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-rw-r--r--util-src/ringbuffer.c141
1 files changed, 121 insertions, 20 deletions
diff --git a/util-src/ringbuffer.c b/util-src/ringbuffer.c
index 8f9013f7..0f250c12 100644
--- a/util-src/ringbuffer.c
+++ b/util-src/ringbuffer.c
@@ -2,11 +2,14 @@
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
-#include <stdio.h>
#include <lua.h>
#include <lauxlib.h>
+#if (LUA_VERSION_NUM < 504)
+#define luaL_pushfail lua_pushnil
+#endif
+
typedef struct {
size_t rpos; /* read position */
size_t wpos; /* write position */
@@ -15,23 +18,67 @@ typedef struct {
char buffer[];
} ringbuffer;
-char readchar(ringbuffer *b) {
- b->blen--;
- return b->buffer[(b->rpos++) % b->alen];
+/* Translate absolute idx to a wrapped index within the buffer,
+ based on current read position */
+static int wrap_pos(const ringbuffer *b, const long idx, long *pos) {
+ if(idx > (long)b->blen) {
+ return 0;
+ }
+ if(idx + (long)b->rpos > (long)b->alen) {
+ *pos = idx - (b->alen - b->rpos);
+ } else {
+ *pos = b->rpos + idx;
+ }
+ return 1;
+}
+
+static int calc_splice_positions(const ringbuffer *b, long start, long end, long *out_start, long *out_end) {
+ if(start < 0) {
+ start = 1 + start + b->blen;
+ }
+ if(start <= 0) {
+ start = 1;
+ }
+
+ if(end < 0) {
+ end = 1 + end + b->blen;
+ }
+
+ if(end > (long)b->blen) {
+ end = b->blen;
+ }
+ if(start < 1) {
+ start = 1;
+ }
+
+ if(start > end) {
+ return 0;
+ }
+
+ start = start - 1;
+
+ if(!wrap_pos(b, start, out_start)) {
+ return 0;
+ }
+ if(!wrap_pos(b, end, out_end)) {
+ return 0;
+ }
+
+ return 1;
}
-void writechar(ringbuffer *b, char c) {
+static void writechar(ringbuffer *b, char c) {
b->blen++;
b->buffer[(b->wpos++) % b->alen] = c;
}
/* make sure position counters stay within the allocation */
-void modpos(ringbuffer *b) {
+static void modpos(ringbuffer *b) {
b->rpos = b->rpos % b->alen;
b->wpos = b->wpos % b->alen;
}
-int find(ringbuffer *b, const char *s, size_t l) {
+static int find(ringbuffer *b, const char *s, size_t l) {
size_t i, j;
int m;
@@ -64,7 +111,7 @@ int find(ringbuffer *b, const char *s, size_t l) {
* Find first position of a substring in buffer
* (buffer, string) -> number
*/
-int rb_find(lua_State *L) {
+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);
@@ -82,7 +129,7 @@ int rb_find(lua_State *L) {
* Move read position forward without returning the data
* (buffer, number) -> boolean
*/
-int rb_discard(lua_State *L) {
+static int rb_discard(lua_State *L) {
ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt");
size_t r = luaL_checkinteger(L, 2);
@@ -103,13 +150,13 @@ int rb_discard(lua_State *L) {
* Read bytes from buffer
* (buffer, number, boolean?) -> string
*/
-int rb_read(lua_State *L) {
+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);
+ luaL_pushfail(L);
return 1;
}
@@ -135,7 +182,7 @@ int rb_read(lua_State *L) {
* Read buffer until first occurrence of a substring
* (buffer, string) -> string
*/
-int rb_readuntil(lua_State *L) {
+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);
@@ -154,14 +201,14 @@ int rb_readuntil(lua_State *L) {
* Write bytes into the buffer
* (buffer, string) -> integer
*/
-int rb_write(lua_State *L) {
+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);
+ luaL_pushfail(L);
return 1;
}
@@ -177,32 +224,82 @@ int rb_write(lua_State *L) {
return 1;
}
-int rb_tostring(lua_State *L) {
+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;
}
-int rb_length(lua_State *L) {
+static int rb_sub(lua_State *L) {
+ ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt");
+
+ long start = luaL_checkinteger(L, 2);
+ long end = luaL_optinteger(L, 3, -1);
+
+ long wrapped_start, wrapped_end;
+ if(!calc_splice_positions(b, start, end, &wrapped_start, &wrapped_end)) {
+ lua_pushstring(L, "");
+ } else if(wrapped_end <= wrapped_start) {
+ lua_pushlstring(L, &b->buffer[wrapped_start], b->alen - wrapped_start);
+ lua_pushlstring(L, b->buffer, wrapped_end);
+ lua_concat(L, 2);
+ } else {
+ lua_pushlstring(L, &b->buffer[wrapped_start], (wrapped_end - wrapped_start));
+ }
+
+ return 1;
+}
+
+static int rb_byte(lua_State *L) {
+ ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt");
+
+ long start = luaL_optinteger(L, 2, 1);
+ long end = luaL_optinteger(L, 3, start);
+
+ long i;
+
+ long wrapped_start, wrapped_end;
+ if(calc_splice_positions(b, start, end, &wrapped_start, &wrapped_end)) {
+ if(wrapped_end <= wrapped_start) {
+ for(i = wrapped_start; i < (long)b->alen; i++) {
+ lua_pushinteger(L, (unsigned char)b->buffer[i]);
+ }
+ for(i = 0; i < wrapped_end; i++) {
+ lua_pushinteger(L, (unsigned char)b->buffer[i]);
+ }
+ return wrapped_end + (b->alen - wrapped_start);
+ } else {
+ for(i = wrapped_start; i < wrapped_end; i++) {
+ lua_pushinteger(L, (unsigned char)b->buffer[i]);
+ }
+ return wrapped_end - wrapped_start;
+ }
+ }
+
+ return 0;
+}
+
+static int rb_length(lua_State *L) {
ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt");
lua_pushinteger(L, b->blen);
return 1;
}
-int rb_size(lua_State *L) {
+static int rb_size(lua_State *L) {
ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt");
lua_pushinteger(L, b->alen);
return 1;
}
-int rb_free(lua_State *L) {
+static int rb_free(lua_State *L) {
ringbuffer *b = luaL_checkudata(L, 1, "ringbuffer_mt");
lua_pushinteger(L, b->alen - b->blen);
return 1;
}
-int rb_new(lua_State *L) {
- size_t size = luaL_optinteger(L, 1, sysconf(_SC_PAGESIZE));
+static int rb_new(lua_State *L) {
+ lua_Integer size = luaL_optinteger(L, 1, sysconf(_SC_PAGESIZE));
+ luaL_argcheck(L, size > 0, 1, "positive integer expected");
ringbuffer *b = lua_newuserdata(L, sizeof(ringbuffer) + size);
b->rpos = 0;
@@ -243,6 +340,10 @@ int luaopen_util_ringbuffer(lua_State *L) {
lua_setfield(L, -2, "size");
lua_pushcfunction(L, rb_length);
lua_setfield(L, -2, "length");
+ lua_pushcfunction(L, rb_sub);
+ lua_setfield(L, -2, "sub");
+ lua_pushcfunction(L, rb_byte);
+ lua_setfield(L, -2, "byte");
lua_pushcfunction(L, rb_free);
lua_setfield(L, -2, "free");
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-03 15:16:21 +0000