/*
* io_dp.c
*
* Implements the dynamic pointer interface.
*
* Based on GD.pm code by Lincoln Stein for interfacing to libgd.
* Added support for reading as well as support for 'tell' and 'seek'.
*
* As will all I/O modules, most functions are for local use only (called
* via function pointers in the I/O context).
*
* gdDPExtractData is the exception to this: it will return the pointer to
* the internal data, and reset the internal storage.
*
* Written/Modified 1999, Philip Warner.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <math.h>
#include <string.h>
#include <stdlib.h>
#include "gd.h"
#include "gdhelpers.h"
#define TRUE 1
#define FALSE 0
/* this is used for creating images in main memory */
typedef struct dpStruct {
void *data;
int logicalSize;
int realSize;
int dataGood;
int pos;
int freeOK;
}
dynamicPtr;
typedef struct dpIOCtx {
gdIOCtx ctx;
dynamicPtr *dp;
}
dpIOCtx;
typedef struct dpIOCtx *dpIOCtxPtr;
/* these functions operate on in-memory dynamic pointers */
static int allocDynamic(dynamicPtr *dp, int initialSize, void *data);
static int appendDynamic(dynamicPtr *dp, const void *src, int size);
static int gdReallocDynamic(dynamicPtr *dp, int required);
static int trimDynamic(dynamicPtr *dp);
static void gdFreeDynamicCtx(struct gdIOCtx *ctx);
static dynamicPtr *newDynamic(int initialSize, void *data, int freeOKFlag);
static int dynamicPutbuf(struct gdIOCtx *, const void *, int);
static void dynamicPutchar(struct gdIOCtx *, int a);
static int dynamicGetbuf(gdIOCtxPtr ctx, void *buf, int len);
static int dynamicGetchar(gdIOCtxPtr ctx);
static int dynamicSeek(struct gdIOCtx *, const int);
static long dynamicTell(struct gdIOCtx *);
/*
Function: gdNewDynamicCtx
Return data as a dynamic pointer.
*/
BGD_DECLARE(gdIOCtx *) gdNewDynamicCtx(int initialSize, void *data)
{
/* 2.0.23: Phil Moore: 'return' keyword was missing! */
return gdNewDynamicCtxEx(initialSize, data, 1);
}
/*
Function: gdNewDynamicCtxEx
*/
BGD_DECLARE(gdIOCtx *) gdNewDynamicCtxEx(int initialSize, void *data, int freeOKFlag)
{
dpIOCtx *ctx;
dynamicPtr *dp;
ctx = (dpIOCtx *)gdMalloc(sizeof (dpIOCtx));
if(ctx == NULL) {
return NULL;
}
dp = newDynamic(initialSize, data, freeOKFlag);
if(!dp) {
gdFree (ctx);
return NULL;
};
ctx->dp = dp;
ctx->ctx.getC = dynamicGetchar;
ctx->ctx.putC = dynamicPutchar;
ctx->ctx.getBuf = dynamicGetbuf;
ctx->ctx.putBuf = dynamicPutbuf;
ctx->ctx.seek = dynamicSeek;
ctx->ctx.tell = dynamicTell;
ctx->ctx.gd_free = gdFreeDynamicCtx;
return (gdIOCtx *)ctx;
}
/*
Function: gdDPExtractData
*/
BGD_DECLARE(void *) gdDPExtractData (struct gdIOCtx *ctx, int *size)
{
dynamicPtr *dp;
dpIOCtx *dctx;
void *data;
dctx = (dpIOCtx *)ctx;
dp = dctx->dp;
/* clean up the data block and return it */
if(dp->dataGood) {
trimDynamic(dp);
*size = dp->logicalSize;
data = dp->data;
} else {
*size = 0;
data = NULL;
/* 2.0.21: never free memory we don't own */
if((dp->data != NULL) && (dp->freeOK)) {
gdFree(dp->data);
}
}
dp->data = NULL;
dp->realSize = 0;
dp->logicalSize = 0;
return data;
}
static void gdFreeDynamicCtx(struct gdIOCtx *ctx)
{
dynamicPtr *dp;
dpIOCtx *dctx;
dctx = (dpIOCtx *)ctx;
dp = dctx->dp;
gdFree(ctx);
/* clean up the data block and return it */
/* 2.0.21: never free memory we don't own */
if((dp->data != NULL) && (dp->freeOK)) {
gdFree(dp->data);
dp->data = NULL;
}
dp->realSize = 0;
dp->logicalSize = 0;
gdFree(dp);
}
static long dynamicTell(struct gdIOCtx *ctx)
{
dpIOCtx *dctx;
dctx = (dpIOCtx *)ctx;
return (dctx->dp->pos);
}
static int dynamicSeek(struct gdIOCtx *ctx, const int pos)
{
int bytesNeeded;
dynamicPtr *dp;
dpIOCtx *dctx;
if (pos < 0) {
return FALSE;
}
dctx = (dpIOCtx *)ctx;
dp = dctx->dp;
if(!dp->dataGood) {
return FALSE;
}
bytesNeeded = pos;
if(bytesNeeded > dp->realSize) {
/* 2.0.21 */
if(!dp->freeOK) {
return FALSE;
}
if(overflow2(dp->realSize, 2)) {
return FALSE;
}
if(!gdReallocDynamic(dp, dp->realSize * 2)) {
dp->dataGood = FALSE;
return FALSE;
}
}
/* if we get here, we can be sure that we have enough bytes
* to copy safely */
/* Extend the logical size if we seek beyond EOF. */
if(pos > dp->logicalSize) {
dp->logicalSize = pos;
};
dp->pos = pos;
return TRUE;
}
/* return data as a dynamic pointer */
static dynamicPtr *newDynamic(int initialSize, void *data, int freeOKFlag)
{
dynamicPtr *dp;
dp = (dynamicPtr *) gdMalloc(sizeof (dynamicPtr));
if(dp == NULL) {
return NULL;
}
if(!allocDynamic(dp, initialSize, data)) {
gdFree(dp);
return NULL;
}
dp->pos = 0;
dp->freeOK = freeOKFlag;
return dp;
}
static int dynamicPutbuf(struct gdIOCtx *ctx, const void *buf, int size)
{
dpIOCtx *dctx;
dctx = (dpIOCtx *)ctx;
appendDynamic(dctx->dp, buf, size);
if(dctx->dp->dataGood) {
return size;
} else {
return -1;
};
}
static void dynamicPutchar(struct gdIOCtx *ctx, int a)
{
unsigned char b;
dpIOCtxPtr dctx;
b = a;
dctx = (dpIOCtxPtr) ctx;
appendDynamic(dctx->dp, &b, 1);
}
/* returns the number of bytes actually read; 0 on EOF and error */
static int dynamicGetbuf(gdIOCtxPtr ctx, void *buf, int len)
{
int rlen, remain;
dpIOCtxPtr dctx;
dynamicPtr *dp;
dctx = (dpIOCtxPtr) ctx;
dp = dctx->dp;
if (dp->pos < 0 || dp->pos >= dp->realSize) {
return 0;
}
remain = dp->logicalSize - dp->pos;
if(remain >= len) {
rlen = len;
} else {
if(remain <= 0) {
return 0;
}
rlen = remain;
}
if (dp->pos + rlen > dp->realSize) {
rlen = dp->realSize - dp->pos;
}
if (rlen < 0) {
return 0;
}
memcpy(buf, (void *) ((char *)dp->data + dp->pos), rlen);
dp->pos += rlen;
return rlen;
}
static int dynamicGetchar(gdIOCtxPtr ctx)
{
unsigned char b;
int rv;
rv = dynamicGetbuf(ctx, &b, 1);
if(rv != 1) {
return EOF;
} else {
return b; /* (b & 0xff); */
}
}
/**********************************************************************
* InitDynamic - Return a dynamically resizable void*
**********************************************************************/
static int allocDynamic(dynamicPtr *dp, int initialSize, void *data)
{
if(data == NULL) {
dp->logicalSize = 0;
dp->dataGood = FALSE;
dp->data = gdMalloc(initialSize);
} else {
dp->logicalSize = initialSize;
dp->dataGood = TRUE;
dp->data = data;
}
if(dp->data != NULL) {
dp->realSize = initialSize;
dp->dataGood = TRUE;
dp->pos = 0;
return TRUE;
} else {
dp->realSize = 0;
return FALSE;
}
}
/* append bytes to the end of a dynamic pointer */
static int appendDynamic(dynamicPtr * dp, const void *src, int size)
{
int bytesNeeded;
char *tmp;
if(!dp->dataGood) {
return FALSE;
}
/* bytesNeeded = dp->logicalSize + size; */
bytesNeeded = dp->pos + size;
if(bytesNeeded > dp->realSize) {
/* 2.0.21 */
if(!dp->freeOK) {
return FALSE;
}
if(overflow2(dp->realSize, 2)) {
return FALSE;
}
if(!gdReallocDynamic(dp, bytesNeeded * 2)) {
dp->dataGood = FALSE;
return FALSE;
}
}
/* if we get here, we can be sure that we have enough bytes
* to copy safely */
/*printf("Mem OK Size: %d, Pos: %d\n", dp->realSize, dp->pos); */
tmp = (char *)dp->data;
memcpy ((void *)(tmp + (dp->pos)), src, size);
dp->pos += size;
if(dp->pos > dp->logicalSize) {
dp->logicalSize = dp->pos;
};
return TRUE;
}
/* grow (or shrink) dynamic pointer */
static int gdReallocDynamic(dynamicPtr *dp, int required)
{
void *newPtr;
/* First try gdRealloc(). If that doesn't work, make a new
* memory block and copy. */
if((newPtr = gdRealloc(dp->data, required))) {
dp->realSize = required;
dp->data = newPtr;
return TRUE;
}
/* create a new pointer */
newPtr = gdMalloc(required);
if(!newPtr) {
dp->dataGood = FALSE;
return FALSE;
}
/* copy the old data into it */
memcpy(newPtr, dp->data, dp->logicalSize);
gdFree(dp->data);
dp->data = newPtr;
dp->realSize = required;
return TRUE;
}
/* trim pointer so that its real and logical sizes match */
static int trimDynamic(dynamicPtr *dp)
{
/* 2.0.21: we don't reallocate memory we don't own */
if(!dp->freeOK) {
return TRUE;
}
return gdReallocDynamic(dp, dp->logicalSize);
}