commit a2249885b2174f5ef3d0e5a0238378f2150128f1
parent 695fa3d8bb45755c9eaaa8e256293567060dd7c1
Author: Remy Noulin <loader2x@gmail.com>
Date: Sat, 3 Feb 2018 10:45:01 +0100
implement dynamic array
README.md | 48 +++++++++++++++++++++++++++++++
clean.sh | 3 ++
libdarray.c | 40 ++++++++++++++++++++++++++
libdarray.h | 93 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
main.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
make.sh | 4 +++
6 files changed, 275 insertions(+)
Diffstat:
| A | README.md | | | 48 | ++++++++++++++++++++++++++++++++++++++++++++++++ |
| A | clean.sh | | | 3 | +++ |
| A | libdarray.c | | | 40 | ++++++++++++++++++++++++++++++++++++++++ |
| A | libdarray.h | | | 93 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
| A | main.c | | | 87 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
| A | make.sh | | | 4 | ++++ |
6 files changed, 275 insertions(+), 0 deletions(-)
diff --git a/README.md b/README.md
@@ -0,0 +1,48 @@
+# Dynamic array
+
+- prefix: __dArray__
+- direct access to array elements like regular C arrays with __dArrayAt__
+- the size is increased by pushing elements with __dArrayPush__
+- compile with gcc on linux
+
+# Usage
+
+Create a dynamic array type to define the element type:
+```
+dArrayT(myDynt, type);
+```
+
+Declare a variable dynamic array:
+```
+myDynt darray;
+```
+
+Initialize the array:
+```
+dArrayInit(&darray);
+or
+dArrayInitCount(&darray, 17);
+```
+
+Push elements, it increases the size of the array when needed:
+```
+dArrayPush(&darray, value);
+```
+
+Get and set values with __dArrayAt__:
+```
+// get
+int a = dArrayAt(&darray, 0);
+
+// set
+dArrayAt(&darray, 1) = 3;
+```
+
+Free the dynamic array with:
+```
+dArrayFree(&darray);
+```
+
+# Example
+
+See __main.c__.
diff --git a/clean.sh b/clean.sh
@@ -0,0 +1,3 @@
+rm -f darray
+rm -f main.o
+rm -f libdarray.o
diff --git a/libdarray.c b/libdarray.c
@@ -0,0 +1,40 @@
+
+#include "libdarray.h"
+
+bool dArrayIsValidIndex(intmax_t index) {
+ if (index >= ((intmax_t)1)<<dArrayAddrSpace) {
+ return false;
+ }
+ return true;
+}
+
+dArrayIxt dArrayIndex(intmax_t index) {
+ dArrayIxt r;
+ if (index >= ((intmax_t)1)<<dArrayAddrSpace) {
+ r.error = true;
+ return r;
+ }
+ r.error = false;
+
+ intmax_t bufx = index >> dArrayBaseBits;
+ if (!bufx) {
+ r.ix = 0;
+ r.offset = index;
+ }
+ else {
+ //int pos = 0;
+ /* for (int i = (bufx >> 1); i != 0; pos++) { */
+ /* i >>= 1; */
+ /* } */
+ /* find position of MSB */
+#if __LP64__
+ asm ("bsrq %1, %0" : "=r" (r.ix) : "r" (bufx));
+#else
+ asm ("bsrl %1, %0" : "=r" (r.ix) : "r" (bufx));
+#endif
+ intmax_t mask = ~(0xFFFFFFFFFFFFFFFF << (dArrayBaseBits+r.ix));
+ r.ix++;
+ r.offset = index & mask;
+ }
+ return r;
+}
diff --git a/libdarray.h b/libdarray.h
@@ -0,0 +1,93 @@
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+// user parameters
+// the dynamic arrays hold an absolute max of 2^dArrayAddrSpace elements
+#define dArrayAddrSpace 24
+// number of elements in the smallest buffer 2^dArrayBaseBits
+#define dArrayBaseBits 4
+// user parameters end
+
+
+#define dArrayBaseSz (1<<dArrayBaseBits)
+#define dArrayAddrBits dArrayAddrSpace-dArrayBaseBits
+
+
+#define dArrayT(typeName, elementType)\
+ typedef struct {\
+ intmax_t last;\
+ intmax_t maxCount;\
+ void* buffers[dArrayAddrBits+1];\
+ elementType element;\
+ } typeName
+
+typedef struct {
+ uint64_t offset;
+ intmax_t ix;
+ bool error;
+} dArrayIxt;
+
+
+#define dArrayInit(a) do{\
+ (a)->last = 0;\
+ (a)->buffers[0] = malloc(dArrayBaseSz * sizeof((a)->element));\
+ (a)->maxCount = dArrayBaseSz;\
+}while(0)
+
+
+#define dArrayInitCount(a, count) do{\
+ (a)->last = 0;\
+ (a)->buffers[0] = malloc(dArrayBaseSz * sizeof((a)->element));\
+ (a)->maxCount = dArrayBaseSz;\
+ if (count > dArrayBaseSz) {\
+ dArrayIxt da = dArrayIndex(count);\
+ if (!da.error) {\
+ (a)->maxCount <<= da.ix;\
+ for(int i=0 ; i<da.ix ; i++) {\
+ (a)->buffers[i+1] = malloc((dArrayBaseSz<<(i)) * sizeof((a)->element));\
+ }\
+ }\
+ }\
+}while(0)
+
+
+#define dArrayFree(a) do{\
+ for(int i = 0 ; i < dArrayIndex((a)->maxCount-1).ix+1 ; i++) {\
+ free((a)->buffers[i]);\
+ }\
+}while(0)
+
+
+#define dArrayAlloc(a) do{\
+ if ((a)->last == (a)->maxCount) {\
+ dArrayIxt da = dArrayIndex((a)->maxCount);\
+ if (!da.error) {\
+ (a)->maxCount <<= 1;\
+ (a)->buffers[da.ix] = malloc((dArrayBaseSz<<(da.ix-1)) * sizeof((a)->element));\
+ }\
+ }\
+}while(0)
+
+
+#define dArrayPush(a, v) do{\
+ dArrayAlloc(a);\
+ if ((a)->last < (a)->maxCount) {\
+ dArrayIxt da = dArrayIndex((a)->last);\
+ typeof((a)->element) *dArrayB = (a)->buffers[da.ix];\
+ *(dArrayB+da.offset) = v;\
+ (a)->last++;\
+ }\
+}while(0)
+
+
+#define dArrayPop(a) (*((typeof((a)->element)*)((a)->buffers[dArrayIndex(--(a)->last).ix])+dArrayIndex((a)->last).offset))
+
+#define dArrayAt(a, index) (*((typeof((a)->element)*)((a)->buffers[dArrayIndex(index).ix])+dArrayIndex(index).offset))
+
+
+bool dArrayIsValidIndex(intmax_t index);
+dArrayIxt dArrayIndex(intmax_t index);
+
diff --git a/main.c b/main.c
@@ -0,0 +1,87 @@
+#include "libdarray.h"
+#include <stdio.h>
+#include <inttypes.h>
+
+typedef struct {
+ uint32_t a,b;
+} elementt;
+
+
+// dynamic array of int elements
+dArrayT(intDynt, int);
+
+// dynamic array of elementt elements
+dArrayT(myDynt, elementt);
+
+
+int main(int ARGC, char** ARGV) {
+
+ // EXAMPLE 1
+
+ // dynamic array of int elements
+ intDynt a;
+
+ // the size of the dynamic array depends on dArrayAddrSpace and dArrayBaseBits in libdarray.h
+ printf("sizeof intDyn: %d\n", sizeof a);
+
+ // initialize a (malloc first buffer)
+ dArrayInit(&a);
+
+ // current maxCount for a
+ printf("max %"PRIiMAX"\n", a.maxCount);
+
+ // add elements
+ dArrayPush(&a, 1);
+ dArrayPush(&a, 2);
+
+ // set value
+ dArrayAt(&a, 1) = 3;
+
+ // get value
+ printf("get %"PRIi32"\n", dArrayAt(&a, 0));
+
+ // pop an element
+ printf("pop %"PRIi32"\n", dArrayPop(&a));
+
+
+ // free the internal buffers in a
+ dArrayFree(&a);
+
+
+ // EXAMPLE 2
+
+ // dynamic array of elementt elements
+ myDynt b;
+
+ // the size of the dynamic array depends on dArrayAddrSpace and dArrayBaseBits in libdarray.h
+ printf("\n\nsizeof myDyn: %d\n", sizeof b);
+
+ // initialize b of size at least 17
+ dArrayInitCount(&b, 17);
+
+ // current maxCount for a
+ printf("max %"PRIiMAX"\n\n", b.maxCount);
+
+ // local elements
+ typeof(b.element) dta;
+
+ dta.a = 123;
+ dta.b = 2018;
+
+ for(int i = 0; i < 1+(1<<2); i++) {
+ dta.a += i;
+ dArrayPush(&b, dta);
+ printf("index %"PRIi32"\n", i);
+ printf("maxcount %"PRIiMAX"\n", a.maxCount);
+ printf("get e.a %"PRIi32"\n", dArrayAt(&b, i).a);
+ dArrayAt(&b, i).a -= i-1;
+ printf("modified e.a %"PRIi32"\n", dArrayAt(&b, i).a);
+ printf("get e.b %"PRIi32"\n", dArrayAt(&b, i).b);
+ }
+
+ // get first element
+ printf("\nget e(0).a %"PRIi32"\n", dArrayAt(&b, 0).a);
+
+ // free the internal buffers in b
+ dArrayFree(&b);
+}
diff --git a/make.sh b/make.sh
@@ -0,0 +1,4 @@
+gcc -ggdb -std=gnu11 -o main.o -c main.c
+gcc -ggdb -std=gnu11 -c -o libdarray.o libdarray.c
+gcc -o darray main.o libdarray.o
+echo Built: darray
