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mz_strm_ppmd.c reader issue: it can't detect EOF #953

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Merged
nmoinvaz merged 1 commit into from
Feb 2, 2026
Merged

mz_strm_ppmd.c reader issue: it can't detect EOF #953

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22 changes: 14 additions & 8 deletions mz_strm_ppmd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,10 @@ static mz_stream_vtbl mz_stream_ppmd_vtbl = {

#define PPMD_PRESET_DEFAULT 9 // Should match default in 7-Zip

// Return values from Ppmd8_DecodeSymbol
#define PPMD_RESULT_EOF (-1)
#define PPMD_RESULT_ERROR (-2)

/***************************************************************************/

typedef struct mz_in_buffer_s {
Expand Down Expand Up @@ -148,10 +152,7 @@ static Byte reader(void *p) {
int32_t status;

if ((status = mz_stream_read_uint8((mz_stream_ppmd *)ppmd->stream.base, &b)) != MZ_OK) {
if (b == -1) // EOF
ppmd->end_stream = 1;
else
ppmd->error = status;
ppmd->error = status;
b = 0;
} else
++ppmd->total_in;
Expand Down Expand Up @@ -323,19 +324,24 @@ int32_t mz_stream_ppmd_read(void *stream, void *buf, int32_t size) {
for (avail_out = size; avail_out > 0 && avail_in > 0; avail_out--, avail_in--) {
sym = Ppmd8_DecodeSymbol(&ppmd->ppmd8);

if (sym < 0 || ppmd->end_stream || ppmd->error)
/* There are two ways to terminate the loop early:
1. Ppmd8_DecodeSymbol returns a negative number to flag EOF or stream error.
2. ppmd->error gets set to true here when the call to mz_stream_read_uint8
in reader() does not return MZ_OK.
*/
if (sym < 0 || ppmd->error)
break;

*(next_out++) = sym;
++written;
}

if (sym == -1) {
// end_stream
// sym contains the return code from Ppmd8_DecodeSymbol
if (sym == PPMD_RESULT_EOF) {
ppmd->end_stream = 1;

// Drop through and return written bytes
} else if (sym == -2) {
} else if (sym == PPMD_RESULT_ERROR) {
/* Insufficient input data. */
return MZ_STREAM_ERROR;
} else if (ppmd->error) {
Expand Down
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