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Fix transposed copy size and buffer offset in wh_FlashUnit_ReadBytes #295

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Merged
bigbrett merged 1 commit into from
Mar 10, 2026
Merged

Fix transposed copy size and buffer offset in wh_FlashUnit_ReadBytes #295

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4 changes: 2 additions & 2 deletions src/wh_flash_unit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -169,9 +169,9 @@ int wh_FlashUnit_ReadBytes(const whFlashCb* cb, void* context,
if (offset_rem != 0) {
ret = wh_FlashUnit_Read(cb, context, offset_units, 1, &buffer.unit);
if (ret == 0) {
uint32_t this_size = offset_rem;
uint32_t this_size = WHFU_BYTES_PER_UNIT - offset_rem;
if (data_len < this_size) this_size = data_len;
memcpy(data, &buffer.bytes[WHFU_BYTES_PER_UNIT - offset_rem], this_size);
memcpy(data, &buffer.bytes[offset_rem], this_size);
data += this_size;
data_len -= this_size;
offset_units++;
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41 changes: 41 additions & 0 deletions test/wh_test_nvm_flash.c
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Original file line number Diff line number Diff line change
Expand Up @@ -301,6 +301,47 @@ int whTest_Flash(const whFlashCb* fcb, void* fctx, const void* cfg)
17 * WHFU_BYTES_PER_UNIT, 8, read_bytes));
WH_TEST_RETURN_ON_FAIL(memcmp(write_bytes, read_bytes, 8));

/* Test unaligned ReadBytes (exercises the offset_rem != 0 path) */
{
uint8_t pattern[WHFU_BYTES_PER_UNIT * 4];
uint8_t readback[WHFU_BYTES_PER_UNIT * 4];
uint32_t base_unit = 20;
uint32_t i;

for (i = 0; i < sizeof(pattern); i++) {
pattern[i] = (uint8_t)(0x10 + i);
}

/* Program 4 full units at base_unit */
WH_TEST_RETURN_ON_FAIL(wh_FlashUnit_ProgramBytes(fcb, fctx,
base_unit * WHFU_BYTES_PER_UNIT, sizeof(pattern), pattern));

/* offset_rem = 3: should read pattern[3..7] */
memset(readback, 0, sizeof(readback));
WH_TEST_RETURN_ON_FAIL(wh_FlashUnit_ReadBytes(fcb, fctx,
base_unit * WHFU_BYTES_PER_UNIT + 3, 5, readback));
WH_TEST_ASSERT_RETURN(0 == memcmp(readback, &pattern[3], 5));

/* offset_rem = 1: should read pattern[1..10] */
memset(readback, 0, sizeof(readback));
WH_TEST_RETURN_ON_FAIL(wh_FlashUnit_ReadBytes(fcb, fctx,
base_unit * WHFU_BYTES_PER_UNIT + 1, 10, readback));
WH_TEST_ASSERT_RETURN(0 == memcmp(readback, &pattern[1], 10));

/* offset_rem = 5: should read pattern[5..7] */
memset(readback, 0, sizeof(readback));
WH_TEST_RETURN_ON_FAIL(wh_FlashUnit_ReadBytes(fcb, fctx,
base_unit * WHFU_BYTES_PER_UNIT + 5, 3, readback));
WH_TEST_ASSERT_RETURN(0 == memcmp(readback, &pattern[5], 3));

/* Full 3-phase read: leading partial + aligned middle + trailing
* offset_rem = 2, len = 21: 6 leading + 8 aligned + 7 trailing */
memset(readback, 0, sizeof(readback));
WH_TEST_RETURN_ON_FAIL(wh_FlashUnit_ReadBytes(fcb, fctx,
base_unit * WHFU_BYTES_PER_UNIT + 2, 21, readback));
WH_TEST_ASSERT_RETURN(0 == memcmp(readback, &pattern[2], 21));
}

/* Erase the first partition */
WH_TEST_RETURN_ON_FAIL(wh_FlashUnit_Erase(fcb, fctx,
0, partition_units));
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