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gif.c: use malloc instead of alloca for LZW buffer as fails for large scale

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gitlost
2021-09-18 17:15:16 +01:00
parent 537990e32e
commit 5766b39845
3 changed files with 87 additions and 40 deletions
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38
backend/gif.c
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@ -41,7 +41,8 @@
#include <malloc.h>
#endif
#define SSET "0123456789ABCDEF"
/* Limit initial ZLW buffer size to this in expectation that compressed data will fit for typical scalings */
#define GIF_ZLW_PAGE_SIZE 0x100000 /* Megabyte */
typedef struct s_statestruct {
unsigned char *pOut;
@ -95,8 +96,15 @@ static int BufferNextByte(statestruct *pState) {
pState->OutByteCountPos = pState->OutPosCur;
(pState->OutPosCur)++;
}
if (pState->OutPosCur >= pState->OutLength)
return 1;
if (pState->OutPosCur >= pState->OutLength) {
unsigned char *pOut;
pState->OutLength += GIF_ZLW_PAGE_SIZE;
/* Note pState->pOut not free()d by realloc() on failure */
if (!(pOut = (unsigned char *) realloc(pState->pOut, pState->OutLength))) {
return 1;
}
pState->pOut = pOut;
}
(pState->pOut)[pState->OutPosCur] = 0x00;
return 0;
@ -301,15 +309,9 @@ INTERNAL int gif_pixel_plot(struct zint_symbol *symbol, unsigned char *pixelbuf)
/* Allow for overhead of 4 == code size + byte count + overflow byte + zero terminator */
unsigned int lzoutbufSize = bitmapSize + 4;
#ifdef _MSC_VER
char *lzwoutbuf;
#endif
#ifndef _MSC_VER
char lzwoutbuf[lzoutbufSize];
#else
lzwoutbuf = (char *) _alloca(lzoutbufSize);
#endif /* _MSC_VER */
if (lzoutbufSize > GIF_ZLW_PAGE_SIZE) {
lzoutbufSize = GIF_ZLW_PAGE_SIZE;
}
/*
* Build a table of the used palette items.
@ -582,19 +584,27 @@ INTERNAL int gif_pixel_plot(struct zint_symbol *symbol, unsigned char *pixelbuf)
/* prepare state array */
State.pIn = pixelbuf;
State.InLen = bitmapSize;
State.pOut = (unsigned char *) lzwoutbuf;
if (!(State.pOut = (unsigned char *) malloc(lzoutbufSize))) {
if (!output_to_stdout) {
fclose(gif_file);
}
strcpy(symbol->errtxt, "614: Insufficient memory for LZW buffer");
return ZINT_ERROR_MEMORY;
}
State.OutLength = lzoutbufSize;
/* call lzw encoding */
byte_out = gif_lzw(&State, paletteBitSize);
if (byte_out <= 0) {
free(State.pOut);
if (!output_to_stdout) {
fclose(gif_file);
}
strcpy(symbol->errtxt, "613: Insufficient memory for LZW buffer");
return ZINT_ERROR_MEMORY;
}
fwrite(lzwoutbuf, byte_out, 1, gif_file);
fwrite((const char *) State.pOut, byte_out, 1, gif_file);
free(State.pOut);
/* GIF terminator */
fputc('\x3b', gif_file);