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fix thread unsafety in the gif reader code (merge from libgd cvs)
This commit is contained in:
Nuno Lopes
parent
79195bfe2e
commit
5116b67016
@ -68,11 +68,29 @@ static struct {
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int disposal;
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} Gif89 = { -1, -1, -1, 0 };
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#define STACK_SIZE ((1<<(MAX_LWZ_BITS))*2)
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typedef struct {
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unsigned char buf[280];
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int curbit, lastbit, done, last_byte;
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} CODE_STATIC_DATA;
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typedef struct {
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int fresh;
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int code_size, set_code_size;
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int max_code, max_code_size;
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int firstcode, oldcode;
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int clear_code, end_code;
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int table[2][(1<< MAX_LWZ_BITS)];
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int stack[STACK_SIZE], *sp;
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CODE_STATIC_DATA scd;
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} LZW_STATIC_DATA;
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static int ReadColorMap (gdIOCtx *fd, int number, unsigned char (*buffer)[256]);
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static int DoExtension (gdIOCtx *fd, int label, int *Transparent);
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static int GetDataBlock (gdIOCtx *fd, unsigned char *buf);
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static int GetCode (gdIOCtx *fd, int code_size, int flag);
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static int LWZReadByte (gdIOCtx *fd, int flag, int input_code_size);
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static int GetCode (gdIOCtx *fd, CODE_STATIC_DATA *scd, int code_size, int flag);
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static int LWZReadByte (gdIOCtx *fd, LZW_STATIC_DATA *sd, int flag, int input_code_size);
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static void ReadImage (gdImagePtr im, gdIOCtx *fd, int len, int height, unsigned char (*cmap)[256], int interlace); /*1.4//, int ignore); */
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@ -257,10 +275,11 @@ static int ReadColorMap(gdIOCtx *fd, int number, unsigned char (*buffer)[256]) /
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static int DoExtension(gdIOCtx *fd, int label, int *Transparent) /* {{{ */
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{
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static unsigned char buf[256];
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unsigned char buf[256];
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switch (label) {
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case 0xf9: /* Graphic Control Extension */
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memset(buf, 0, 4); /* initialize a few bytes in the case the next function fails */
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(void) GetDataBlock(fd, (unsigned char*) buf);
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Gif89.disposal = (buf[0] >> 2) & 0x7;
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Gif89.inputFlag = (buf[0] >> 1) & 0x1;
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@ -322,119 +341,109 @@ static int GetDataBlock(gdIOCtx *fd, unsigned char *buf) /* {{{ */
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}
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/* }}} */
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static int GetCode_(gdIOCtx *fd, int code_size, int flag) /* {{{ */
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static int GetCode_(gdIOCtx *fd, CODE_STATIC_DATA *scd, int code_size, int flag) /* {{{ */
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{
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static unsigned char buf[280];
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static int curbit, lastbit, done, last_byte;
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int i, j, ret;
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unsigned char count;
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int i, j, ret;
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unsigned char count;
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if (flag) {
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curbit = 0;
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lastbit = 0;
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done = FALSE;
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scd->curbit = 0;
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scd->lastbit = 0;
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scd->last_byte = 0;
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scd->done = FALSE;
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return 0;
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}
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if ( (curbit+code_size) >= lastbit) {
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if (done) {
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if (curbit >= lastbit) {
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if ( (scd->curbit + code_size) >= scd->lastbit) {
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if (scd->done) {
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if (scd->curbit >= scd->lastbit) {
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/* Oh well */
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}
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return -1;
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}
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buf[0] = buf[last_byte-2];
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buf[1] = buf[last_byte-1];
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scd->buf[0] = scd->buf[scd->last_byte-2];
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scd->buf[1] = scd->buf[scd->last_byte-1];
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if ((count = GetDataBlock(fd, &buf[2])) <= 0)
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done = TRUE;
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if ((count = GetDataBlock(fd, &scd->buf[2])) <= 0)
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scd->done = TRUE;
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last_byte = 2 + count;
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curbit = (curbit - lastbit) + 16;
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lastbit = (2+count)*8 ;
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scd->last_byte = 2 + count;
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scd->curbit = (scd->curbit - scd->lastbit) + 16;
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scd->lastbit = (2+count)*8 ;
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}
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ret = 0;
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for (i = curbit, j = 0; j < code_size; ++i, ++j)
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ret |= ((buf[ i / 8 ] & (1 << (i % 8))) != 0) << j;
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for (i = scd->curbit, j = 0; j < code_size; ++i, ++j)
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ret |= ((scd->buf[ i / 8 ] & (1 << (i % 8))) != 0) << j;
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curbit += code_size;
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scd->curbit += code_size;
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return ret;
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}
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static int GetCode(gdIOCtx *fd, int code_size, int flag) /* {{{ */
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static int GetCode(gdIOCtx *fd, CODE_STATIC_DATA *scd, int code_size, int flag) /* {{{ */
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{
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int rv;
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rv = GetCode_(fd,code_size,flag);
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rv = GetCode_(fd, scd, code_size, flag);
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if (VERBOSE) php_gd_error_ex(E_NOTICE, "[GetCode(,%d,%d) returning %d]",code_size,flag,rv);
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return(rv);
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}
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/* }}} */
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#define STACK_SIZE ((1<<(MAX_LWZ_BITS))*2)
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static int LWZReadByte_(gdIOCtx *fd, int flag, int input_code_size) /* {{{ */
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static int LWZReadByte_(gdIOCtx *fd, LZW_STATIC_DATA *sd, int flag, int input_code_size) /* {{{ */
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{
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static int fresh = FALSE;
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int code, incode;
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static int code_size, set_code_size;
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static int max_code, max_code_size;
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static int firstcode, oldcode;
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static int clear_code, end_code;
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static int table[2][(1<< MAX_LWZ_BITS)];
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static int stack[STACK_SIZE], *sp;
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register int i;
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int code, incode, i;
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if (flag) {
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set_code_size = input_code_size;
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code_size = set_code_size+1;
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clear_code = 1 << set_code_size ;
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end_code = clear_code + 1;
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max_code_size = 2*clear_code;
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max_code = clear_code+2;
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sd->set_code_size = input_code_size;
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sd->code_size = sd->set_code_size+1;
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sd->clear_code = 1 << sd->set_code_size ;
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sd->end_code = sd->clear_code + 1;
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sd->max_code_size = 2*sd->clear_code;
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sd->max_code = sd->clear_code+2;
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GetCode(fd, 0, TRUE);
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GetCode(fd, &sd->scd, 0, TRUE);
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fresh = TRUE;
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sd->fresh = TRUE;
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for (i = 0; i < clear_code; ++i) {
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table[0][i] = 0;
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table[1][i] = i;
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for (i = 0; i < sd->clear_code; ++i) {
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sd->table[0][i] = 0;
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sd->table[1][i] = i;
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}
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for (; i < (1<<MAX_LWZ_BITS); ++i)
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table[0][i] = table[1][0] = 0;
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sd->table[0][i] = sd->table[1][0] = 0;
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sp = stack;
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sd->sp = sd->stack;
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return 0;
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} else if (fresh) {
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fresh = FALSE;
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} else if (sd->fresh) {
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sd->fresh = FALSE;
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do {
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firstcode = oldcode =
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GetCode(fd, code_size, FALSE);
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} while (firstcode == clear_code);
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return firstcode;
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sd->firstcode = sd->oldcode =
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GetCode(fd, &sd->scd, sd->code_size, FALSE);
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} while (sd->firstcode == sd->clear_code);
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return sd->firstcode;
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}
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if (sp > stack)
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return *--sp;
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if (sd->sp > sd->stack)
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return *--sd->sp;
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while ((code = GetCode(fd, code_size, FALSE)) >= 0) {
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if (code == clear_code) {
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for (i = 0; i < clear_code; ++i) {
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table[0][i] = 0;
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table[1][i] = i;
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while ((code = GetCode(fd, &sd->scd, sd->code_size, FALSE)) >= 0) {
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if (code == sd->clear_code) {
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for (i = 0; i < sd->clear_code; ++i) {
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sd->table[0][i] = 0;
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sd->table[1][i] = i;
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}
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for (; i < (1<<MAX_LWZ_BITS); ++i)
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table[0][i] = table[1][i] = 0;
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code_size = set_code_size+1;
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max_code_size = 2*clear_code;
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max_code = clear_code+2;
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sp = stack;
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firstcode = oldcode =
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GetCode(fd, code_size, FALSE);
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return firstcode;
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} else if (code == end_code) {
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sd->table[0][i] = sd->table[1][i] = 0;
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sd->code_size = sd->set_code_size+1;
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sd->max_code_size = 2*sd->clear_code;
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sd->max_code = sd->clear_code+2;
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sd->sp = sd->stack;
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sd->firstcode = sd->oldcode =
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GetCode(fd, &sd->scd, sd->code_size, FALSE);
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return sd->firstcode;
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} else if (code == sd->end_code) {
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int count;
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unsigned char buf[260];
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@ -450,55 +459,55 @@ static int LWZReadByte_(gdIOCtx *fd, int flag, int input_code_size) /* {{{ */
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incode = code;
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if (sp == (stack + STACK_SIZE)) {
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if (sd->sp == (sd->stack + STACK_SIZE)) {
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/* Bad compressed data stream */
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return -1;
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}
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if (code >= max_code) {
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*sp++ = firstcode;
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code = oldcode;
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if (code >= sd->max_code) {
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*sd->sp++ = sd->firstcode;
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code = sd->oldcode;
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}
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while (code >= clear_code) {
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if (sp == (stack + STACK_SIZE)) {
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while (code >= sd->clear_code) {
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if (sd->sp == (sd->stack + STACK_SIZE)) {
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/* Bad compressed data stream */
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return -1;
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}
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*sp++ = table[1][code];
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if (code == table[0][code]) {
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*sd->sp++ = sd->table[1][code];
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if (code == sd->table[0][code]) {
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/* Oh well */
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}
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code = table[0][code];
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code = sd->table[0][code];
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}
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*sp++ = firstcode = table[1][code];
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*sd->sp++ = sd->firstcode = sd->table[1][code];
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if ((code = max_code) <(1<<MAX_LWZ_BITS)) {
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table[0][code] = oldcode;
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table[1][code] = firstcode;
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++max_code;
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if ((max_code >= max_code_size) &&
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(max_code_size < (1<<MAX_LWZ_BITS))) {
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max_code_size *= 2;
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++code_size;
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if ((code = sd->max_code) <(1<<MAX_LWZ_BITS)) {
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sd->table[0][code] = sd->oldcode;
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sd->table[1][code] = sd->firstcode;
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++sd->max_code;
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if ((sd->max_code >= sd->max_code_size) &&
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(sd->max_code_size < (1<<MAX_LWZ_BITS))) {
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sd->max_code_size *= 2;
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++sd->code_size;
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}
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}
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oldcode = incode;
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sd->oldcode = incode;
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if (sp > stack)
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return *--sp;
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if (sd->sp > sd->stack)
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return *--sd->sp;
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}
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return code;
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}
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/* }}} */
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static int LWZReadByte(gdIOCtx *fd, int flag, int input_code_size) /* {{{ */
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static int LWZReadByte(gdIOCtx *fd, LZW_STATIC_DATA *sd, int flag, int input_code_size) /* {{{ */
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{
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int rv;
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rv = LWZReadByte_(fd,flag,input_code_size);
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rv = LWZReadByte_(fd, sd, flag, input_code_size);
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if (VERBOSE) php_gd_error_ex(E_NOTICE, "[LWZReadByte(,%d,%d) returning %d]",flag,input_code_size,rv);
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return(rv);
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}
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@ -510,6 +519,7 @@ static void ReadImage(gdImagePtr im, gdIOCtx *fd, int len, int height, unsigned
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int v;
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int xpos = 0, ypos = 0, pass = 0;
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int i;
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LZW_STATIC_DATA sd;
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/*
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@ -532,7 +542,7 @@ static void ReadImage(gdImagePtr im, gdIOCtx *fd, int len, int height, unsigned
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}
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/* Many (perhaps most) of these colors will remain marked open. */
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im->colorsTotal = gdMaxColors;
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if (LWZReadByte(fd, TRUE, c) < 0) {
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if (LWZReadByte(fd, &sd, TRUE, c) < 0) {
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return;
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}
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@ -541,12 +551,12 @@ static void ReadImage(gdImagePtr im, gdIOCtx *fd, int len, int height, unsigned
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** REMOVED For 1.4
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*/
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/*if (ignore) { */
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/* while (LWZReadByte(fd, FALSE, c) >= 0) */
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/* while (LWZReadByte(fd, &sd, FALSE, c) >= 0) */
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/* ; */
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/* return; */
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/*} */
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while ((v = LWZReadByte(fd,FALSE,c)) >= 0 ) {
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while ((v = LWZReadByte(fd, &sd, FALSE, c)) >= 0 ) {
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/* This how we recognize which colors are actually used. */
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if (im->open[v]) {
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im->open[v] = 0;
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@ -588,7 +598,7 @@ static void ReadImage(gdImagePtr im, gdIOCtx *fd, int len, int height, unsigned
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}
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fini:
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if (LWZReadByte(fd,FALSE,c)>=0) {
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if (LWZReadByte(fd, &sd, FALSE, c)>=0) {
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/* Ignore extra */
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}
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}
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