).
author | Matthew Wild <mwild1@gmail.com> |
---|---|
date | Thu, 12 Mar 2020 16:10:44 +0000 |
parent | 10480:94cacf9fd0ae |
child | 10898:c6465fb3c839 |
line wrap: on
line source
#include <stdlib.h> #include <unistd.h> #include <string.h> #include <stdio.h> #include <lua.h> #include <lauxlib.h> typedef struct { size_t rpos; /* read position */ size_t wpos; /* write position */ size_t alen; /* allocated size */ size_t blen; /* current content size */ char buffer[]; } ringbuffer; static void writechar(ringbuffer *b, char c) { b->blen++; b->buffer[(b->wpos++) % b->alen] = c; } /* make sure position counters stay within the allocation */ static void modpos(ringbuffer *b) { b->rpos = b->rpos % b->alen; b->wpos = b->wpos % b->alen; } static int find(ringbuffer *b, const char *s, size_t l) { size_t i, j; int m; if(b->rpos == b->wpos) { /* empty */ return 0; } /* look for a matching first byte */ for(i = 0; i <= b->blen - l; i++) { if(b->buffer[(b->rpos + i) % b->alen] == *s) { m = 1; /* check if the following byte also match */ for(j = 1; j < l; j++) if(b->buffer[(b->rpos + i + j) % b->alen] != s[j]) { m = 0; break; } if(m) { return i + l; } } } return 0; } /* * Find first position of a substring in buffer * (buffer, string) -> number */ static int rb_find(lua_State *L) { size_t l, m; ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt"); const char *s = luaL_checklstring(L, 2, &l); m = find(b, s, l); if(m > 0) { lua_pushinteger(L, m); return 1; } return 0; } /* * Move read position forward without returning the data * (buffer, number) -> boolean */ static int rb_discard(lua_State *L) { ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt"); size_t r = luaL_checkinteger(L, 2); if(r > b->blen) { lua_pushboolean(L, 0); return 1; } b->blen -= r; b->rpos += r; modpos(b); lua_pushboolean(L, 1); return 1; } /* * Read bytes from buffer * (buffer, number, boolean?) -> string */ static int rb_read(lua_State *L) { ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt"); size_t r = luaL_checkinteger(L, 2); int peek = lua_toboolean(L, 3); if(r > b->blen) { lua_pushnil(L); return 1; } if((b->rpos + r) > b->alen) { /* Substring wraps around to the beginning of the buffer */ lua_pushlstring(L, &b->buffer[b->rpos], b->alen - b->rpos); lua_pushlstring(L, b->buffer, r - (b->alen - b->rpos)); lua_concat(L, 2); } else { lua_pushlstring(L, &b->buffer[b->rpos], r); } if(!peek) { b->blen -= r; b->rpos += r; modpos(b); } return 1; } /* * Read buffer until first occurrence of a substring * (buffer, string) -> string */ static int rb_readuntil(lua_State *L) { size_t l, m; ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt"); const char *s = luaL_checklstring(L, 2, &l); m = find(b, s, l); if(m > 0) { lua_settop(L, 1); lua_pushinteger(L, m); return rb_read(L); } return 0; } /* * Write bytes into the buffer * (buffer, string) -> integer */ static int rb_write(lua_State *L) { size_t l, w = 0; ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt"); const char *s = luaL_checklstring(L, 2, &l); /* Does `l` bytes fit? */ if((l + b->blen) > b->alen) { lua_pushnil(L); return 1; } while(l-- > 0) { writechar(b, *s++); w++; } modpos(b); lua_pushinteger(L, w); return 1; } static int rb_tostring(lua_State *L) { ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt"); lua_pushfstring(L, "ringbuffer: %p %d/%d", b, b->blen, b->alen); return 1; } static int rb_length(lua_State *L) { ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt"); lua_pushinteger(L, b->blen); return 1; } static int rb_size(lua_State *L) { ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt"); lua_pushinteger(L, b->alen); return 1; } static int rb_free(lua_State *L) { ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt"); lua_pushinteger(L, b->alen - b->blen); return 1; } static int rb_new(lua_State *L) { size_t size = luaL_optinteger(L, 1, sysconf(_SC_PAGESIZE)); ringbuffer *b = lua_newuserdata(L, sizeof(ringbuffer) + size); b->rpos = 0; b->wpos = 0; b->alen = size; b->blen = 0; luaL_getmetatable(L, "ringbuffer_mt"); lua_setmetatable(L, -2); return 1; } int luaopen_util_ringbuffer(lua_State *L) { #if (LUA_VERSION_NUM > 501) luaL_checkversion(L); #endif if(luaL_newmetatable(L, "ringbuffer_mt")) { lua_pushcfunction(L, rb_tostring); lua_setfield(L, -2, "__tostring"); lua_pushcfunction(L, rb_length); lua_setfield(L, -2, "__len"); lua_createtable(L, 0, 7); /* __index */ { lua_pushcfunction(L, rb_find); lua_setfield(L, -2, "find"); lua_pushcfunction(L, rb_discard); lua_setfield(L, -2, "discard"); lua_pushcfunction(L, rb_read); lua_setfield(L, -2, "read"); lua_pushcfunction(L, rb_readuntil); lua_setfield(L, -2, "readuntil"); lua_pushcfunction(L, rb_write); lua_setfield(L, -2, "write"); lua_pushcfunction(L, rb_size); lua_setfield(L, -2, "size"); lua_pushcfunction(L, rb_length); lua_setfield(L, -2, "length"); lua_pushcfunction(L, rb_free); lua_setfield(L, -2, "free"); } lua_setfield(L, -2, "__index"); } lua_createtable(L, 0, 1); lua_pushcfunction(L, rb_new); lua_setfield(L, -2, "new"); return 1; }